diff --git a/.github/workflows/check-labels.yml b/.github/workflows/check-labels.yml
index ee03075176995..7180e7b509662 100644
--- a/.github/workflows/check-labels.yml
+++ b/.github/workflows/check-labels.yml
@@ -9,8 +9,13 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+          ref: ${{ github.event.pull_request.head.ref }}
+          repository: ${{ github.event.pull_request.head.repo.full_name }}
       - name: Check labels
         run: bash ${{ github.workspace }}/.maintain/github/check_labels.sh
         env:
           GITHUB_PR: ${{ github.event.pull_request.number }}
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          HEAD_SHA: ${{ github.event.pull_request.head.sha }}
diff --git a/.gitignore b/.gitignore
index ce302c74e10a0..0486a1a716e5c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -24,3 +24,4 @@ rls*.log
 .cargo/
 .cargo-remote.toml
 *.bin
+*.iml
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index a7eedee9aa24a..e9f17f54503f4 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -119,6 +119,11 @@ default:
     - if: $CI_COMMIT_REF_NAME == "tags"
     - if: $CI_COMMIT_REF_NAME =~ /^v[0-9]+\.[0-9]+.*$/              # i.e. v1.0, v2.1rc1
 
+.nightly-pipeline:                 &nightly-pipeline
+  rules:
+    # this job runs only on nightly pipeline with the mentioned variable, against `master` branch
+    - if: $CI_COMMIT_REF_NAME == "master" && $CI_PIPELINE_SOURCE == "schedule" && $PIPELINE == "nightly"
+
 #### stage:                       .pre
 
 skip-if-draft:
@@ -199,17 +204,7 @@ test-prometheus-alerting-rules:
 cargo-deny:
   stage:                           test
   <<:                              *docker-env
-  rules:
-    - if: $CI_PIPELINE_SOURCE == "pipeline"
-      when: never
-    - changes:
-      - "Cargo.lock"
-      - "**/Cargo.toml"
-    - if: $CI_PIPELINE_SOURCE == "web"
-    - if: $CI_PIPELINE_SOURCE == "schedule"
-    - if: $CI_COMMIT_REF_NAME == "master"
-    - if: $CI_COMMIT_REF_NAME == "tags"
-    - if: $CI_COMMIT_REF_NAME =~ /^v[0-9]+\.[0-9]+.*$/              # i.e. v1.0, v2.1rc1
+  <<:                              *nightly-pipeline
   script:
     - cargo deny check --hide-inclusion-graph -c .maintain/deny.toml
   after_script:
@@ -277,6 +272,7 @@ test-linux-stable:                 &test-linux
   script:
     # this job runs all tests in former runtime-benchmarks, frame-staking and wasmtime tests
     - time cargo test --workspace --locked --release --verbose --features runtime-benchmarks --manifest-path bin/node/cli/Cargo.toml
+    - time cargo test -p frame-support-test --features=conditional-storage --manifest-path frame/support/test/Cargo.toml
     - SUBSTRATE_TEST_TIMEOUT=1 time cargo test -p substrate-test-utils --release --verbose --locked -- --ignored timeout
     - sccache -s
 
@@ -340,7 +336,7 @@ check-web-wasm:
     # Note: we don't need to test crates imported in `bin/node/cli`
     - time cargo build --manifest-path=client/consensus/aura/Cargo.toml --target=wasm32-unknown-unknown --features getrandom
     # Note: the command below is a bit weird because several Cargo issues prevent us from compiling the node in a more straight-forward way.
-    - time cargo +nightly build --manifest-path=bin/node/cli/Cargo.toml --no-default-features --features browser --target=wasm32-unknown-unknown -Z features=itarget
+    - time cargo +nightly build --manifest-path=bin/node/cli/Cargo.toml --no-default-features --features browser --target=wasm32-unknown-unknown
     # with-tracing must be explicitly activated, we run a test to ensure this works as expected in both cases
     - time cargo +nightly test --manifest-path primitives/tracing/Cargo.toml --no-default-features
     - time cargo +nightly test --manifest-path primitives/tracing/Cargo.toml --no-default-features --features=with-tracing
@@ -411,7 +407,7 @@ test-browser-node:
     CARGO_TARGET_WASM32_UNKNOWN_UNKNOWN_RUNNER: "wasm-bindgen-test-runner"
     WASM_BINDGEN_TEST_TIMEOUT:                  120
   script:
-    - cargo +nightly test --target wasm32-unknown-unknown -p node-browser-testing -Z features=itarget
+    - cargo +nightly test --target wasm32-unknown-unknown -p node-browser-testing
 
 build-linux-substrate:             &build-binary
   stage:                           build
@@ -523,6 +519,10 @@ build-rust-doc:
     - buildah info
     - buildah push --format=v2s2 "$IMAGE_NAME:$VERSION"
     - buildah push --format=v2s2 "$IMAGE_NAME:latest"
+    # pass artifacts to the trigget-simnet job
+    - echo "VERSION=${VERSION}" > build.env
+    - echo "TRIGGERER=${CI_PROJECT_NAME}" >> build.env
+  after_script:
     - buildah logout "$IMAGE_NAME"
 
 publish-docker-substrate:
@@ -534,8 +534,6 @@ publish-docker-substrate:
   variables:
     <<:                            *docker-build-vars
     PRODUCT:                       substrate
-  after_script:
-    - echo "VERSION=${VERSION}" >> build.env
   artifacts:
     reports:
       # this artifact is used in trigger-simnet job
@@ -653,9 +651,7 @@ deploy-prometheus-alerting-rules:
 
 trigger-simnet:
   stage:                           deploy
-  rules:
-    # this job runs only on nightly pipeline with the mentioned variable, against `master` branch
-    - if: $CI_COMMIT_REF_NAME == "master" && $CI_PIPELINE_SOURCE == "schedule" && $PIPELINE == "nightly"
+  <<:                              *nightly-pipeline
   needs:
     - job:                         publish-docker-substrate
   trigger:
diff --git a/.maintain/common/lib.sh b/.maintain/common/lib.sh
index 1d4be0ecc7296..ce6c566d799ab 100755
--- a/.maintain/common/lib.sh
+++ b/.maintain/common/lib.sh
@@ -82,7 +82,7 @@ has_label(){
 
 # Formats a message into a JSON string for posting to Matrix
 # message: 'any plaintext message'
-# formatted_message: '<strong>optional message formatted in <em>html</em></strong>' 
+# formatted_message: '<strong>optional message formatted in <em>html</em></strong>'
 # Usage: structure_message $content $formatted_content (optional)
 structure_message() {
   if [ -z "$2" ]; then
@@ -101,3 +101,17 @@ structure_message() {
 send_message() {
 curl -XPOST -d "$1" "https://matrix.parity.io/_matrix/client/r0/rooms/$2/send/m.room.message?access_token=$3"
 }
+
+# Check for runtime changes between two commits. This is defined as any changes
+# to bin/node/src/runtime, frame/ and primitives/sr_* trees.
+has_runtime_changes() {
+  from=$1
+  to=$2
+  if git diff --name-only "${from}...${to}" \
+    | grep -q -e '^frame/' -e '^primitives/'
+  then
+    return 0
+  else
+    return 1
+  fi
+}
diff --git a/.maintain/github/check_labels.sh b/.maintain/github/check_labels.sh
index 75190db6683fa..7b0aed9fe7345 100755
--- a/.maintain/github/check_labels.sh
+++ b/.maintain/github/check_labels.sh
@@ -1,4 +1,5 @@
 #!/usr/bin/env bash
+set -e
 
 #shellcheck source=../common/lib.sh
 source "$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )/../common/lib.sh"
@@ -24,10 +25,18 @@ releasenotes_labels=(
 )
 
 criticality_labels=(
-  'C1-low'
-  'C3-medium'
-  'C7-high'
-  'C9-critical'
+  'C1-low 📌'
+  'C3-medium 📣'
+  'C7-high ❗️'
+  'C9-critical ‼️'
+)
+
+audit_labels=(
+  'D1-audited 👍'
+  'D2-notlive 💤'
+  'D3-trivial 🧸'
+  'D5-nicetohaveaudit ⚠️'
+  'D9-needsaudit 👮'
 )
 
 echo "[+] Checking release notes (B) labels"
@@ -46,4 +55,14 @@ else
   exit 1
 fi
 
+if has_runtime_changes origin/master "${HEAD_SHA}"; then
+  echo "[+] Runtime changes detected. Checking audit (D) labels"
+  if ensure_labels "${audit_labels[@]}";  then
+    echo "[+] Release audit label detected. All is well."
+  else
+    echo "[!] Release audit label not detected. Please add one of: ${audit_labels[*]}"
+    exit 1
+  fi
+fi
+
 exit 0
diff --git a/.maintain/gitlab/check_polkadot_companion_build.sh b/.maintain/gitlab/check_polkadot_companion_build.sh
index bf8fbf5aaf410..c1fd7365237de 100755
--- a/.maintain/gitlab/check_polkadot_companion_build.sh
+++ b/.maintain/gitlab/check_polkadot_companion_build.sh
@@ -86,10 +86,9 @@ else
 fi
 
 # Patch all Substrate crates in Polkadot
-diener patch --crates-to-patch ../ --substrate
+diener patch --crates-to-patch ../ --substrate --path Cargo.toml
 
 # Test Polkadot pr or master branch with this Substrate commit.
-cargo update -p sp-io
 time cargo test --all --release --verbose --features=real-overseer
 
 cd parachain/test-parachains/adder/collator/
diff --git a/.maintain/gitlab/check_polkadot_companion_status.sh b/.maintain/gitlab/check_polkadot_companion_status.sh
index 4714baf54fb2f..e0412c7b7bec7 100755
--- a/.maintain/gitlab/check_polkadot_companion_status.sh
+++ b/.maintain/gitlab/check_polkadot_companion_status.sh
@@ -56,7 +56,7 @@ fi
 boldprint "companion pr: #${pr_companion}"
 
 # check the status of that pull request - needs to be
-# mergable and approved
+# approved and mergable
 
 curl -H "${github_header}" -sS -o companion_pr.json \
   ${github_api_polkadot_pull_url}/${pr_companion}
@@ -64,20 +64,6 @@ curl -H "${github_header}" -sS -o companion_pr.json \
 pr_head_sha=$(jq -r -e '.head.sha' < companion_pr.json)
 boldprint "Polkadot PR's HEAD SHA: $pr_head_sha"
 
-if jq -e .merged < companion_pr.json >/dev/null
-then
-  boldprint "polkadot pr #${pr_companion} already merged"
-  exit 0
-fi
-
-if jq -e '.mergeable' < companion_pr.json >/dev/null
-then
-  boldprint "polkadot pr #${pr_companion} mergeable"
-else
-  boldprint "polkadot pr #${pr_companion} not mergeable"
-  exit 1
-fi
-
 curl -H "${github_header}" -sS -o companion_pr_reviews.json \
   ${github_api_polkadot_pull_url}/${pr_companion}/reviews
 
@@ -98,6 +84,19 @@ if [ -z "$(jq -r -e '.[].state | select(. == "APPROVED")' < companion_pr_reviews
 fi
 
 boldprint "polkadot pr #${pr_companion} state APPROVED"
-exit 0
 
+if jq -e .merged < companion_pr.json >/dev/null
+then
+  boldprint "polkadot pr #${pr_companion} already merged"
+  exit 0
+fi
+
+if jq -e '.mergeable' < companion_pr.json >/dev/null
+then
+  boldprint "polkadot pr #${pr_companion} mergeable"
+else
+  boldprint "polkadot pr #${pr_companion} not mergeable"
+  exit 1
+fi
 
+exit 0
diff --git a/.maintain/gitlab/check_runtime.sh b/.maintain/gitlab/check_runtime.sh
index 6d009c5aafc6a..af392e1b7d118 100755
--- a/.maintain/gitlab/check_runtime.sh
+++ b/.maintain/gitlab/check_runtime.sh
@@ -8,12 +8,13 @@
 
 set -e # fail on any error
 
-
+#shellcheck source=../common/lib.sh
+. "$(dirname "${0}")/../common/lib.sh"
 
 VERSIONS_FILE="bin/node/runtime/src/lib.rs"
 
-boldprint () { printf "|\n| \033[1m${@}\033[0m\n|\n" ; }
-boldcat () { printf "|\n"; while read l; do printf "| \033[1m${l}\033[0m\n"; done; printf "|\n" ; }
+boldprint () { printf "|\n| \033[1m%s\033[0m\n|\n" "${@}"; }
+boldcat () { printf "|\n"; while read -r l; do printf "| \033[1m%s\033[0m\n" "${l}"; done; printf "|\n" ; }
 
 github_label () {
 	echo
@@ -23,7 +24,7 @@ github_label () {
 		-F "ref=master" \
 		-F "variables[LABEL]=${1}" \
 		-F "variables[PRNO]=${CI_COMMIT_REF_NAME}" \
-		${GITLAB_API}/projects/${GITHUB_API_PROJECT}/trigger/pipeline
+		"${GITLAB_API}/projects/${GITHUB_API_PROJECT}/trigger/pipeline"
 }
 
 
@@ -31,16 +32,14 @@ boldprint "latest 10 commits of ${CI_COMMIT_REF_NAME}"
 git log --graph --oneline --decorate=short -n 10
 
 boldprint "make sure the master branch and release tag are available in shallow clones"
-git fetch --depth=${GIT_DEPTH:-100} origin master
-git fetch --depth=${GIT_DEPTH:-100} origin release
+git fetch --depth="${GIT_DEPTH:-100}" origin master
+git fetch --depth="${GIT_DEPTH:-100}" origin release
 git tag -f release FETCH_HEAD
 git log -n1 release
 
 
 boldprint "check if the wasm sources changed"
-if ! git diff --name-only origin/master...${CI_COMMIT_SHA} \
-	| grep -v -e '^primitives/sr-arithmetic/fuzzer' \
-	| grep -q -e '^bin/node/src/runtime' -e '^frame/' -e '^primitives/sr-'
+if ! has_runtime_changes origin/master "${CI_COMMIT_SHA}"
 then
 	boldcat <<-EOT
 
@@ -57,9 +56,9 @@ fi
 # consensus-critical logic that has changed. the runtime wasm blobs must be
 # rebuilt.
 
-add_spec_version="$(git diff tags/release...${CI_COMMIT_SHA} ${VERSIONS_FILE} \
+add_spec_version="$(git diff "tags/release...${CI_COMMIT_SHA}" "${VERSIONS_FILE}" \
 	| sed -n -r "s/^\+[[:space:]]+spec_version: +([0-9]+),$/\1/p")"
-sub_spec_version="$(git diff tags/release...${CI_COMMIT_SHA} ${VERSIONS_FILE} \
+sub_spec_version="$(git diff "tags/release...${CI_COMMIT_SHA}" "${VERSIONS_FILE}" \
 	| sed -n -r "s/^\-[[:space:]]+spec_version: +([0-9]+),$/\1/p")"
 
 
@@ -67,8 +66,6 @@ sub_spec_version="$(git diff tags/release...${CI_COMMIT_SHA} ${VERSIONS_FILE} \
 if [ "${add_spec_version}" != "${sub_spec_version}" ]
 then
 
-	github_label "D2-breaksapi"
-
 	boldcat <<-EOT
 
 		changes to the runtime sources and changes in the spec version.
@@ -82,9 +79,9 @@ else
 	# check for impl_version updates: if only the impl versions changed, we assume
 	# there is no consensus-critical logic that has changed.
 
-	add_impl_version="$(git diff tags/release...${CI_COMMIT_SHA} ${VERSIONS_FILE} \
+	add_impl_version="$(git diff "tags/release...${CI_COMMIT_SHA}" "${VERSIONS_FILE}" \
 		| sed -n -r 's/^\+[[:space:]]+impl_version: +([0-9]+),$/\1/p')"
-	sub_impl_version="$(git diff tags/release...${CI_COMMIT_SHA} ${VERSIONS_FILE} \
+	sub_impl_version="$(git diff "tags/release...${CI_COMMIT_SHA}" "${VERSIONS_FILE}" \
 		| sed -n -r 's/^\-[[:space:]]+impl_version: +([0-9]+),$/\1/p')"
 
 
diff --git a/.maintain/monitoring/alerting-rules/alerting-rules.yaml b/.maintain/monitoring/alerting-rules/alerting-rules.yaml
index 5ee2376677677..1aed87ad84f88 100644
--- a/.maintain/monitoring/alerting-rules/alerting-rules.yaml
+++ b/.maintain/monitoring/alerting-rules/alerting-rules.yaml
@@ -135,7 +135,7 @@ groups:
 
   - alert: ContinuousTaskEnded
     expr: '(polkadot_tasks_spawned_total{task_name != "basic-authorship-proposer"} == 1)
-        - on(instance, task_name) (polkadot_tasks_ended_total == 1)'
+        - on(instance, task_name) group_left() (polkadot_tasks_ended_total == 1)'
     for: 5m
     labels:
       severity: warning
diff --git a/.maintain/node-template-release.sh b/.maintain/node-template-release.sh
index 1a6c245320593..fd470a3dce17a 100755
--- a/.maintain/node-template-release.sh
+++ b/.maintain/node-template-release.sh
@@ -10,7 +10,7 @@ if [ "$#" -ne 1 ]; then
   exit 1
 fi
 
-PATH_TO_ARCHIVE=$(pwd)/$1
+PATH_TO_ARCHIVE=$1
 cd $PROJECT_ROOT/.maintain/node-template-release
 
 cargo run $PROJECT_ROOT/bin/node-template $PATH_TO_ARCHIVE
diff --git a/.maintain/node-template-release/Cargo.toml b/.maintain/node-template-release/Cargo.toml
index dd3166d58ddf4..c1d9f2da7faea 100644
--- a/.maintain/node-template-release/Cargo.toml
+++ b/.maintain/node-template-release/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "node-template-release"
-version = "2.0.0"
+version = "3.0.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
 license = "GPL-3.0"
diff --git a/Cargo.lock b/Cargo.lock
index 3c8900a790f3b..f038ec8bed2dc 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -23,9 +23,9 @@ dependencies = [
 
 [[package]]
 name = "adler"
-version = "0.2.3"
+version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ee2a4ec343196209d6594e19543ae87a39f96d5534d7174822a3ad825dd6ed7e"
+checksum = "f26201604c87b1e01bd3d98f8d5d9a8fcbb815e8cedb41ffccbeb4bf593a35fe"
 
 [[package]]
 name = "aead"
@@ -131,9 +131,9 @@ dependencies = [
 
 [[package]]
 name = "arbitrary"
-version = "0.4.7"
+version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "db55d72333851e17d572bec876e390cd3b11eb1ef53ae821dd9f3b653d2b4569"
+checksum = "698b65a961a9d730fb45b6b0327e20207810c9f61ee421b082b27ba003f49e2b"
 
 [[package]]
 name = "arrayref"
@@ -177,10 +177,11 @@ dependencies = [
 
 [[package]]
 name = "assert_cmd"
-version = "1.0.2"
+version = "1.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3dc1679af9a1ab4bea16f228b05d18f8363f8327b1fa8db00d2760cfafc6b61e"
+checksum = "f2475b58cd94eb4f70159f4fd8844ba3b807532fe3131b3373fae060bbe30396"
 dependencies = [
+ "bstr",
  "doc-comment",
  "predicates",
  "predicates-core",
@@ -190,9 +191,9 @@ dependencies = [
 
 [[package]]
 name = "assert_matches"
-version = "1.4.0"
+version = "1.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "695579f0f2520f3774bb40461e5adb066459d4e0af4d59d20175484fb8e9edf1"
+checksum = "9b34d609dfbaf33d6889b2b7106d3ca345eacad44200913df5ba02bfd31d2ba9"
 
 [[package]]
 name = "async-attributes"
@@ -206,9 +207,9 @@ dependencies = [
 
 [[package]]
 name = "async-channel"
-version = "1.5.1"
+version = "1.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "59740d83946db6a5af71ae25ddf9562c2b176b2ca42cf99a455f09f4a220d6b9"
+checksum = "2114d64672151c0c5eaa5e131ec84a74f06e1e559830dabba01ca30605d66319"
 dependencies = [
  "concurrent-queue",
  "event-listener",
@@ -285,13 +286,13 @@ dependencies = [
 
 [[package]]
 name = "async-process"
-version = "1.0.1"
+version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4c8cea09c1fb10a317d1b5af8024eeba256d6554763e85ecd90ff8df31c7bbda"
+checksum = "ef37b86e2fa961bae5a4d212708ea0154f904ce31d1a4a7f47e1bbc33a0c040b"
 dependencies = [
  "async-io",
  "blocking",
- "cfg-if 0.1.10",
+ "cfg-if 1.0.0",
  "event-listener",
  "futures-lite",
  "once_cell",
@@ -311,7 +312,7 @@ dependencies = [
  "async-io",
  "async-lock",
  "async-process",
- "crossbeam-utils 0.8.1",
+ "crossbeam-utils 0.8.3",
  "futures-channel",
  "futures-core",
  "futures-io",
@@ -322,12 +323,26 @@ dependencies = [
  "memchr",
  "num_cpus",
  "once_cell",
- "pin-project-lite 0.2.5",
+ "pin-project-lite 0.2.6",
  "pin-utils",
  "slab",
  "wasm-bindgen-futures",
 ]
 
+[[package]]
+name = "async-std-resolver"
+version = "0.20.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f665c56111e244fe38e7708ee10948a4356ad6a548997c21f5a63a0f4e0edc4d"
+dependencies = [
+ "async-std",
+ "async-trait",
+ "futures-io",
+ "futures-util",
+ "pin-utils",
+ "trust-dns-resolver",
+]
+
 [[package]]
 name = "async-task"
 version = "4.0.3"
@@ -336,9 +351,9 @@ checksum = "e91831deabf0d6d7ec49552e489aed63b7456a7a3c46cff62adad428110b0af0"
 
 [[package]]
 name = "async-trait"
-version = "0.1.42"
+version = "0.1.47"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8d3a45e77e34375a7923b1e8febb049bb011f064714a8e17a1a616fef01da13d"
+checksum = "7e098e9c493fdf92832223594d9a164f96bdf17ba81a42aff86f85c76768726a"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -355,7 +370,7 @@ dependencies = [
  "futures-sink",
  "futures-util",
  "memchr",
- "pin-project-lite 0.2.5",
+ "pin-project-lite 0.2.6",
 ]
 
 [[package]]
@@ -368,7 +383,7 @@ dependencies = [
  "futures-sink",
  "futures-util",
  "memchr",
- "pin-project-lite 0.2.5",
+ "pin-project-lite 0.2.6",
 ]
 
 [[package]]
@@ -443,9 +458,9 @@ checksum = "904dfeac50f3cdaba28fc6f57fdcddb75f49ed61346676a78c4ffe55877802fd"
 
 [[package]]
 name = "bincode"
-version = "1.3.1"
+version = "1.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f30d3a39baa26f9651f17b375061f3233dde33424a8b72b0dbe93a68a0bc896d"
+checksum = "d175dfa69e619905c4c3cdb7c3c203fa3bdd5d51184e3afdb2742c0280493772"
 dependencies = [
  "byteorder",
  "serde",
@@ -483,12 +498,22 @@ checksum = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"
 
 [[package]]
 name = "bitvec"
-version = "0.20.1"
+version = "0.17.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "41262f11d771fd4a61aa3ce019fca363b4b6c282fca9da2a31186d3965a47a5c"
+dependencies = [
+ "either",
+ "radium 0.3.0",
+]
+
+[[package]]
+name = "bitvec"
+version = "0.20.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f5011ffc90248764d7005b0e10c7294f5aa1bd87d9dd7248f4ad475b347c294d"
+checksum = "1f682656975d3a682daff957be4ddeb65d6ad656737cd821f2d00685ae466af1"
 dependencies = [
  "funty",
- "radium",
+ "radium 0.6.2",
  "tap",
  "wyz",
 ]
@@ -560,7 +585,7 @@ dependencies = [
  "block-padding 0.1.5",
  "byte-tools",
  "byteorder",
- "generic-array 0.12.3",
+ "generic-array 0.12.4",
 ]
 
 [[package]]
@@ -619,9 +644,9 @@ checksum = "771fe0050b883fcc3ea2359b1a96bcfbc090b7116eae7c3c512c7a083fdf23d3"
 
 [[package]]
 name = "bstr"
-version = "0.2.14"
+version = "0.2.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "473fc6b38233f9af7baa94fb5852dca389e3d95b8e21c8e3719301462c5d9faf"
+checksum = "a40b47ad93e1a5404e6c18dec46b628214fee441c70f4ab5d6942142cc268a3d"
 dependencies = [
  "lazy_static",
  "memchr",
@@ -640,9 +665,15 @@ dependencies = [
 
 [[package]]
 name = "bumpalo"
-version = "3.6.0"
+version = "3.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "099e596ef14349721d9016f6b80dd3419ea1bf289ab9b44df8e4dfd3a005d5d9"
+checksum = "63396b8a4b9de3f4fdfb320ab6080762242f66a8ef174c49d8e19b674db4cdbe"
+
+[[package]]
+name = "byte-slice-cast"
+version = "0.3.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b0a5e3906bcbf133e33c1d4d95afc664ad37fbdb9f6568d8043e7ea8c27d93d3"
 
 [[package]]
 name = "byte-slice-cast"
@@ -658,9 +689,9 @@ checksum = "e3b5ca7a04898ad4bcd41c90c5285445ff5b791899bb1b0abdd2a2aa791211d7"
 
 [[package]]
 name = "byteorder"
-version = "1.4.2"
+version = "1.3.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ae44d1a3d5a19df61dd0c8beb138458ac2a53a7ac09eba97d55592540004306b"
+checksum = "08c48aae112d48ed9f069b33538ea9e3e90aa263cfa3d1c24309612b1f7472de"
 
 [[package]]
 name = "bytes"
@@ -724,9 +755,9 @@ dependencies = [
 
 [[package]]
 name = "cc"
-version = "1.0.66"
+version = "1.0.67"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4c0496836a84f8d0495758516b8621a622beb77c0fed418570e50764093ced48"
+checksum = "e3c69b077ad434294d3ce9f1f6143a2a4b89a8a2d54ef813d85003a4fd1137fd"
 dependencies = [
  "jobserver",
 ]
@@ -806,9 +837,9 @@ dependencies = [
 
 [[package]]
 name = "cid"
-version = "0.6.0"
+version = "0.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7d88f30b1e74e7063df5711496f3ee6e74a9735d62062242d70cddf77717f18e"
+checksum = "ff0e3bc0b6446b3f9663c1a6aba6ef06c5aeaa1bc92bd18077be337198ab9768"
 dependencies = [
  "multibase",
  "multihash",
@@ -887,12 +918,6 @@ dependencies = [
  "wasm-bindgen",
 ]
 
-[[package]]
-name = "const_fn"
-version = "0.4.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "28b9d6de7f49e22cf97ad17fc4036ece69300032f45f78f30b4a4482cdc3f4a6"
-
 [[package]]
 name = "constant_time_eq"
 version = "0.1.5"
@@ -1085,7 +1110,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dca26ee1f8d361640700bde38b2c37d8c22b3ce2d360e1fc1c74ea4b0aa7d775"
 dependencies = [
  "cfg-if 1.0.0",
- "crossbeam-utils 0.8.1",
+ "crossbeam-utils 0.8.3",
 ]
 
 [[package]]
@@ -1106,8 +1131,8 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "94af6efb46fef72616855b036a624cf27ba656ffc9be1b9a3c931cfc7749a9a9"
 dependencies = [
  "cfg-if 1.0.0",
- "crossbeam-epoch 0.9.1",
- "crossbeam-utils 0.8.1",
+ "crossbeam-epoch 0.9.3",
+ "crossbeam-utils 0.8.3",
 ]
 
 [[package]]
@@ -1127,13 +1152,12 @@ dependencies = [
 
 [[package]]
 name = "crossbeam-epoch"
-version = "0.9.1"
+version = "0.9.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a1aaa739f95311c2c7887a76863f500026092fb1dce0161dab577e559ef3569d"
+checksum = "2584f639eb95fea8c798496315b297cf81b9b58b6d30ab066a75455333cf4b12"
 dependencies = [
  "cfg-if 1.0.0",
- "const_fn",
- "crossbeam-utils 0.8.1",
+ "crossbeam-utils 0.8.3",
  "lazy_static",
  "memoffset 0.6.1",
  "scopeguard",
@@ -1163,9 +1187,9 @@ dependencies = [
 
 [[package]]
 name = "crossbeam-utils"
-version = "0.8.1"
+version = "0.8.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "02d96d1e189ef58269ebe5b97953da3274d83a93af647c2ddd6f9dab28cedb8d"
+checksum = "e7e9d99fa91428effe99c5c6d4634cdeba32b8cf784fc428a2a687f61a952c49"
 dependencies = [
  "autocfg",
  "cfg-if 1.0.0",
@@ -1184,7 +1208,7 @@ version = "0.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4434400df11d95d556bac068ddfedd482915eb18fe8bea89bc80b6e4b1c179e5"
 dependencies = [
- "generic-array 0.12.3",
+ "generic-array 0.12.4",
  "subtle 1.0.0",
 ]
 
@@ -1200,9 +1224,9 @@ dependencies = [
 
 [[package]]
 name = "csv"
-version = "1.1.5"
+version = "1.1.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f9d58633299b24b515ac72a3f869f8b91306a3cec616a602843a383acd6f9e97"
+checksum = "22813a6dc45b335f9bade10bf7271dc477e81113e89eb251a0bc2a8a81c536e1"
 dependencies = [
  "bstr",
  "csv-core",
@@ -1231,9 +1255,9 @@ dependencies = [
 
 [[package]]
 name = "ctor"
-version = "0.1.18"
+version = "0.1.19"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "10bcb9d7dcbf7002aaffbb53eac22906b64cdcc127971dcc387d8eb7c95d5560"
+checksum = "e8f45d9ad417bcef4817d614a501ab55cdd96a6fdb24f49aab89a54acfd66b19"
 dependencies = [
  "quote",
  "syn",
@@ -1325,7 +1349,7 @@ version = "0.8.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f3d0c8c8752312f9713efd397ff63acb9f85585afbf179282e720e7704954dd5"
 dependencies = [
- "generic-array 0.12.3",
+ "generic-array 0.12.4",
 ]
 
 [[package]]
@@ -1456,6 +1480,18 @@ version = "1.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e78d4f1cc4ae33bbfc157ed5d5a5ef3bc29227303d595861deb238fcec4e9457"
 
+[[package]]
+name = "enum-as-inner"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7c5f0096a91d210159eceb2ff5e1c4da18388a170e1e3ce948aac9c8fdbbf595"
+dependencies = [
+ "heck",
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "enumflags2"
 version = "0.6.4"
@@ -1491,9 +1527,9 @@ dependencies = [
 
 [[package]]
 name = "env_logger"
-version = "0.8.2"
+version = "0.8.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f26ecb66b4bdca6c1409b40fb255eefc2bd4f6d135dab3c3124f80ffa2a9661e"
+checksum = "17392a012ea30ef05a610aa97dfb49496e71c9f676b27879922ea5bdf60d9d3f"
 dependencies = [
  "atty",
  "humantime 2.1.0",
@@ -1550,7 +1586,7 @@ version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e43f2f1833d64e33f15592464d6fdd70f349dda7b1a53088eb83cd94014008c5"
 dependencies = [
- "futures 0.3.12",
+ "futures 0.3.13",
 ]
 
 [[package]]
@@ -1622,11 +1658,11 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c6447e2f8178843749e8c8003206def83ec124a7859475395777a28b5338647c"
 dependencies = [
  "either",
- "futures 0.3.12",
+ "futures 0.3.13",
  "futures-timer 3.0.2",
  "log",
  "num-traits",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parking_lot 0.11.1",
  "rand 0.8.3",
 ]
@@ -1672,14 +1708,14 @@ checksum = "3f9eec918d3f24069decb9af1554cad7c880e2da24a9afd88aca000531ab82c1"
 name = "fork-tree"
 version = "3.0.0"
 dependencies = [
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
 ]
 
 [[package]]
 name = "form_urlencoded"
-version = "1.0.0"
+version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ece68d15c92e84fa4f19d3780f1294e5ca82a78a6d515f1efaabcc144688be00"
+checksum = "5fc25a87fa4fd2094bffb06925852034d90a17f0d1e05197d4956d3555752191"
 dependencies = [
  "matches",
  "percent-encoding 2.1.0",
@@ -1694,7 +1730,7 @@ dependencies = [
  "hex-literal",
  "linregress",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "paste 1.0.4",
  "serde",
  "sp-api",
@@ -1713,7 +1749,7 @@ dependencies = [
  "chrono",
  "frame-benchmarking",
  "handlebars",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sc-cli",
  "sc-client-db",
  "sc-executor",
@@ -1727,6 +1763,19 @@ dependencies = [
  "structopt",
 ]
 
+[[package]]
+name = "frame-election-provider-support"
+version = "3.0.0"
+dependencies = [
+ "frame-support",
+ "frame-system",
+ "parity-scale-codec 2.0.1",
+ "sp-arithmetic",
+ "sp-npos-elections",
+ "sp-runtime",
+ "sp-std",
+]
+
 [[package]]
 name = "frame-executive"
 version = "3.0.0"
@@ -1737,7 +1786,7 @@ dependencies = [
  "pallet-balances",
  "pallet-indices",
  "pallet-transaction-payment",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -1751,7 +1800,7 @@ dependencies = [
 name = "frame-metadata"
 version = "13.0.0"
 dependencies = [
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-std",
@@ -1768,7 +1817,7 @@ dependencies = [
  "impl-trait-for-tuples",
  "log",
  "once_cell",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parity-util-mem",
  "paste 1.0.4",
  "pretty_assertions",
@@ -1823,7 +1872,7 @@ dependencies = [
  "frame-metadata",
  "frame-support",
  "frame-system",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "pretty_assertions",
  "rustversion",
  "serde",
@@ -1844,7 +1893,7 @@ dependencies = [
  "frame-support",
  "impl-trait-for-tuples",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-externalities",
@@ -1862,7 +1911,7 @@ dependencies = [
  "frame-benchmarking",
  "frame-support",
  "frame-system",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -1874,7 +1923,7 @@ dependencies = [
 name = "frame-system-rpc-runtime-api"
 version = "3.0.0"
 dependencies = [
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sp-api",
 ]
 
@@ -1883,7 +1932,7 @@ name = "frame-try-runtime"
 version = "0.9.0"
 dependencies = [
  "frame-support",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sp-api",
  "sp-runtime",
  "sp-std",
@@ -1891,9 +1940,9 @@ dependencies = [
 
 [[package]]
 name = "fs-swap"
-version = "0.2.5"
+version = "0.2.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5839fda247e24ca4919c87c71dd5ca658f1f39e4f06829f80e3f15c3bafcfc2c"
+checksum = "03d47dad3685eceed8488986cad3d5027165ea5edb164331770e2059555f10a5"
 dependencies = [
  "lazy_static",
  "libc",
@@ -1901,6 +1950,16 @@ dependencies = [
  "winapi 0.3.9",
 ]
 
+[[package]]
+name = "fs2"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9564fc758e15025b46aa6643b1b77d047d1a56a1aea6e01002ac0c7026876213"
+dependencies = [
+ "libc",
+ "winapi 0.3.9",
+]
+
 [[package]]
 name = "fs_extra"
 version = "1.2.0"
@@ -1937,15 +1996,15 @@ checksum = "fed34cd105917e91daa4da6b3728c47b068749d6a62c59811f06ed2ac71d9da7"
 
 [[package]]
 name = "futures"
-version = "0.1.30"
+version = "0.1.31"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4c7e4c2612746b0df8fed4ce0c69156021b704c9aefa360311c04e6e9e002eed"
+checksum = "3a471a38ef8ed83cd6e40aa59c1ffe17db6855c18e3604d9c4ed8c08ebc28678"
 
 [[package]]
 name = "futures"
-version = "0.3.12"
+version = "0.3.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "da9052a1a50244d8d5aa9bf55cbc2fb6f357c86cc52e46c62ed390a7180cf150"
+checksum = "7f55667319111d593ba876406af7c409c0ebb44dc4be6132a783ccf163ea14c1"
 dependencies = [
  "futures-channel",
  "futures-core",
@@ -1958,9 +2017,9 @@ dependencies = [
 
 [[package]]
 name = "futures-channel"
-version = "0.3.12"
+version = "0.3.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f2d31b7ec7efab6eefc7c57233bb10b847986139d88cc2f5a02a1ae6871a1846"
+checksum = "8c2dd2df839b57db9ab69c2c9d8f3e8c81984781937fe2807dc6dcf3b2ad2939"
 dependencies = [
  "futures-core",
  "futures-sink",
@@ -1968,9 +2027,9 @@ dependencies = [
 
 [[package]]
 name = "futures-core"
-version = "0.3.12"
+version = "0.3.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "79e5145dde8da7d1b3892dad07a9c98fc04bc39892b1ecc9692cf53e2b780a65"
+checksum = "15496a72fabf0e62bdc3df11a59a3787429221dd0710ba8ef163d6f7a9112c94"
 
 [[package]]
 name = "futures-cpupool"
@@ -1978,7 +2037,7 @@ version = "0.1.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ab90cde24b3319636588d0c35fe03b1333857621051837ed769faefb4c2162e4"
 dependencies = [
- "futures 0.1.30",
+ "futures 0.1.31",
  "num_cpus",
 ]
 
@@ -1988,8 +2047,8 @@ version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fdcef58a173af8148b182684c9f2d5250875adbcaff7b5794073894f9d8634a9"
 dependencies = [
- "futures 0.1.30",
- "futures 0.3.12",
+ "futures 0.1.31",
+ "futures 0.3.13",
  "lazy_static",
  "log",
  "parking_lot 0.9.0",
@@ -2000,9 +2059,9 @@ dependencies = [
 
 [[package]]
 name = "futures-executor"
-version = "0.3.12"
+version = "0.3.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e9e59fdc009a4b3096bf94f740a0f2424c082521f20a9b08c5c07c48d90fd9b9"
+checksum = "891a4b7b96d84d5940084b2a37632dd65deeae662c114ceaa2c879629c9c0ad1"
 dependencies = [
  "futures-core",
  "futures-task",
@@ -2012,9 +2071,9 @@ dependencies = [
 
 [[package]]
 name = "futures-io"
-version = "0.3.12"
+version = "0.3.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "28be053525281ad8259d47e4de5de657b25e7bac113458555bb4b70bc6870500"
+checksum = "d71c2c65c57704c32f5241c1223167c2c3294fd34ac020c807ddbe6db287ba59"
 
 [[package]]
 name = "futures-lite"
@@ -2027,15 +2086,15 @@ dependencies = [
  "futures-io",
  "memchr",
  "parking",
- "pin-project-lite 0.2.5",
+ "pin-project-lite 0.2.6",
  "waker-fn",
 ]
 
 [[package]]
 name = "futures-macro"
-version = "0.3.12"
+version = "0.3.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c287d25add322d9f9abdcdc5927ca398917996600182178774032e9f8258fedd"
+checksum = "ea405816a5139fb39af82c2beb921d52143f556038378d6db21183a5c37fbfb7"
 dependencies = [
  "proc-macro-hack",
  "proc-macro2",
@@ -2056,18 +2115,15 @@ dependencies = [
 
 [[package]]
 name = "futures-sink"
-version = "0.3.12"
+version = "0.3.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "caf5c69029bda2e743fddd0582d1083951d65cc9539aebf8812f36c3491342d6"
+checksum = "85754d98985841b7d4f5e8e6fbfa4a4ac847916893ec511a2917ccd8525b8bb3"
 
 [[package]]
 name = "futures-task"
-version = "0.3.12"
+version = "0.3.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "13de07eb8ea81ae445aca7b69f5f7bf15d7bf4912d8ca37d6645c77ae8a58d86"
-dependencies = [
- "once_cell",
-]
+checksum = "fa189ef211c15ee602667a6fcfe1c1fd9e07d42250d2156382820fba33c9df80"
 
 [[package]]
 name = "futures-timer"
@@ -2087,11 +2143,11 @@ dependencies = [
 
 [[package]]
 name = "futures-util"
-version = "0.3.12"
+version = "0.3.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "632a8cd0f2a4b3fdea1657f08bde063848c3bd00f9bbf6e256b8be78802e624b"
+checksum = "1812c7ab8aedf8d6f2701a43e1243acdbcc2b36ab26e2ad421eb99ac963d96d1"
 dependencies = [
- "futures 0.1.30",
+ "futures 0.1.31",
  "futures-channel",
  "futures-core",
  "futures-io",
@@ -2099,7 +2155,7 @@ dependencies = [
  "futures-sink",
  "futures-task",
  "memchr",
- "pin-project-lite 0.2.5",
+ "pin-project-lite 0.2.6",
  "pin-utils",
  "proc-macro-hack",
  "proc-macro-nested",
@@ -2114,18 +2170,18 @@ checksum = "8f5f3913fa0bfe7ee1fd8248b6b9f42a5af4b9d65ec2dd2c3c26132b950ecfc2"
 
 [[package]]
 name = "generic-array"
-version = "0.12.3"
+version = "0.12.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c68f0274ae0e023facc3c97b2e00f076be70e254bc851d972503b328db79b2ec"
+checksum = "ffdf9f34f1447443d37393cc6c2b8313aebddcd96906caf34e54c68d8e57d7bd"
 dependencies = [
  "typenum",
 ]
 
 [[package]]
 name = "generic-array"
-version = "0.13.2"
+version = "0.13.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0ed1e761351b56f54eb9dcd0cfaca9fd0daecf93918e1cfc01c8a3d26ee7adcd"
+checksum = "f797e67af32588215eaaab8327027ee8e71b9dd0b2b26996aedf20c030fce309"
 dependencies = [
  "typenum",
 ]
@@ -2228,7 +2284,7 @@ dependencies = [
  "byteorder",
  "bytes 0.4.12",
  "fnv",
- "futures 0.1.30",
+ "futures 0.1.31",
  "http 0.1.21",
  "indexmap",
  "log",
@@ -2265,9 +2321,9 @@ checksum = "62aca2aba2d62b4a7f5b33f3712cb1b0692779a56fb510499d5c0aa594daeaf3"
 
 [[package]]
 name = "handlebars"
-version = "3.5.2"
+version = "3.5.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "964d0e99a61fe9b1b347389b77ebf8b7e1587b70293676aaca7d27e59b9073b2"
+checksum = "cdb0867bbc5a3da37a753e78021d5fcf8a4db00e18dd2dd90fd36e24190e162d"
 dependencies = [
  "log",
  "pest",
@@ -2321,9 +2377,9 @@ dependencies = [
 
 [[package]]
 name = "hex"
-version = "0.4.2"
+version = "0.4.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "644f9158b2f133fd50f5fb3242878846d9eb792e445c893805ff0e3824006e35"
+checksum = "7f24254aa9a54b5c858eaee2f5bccdb46aaf0e486a595ed5fd8f86ba55232a70"
 
 [[package]]
 name = "hex-literal"
@@ -2364,21 +2420,32 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c6e570451493f10f6581b48cdd530413b63ea9e780f544bfd3bdcaa0d89d1a7b"
 dependencies = [
  "digest 0.8.1",
- "generic-array 0.12.3",
+ "generic-array 0.12.4",
  "hmac 0.7.1",
 ]
 
 [[package]]
 name = "honggfuzz"
-version = "0.5.52"
+version = "0.5.54"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ead88897bcad1c396806d6ccba260a0363e11da997472e9e19ab9889969083a2"
+checksum = "bea09577d948a98a5f59b7c891e274c4fb35ad52f67782b3d0cb53b9c05301f1"
 dependencies = [
  "arbitrary",
  "lazy_static",
  "memmap",
 ]
 
+[[package]]
+name = "hostname"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3c731c3e10504cc8ed35cfe2f1db4c9274c3d35fa486e3b31df46f068ef3e867"
+dependencies = [
+ "libc",
+ "match_cfg",
+ "winapi 0.3.9",
+]
+
 [[package]]
 name = "http"
 version = "0.1.21"
@@ -2408,7 +2475,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6741c859c1b2463a423a1dbce98d418e6c3c3fc720fb0d45528657320920292d"
 dependencies = [
  "bytes 0.4.12",
- "futures 0.1.30",
+ "futures 0.1.31",
  "http 0.1.21",
  "tokio-buf",
 ]
@@ -2425,9 +2492,9 @@ dependencies = [
 
 [[package]]
 name = "httparse"
-version = "1.3.4"
+version = "1.3.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cd179ae861f0c2e53da70d892f5f3029f9594be0c41dc5269cd371691b1dc2f9"
+checksum = "615caabe2c3160b313d52ccc905335f4ed5f10881dd63dc5699d47e90be85691"
 
 [[package]]
 name = "httpdate"
@@ -2452,12 +2519,12 @@ checksum = "9a3a5bfb195931eeb336b2a7b4d761daec841b97f947d34394601737a7bba5e4"
 
 [[package]]
 name = "hyper"
-version = "0.12.35"
+version = "0.12.36"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9dbe6ed1438e1f8ad955a4701e9a944938e9519f6888d12d8558b645e247d5f6"
+checksum = "5c843caf6296fc1f93444735205af9ed4e109a539005abb2564ae1d6fad34c52"
 dependencies = [
  "bytes 0.4.12",
- "futures 0.1.30",
+ "futures 0.1.31",
  "futures-cpupool",
  "h2 0.1.26",
  "http 0.1.21",
@@ -2482,9 +2549,9 @@ dependencies = [
 
 [[package]]
 name = "hyper"
-version = "0.13.9"
+version = "0.13.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f6ad767baac13b44d4529fcf58ba2cd0995e36e7b435bc5b039de6f47e880dbf"
+checksum = "8a6f157065790a3ed2f88679250419b5cdd96e714a0d65f7797fd337186e96bb"
 dependencies = [
  "bytes 0.5.6",
  "futures-channel",
@@ -2496,8 +2563,8 @@ dependencies = [
  "httparse",
  "httpdate",
  "itoa",
- "pin-project 1.0.4",
- "socket2",
+ "pin-project 1.0.5",
+ "socket2 0.3.19",
  "tokio 0.2.25",
  "tower-service",
  "tracing",
@@ -2513,7 +2580,7 @@ dependencies = [
  "bytes 0.5.6",
  "ct-logs",
  "futures-util",
- "hyper 0.13.9",
+ "hyper 0.13.10",
  "log",
  "rustls 0.18.1",
  "rustls-native-certs",
@@ -2535,9 +2602,9 @@ dependencies = [
 
 [[package]]
 name = "idna"
-version = "0.2.0"
+version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "02e2673c30ee86b5b96a9cb52ad15718aa1f966f5ab9ad54a8b95d5ca33120a9"
+checksum = "89829a5d69c23d348314a7ac337fe39173b61149a9864deabd260983aed48c21"
 dependencies = [
  "matches",
  "unicode-bidi",
@@ -2567,12 +2634,12 @@ dependencies = [
 
 [[package]]
 name = "if-watch"
-version = "0.1.8"
+version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "97b8538953a3f0d0d3868f0a706eb4273535e10d72acb5c82c1c23ae48835c85"
+checksum = "6a6d52908d4ea4ab2bc22474ba149bf1011c8e2c3ebc1ff593ae28ac44f494b6"
 dependencies = [
  "async-io",
- "futures 0.3.12",
+ "futures 0.3.13",
  "futures-lite",
  "if-addrs",
  "ipnet",
@@ -2587,7 +2654,7 @@ version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "df170efa359aebdd5cb7fe78edcc67107748e4737bdca8a8fb40d15ea7a877ed"
 dependencies = [
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
 ]
 
 [[package]]
@@ -2612,9 +2679,9 @@ dependencies = [
 
 [[package]]
 name = "indexmap"
-version = "1.6.1"
+version = "1.6.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4fb1fa934250de4de8aef298d81c729a7d33d8c239daa3a7575e6b92bfc7313b"
+checksum = "824845a0bf897a9042383849b02c1bc219c2383772efcd5c6f9766fa4b81aef3"
 dependencies = [
  "autocfg",
  "hashbrown",
@@ -2648,7 +2715,7 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "64fa110ec7b8f493f416eed552740d10e7030ad5f63b2308f82c9608ec2df275"
 dependencies = [
- "futures 0.3.12",
+ "futures 0.3.13",
  "futures-timer 2.0.2",
 ]
 
@@ -2667,6 +2734,18 @@ version = "0.3.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2ee15951c035f79eddbef745611ec962f63f4558f1dadf98ab723cc603487c6f"
 
+[[package]]
+name = "ipconfig"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f7e2f18aece9709094573a9f24f483c4f65caa4298e2f7ae1b71cc65d853fad7"
+dependencies = [
+ "socket2 0.3.19",
+ "widestring",
+ "winapi 0.3.9",
+ "winreg",
+]
+
 [[package]]
 name = "ipnet"
 version = "2.3.0"
@@ -2708,9 +2787,9 @@ dependencies = [
 
 [[package]]
 name = "js-sys"
-version = "0.3.46"
+version = "0.3.47"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cf3d7383929f7c9c7c2d0fa596f325832df98c3704f2c60553080f7127a58175"
+checksum = "5cfb73131c35423a367daf8cbd24100af0d077668c8c2943f0e7dd775fef0f65"
 dependencies = [
  "wasm-bindgen",
 ]
@@ -2722,8 +2801,8 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "489b9c612e60c766f751ab40fcb43cbb55a1e10bb44a9b4307ed510ca598cbd7"
 dependencies = [
  "failure",
- "futures 0.1.30",
- "hyper 0.12.35",
+ "futures 0.1.31",
+ "hyper 0.12.36",
  "jsonrpc-core",
  "jsonrpc-pubsub",
  "log",
@@ -2738,7 +2817,7 @@ version = "15.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0745a6379e3edc893c84ec203589790774e4247420033e71a76d3ab4687991fa"
 dependencies = [
- "futures 0.1.30",
+ "futures 0.1.31",
  "log",
  "serde",
  "serde_derive",
@@ -2772,7 +2851,7 @@ version = "15.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4fb5c4513b7b542f42da107942b7b759f27120b5cc894729f88254b28dff44b7"
 dependencies = [
- "hyper 0.12.35",
+ "hyper 0.12.36",
  "jsonrpc-core",
  "jsonrpc-server-utils",
  "log",
@@ -2845,8 +2924,8 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "124797a4ea7430d0675db78e065e53316e3f1a3cbf0ee4d6dbdd42db7b08e193"
 dependencies = [
  "async-trait",
- "futures 0.3.12",
- "hyper 0.13.9",
+ "futures 0.3.13",
+ "hyper 0.13.10",
  "jsonrpsee-types",
  "jsonrpsee-utils",
  "log",
@@ -2854,7 +2933,7 @@ dependencies = [
  "serde_json",
  "thiserror",
  "unicase",
- "url 2.2.0",
+ "url 2.2.1",
 ]
 
 [[package]]
@@ -2876,7 +2955,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5a8cd20c190e75dc56f7543b9d5713c3186351b301b5507ea6b85d8c403aac78"
 dependencies = [
  "async-trait",
- "futures 0.3.12",
+ "futures 0.3.13",
  "log",
  "serde",
  "serde_json",
@@ -2890,9 +2969,9 @@ version = "0.2.0-alpha"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c0e45394ec3175a767c3c5bac584560e6ad9b56ebd73216c85ec8bab49619244"
 dependencies = [
- "futures 0.3.12",
+ "futures 0.3.13",
  "globset",
- "hyper 0.13.9",
+ "hyper 0.13.10",
  "jsonrpsee-types",
  "lazy_static",
  "log",
@@ -2980,7 +3059,7 @@ version = "0.9.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "eb1e98ba343d0b35f9009a8844cd2b87fa3192f7e79033ac05b00aeae0f3b0b5"
 dependencies = [
- "futures 0.3.12",
+ "futures 0.3.13",
  "js-sys",
  "kvdb",
  "kvdb-memorydb",
@@ -3012,9 +3091,9 @@ checksum = "3576a87f2ba00f6f106fdfcd16db1d698d648a26ad8e0573cad8537c3c362d2a"
 
 [[package]]
 name = "libc"
-version = "0.2.84"
+version = "0.2.90"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1cca32fa0182e8c0989459524dc356b8f2b5c10f1b9eb521b7d182c03cf8c5ff"
+checksum = "ba4aede83fc3617411dc6993bc8c70919750c1c257c6ca6a502aed6e0e2394ae"
 
 [[package]]
 name = "libloading"
@@ -3034,13 +3113,13 @@ checksum = "c7d73b3f436185384286bd8098d17ec07c9a7d2388a6599f824d8502b529702a"
 
 [[package]]
 name = "libp2p"
-version = "0.35.1"
+version = "0.36.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "adc225a49973cf9ab10d0cdd6a4b8f0cda299df9b760824bbb623f15f8f0c95a"
+checksum = "fe5759b526f75102829c15e4d8566603b4bf502ed19b5f35920d98113873470d"
 dependencies = [
  "atomic",
  "bytes 1.0.1",
- "futures 0.3.12",
+ "futures 0.3.13",
  "lazy_static",
  "libp2p-core",
  "libp2p-deflate",
@@ -3055,6 +3134,7 @@ dependencies = [
  "libp2p-ping",
  "libp2p-plaintext",
  "libp2p-pnet",
+ "libp2p-relay",
  "libp2p-request-response",
  "libp2p-swarm",
  "libp2p-swarm-derive",
@@ -3065,23 +3145,23 @@ dependencies = [
  "libp2p-yamux",
  "parity-multiaddr",
  "parking_lot 0.11.1",
- "pin-project 1.0.4",
+ "pin-project 1.0.5",
  "smallvec 1.6.1",
  "wasm-timer",
 ]
 
 [[package]]
 name = "libp2p-core"
-version = "0.27.1"
+version = "0.28.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8a2d56aadc2c2bf22cd7797f86e56a65b5b3994a0136b65be3106938acae7a26"
+checksum = "c1e1797734bbd4c453664fefb029628f77c356ffc5bce98f06b18a7db3ebb0f7"
 dependencies = [
  "asn1_der",
  "bs58",
  "ed25519-dalek",
  "either",
  "fnv",
- "futures 0.3.12",
+ "futures 0.3.13",
  "futures-timer 3.0.2",
  "lazy_static",
  "libsecp256k1",
@@ -3090,7 +3170,7 @@ dependencies = [
  "multistream-select",
  "parity-multiaddr",
  "parking_lot 0.11.1",
- "pin-project 1.0.4",
+ "pin-project 1.0.5",
  "prost",
  "prost-build",
  "rand 0.7.3",
@@ -3106,35 +3186,38 @@ dependencies = [
 
 [[package]]
 name = "libp2p-deflate"
-version = "0.27.1"
+version = "0.28.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6d42eed63305f0420736fa487f9acef720c4528bd7852a6a760f5ccde4813345"
+checksum = "a2181a641cd15f9b6ba71b1335800f309012a0a97a29ffaabbbf40e9d3d58f08"
 dependencies = [
  "flate2",
- "futures 0.3.12",
+ "futures 0.3.13",
  "libp2p-core",
 ]
 
 [[package]]
 name = "libp2p-dns"
-version = "0.27.0"
+version = "0.28.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5153b6db68fd4baa3b304e377db744dd8fea8ff4e4504509ee636abcde88d3e3"
+checksum = "9712eb3e9f7dcc77cc5ca7d943b6a85ce4b1faaf91a67e003442412a26d6d6f8"
 dependencies = [
- "futures 0.3.12",
+ "async-std-resolver",
+ "futures 0.3.13",
  "libp2p-core",
  "log",
+ "smallvec 1.6.1",
+ "trust-dns-resolver",
 ]
 
 [[package]]
 name = "libp2p-floodsub"
-version = "0.27.0"
+version = "0.28.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b3c63dfa06581b24b1d12bf9815b43689a784424be217d6545c800c7c75a207f"
+checksum = "897645f99e9b396df256a6aa8ba8c4bc019ac6b7c62556f624b5feea9acc82bb"
 dependencies = [
  "cuckoofilter",
  "fnv",
- "futures 0.3.12",
+ "futures 0.3.13",
  "libp2p-core",
  "libp2p-swarm",
  "log",
@@ -3146,16 +3229,16 @@ dependencies = [
 
 [[package]]
 name = "libp2p-gossipsub"
-version = "0.28.0"
+version = "0.29.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "502dc5fcbfec4aa1c63ef3f7307ffe20e90c1a1387bf23ed0bec087f2dde58a1"
+checksum = "794b0c85f5df1acbc1fc38414d37272594811193b6325c76d3931c3e3f5df8c0"
 dependencies = [
  "asynchronous-codec 0.6.0",
  "base64 0.13.0",
  "byteorder",
  "bytes 1.0.1",
  "fnv",
- "futures 0.3.12",
+ "futures 0.3.13",
  "hex_fmt",
  "libp2p-core",
  "libp2p-swarm",
@@ -3172,11 +3255,11 @@ dependencies = [
 
 [[package]]
 name = "libp2p-identify"
-version = "0.27.0"
+version = "0.28.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b40fb36a059b7a8cce1514bd8b546fa612e006c9937caa7f5950cb20021fe91e"
+checksum = "f88ebc841d744979176ab4b8b294a3e655a7ba4ef26a905d073a52b49ed4dff5"
 dependencies = [
- "futures 0.3.12",
+ "futures 0.3.13",
  "libp2p-core",
  "libp2p-swarm",
  "log",
@@ -3188,16 +3271,16 @@ dependencies = [
 
 [[package]]
 name = "libp2p-kad"
-version = "0.28.1"
+version = "0.29.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cf3da6c9acbcc05f93235d201d7d45ef4e8b88a45d8836f98becd8b4d443f066"
+checksum = "bbb5b90b6bda749023a85f60b49ea74b387c25f17d8df541ae72a3c75dd52e63"
 dependencies = [
  "arrayvec 0.5.2",
  "asynchronous-codec 0.6.0",
  "bytes 1.0.1",
  "either",
  "fnv",
- "futures 0.3.12",
+ "futures 0.3.13",
  "libp2p-core",
  "libp2p-swarm",
  "log",
@@ -3214,34 +3297,34 @@ dependencies = [
 
 [[package]]
 name = "libp2p-mdns"
-version = "0.28.1"
+version = "0.29.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0e9e6374814d1b118d97ccabdfc975c8910bd16dc38a8bc058eeb08bf2080fe1"
+checksum = "be28ca13bb648d249a9baebd750ebc64ce7040ddd5f0ce1035ff1f4549fb596d"
 dependencies = [
  "async-io",
  "data-encoding",
  "dns-parser",
- "futures 0.3.12",
+ "futures 0.3.13",
  "if-watch",
  "lazy_static",
  "libp2p-core",
  "libp2p-swarm",
  "log",
- "rand 0.7.3",
+ "rand 0.8.3",
  "smallvec 1.6.1",
- "socket2",
+ "socket2 0.4.0",
  "void",
 ]
 
 [[package]]
 name = "libp2p-mplex"
-version = "0.27.1"
+version = "0.28.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "350ce8b3923594aedabd5d6e3f875d058435052a29c3f32df378bc70d10be464"
+checksum = "85e9b544335d1ed30af71daa96edbefadef6f19c7a55f078b9fc92c87163105d"
 dependencies = [
  "asynchronous-codec 0.6.0",
  "bytes 1.0.1",
- "futures 0.3.12",
+ "futures 0.3.13",
  "libp2p-core",
  "log",
  "nohash-hasher",
@@ -3253,13 +3336,13 @@ dependencies = [
 
 [[package]]
 name = "libp2p-noise"
-version = "0.29.0"
+version = "0.30.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4aca322b52a0c5136142a7c3971446fb1e9964923a526c9cc6ef3b7c94e57778"
+checksum = "36db0f0db3b0433f5b9463f1c0cd9eadc0a3734a9170439ce501ff99733a88bd"
 dependencies = [
  "bytes 1.0.1",
  "curve25519-dalek 3.0.2",
- "futures 0.3.12",
+ "futures 0.3.13",
  "lazy_static",
  "libp2p-core",
  "log",
@@ -3275,11 +3358,11 @@ dependencies = [
 
 [[package]]
 name = "libp2p-ping"
-version = "0.27.0"
+version = "0.28.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6f3813276d0708c8db0f500d8beda1bda9ad955723b9cb272c41f4727256f73c"
+checksum = "dea10fc5209260915ea65b78f612d7ff78a29ab288e7aa3250796866af861c45"
 dependencies = [
- "futures 0.3.12",
+ "futures 0.3.13",
  "libp2p-core",
  "libp2p-swarm",
  "log",
@@ -3290,13 +3373,13 @@ dependencies = [
 
 [[package]]
 name = "libp2p-plaintext"
-version = "0.27.1"
+version = "0.28.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9d58defcadb646ae4b033e130b48d87410bf76394dc3335496cae99dac803e61"
+checksum = "0c8c37b4d2a075b4be8442760a5f8c037180f0c8dd5b5734b9978ab868b3aa11"
 dependencies = [
  "asynchronous-codec 0.6.0",
  "bytes 1.0.1",
- "futures 0.3.12",
+ "futures 0.3.13",
  "libp2p-core",
  "log",
  "prost",
@@ -3311,23 +3394,46 @@ version = "0.20.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6ce3374f3b28162db9d3442c9347c4f14cb01e8290052615c7d341d40eae0599"
 dependencies = [
- "futures 0.3.12",
+ "futures 0.3.13",
  "log",
- "pin-project 1.0.4",
+ "pin-project 1.0.5",
  "rand 0.7.3",
  "salsa20",
  "sha3",
 ]
 
+[[package]]
+name = "libp2p-relay"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3ff268be6a9d6f3c6cca3b81bbab597b15217f9ad8787c6c40fc548c1af7cd24"
+dependencies = [
+ "asynchronous-codec 0.6.0",
+ "bytes 1.0.1",
+ "futures 0.3.13",
+ "futures-timer 3.0.2",
+ "libp2p-core",
+ "libp2p-swarm",
+ "log",
+ "pin-project 1.0.5",
+ "prost",
+ "prost-build",
+ "rand 0.7.3",
+ "smallvec 1.6.1",
+ "unsigned-varint 0.7.0",
+ "void",
+ "wasm-timer",
+]
+
 [[package]]
 name = "libp2p-request-response"
-version = "0.9.1"
+version = "0.10.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "10e5552827c33d8326502682da73a0ba4bfa40c1b55b216af3c303f32169dd89"
+checksum = "725367dd2318c54c5ab1a6418592e5b01c63b0dedfbbfb8389220b2bcf691899"
 dependencies = [
  "async-trait",
  "bytes 1.0.1",
- "futures 0.3.12",
+ "futures 0.3.13",
  "libp2p-core",
  "libp2p-swarm",
  "log",
@@ -3341,12 +3447,12 @@ dependencies = [
 
 [[package]]
 name = "libp2p-swarm"
-version = "0.27.2"
+version = "0.28.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7955b973e1fd2bd61ffd43ce261c1223f61f4aacd5bae362a924993f9a25fd98"
+checksum = "75c26980cadd7c25d89071cb23e1f7f5df4863128cc91d83c6ddc72338cecafa"
 dependencies = [
  "either",
- "futures 0.3.12",
+ "futures 0.3.13",
  "libp2p-core",
  "log",
  "rand 0.7.3",
@@ -3367,40 +3473,40 @@ dependencies = [
 
 [[package]]
 name = "libp2p-tcp"
-version = "0.27.1"
+version = "0.28.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "88a5aef80e519a6cb8e2663605142f97baaaea1a252eecbf8756184765f7471b"
+checksum = "2b1a27d21c477951799e99d5c105d78868258502ce092988040a808d5a19bbd9"
 dependencies = [
  "async-io",
- "futures 0.3.12",
+ "futures 0.3.13",
  "futures-timer 3.0.2",
  "if-watch",
  "ipnet",
  "libc",
  "libp2p-core",
  "log",
- "socket2",
+ "socket2 0.4.0",
 ]
 
 [[package]]
 name = "libp2p-uds"
-version = "0.27.0"
+version = "0.28.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "80ac51ce419f60be966e02103c17f67ff5dc4422ba83ba54d251d6c62a4ed487"
+checksum = "ffd6564bb3b7ff203661ccbb69003c2b551e34cef974f2d6c6a28306a12170b5"
 dependencies = [
  "async-std",
- "futures 0.3.12",
+ "futures 0.3.13",
  "libp2p-core",
  "log",
 ]
 
 [[package]]
 name = "libp2p-wasm-ext"
-version = "0.27.0"
+version = "0.28.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6149c46cb76935c80bc8be6ec6e3ebd5f5e1679765a255fb34331d54610f15dd"
+checksum = "6df65fc13f6188edf7e6927b086330448b3ca27af86b49748c6d299d7c8d9040"
 dependencies = [
- "futures 0.3.12",
+ "futures 0.3.13",
  "js-sys",
  "libp2p-core",
  "parity-send-wrapper",
@@ -3410,29 +3516,29 @@ dependencies = [
 
 [[package]]
 name = "libp2p-websocket"
-version = "0.28.0"
+version = "0.29.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d3b1c6a3431045da8b925ed83384e4c5163e14b990572307fca9c507435d4d22"
+checksum = "cace60995ef6f637e4752cccbb2590f6bc358e8741a0d066307636c69a4b3a74"
 dependencies = [
  "either",
- "futures 0.3.12",
+ "futures 0.3.13",
  "futures-rustls",
  "libp2p-core",
  "log",
  "quicksink",
  "rw-stream-sink",
  "soketto",
- "url 2.2.0",
+ "url 2.2.1",
  "webpki-roots",
 ]
 
 [[package]]
 name = "libp2p-yamux"
-version = "0.30.1"
+version = "0.31.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4819358c542a86ff95f6ae691efb4b94ddaf477079b01a686f5705b79bfc232a"
+checksum = "96d6144cc94143fb0a8dd1e7c2fbcc32a2808168bcd1d69920635424d5993b7b"
 dependencies = [
- "futures 0.3.12",
+ "futures 0.3.13",
  "libp2p-core",
  "parking_lot 0.11.1",
  "thiserror",
@@ -3558,6 +3664,15 @@ dependencies = [
  "hashbrown",
 ]
 
+[[package]]
+name = "lru-cache"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "31e24f1ad8321ca0e8a1e0ac13f23cb668e6f5466c2c57319f6a5cf1cc8e3b1c"
+dependencies = [
+ "linked-hash-map",
+]
+
 [[package]]
 name = "mach"
 version = "0.3.2"
@@ -3573,6 +3688,12 @@ version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3e2e65a1a2e43cfcb47a895c4c8b10d1f4a61097f9f254f183aee60cad9c651d"
 
+[[package]]
+name = "match_cfg"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ffbee8634e0d45d258acb448e7eaab3fce7a0a467395d4d9f228e3c1f01fb2e4"
+
 [[package]]
 name = "matchers"
 version = "0.0.1"
@@ -3621,9 +3742,9 @@ dependencies = [
 
 [[package]]
 name = "memmap2"
-version = "0.2.0"
+version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e73be3b7d04a0123e933fea1d50d126cc7196bbc0362c0ce426694f777194eee"
+checksum = "04e3e85b970d650e2ae6d70592474087051c11c54da7f7b4949725c5735fbcc6"
 dependencies = [
  "libc",
 ]
@@ -3677,18 +3798,18 @@ dependencies = [
 
 [[package]]
 name = "minicbor"
-version = "0.7.1"
+version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3265a9f5210bb726f81ef9c456ae0aff5321cd95748c0e71889b0e19d8f0332b"
+checksum = "ea79ce4ab9f445ec6b71833a2290ac0a29c9dde0fa7cae4c481eecae021d9bd9"
 dependencies = [
  "minicbor-derive",
 ]
 
 [[package]]
 name = "minicbor-derive"
-version = "0.6.1"
+version = "0.6.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "130b9455e28a3f308f6579671816a6f2621e2e0cbf55dc2f886345bef699481e"
+checksum = "19ce18b5423c573a13e80cb3046ea0af6379ef725dc3af4886bdb8f4e5093068"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -3697,9 +3818,9 @@ dependencies = [
 
 [[package]]
 name = "miniz_oxide"
-version = "0.4.3"
+version = "0.4.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0f2d26ec3309788e423cfbf68ad1800f061638098d76a83681af979dc4eda19d"
+checksum = "a92518e98c078586bc6c934028adcca4c92a53d6a958196de835170a01d84e4b"
 dependencies = [
  "adler",
  "autocfg",
@@ -3777,7 +3898,7 @@ version = "0.3.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5a33c1b55807fbed163481b5ba66db4b2fa6cde694a5027be10fb724206c5897"
 dependencies = [
- "socket2",
+ "socket2 0.3.19",
  "winapi 0.3.9",
 ]
 
@@ -3837,16 +3958,16 @@ checksum = "1255076139a83bb467426e7f8d0134968a8118844faa755985e077cf31850333"
 
 [[package]]
 name = "multistream-select"
-version = "0.10.0"
+version = "0.10.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "10ddc0eb0117736f19d556355464fc87efc8ad98b29e3fd84f02531eb6e90840"
+checksum = "7d91ec0a2440aaff5f78ec35631a7027d50386c6163aa975f7caa0d5da4b6ff8"
 dependencies = [
  "bytes 1.0.1",
- "futures 0.3.12",
+ "futures 0.3.13",
  "log",
- "pin-project 1.0.4",
+ "pin-project 1.0.5",
  "smallvec 1.6.1",
- "unsigned-varint 0.6.0",
+ "unsigned-varint 0.7.0",
 ]
 
 [[package]]
@@ -3856,7 +3977,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d6b6147c3d50b4f3cdabfe2ecc94a0191fd3d6ad58aefd9664cf396285883486"
 dependencies = [
  "approx",
- "generic-array 0.13.2",
+ "generic-array 0.13.3",
  "matrixmultiply",
  "num-complex",
  "num-rational",
@@ -3883,7 +4004,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "670361df1bc2399ee1ff50406a0d422587dd3bb0da596e1978fe8e05dabddf4f"
 dependencies = [
  "libc",
- "socket2",
+ "socket2 0.3.19",
 ]
 
 [[package]]
@@ -3915,7 +4036,7 @@ version = "0.8.0"
 dependencies = [
  "derive_more",
  "fs_extra",
- "futures 0.3.12",
+ "futures 0.3.13",
  "hash-db",
  "hex",
  "kvdb",
@@ -3951,7 +4072,7 @@ dependencies = [
 name = "node-browser-testing"
 version = "2.0.0"
 dependencies = [
- "futures 0.3.12",
+ "futures 0.3.13",
  "futures-timer 3.0.2",
  "jsonrpc-core",
  "libp2p",
@@ -3973,7 +4094,7 @@ dependencies = [
  "frame-benchmarking-cli",
  "frame-support",
  "frame-system",
- "futures 0.3.12",
+ "futures 0.3.13",
  "hex-literal",
  "libp2p-wasm-ext",
  "log",
@@ -3992,7 +4113,7 @@ dependencies = [
  "pallet-staking",
  "pallet-timestamp",
  "pallet-transaction-payment",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parking_lot 0.11.1",
  "platforms",
  "rand 0.7.3",
@@ -4052,6 +4173,7 @@ dependencies = [
  "frame-benchmarking",
  "frame-support",
  "frame-system",
+ "futures 0.3.13",
  "node-primitives",
  "node-runtime",
  "node-testing",
@@ -4064,7 +4186,7 @@ dependencies = [
  "pallet-timestamp",
  "pallet-transaction-payment",
  "pallet-treasury",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sc-executor",
  "sp-application-crypto",
  "sp-consensus-babe",
@@ -4086,7 +4208,7 @@ version = "0.8.0"
 dependencies = [
  "derive_more",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sc-cli",
  "sc-client-api",
  "sc-service",
@@ -4101,7 +4223,7 @@ name = "node-primitives"
 version = "2.0.0"
 dependencies = [
  "frame-system",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "pretty_assertions",
  "sp-application-crypto",
  "sp-core",
@@ -4145,8 +4267,8 @@ dependencies = [
 name = "node-rpc-client"
 version = "2.0.0"
 dependencies = [
- "futures 0.1.30",
- "hyper 0.12.35",
+ "futures 0.1.31",
+ "hyper 0.12.36",
  "jsonrpc-core-client",
  "log",
  "node-primitives",
@@ -4209,7 +4331,7 @@ dependencies = [
  "pallet-treasury",
  "pallet-utility",
  "pallet-vesting",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-api",
  "sp-authority-discovery",
@@ -4219,6 +4341,7 @@ dependencies = [
  "sp-inherents",
  "sp-io",
  "sp-keyring",
+ "sp-npos-elections",
  "sp-offchain",
  "sp-runtime",
  "sp-session",
@@ -4232,7 +4355,7 @@ dependencies = [
 
 [[package]]
 name = "node-template"
-version = "2.0.0"
+version = "3.0.0"
 dependencies = [
  "frame-benchmarking",
  "frame-benchmarking-cli",
@@ -4269,7 +4392,7 @@ dependencies = [
 
 [[package]]
 name = "node-template-runtime"
-version = "2.0.0"
+version = "3.0.0"
 dependencies = [
  "frame-benchmarking",
  "frame-executive",
@@ -4287,7 +4410,7 @@ dependencies = [
  "pallet-timestamp",
  "pallet-transaction-payment",
  "pallet-transaction-payment-rpc-runtime-api",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-api",
  "sp-block-builder",
@@ -4311,7 +4434,7 @@ dependencies = [
  "frame-support",
  "frame-system",
  "fs_extra",
- "futures 0.3.12",
+ "futures 0.3.13",
  "log",
  "node-executor",
  "node-primitives",
@@ -4326,7 +4449,7 @@ dependencies = [
  "pallet-timestamp",
  "pallet-transaction-payment",
  "pallet-treasury",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sc-block-builder",
  "sc-cli",
  "sc-client-api",
@@ -4444,9 +4567,9 @@ dependencies = [
 
 [[package]]
 name = "once_cell"
-version = "1.5.2"
+version = "1.7.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "13bd41f508810a131401606d54ac32a467c97172d74ba7662562ebba5ad07fa0"
+checksum = "af8b08b04175473088b46763e51ee54da5f9a164bc162f615b91bc179dbf15a3"
 dependencies = [
  "parking_lot 0.11.1",
 ]
@@ -4501,7 +4624,7 @@ dependencies = [
  "frame-support",
  "frame-system",
  "pallet-balances",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -4516,7 +4639,7 @@ dependencies = [
  "frame-support",
  "frame-system",
  "pallet-balances",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -4533,7 +4656,7 @@ dependencies = [
  "lazy_static",
  "pallet-session",
  "pallet-timestamp",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parking_lot 0.11.1",
  "serde",
  "sp-application-crypto",
@@ -4551,7 +4674,7 @@ dependencies = [
  "frame-support",
  "frame-system",
  "pallet-session",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-application-crypto",
  "sp-authority-discovery",
@@ -4569,7 +4692,7 @@ dependencies = [
  "frame-support",
  "frame-system",
  "impl-trait-for-tuples",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-authorship",
  "sp-core",
@@ -4584,6 +4707,7 @@ name = "pallet-babe"
 version = "3.0.0"
 dependencies = [
  "frame-benchmarking",
+ "frame-election-provider-support",
  "frame-support",
  "frame-system",
  "log",
@@ -4594,13 +4718,12 @@ dependencies = [
  "pallet-staking",
  "pallet-staking-reward-curve",
  "pallet-timestamp",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-application-crypto",
  "sp-consensus-babe",
  "sp-consensus-vrf",
  "sp-core",
- "sp-election-providers",
  "sp-io",
  "sp-runtime",
  "sp-session",
@@ -4617,7 +4740,7 @@ dependencies = [
  "frame-system",
  "log",
  "pallet-transaction-payment",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -4634,7 +4757,7 @@ dependencies = [
  "frame-system",
  "pallet-balances",
  "pallet-treasury",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -4653,7 +4776,7 @@ dependencies = [
  "hex-literal",
  "log",
  "pallet-balances",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -4676,7 +4799,7 @@ dependencies = [
  "pallet-contracts-proc-macro",
  "pallet-randomness-collective-flip",
  "pallet-timestamp",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parity-wasm 0.41.0",
  "paste 1.0.4",
  "pretty_assertions",
@@ -4698,7 +4821,7 @@ name = "pallet-contracts-primitives"
 version = "3.0.0"
 dependencies = [
  "bitflags",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sp-runtime",
  "sp-std",
 ]
@@ -4721,7 +4844,7 @@ dependencies = [
  "jsonrpc-derive",
  "pallet-contracts-primitives",
  "pallet-contracts-rpc-runtime-api",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "serde_json",
  "sp-api",
@@ -4736,7 +4859,7 @@ name = "pallet-contracts-rpc-runtime-api"
 version = "3.0.0"
 dependencies = [
  "pallet-contracts-primitives",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sp-api",
  "sp-runtime",
  "sp-std",
@@ -4752,7 +4875,7 @@ dependencies = [
  "hex-literal",
  "pallet-balances",
  "pallet-scheduler",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -4767,19 +4890,19 @@ name = "pallet-election-provider-multi-phase"
 version = "3.0.0"
 dependencies = [
  "frame-benchmarking",
+ "frame-election-provider-support",
  "frame-support",
  "frame-system",
  "hex-literal",
  "log",
  "pallet-balances",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parking_lot 0.11.1",
  "paste 1.0.4",
  "rand 0.7.3",
  "serde",
  "sp-arithmetic",
  "sp-core",
- "sp-election-providers",
  "sp-io",
  "sp-npos-elections",
  "sp-runtime",
@@ -4797,7 +4920,7 @@ dependencies = [
  "frame-system",
  "hex-literal",
  "pallet-balances",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -4815,7 +4938,7 @@ dependencies = [
  "hex-literal",
  "log",
  "pallet-balances",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -4827,13 +4950,14 @@ dependencies = [
 
 [[package]]
 name = "pallet-example"
-version = "2.0.0"
+version = "3.0.0"
 dependencies = [
  "frame-benchmarking",
  "frame-support",
  "frame-system",
+ "log",
  "pallet-balances",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -4849,7 +4973,7 @@ dependencies = [
  "frame-system",
  "lite-json",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -4864,7 +4988,7 @@ version = "2.0.1"
 dependencies = [
  "frame-support",
  "frame-system",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -4881,7 +5005,7 @@ dependencies = [
  "frame-support",
  "frame-system",
  "pallet-balances",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-arithmetic",
  "sp-core",
@@ -4896,6 +5020,7 @@ version = "3.0.0"
 dependencies = [
  "finality-grandpa",
  "frame-benchmarking",
+ "frame-election-provider-support",
  "frame-support",
  "frame-system",
  "log",
@@ -4906,11 +5031,10 @@ dependencies = [
  "pallet-staking",
  "pallet-staking-reward-curve",
  "pallet-timestamp",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-application-crypto",
  "sp-core",
- "sp-election-providers",
  "sp-finality-grandpa",
  "sp-io",
  "sp-keyring",
@@ -4929,7 +5053,7 @@ dependencies = [
  "frame-support",
  "frame-system",
  "pallet-balances",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -4947,7 +5071,7 @@ dependencies = [
  "log",
  "pallet-authorship",
  "pallet-session",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-application-crypto",
  "sp-core",
@@ -4965,7 +5089,7 @@ dependencies = [
  "frame-support",
  "frame-system",
  "pallet-balances",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -4983,7 +5107,7 @@ dependencies = [
  "frame-support-test",
  "frame-system",
  "pallet-balances",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -4997,7 +5121,7 @@ version = "3.0.0"
 dependencies = [
  "frame-support",
  "frame-system",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -5010,13 +5134,13 @@ name = "pallet-mmr"
 version = "3.0.0"
 dependencies = [
  "ckb-merkle-mountain-range",
- "env_logger 0.8.2",
+ "env_logger 0.8.3",
  "frame-benchmarking",
  "frame-support",
  "frame-system",
  "hex-literal",
  "pallet-mmr-primitives",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -5032,7 +5156,7 @@ dependencies = [
  "frame-system",
  "hex-literal",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-api",
  "sp-core",
@@ -5048,7 +5172,7 @@ dependencies = [
  "jsonrpc-core-client",
  "jsonrpc-derive",
  "pallet-mmr-primitives",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "serde_json",
  "sp-api",
@@ -5066,7 +5190,7 @@ dependencies = [
  "frame-support",
  "frame-system",
  "pallet-balances",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -5081,7 +5205,7 @@ dependencies = [
  "frame-support",
  "frame-system",
  "pallet-balances",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -5091,12 +5215,12 @@ dependencies = [
 
 [[package]]
 name = "pallet-node-authorization"
-version = "2.0.0"
+version = "3.0.0"
 dependencies = [
  "frame-support",
  "frame-system",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -5112,7 +5236,7 @@ dependencies = [
  "frame-system",
  "log",
  "pallet-balances",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -5126,6 +5250,7 @@ name = "pallet-offences-benchmarking"
 version = "3.0.0"
 dependencies = [
  "frame-benchmarking",
+ "frame-election-provider-support",
  "frame-support",
  "frame-system",
  "pallet-babe",
@@ -5137,10 +5262,9 @@ dependencies = [
  "pallet-staking",
  "pallet-staking-reward-curve",
  "pallet-timestamp",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
- "sp-election-providers",
  "sp-io",
  "sp-runtime",
  "sp-staking",
@@ -5156,7 +5280,7 @@ dependencies = [
  "frame-system",
  "pallet-balances",
  "pallet-utility",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -5170,7 +5294,7 @@ version = "3.0.0"
 dependencies = [
  "frame-support",
  "frame-system",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "safe-mix",
  "serde",
  "sp-core",
@@ -5187,7 +5311,7 @@ dependencies = [
  "frame-support",
  "frame-system",
  "pallet-balances",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -5203,7 +5327,7 @@ dependencies = [
  "frame-support",
  "frame-system",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -5219,7 +5343,7 @@ dependencies = [
  "frame-support",
  "frame-system",
  "pallet-balances",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -5236,7 +5360,7 @@ dependencies = [
  "impl-trait-for-tuples",
  "lazy_static",
  "pallet-timestamp",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-application-crypto",
  "sp-core",
@@ -5253,6 +5377,7 @@ name = "pallet-session-benchmarking"
 version = "3.0.0"
 dependencies = [
  "frame-benchmarking",
+ "frame-election-provider-support",
  "frame-support",
  "frame-system",
  "pallet-balances",
@@ -5260,11 +5385,10 @@ dependencies = [
  "pallet-staking",
  "pallet-staking-reward-curve",
  "pallet-timestamp",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "rand 0.7.3",
  "serde",
  "sp-core",
- "sp-election-providers",
  "sp-io",
  "sp-runtime",
  "sp-session",
@@ -5279,7 +5403,7 @@ dependencies = [
  "frame-support-test",
  "frame-system",
  "pallet-balances",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "rand_chacha 0.2.2",
  "serde",
  "sp-core",
@@ -5293,6 +5417,7 @@ name = "pallet-staking"
 version = "3.0.0"
 dependencies = [
  "frame-benchmarking",
+ "frame-election-provider-support",
  "frame-support",
  "frame-system",
  "hex",
@@ -5302,15 +5427,14 @@ dependencies = [
  "pallet-session",
  "pallet-staking-reward-curve",
  "pallet-timestamp",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parking_lot 0.11.1",
+ "paste 1.0.4",
  "rand_chacha 0.2.2",
  "serde",
  "sp-application-crypto",
  "sp-core",
- "sp-election-providers",
  "sp-io",
- "sp-npos-elections",
  "sp-runtime",
  "sp-staking",
  "sp-std",
@@ -5320,29 +5444,6 @@ dependencies = [
  "substrate-test-utils",
 ]
 
-[[package]]
-name = "pallet-staking-fuzz"
-version = "0.0.0"
-dependencies = [
- "frame-support",
- "frame-system",
- "honggfuzz",
- "pallet-balances",
- "pallet-indices",
- "pallet-session",
- "pallet-staking",
- "pallet-staking-reward-curve",
- "pallet-timestamp",
- "parity-scale-codec",
- "serde",
- "sp-core",
- "sp-election-providers",
- "sp-io",
- "sp-npos-elections",
- "sp-runtime",
- "sp-std",
-]
-
 [[package]]
 name = "pallet-staking-reward-curve"
 version = "3.0.0"
@@ -5354,13 +5455,21 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "pallet-staking-reward-fn"
+version = "3.0.0"
+dependencies = [
+ "log",
+ "sp-arithmetic",
+]
+
 [[package]]
 name = "pallet-sudo"
 version = "3.0.0"
 dependencies = [
  "frame-support",
  "frame-system",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -5370,12 +5479,12 @@ dependencies = [
 
 [[package]]
 name = "pallet-template"
-version = "2.0.0"
+version = "3.0.0"
 dependencies = [
  "frame-benchmarking",
  "frame-support",
  "frame-system",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -5391,7 +5500,7 @@ dependencies = [
  "frame-system",
  "impl-trait-for-tuples",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-inherents",
@@ -5410,7 +5519,7 @@ dependencies = [
  "frame-system",
  "pallet-balances",
  "pallet-treasury",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -5426,7 +5535,7 @@ dependencies = [
  "frame-support",
  "frame-system",
  "pallet-balances",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "serde_json",
  "smallvec 1.6.1",
@@ -5445,7 +5554,7 @@ dependencies = [
  "jsonrpc-core-client",
  "jsonrpc-derive",
  "pallet-transaction-payment-rpc-runtime-api",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sp-api",
  "sp-blockchain",
  "sp-core",
@@ -5458,7 +5567,7 @@ name = "pallet-transaction-payment-rpc-runtime-api"
 version = "3.0.0"
 dependencies = [
  "pallet-transaction-payment",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sp-api",
  "sp-runtime",
 ]
@@ -5472,7 +5581,7 @@ dependencies = [
  "frame-system",
  "impl-trait-for-tuples",
  "pallet-balances",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -5489,7 +5598,7 @@ dependencies = [
  "frame-support",
  "frame-system",
  "pallet-balances",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -5507,7 +5616,7 @@ dependencies = [
  "frame-system",
  "hex-literal",
  "pallet-balances",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -5518,12 +5627,13 @@ dependencies = [
 
 [[package]]
 name = "parity-db"
-version = "0.2.2"
+version = "0.2.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "111e193c96758d476d272093a853882668da17489f76bf4361b8decae0b6c515"
+checksum = "495197c078e54b8735181aa35c00a327f7f3a3cc00a1ee8c95926dd010f0ec6b"
 dependencies = [
  "blake2-rfc",
  "crc32fast",
+ "fs2",
  "hex",
  "libc",
  "log",
@@ -5534,9 +5644,9 @@ dependencies = [
 
 [[package]]
 name = "parity-multiaddr"
-version = "0.11.1"
+version = "0.11.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d2c6805f98667a3828afb2ec2c396a8d610497e8d546f5447188aae47c5a79ec"
+checksum = "58341485071825827b7f03cf7efd1cb21e6a709bea778fb50227fd45d2f361b4"
 dependencies = [
  "arrayref",
  "bs58",
@@ -5547,27 +5657,39 @@ dependencies = [
  "serde",
  "static_assertions",
  "unsigned-varint 0.7.0",
- "url 2.2.0",
+ "url 2.2.1",
 ]
 
 [[package]]
 name = "parity-scale-codec"
-version = "2.0.0"
+version = "1.3.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "75c823fdae1bb5ff5708ee61a62697e6296175dc671710876871c853f48592b3"
+checksum = "a4b26b16c7687c3075982af47719e481815df30bc544f7a6690763a25ca16e9d"
 dependencies = [
  "arrayvec 0.5.2",
- "bitvec",
- "byte-slice-cast",
+ "bitvec 0.17.4",
+ "byte-slice-cast 0.3.5",
+ "serde",
+]
+
+[[package]]
+name = "parity-scale-codec"
+version = "2.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0cd3dab59b5cf4bc81069ade0fc470341a1ef3ad5fa73e5a8943bed2ec12b2e8"
+dependencies = [
+ "arrayvec 0.5.2",
+ "bitvec 0.20.2",
+ "byte-slice-cast 1.0.0",
  "parity-scale-codec-derive",
  "serde",
 ]
 
 [[package]]
 name = "parity-scale-codec-derive"
-version = "2.0.0"
+version = "2.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9029e65297c7fd6d7013f0579e193ec2b34ae78eabca854c9417504ad8a2d214"
+checksum = "fa04976a81fde04924b40cc4036c4d12841e8bb04325a5cf2ada75731a150a7d"
 dependencies = [
  "proc-macro-crate 0.1.5",
  "proc-macro2",
@@ -5588,7 +5710,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1e57fea504fea33f9fbb5f49f378359030e7e026a6ab849bb9e8f0787376f1bf"
 dependencies = [
  "bytes 0.4.12",
- "futures 0.1.30",
+ "futures 0.1.31",
  "libc",
  "log",
  "mio-named-pipes",
@@ -5657,7 +5779,7 @@ dependencies = [
  "rand 0.7.3",
  "sha-1 0.8.2",
  "slab",
- "url 2.2.0",
+ "url 2.2.1",
 ]
 
 [[package]]
@@ -5695,7 +5817,7 @@ checksum = "6d7744ac029df22dca6284efe4e898991d28e3085c706c972bcd7da4a27a15eb"
 dependencies = [
  "instant",
  "lock_api 0.4.2",
- "parking_lot_core 0.8.2",
+ "parking_lot_core 0.8.3",
 ]
 
 [[package]]
@@ -5729,14 +5851,14 @@ dependencies = [
 
 [[package]]
 name = "parking_lot_core"
-version = "0.8.2"
+version = "0.8.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9ccb628cad4f84851442432c60ad8e1f607e29752d0bf072cbd0baf28aa34272"
+checksum = "fa7a782938e745763fe6907fc6ba86946d72f49fe7e21de074e08128a99fb018"
 dependencies = [
  "cfg-if 1.0.0",
  "instant",
  "libc",
- "redox_syscall 0.1.57",
+ "redox_syscall 0.2.5",
  "smallvec 1.6.1",
  "winapi 0.3.9",
 ]
@@ -5873,11 +5995,11 @@ dependencies = [
 
 [[package]]
 name = "pin-project"
-version = "1.0.4"
+version = "1.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "95b70b68509f17aa2857863b6fa00bf21fc93674c7a8893de2f469f6aa7ca2f2"
+checksum = "96fa8ebb90271c4477f144354485b8068bd8f6b78b428b01ba892ca26caf0b63"
 dependencies = [
- "pin-project-internal 1.0.4",
+ "pin-project-internal 1.0.5",
 ]
 
 [[package]]
@@ -5893,9 +6015,9 @@ dependencies = [
 
 [[package]]
 name = "pin-project-internal"
-version = "1.0.4"
+version = "1.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "caa25a6393f22ce819b0f50e0be89287292fda8d425be38ee0ca14c4931d9e71"
+checksum = "758669ae3558c6f74bd2a18b41f7ac0b5a195aea6639d6a9b5e5d1ad5ba24c0b"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -5910,9 +6032,9 @@ checksum = "257b64915a082f7811703966789728173279bdebb956b143dbcd23f6f970a777"
 
 [[package]]
 name = "pin-project-lite"
-version = "0.2.5"
+version = "0.2.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0cf491442e4b033ed1c722cb9f0df5fcfcf4de682466c46469c36bc47dc5548a"
+checksum = "dc0e1f259c92177c30a4c9d177246edd0a3568b25756a977d0632cf8fa37e905"
 
 [[package]]
 name = "pin-utils"
@@ -6228,7 +6350,7 @@ version = "1.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "588f6378e4dd99458b60ec275b4477add41ce4fa9f64dcba6f15adccb19b50d6"
 dependencies = [
- "env_logger 0.8.2",
+ "env_logger 0.8.3",
  "log",
  "rand 0.8.3",
 ]
@@ -6246,13 +6368,19 @@ dependencies = [
 
 [[package]]
 name = "quote"
-version = "1.0.8"
+version = "1.0.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "991431c3519a3f36861882da93630ce66b52918dcf1b8e2fd66b397fc96f28df"
+checksum = "c3d0b9745dc2debf507c8422de05d7226cc1f0644216dfdfead988f9b1ab32a7"
 dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "radium"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "def50a86306165861203e7f84ecffbbdfdea79f0e51039b33de1e952358c47ac"
+
 [[package]]
 name = "radium"
 version = "0.6.2"
@@ -6423,7 +6551,7 @@ checksum = "9ab346ac5921dc62ffa9f89b7a773907511cdfa5490c572ae9be1be33e8afa4a"
 dependencies = [
  "crossbeam-channel",
  "crossbeam-deque 0.8.0",
- "crossbeam-utils 0.8.1",
+ "crossbeam-utils 0.8.3",
  "lazy_static",
  "num_cpus",
 ]
@@ -6445,9 +6573,9 @@ checksum = "41cc0f7e4d5d4544e8861606a285bb08d3e70712ccc7d2b84d7c0ccfaf4b05ce"
 
 [[package]]
 name = "redox_syscall"
-version = "0.2.4"
+version = "0.2.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "05ec8ca9416c5ea37062b502703cd7fcb207736bc294f6e0cf367ac6fc234570"
+checksum = "94341e4e44e24f6b591b59e47a8a027df12e008d73fd5672dbea9cc22f4507d9"
 dependencies = [
  "bitflags",
 ]
@@ -6470,7 +6598,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "528532f3d801c87aec9def2add9ca802fe569e44a544afe633765267840abe64"
 dependencies = [
  "getrandom 0.2.2",
- "redox_syscall 0.2.4",
+ "redox_syscall 0.2.5",
 ]
 
 [[package]]
@@ -6549,16 +6677,17 @@ dependencies = [
 name = "remote-externalities"
 version = "0.9.0"
 dependencies = [
- "async-std",
- "env_logger 0.8.2",
+ "env_logger 0.8.3",
  "hex-literal",
  "jsonrpsee-http-client",
  "jsonrpsee-proc-macros",
  "jsonrpsee-types",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sp-core",
  "sp-io",
+ "sp-runtime",
+ "tokio 0.2.25",
 ]
 
 [[package]]
@@ -6570,6 +6699,16 @@ dependencies = [
  "winapi 0.3.9",
 ]
 
+[[package]]
+name = "resolv-conf"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "52e44394d2086d010551b14b53b1f24e31647570cd1deb0379e2c21b329aba00"
+dependencies = [
+ "hostname",
+ "quick-error 1.2.3",
+]
+
 [[package]]
 name = "retain_mut"
 version = "0.1.2"
@@ -6578,9 +6717,9 @@ checksum = "53552c6c49e1e13f1a203ef0080ab3bbef0beb570a528993e83df057a9d9bba1"
 
 [[package]]
 name = "ring"
-version = "0.16.19"
+version = "0.16.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "024a1e66fea74c66c66624ee5622a7ff0e4b73a13b4f5c326ddb50c708944226"
+checksum = "3053cf52e236a3ed746dfc745aa9cacf1b791d846bdaf412f60a8d7d6e17c8fc"
 dependencies = [
  "cc",
  "libc",
@@ -6620,7 +6759,7 @@ dependencies = [
  "base64 0.13.0",
  "blake2b_simd",
  "constant_time_eq",
- "crossbeam-utils 0.8.1",
+ "crossbeam-utils 0.8.3",
 ]
 
 [[package]]
@@ -6700,7 +6839,7 @@ version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4da5fcb054c46f5a5dff833b129285a93d3f0179531735e6c866e8cc307d2020"
 dependencies = [
- "futures 0.3.12",
+ "futures 0.3.13",
  "pin-project 0.4.27",
  "static_assertions",
 ]
@@ -6745,11 +6884,11 @@ dependencies = [
  "async-trait",
  "derive_more",
  "either",
- "futures 0.3.12",
+ "futures 0.3.13",
  "futures-timer 3.0.2",
  "libp2p",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "prost",
  "prost-build",
  "quickcheck",
@@ -6773,10 +6912,10 @@ dependencies = [
 name = "sc-basic-authorship"
 version = "0.9.0"
 dependencies = [
- "futures 0.3.12",
+ "futures 0.3.13",
  "futures-timer 3.0.2",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parking_lot 0.11.1",
  "sc-block-builder",
  "sc-client-api",
@@ -6798,7 +6937,7 @@ dependencies = [
 name = "sc-block-builder"
 version = "0.9.0"
 dependencies = [
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sc-client-api",
  "sp-api",
  "sp-block-builder",
@@ -6816,7 +6955,7 @@ name = "sc-chain-spec"
 version = "3.0.0"
 dependencies = [
  "impl-trait-for-tuples",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sc-chain-spec-derive",
  "sc-consensus-babe",
  "sc-consensus-epochs",
@@ -6847,12 +6986,12 @@ version = "0.9.0"
 dependencies = [
  "chrono",
  "fdlimit",
- "futures 0.3.12",
+ "futures 0.3.13",
  "hex",
  "libp2p",
  "log",
  "names",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "rand 0.7.3",
  "regex",
  "rpassword",
@@ -6885,13 +7024,13 @@ version = "3.0.0"
 dependencies = [
  "derive_more",
  "fnv",
- "futures 0.3.12",
+ "futures 0.3.13",
  "hash-db",
  "kvdb",
  "kvdb-memorydb",
  "lazy_static",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parking_lot 0.11.1",
  "sc-executor",
  "sp-api",
@@ -6928,7 +7067,7 @@ dependencies = [
  "linked-hash-map",
  "log",
  "parity-db",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parity-util-mem",
  "parking_lot 0.11.1",
  "quickcheck",
@@ -6954,6 +7093,7 @@ dependencies = [
 name = "sc-consensus"
 version = "0.9.0"
 dependencies = [
+ "parking_lot 0.11.1",
  "sc-client-api",
  "sp-blockchain",
  "sp-consensus",
@@ -6964,12 +7104,13 @@ dependencies = [
 name = "sc-consensus-aura"
 version = "0.9.0"
 dependencies = [
+ "async-trait",
  "derive_more",
- "futures 0.3.12",
+ "futures 0.3.13",
  "futures-timer 3.0.2",
  "getrandom 0.2.2",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parking_lot 0.11.1",
  "sc-block-builder",
  "sc-client-api",
@@ -7005,16 +7146,17 @@ dependencies = [
 name = "sc-consensus-babe"
 version = "0.9.0"
 dependencies = [
+ "async-trait",
  "derive_more",
  "fork-tree",
- "futures 0.3.12",
+ "futures 0.3.13",
  "futures-timer 3.0.2",
  "log",
  "merlin",
  "num-bigint",
  "num-rational",
  "num-traits",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parking_lot 0.11.1",
  "pdqselect",
  "rand 0.7.3",
@@ -7061,7 +7203,7 @@ name = "sc-consensus-babe-rpc"
 version = "0.9.0"
 dependencies = [
  "derive_more",
- "futures 0.3.12",
+ "futures 0.3.13",
  "jsonrpc-core",
  "jsonrpc-core-client",
  "jsonrpc-derive",
@@ -7090,9 +7232,9 @@ name = "sc-consensus-epochs"
 version = "0.9.0"
 dependencies = [
  "fork-tree",
- "parity-scale-codec",
- "parking_lot 0.11.1",
+ "parity-scale-codec 2.0.1",
  "sc-client-api",
+ "sc-consensus",
  "sp-blockchain",
  "sp-runtime",
 ]
@@ -7102,13 +7244,14 @@ name = "sc-consensus-manual-seal"
 version = "0.9.0"
 dependencies = [
  "assert_matches",
+ "async-trait",
  "derive_more",
- "futures 0.3.12",
+ "futures 0.3.13",
  "jsonrpc-core",
  "jsonrpc-core-client",
  "jsonrpc-derive",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parking_lot 0.11.1",
  "sc-basic-authorship",
  "sc-client-api",
@@ -7139,11 +7282,12 @@ dependencies = [
 name = "sc-consensus-pow"
 version = "0.9.0"
 dependencies = [
+ "async-trait",
  "derive_more",
- "futures 0.3.12",
+ "futures 0.3.13",
  "futures-timer 3.0.2",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parking_lot 0.11.1",
  "sc-client-api",
  "sp-api",
@@ -7162,11 +7306,11 @@ dependencies = [
 name = "sc-consensus-slots"
 version = "0.9.0"
 dependencies = [
- "futures 0.3.12",
+ "async-trait",
+ "futures 0.3.13",
  "futures-timer 3.0.2",
  "log",
- "parity-scale-codec",
- "parking_lot 0.11.1",
+ "parity-scale-codec 2.0.1",
  "sc-client-api",
  "sc-telemetry",
  "sp-api",
@@ -7179,6 +7323,7 @@ dependencies = [
  "sp-inherents",
  "sp-runtime",
  "sp-state-machine",
+ "sp-timestamp",
  "sp-trie",
  "substrate-test-runtime-client",
  "thiserror",
@@ -7207,7 +7352,7 @@ dependencies = [
  "lazy_static",
  "libsecp256k1",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parity-wasm 0.41.0",
  "parking_lot 0.11.1",
  "paste 1.0.4",
@@ -7242,7 +7387,7 @@ name = "sc-executor-common"
 version = "0.9.0"
 dependencies = [
  "derive_more",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parity-wasm 0.41.0",
  "sp-allocator",
  "sp-core",
@@ -7257,7 +7402,7 @@ name = "sc-executor-wasmi"
 version = "0.9.0"
 dependencies = [
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sc-executor-common",
  "sp-allocator",
  "sp-core",
@@ -7272,7 +7417,7 @@ version = "0.9.0"
 dependencies = [
  "assert_matches",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parity-wasm 0.41.0",
  "pwasm-utils 0.14.0",
  "sc-executor-common",
@@ -7289,17 +7434,18 @@ name = "sc-finality-grandpa"
 version = "0.9.0"
 dependencies = [
  "assert_matches",
+ "async-trait",
  "derive_more",
  "dyn-clone",
  "finality-grandpa",
  "fork-tree",
- "futures 0.3.12",
+ "futures 0.3.13",
  "futures-timer 3.0.2",
  "linked-hash-map",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parking_lot 0.11.1",
- "pin-project 1.0.4",
+ "pin-project 1.0.5",
  "rand 0.7.3",
  "sc-block-builder",
  "sc-client-api",
@@ -7337,14 +7483,14 @@ version = "0.9.0"
 dependencies = [
  "derive_more",
  "finality-grandpa",
- "futures 0.3.12",
+ "futures 0.3.13",
  "jsonrpc-core",
  "jsonrpc-core-client",
  "jsonrpc-derive",
  "jsonrpc-pubsub",
  "lazy_static",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sc-block-builder",
  "sc-client-api",
  "sc-finality-grandpa",
@@ -7367,10 +7513,10 @@ version = "0.9.0"
 dependencies = [
  "derive_more",
  "finality-grandpa",
- "futures 0.3.12",
+ "futures 0.3.13",
  "log",
  "num-traits",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parking_lot 0.11.1",
  "prost",
  "rand 0.8.3",
@@ -7392,7 +7538,7 @@ name = "sc-informant"
 version = "0.9.0"
 dependencies = [
  "ansi_term 0.12.1",
- "futures 0.3.12",
+ "futures 0.3.13",
  "log",
  "parity-util-mem",
  "sc-client-api",
@@ -7410,7 +7556,7 @@ version = "3.0.0"
 dependencies = [
  "async-trait",
  "derive_more",
- "futures 0.3.12",
+ "futures 0.3.13",
  "futures-util",
  "hex",
  "merlin",
@@ -7430,7 +7576,7 @@ version = "3.0.0"
 dependencies = [
  "hash-db",
  "lazy_static",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parking_lot 0.11.1",
  "sc-client-api",
  "sc-executor",
@@ -7459,7 +7605,7 @@ dependencies = [
  "erased-serde",
  "fnv",
  "fork-tree",
- "futures 0.3.12",
+ "futures 0.3.13",
  "futures-timer 3.0.2",
  "hex",
  "ip_network",
@@ -7469,9 +7615,9 @@ dependencies = [
  "log",
  "lru",
  "nohash-hasher",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parking_lot 0.11.1",
- "pin-project 1.0.4",
+ "pin-project 1.0.5",
  "prost",
  "prost-build",
  "quickcheck",
@@ -7507,7 +7653,7 @@ name = "sc-network-gossip"
 version = "0.9.0"
 dependencies = [
  "async-std",
- "futures 0.3.12",
+ "futures 0.3.13",
  "futures-timer 3.0.2",
  "libp2p",
  "log",
@@ -7518,6 +7664,7 @@ dependencies = [
  "sp-runtime",
  "substrate-prometheus-endpoint",
  "substrate-test-runtime-client",
+ "tracing",
  "wasm-timer",
 ]
 
@@ -7526,7 +7673,8 @@ name = "sc-network-test"
 version = "0.8.0"
 dependencies = [
  "async-std",
- "futures 0.3.12",
+ "async-trait",
+ "futures 0.3.13",
  "futures-timer 3.0.2",
  "libp2p",
  "log",
@@ -7554,15 +7702,15 @@ version = "3.0.0"
 dependencies = [
  "bytes 0.5.6",
  "fnv",
- "futures 0.3.12",
+ "futures 0.3.13",
  "futures-timer 3.0.2",
  "hex",
- "hyper 0.13.9",
+ "hyper 0.13.10",
  "hyper-rustls",
  "lazy_static",
  "log",
  "num_cpus",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parking_lot 0.11.1",
  "rand 0.7.3",
  "sc-block-builder",
@@ -7588,7 +7736,7 @@ dependencies = [
 name = "sc-peerset"
 version = "3.0.0"
 dependencies = [
- "futures 0.3.12",
+ "futures 0.3.13",
  "libp2p",
  "log",
  "rand 0.7.3",
@@ -7610,14 +7758,14 @@ name = "sc-rpc"
 version = "3.0.0"
 dependencies = [
  "assert_matches",
- "futures 0.1.30",
- "futures 0.3.12",
+ "futures 0.1.31",
+ "futures 0.3.13",
  "hash-db",
  "jsonrpc-core",
  "jsonrpc-pubsub",
  "lazy_static",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parking_lot 0.11.1",
  "sc-block-builder",
  "sc-cli",
@@ -7652,13 +7800,13 @@ name = "sc-rpc-api"
 version = "0.9.0"
 dependencies = [
  "derive_more",
- "futures 0.3.12",
+ "futures 0.3.13",
  "jsonrpc-core",
  "jsonrpc-core-client",
  "jsonrpc-derive",
  "jsonrpc-pubsub",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parking_lot 0.11.1",
  "serde",
  "serde_json",
@@ -7674,7 +7822,7 @@ dependencies = [
 name = "sc-rpc-server"
 version = "3.0.0"
 dependencies = [
- "futures 0.1.30",
+ "futures 0.1.31",
  "jsonrpc-core",
  "jsonrpc-http-server",
  "jsonrpc-ipc-server",
@@ -7706,20 +7854,21 @@ name = "sc-service"
 version = "0.9.0"
 dependencies = [
  "async-std",
+ "async-trait",
  "directories",
  "exit-future",
- "futures 0.1.30",
- "futures 0.3.12",
+ "futures 0.1.31",
+ "futures 0.3.13",
  "futures-timer 3.0.2",
  "hash-db",
  "jsonrpc-core",
  "jsonrpc-pubsub",
  "lazy_static",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parity-util-mem",
  "parking_lot 0.11.1",
- "pin-project 1.0.4",
+ "pin-project 1.0.5",
  "rand 0.7.3",
  "sc-block-builder",
  "sc-chain-spec",
@@ -7775,11 +7924,11 @@ name = "sc-service-test"
 version = "2.0.0"
 dependencies = [
  "fdlimit",
- "futures 0.1.30",
- "futures 0.3.12",
+ "futures 0.1.31",
+ "futures 0.3.13",
  "hex-literal",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parking_lot 0.11.1",
  "sc-block-builder",
  "sc-client-api",
@@ -7811,7 +7960,7 @@ name = "sc-state-db"
 version = "0.9.0"
 dependencies = [
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parity-util-mem",
  "parity-util-mem-derive",
  "parking_lot 0.11.1",
@@ -7844,11 +7993,11 @@ name = "sc-telemetry"
 version = "3.0.0"
 dependencies = [
  "chrono",
- "futures 0.3.12",
+ "futures 0.3.13",
  "libp2p",
  "log",
  "parking_lot 0.11.1",
- "pin-project 1.0.4",
+ "pin-project 1.0.5",
  "rand 0.7.3",
  "serde",
  "serde_json",
@@ -7901,10 +8050,10 @@ dependencies = [
  "assert_matches",
  "criterion",
  "derive_more",
- "futures 0.3.12",
+ "futures 0.3.13",
  "linked-hash-map",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parity-util-mem",
  "parking_lot 0.11.1",
  "retain_mut",
@@ -7924,12 +8073,12 @@ name = "sc-transaction-pool"
 version = "3.0.0"
 dependencies = [
  "assert_matches",
- "futures 0.3.12",
+ "futures 0.3.13",
  "futures-diagnose",
  "hex",
  "intervalier",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parity-util-mem",
  "parking_lot 0.11.1",
  "sc-block-builder",
@@ -8111,9 +8260,9 @@ checksum = "930c0acf610d3fdb5e2ab6213019aaa04e227ebe9547b0649ba599b16d788bd7"
 
 [[package]]
 name = "serde"
-version = "1.0.123"
+version = "1.0.124"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "92d5161132722baa40d802cc70b15262b98258453e85e5d1d365c757c73869ae"
+checksum = "bd761ff957cb2a45fbb9ab3da6512de9de55872866160b23c25f1a841e99d29f"
 dependencies = [
  "serde_derive",
 ]
@@ -8130,9 +8279,9 @@ dependencies = [
 
 [[package]]
 name = "serde_derive"
-version = "1.0.123"
+version = "1.0.124"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9391c295d64fc0abb2c556bad848f33cb8296276b1ad2677d1ae1ace4f258f31"
+checksum = "1800f7693e94e186f5e25a28291ae1570da908aff7d97a095dec1e56ff99069b"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -8141,9 +8290,9 @@ dependencies = [
 
 [[package]]
 name = "serde_json"
-version = "1.0.61"
+version = "1.0.64"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4fceb2595057b6891a4ee808f70054bd2d12f0e97f1cbb78689b59f676df325a"
+checksum = "799e97dc9fdae36a5c8b8f2cae9ce2ee9fdce2058c57a93e6099d919fd982f79"
 dependencies = [
  "itoa",
  "ryu",
@@ -8164,9 +8313,9 @@ dependencies = [
 
 [[package]]
 name = "sha-1"
-version = "0.9.2"
+version = "0.9.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ce3cdf1b5e620a498ee6f2a171885ac7e22f0e12089ec4b3d22b84921792507c"
+checksum = "dfebf75d25bd900fd1e7d11501efab59bc846dbc76196839663e6637bba9f25f"
 dependencies = [
  "block-buffer 0.9.0",
  "cfg-if 1.0.0",
@@ -8229,9 +8378,9 @@ checksum = "7fdf1b9db47230893d76faad238fd6097fd6d6a9245cd7a4d90dbd639536bbd2"
 
 [[package]]
 name = "signal-hook"
-version = "0.1.17"
+version = "0.3.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7e31d442c16f047a671b5a71e2161d6e68814012b7f5379d269ebd915fac2729"
+checksum = "8a7f3f92a1da3d6b1d32245d0cbcbbab0cfc45996d8df619c42bccfa6d2bbb5f"
 dependencies = [
  "libc",
  "signal-hook-registry",
@@ -8314,6 +8463,16 @@ dependencies = [
  "winapi 0.3.9",
 ]
 
+[[package]]
+name = "socket2"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9e3dfc207c526015c632472a77be09cf1b6e46866581aecae5cc38fb4235dea2"
+dependencies = [
+ "libc",
+ "winapi 0.3.9",
+]
+
 [[package]]
 name = "soketto"
 version = "0.4.2"
@@ -8323,11 +8482,11 @@ dependencies = [
  "base64 0.12.3",
  "bytes 0.5.6",
  "flate2",
- "futures 0.3.12",
+ "futures 0.3.13",
  "httparse",
  "log",
  "rand 0.7.3",
- "sha-1 0.9.2",
+ "sha-1 0.9.4",
 ]
 
 [[package]]
@@ -8347,7 +8506,7 @@ version = "3.0.0"
 dependencies = [
  "hash-db",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sp-api-proc-macro",
  "sp-core",
  "sp-runtime",
@@ -8375,7 +8534,7 @@ version = "2.0.1"
 dependencies = [
  "criterion",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "rustversion",
  "sc-block-builder",
  "sp-api",
@@ -8394,7 +8553,7 @@ dependencies = [
 name = "sp-application-crypto"
 version = "3.0.0"
 dependencies = [
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-core",
  "sp-io",
@@ -8420,7 +8579,7 @@ dependencies = [
  "criterion",
  "integer-sqrt",
  "num-traits",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "primitive-types",
  "rand 0.7.3",
  "serde",
@@ -8444,7 +8603,7 @@ dependencies = [
 name = "sp-authority-discovery"
 version = "3.0.0"
 dependencies = [
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sp-api",
  "sp-application-crypto",
  "sp-runtime",
@@ -8455,7 +8614,7 @@ dependencies = [
 name = "sp-authorship"
 version = "3.0.0"
 dependencies = [
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sp-inherents",
  "sp-runtime",
  "sp-std",
@@ -8465,7 +8624,7 @@ dependencies = [
 name = "sp-block-builder"
 version = "3.0.0"
 dependencies = [
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sp-api",
  "sp-inherents",
  "sp-runtime",
@@ -8476,10 +8635,10 @@ dependencies = [
 name = "sp-blockchain"
 version = "3.0.0"
 dependencies = [
- "futures 0.3.12",
+ "futures 0.3.13",
  "log",
  "lru",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parking_lot 0.11.1",
  "sp-api",
  "sp-consensus",
@@ -8501,11 +8660,12 @@ dependencies = [
 name = "sp-consensus"
 version = "0.9.0"
 dependencies = [
- "futures 0.3.12",
+ "async-trait",
+ "futures 0.3.13",
  "futures-timer 3.0.2",
  "libp2p",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parking_lot 0.11.1",
  "serde",
  "sp-api",
@@ -8527,9 +8687,10 @@ dependencies = [
 name = "sp-consensus-aura"
 version = "0.9.0"
 dependencies = [
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sp-api",
  "sp-application-crypto",
+ "sp-consensus",
  "sp-consensus-slots",
  "sp-inherents",
  "sp-runtime",
@@ -8542,7 +8703,7 @@ name = "sp-consensus-babe"
 version = "0.9.0"
 dependencies = [
  "merlin",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-api",
  "sp-application-crypto",
@@ -8561,7 +8722,7 @@ dependencies = [
 name = "sp-consensus-pow"
 version = "0.9.0"
 dependencies = [
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sp-api",
  "sp-core",
  "sp-runtime",
@@ -8572,7 +8733,7 @@ dependencies = [
 name = "sp-consensus-slots"
 version = "0.9.0"
 dependencies = [
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sp-arithmetic",
  "sp-runtime",
 ]
@@ -8581,7 +8742,7 @@ dependencies = [
 name = "sp-consensus-vrf"
 version = "0.9.0"
 dependencies = [
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "schnorrkel",
  "sp-core",
  "sp-runtime",
@@ -8598,7 +8759,7 @@ dependencies = [
  "criterion",
  "dyn-clonable",
  "ed25519-dalek",
- "futures 0.3.12",
+ "futures 0.3.13",
  "hash-db",
  "hash256-std-hasher",
  "hex",
@@ -8609,7 +8770,7 @@ dependencies = [
  "log",
  "merlin",
  "num-traits",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parity-util-mem",
  "parking_lot 0.11.1",
  "pretty_assertions",
@@ -8654,23 +8815,12 @@ dependencies = [
  "syn",
 ]
 
-[[package]]
-name = "sp-election-providers"
-version = "3.0.0"
-dependencies = [
- "parity-scale-codec",
- "sp-arithmetic",
- "sp-npos-elections",
- "sp-runtime",
- "sp-std",
-]
-
 [[package]]
 name = "sp-externalities"
 version = "0.9.0"
 dependencies = [
  "environmental",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sp-std",
  "sp-storage",
 ]
@@ -8681,7 +8831,7 @@ version = "3.0.0"
 dependencies = [
  "finality-grandpa",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-api",
  "sp-application-crypto",
@@ -8695,7 +8845,7 @@ dependencies = [
 name = "sp-inherents"
 version = "3.0.0"
 dependencies = [
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parking_lot 0.11.1",
  "sp-core",
  "sp-std",
@@ -8706,11 +8856,11 @@ dependencies = [
 name = "sp-io"
 version = "3.0.0"
 dependencies = [
- "futures 0.3.12",
+ "futures 0.3.13",
  "hash-db",
  "libsecp256k1",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parking_lot 0.11.1",
  "sp-core",
  "sp-externalities",
@@ -8741,9 +8891,9 @@ version = "0.9.0"
 dependencies = [
  "async-trait",
  "derive_more",
- "futures 0.3.12",
+ "futures 0.3.13",
  "merlin",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parking_lot 0.11.1",
  "rand 0.7.3",
  "rand_chacha 0.2.2",
@@ -8757,7 +8907,7 @@ dependencies = [
 name = "sp-npos-elections"
 version = "3.0.0"
 dependencies = [
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "rand 0.7.3",
  "serde",
  "sp-arithmetic",
@@ -8772,10 +8922,14 @@ dependencies = [
 name = "sp-npos-elections-compact"
 version = "3.0.0"
 dependencies = [
+ "parity-scale-codec 2.0.1",
  "proc-macro-crate 1.0.0",
  "proc-macro2",
  "quote",
+ "sp-arithmetic",
+ "sp-npos-elections",
  "syn",
+ "trybuild",
 ]
 
 [[package]]
@@ -8783,7 +8937,7 @@ name = "sp-npos-elections-fuzzer"
 version = "2.0.0-alpha.5"
 dependencies = [
  "honggfuzz",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "rand 0.7.3",
  "sp-arithmetic",
  "sp-npos-elections",
@@ -8826,7 +8980,7 @@ dependencies = [
  "hash256-std-hasher",
  "impl-trait-for-tuples",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parity-util-mem",
  "paste 1.0.4",
  "rand 0.7.3",
@@ -8848,7 +9002,7 @@ name = "sp-runtime-interface"
 version = "3.0.0"
 dependencies = [
  "impl-trait-for-tuples",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "primitive-types",
  "rustversion",
  "sp-core",
@@ -8919,7 +9073,7 @@ name = "sp-sandbox"
 version = "0.9.0"
 dependencies = [
  "assert_matches",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sp-core",
  "sp-io",
  "sp-std",
@@ -8940,7 +9094,7 @@ dependencies = [
 name = "sp-session"
 version = "3.0.0"
 dependencies = [
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sp-api",
  "sp-core",
  "sp-runtime",
@@ -8952,7 +9106,7 @@ dependencies = [
 name = "sp-staking"
 version = "3.0.0"
 dependencies = [
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sp-runtime",
  "sp-std",
 ]
@@ -8965,7 +9119,7 @@ dependencies = [
  "hex-literal",
  "log",
  "num-traits",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parking_lot 0.11.1",
  "pretty_assertions",
  "rand 0.7.3",
@@ -8990,7 +9144,7 @@ name = "sp-storage"
 version = "3.0.0"
 dependencies = [
  "impl-serde",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "ref-cast",
  "serde",
  "sp-debug-derive",
@@ -9002,7 +9156,7 @@ name = "sp-tasks"
 version = "3.0.0"
 dependencies = [
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sp-core",
  "sp-externalities",
  "sp-io",
@@ -9014,7 +9168,7 @@ dependencies = [
 name = "sp-test-primitives"
 version = "2.0.0"
 dependencies = [
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parity-util-mem",
  "serde",
  "sp-application-crypto",
@@ -9026,7 +9180,7 @@ dependencies = [
 name = "sp-timestamp"
 version = "3.0.0"
 dependencies = [
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sp-api",
  "sp-inherents",
  "sp-runtime",
@@ -9039,7 +9193,7 @@ name = "sp-tracing"
 version = "3.0.0"
 dependencies = [
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sp-std",
  "tracing",
  "tracing-core",
@@ -9051,9 +9205,9 @@ name = "sp-transaction-pool"
 version = "3.0.0"
 dependencies = [
  "derive_more",
- "futures 0.3.12",
+ "futures 0.3.13",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-api",
  "sp-blockchain",
@@ -9069,7 +9223,7 @@ dependencies = [
  "hash-db",
  "hex-literal",
  "memory-db",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sp-core",
  "sp-runtime",
  "sp-std",
@@ -9083,7 +9237,7 @@ dependencies = [
 name = "sp-utils"
 version = "3.0.0"
 dependencies = [
- "futures 0.3.12",
+ "futures 0.3.13",
  "futures-core",
  "futures-timer 3.0.2",
  "lazy_static",
@@ -9095,7 +9249,7 @@ name = "sp-version"
 version = "3.0.0"
 dependencies = [
  "impl-serde",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "serde",
  "sp-runtime",
  "sp-std",
@@ -9106,7 +9260,7 @@ name = "sp-wasm-interface"
 version = "3.0.0"
 dependencies = [
  "impl-trait-for-tuples",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sp-std",
  "wasmi",
 ]
@@ -9235,8 +9389,8 @@ version = "0.9.0"
 dependencies = [
  "chrono",
  "console_error_panic_hook",
- "futures 0.1.30",
- "futures 0.3.12",
+ "futures 0.1.31",
+ "futures 0.3.13",
  "futures-timer 3.0.2",
  "getrandom 0.2.2",
  "js-sys",
@@ -9278,10 +9432,10 @@ version = "3.0.0"
 dependencies = [
  "frame-support",
  "frame-system",
- "futures 0.3.12",
+ "futures 0.3.13",
  "jsonrpc-client-transports",
  "jsonrpc-core",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sc-rpc-api",
  "serde",
  "sp-storage",
@@ -9293,12 +9447,12 @@ name = "substrate-frame-rpc-system"
 version = "3.0.0"
 dependencies = [
  "frame-system-rpc-runtime-api",
- "futures 0.3.12",
+ "futures 0.3.13",
  "jsonrpc-core",
  "jsonrpc-core-client",
  "jsonrpc-derive",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sc-client-api",
  "sc-rpc-api",
  "sc-transaction-pool",
@@ -9320,7 +9474,7 @@ dependencies = [
  "async-std",
  "derive_more",
  "futures-util",
- "hyper 0.13.9",
+ "hyper 0.13.10",
  "log",
  "prometheus",
  "tokio 0.2.25",
@@ -9330,11 +9484,12 @@ dependencies = [
 name = "substrate-test-client"
 version = "2.0.1"
 dependencies = [
- "futures 0.1.30",
- "futures 0.3.12",
+ "async-trait",
+ "futures 0.1.31",
+ "futures 0.3.13",
  "hash-db",
  "hex",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "sc-client-api",
  "sc-client-db",
  "sc-consensus",
@@ -9361,11 +9516,12 @@ dependencies = [
  "frame-support",
  "frame-system",
  "frame-system-rpc-runtime-api",
+ "futures 0.3.13",
  "log",
  "memory-db",
  "pallet-babe",
  "pallet-timestamp",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "parity-util-mem",
  "sc-block-builder",
  "sc-executor",
@@ -9400,8 +9556,8 @@ dependencies = [
 name = "substrate-test-runtime-client"
 version = "2.0.0"
 dependencies = [
- "futures 0.3.12",
- "parity-scale-codec",
+ "futures 0.3.13",
+ "parity-scale-codec 2.0.1",
  "sc-block-builder",
  "sc-client-api",
  "sc-consensus",
@@ -9421,8 +9577,8 @@ name = "substrate-test-runtime-transaction-pool"
 version = "2.0.0"
 dependencies = [
  "derive_more",
- "futures 0.3.12",
- "parity-scale-codec",
+ "futures 0.3.13",
+ "parity-scale-codec 2.0.1",
  "parking_lot 0.11.1",
  "sc-transaction-graph",
  "sp-blockchain",
@@ -9435,7 +9591,7 @@ dependencies = [
 name = "substrate-test-utils"
 version = "3.0.0"
 dependencies = [
- "futures 0.3.12",
+ "futures 0.3.13",
  "sc-service",
  "substrate-test-utils-derive",
  "tokio 0.2.25",
@@ -9488,9 +9644,9 @@ checksum = "1e81da0851ada1f3e9d4312c704aa4f8806f0f9d69faaf8df2f3464b4a9437c2"
 
 [[package]]
 name = "syn"
-version = "1.0.60"
+version = "1.0.62"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c700597eca8a5a762beb35753ef6b94df201c81cca676604f547495a0d7f0081"
+checksum = "123a78a3596b24fee53a6464ce52d8ecbf62241e6294c7e7fe12086cd161f512"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -9517,15 +9673,15 @@ checksum = "f764005d11ee5f36500a149ace24e00e3da98b0158b3e2d53a7495660d3f4d60"
 
 [[package]]
 name = "tap"
-version = "1.0.0"
+version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "36474e732d1affd3a6ed582781b3683df3d0563714c59c39591e8ff707cf078e"
+checksum = "55937e1799185b12863d447f42597ed69d9928686b8d88a1df17376a097d8369"
 
 [[package]]
 name = "target-lexicon"
-version = "0.11.1"
+version = "0.11.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4ee5a98e506fb7231a304c3a1bd7c132a55016cf65001e0282480665870dfcb9"
+checksum = "422045212ea98508ae3d28025bc5aaa2bd4a9cdaecd442a08da2ee620ee9ea95"
 
 [[package]]
 name = "tempfile"
@@ -9536,7 +9692,7 @@ dependencies = [
  "cfg-if 1.0.0",
  "libc",
  "rand 0.8.3",
- "redox_syscall 0.2.4",
+ "redox_syscall 0.2.5",
  "remove_dir_all",
  "winapi 0.3.9",
 ]
@@ -9550,6 +9706,87 @@ dependencies = [
  "winapi-util",
 ]
 
+[[package]]
+name = "test-runner"
+version = "0.9.0"
+dependencies = [
+ "env_logger 0.7.1",
+ "frame-system",
+ "futures 0.1.31",
+ "futures 0.3.13",
+ "jsonrpc-core",
+ "log",
+ "node-cli",
+ "parity-scale-codec 1.3.7",
+ "rand 0.7.3",
+ "sc-basic-authorship",
+ "sc-cli",
+ "sc-client-api",
+ "sc-consensus-babe",
+ "sc-consensus-manual-seal",
+ "sc-executor",
+ "sc-finality-grandpa",
+ "sc-informant",
+ "sc-network",
+ "sc-rpc",
+ "sc-rpc-server",
+ "sc-service",
+ "sc-transaction-graph",
+ "sc-transaction-pool",
+ "sp-api",
+ "sp-block-builder",
+ "sp-blockchain",
+ "sp-consensus",
+ "sp-consensus-babe",
+ "sp-core",
+ "sp-externalities",
+ "sp-inherents",
+ "sp-io",
+ "sp-keyring",
+ "sp-keystore",
+ "sp-offchain",
+ "sp-runtime",
+ "sp-runtime-interface",
+ "sp-session",
+ "sp-state-machine",
+ "sp-transaction-pool",
+ "sp-wasm-interface",
+ "tokio 0.2.25",
+]
+
+[[package]]
+name = "test-runner-example"
+version = "0.1.0"
+dependencies = [
+ "frame-benchmarking",
+ "frame-support",
+ "frame-system",
+ "log",
+ "node-cli",
+ "node-primitives",
+ "node-runtime",
+ "pallet-balances",
+ "pallet-sudo",
+ "pallet-transaction-payment",
+ "rand 0.8.3",
+ "sc-client-api",
+ "sc-consensus",
+ "sc-consensus-babe",
+ "sc-consensus-manual-seal",
+ "sc-executor",
+ "sc-finality-grandpa",
+ "sc-informant",
+ "sc-network",
+ "sc-service",
+ "sp-api",
+ "sp-consensus-babe",
+ "sp-inherents",
+ "sp-keyring",
+ "sp-keystore",
+ "sp-runtime",
+ "test-runner",
+]
+
 [[package]]
 name = "textwrap"
 version = "0.11.0"
@@ -9637,9 +9874,9 @@ dependencies = [
 
 [[package]]
 name = "tinytemplate"
-version = "1.2.0"
+version = "1.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a2ada8616fad06a2d0c455adc530de4ef57605a8120cc65da9653e0e9623ca74"
+checksum = "be4d6b5f19ff7664e8c98d03e2139cb510db9b0a60b55f8e8709b689d939b6bc"
 dependencies = [
  "serde",
  "serde_json",
@@ -9667,7 +9904,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5a09c0b5bb588872ab2f09afa13ee6e9dac11e10a0ec9e8e3ba39a5a5d530af6"
 dependencies = [
  "bytes 0.4.12",
- "futures 0.1.30",
+ "futures 0.1.31",
  "mio",
  "num_cpus",
  "tokio-codec",
@@ -9698,6 +9935,7 @@ dependencies = [
  "libc",
  "memchr",
  "mio",
+ "mio-named-pipes",
  "mio-uds",
  "num_cpus",
  "pin-project-lite 0.1.12",
@@ -9715,7 +9953,7 @@ checksum = "8fb220f46c53859a4b7ec083e41dec9778ff0b1851c0942b211edb89e0ccdc46"
 dependencies = [
  "bytes 0.4.12",
  "either",
- "futures 0.1.30",
+ "futures 0.1.31",
 ]
 
 [[package]]
@@ -9725,7 +9963,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "25b2998660ba0e70d18684de5d06b70b70a3a747469af9dea7618cc59e75976b"
 dependencies = [
  "bytes 0.4.12",
- "futures 0.1.30",
+ "futures 0.1.31",
  "tokio-io",
 ]
 
@@ -9735,7 +9973,7 @@ version = "0.1.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b1de0e32a83f131e002238d7ccde18211c0a5397f60cbfffcb112868c2e0e20e"
 dependencies = [
- "futures 0.1.30",
+ "futures 0.1.31",
  "tokio-executor",
 ]
 
@@ -9746,7 +9984,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fb2d1b8f4548dbf5e1f7818512e9c406860678f29c300cdf0ebac72d1a3a1671"
 dependencies = [
  "crossbeam-utils 0.7.2",
- "futures 0.1.30",
+ "futures 0.1.31",
 ]
 
 [[package]]
@@ -9755,7 +9993,7 @@ version = "0.1.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "297a1206e0ca6302a0eed35b700d292b275256f596e2f3fea7729d5e629b6ff4"
 dependencies = [
- "futures 0.1.30",
+ "futures 0.1.31",
  "tokio-io",
  "tokio-threadpool",
 ]
@@ -9767,7 +10005,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "57fc868aae093479e3131e3d165c93b1c7474109d13c90ec0dda2a1bbfff0674"
 dependencies = [
  "bytes 0.4.12",
- "futures 0.1.30",
+ "futures 0.1.31",
  "log",
 ]
 
@@ -9789,7 +10027,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9d282d483052288b2308ba5ee795f5673b159c9bdf63c385a05609da782a5eae"
 dependencies = [
  "bytes 0.4.12",
- "futures 0.1.30",
+ "futures 0.1.31",
  "mio",
  "mio-named-pipes",
  "tokio 0.1.22",
@@ -9802,7 +10040,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "09bc590ec4ba8ba87652da2068d150dcada2cfa2e07faae270a5e0409aa51351"
 dependencies = [
  "crossbeam-utils 0.7.2",
- "futures 0.1.30",
+ "futures 0.1.31",
  "lazy_static",
  "log",
  "mio",
@@ -9832,7 +10070,7 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "24da22d077e0f15f55162bdbdc661228c1581892f52074fb242678d015b45162"
 dependencies = [
- "futures 0.1.30",
+ "futures 0.1.31",
 ]
 
 [[package]]
@@ -9842,7 +10080,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "edfe50152bc8164fcc456dab7891fa9bf8beaf01c5ee7e1dd43a397c3cf87dee"
 dependencies = [
  "fnv",
- "futures 0.1.30",
+ "futures 0.1.31",
 ]
 
 [[package]]
@@ -9852,7 +10090,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "98df18ed66e3b72e742f185882a9e201892407957e45fbff8da17ae7a7c51f72"
 dependencies = [
  "bytes 0.4.12",
- "futures 0.1.30",
+ "futures 0.1.31",
  "iovec",
  "mio",
  "tokio-io",
@@ -9868,7 +10106,7 @@ dependencies = [
  "crossbeam-deque 0.7.3",
  "crossbeam-queue",
  "crossbeam-utils 0.7.2",
- "futures 0.1.30",
+ "futures 0.1.31",
  "lazy_static",
  "log",
  "num_cpus",
@@ -9883,7 +10121,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "93044f2d313c95ff1cb7809ce9a7a05735b012288a888b62d4434fd58c94f296"
 dependencies = [
  "crossbeam-utils 0.7.2",
- "futures 0.1.30",
+ "futures 0.1.31",
  "slab",
  "tokio-executor",
 ]
@@ -9895,7 +10133,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e2a0b10e610b39c38b031a2fcab08e4b82f16ece36504988dcbd81dbba650d82"
 dependencies = [
  "bytes 0.4.12",
- "futures 0.1.30",
+ "futures 0.1.31",
  "log",
  "mio",
  "tokio-codec",
@@ -9910,7 +10148,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ab57a4ac4111c8c9dbcf70779f6fc8bc35ae4b2454809febac840ad19bd7e4e0"
 dependencies = [
  "bytes 0.4.12",
- "futures 0.1.30",
+ "futures 0.1.31",
  "iovec",
  "libc",
  "log",
@@ -9958,16 +10196,16 @@ checksum = "01ebdc2bb4498ab1ab5f5b73c5803825e60199229ccba0698170e3be0e7f959f"
 dependencies = [
  "cfg-if 1.0.0",
  "log",
- "pin-project-lite 0.2.5",
+ "pin-project-lite 0.2.6",
  "tracing-attributes",
  "tracing-core",
 ]
 
 [[package]]
 name = "tracing-attributes"
-version = "0.1.14"
+version = "0.1.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "41768be5b9f3489491825f56f01f25290aa1d3e7cc97e182d4d34360493ba6fa"
+checksum = "a8a9bd1db7706f2373a190b0d067146caa39350c486f3d455b0e33b431f94c07"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -9985,19 +10223,19 @@ dependencies = [
 
 [[package]]
 name = "tracing-futures"
-version = "0.2.4"
+version = "0.2.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ab7bb6f14721aa00656086e9335d363c5c8747bae02ebe32ea2c7dece5689b4c"
+checksum = "97d095ae15e245a057c8e8451bab9b3ee1e1f68e9ba2b4fbc18d0ac5237835f2"
 dependencies = [
- "pin-project 0.4.27",
+ "pin-project 1.0.5",
  "tracing",
 ]
 
 [[package]]
 name = "tracing-log"
-version = "0.1.1"
+version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5e0f8c7178e13481ff6765bd169b33e8d554c5d2bbede5e32c356194be02b9b9"
+checksum = "a6923477a48e41c1951f1999ef8bb5a3023eb723ceadafe78ffb65dc366761e3"
 dependencies = [
  "lazy_static",
  "log",
@@ -10016,9 +10254,9 @@ dependencies = [
 
 [[package]]
 name = "tracing-subscriber"
-version = "0.2.15"
+version = "0.2.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a1fa8f0c8f4c594e4fc9debc1990deab13238077271ba84dd853d54902ee3401"
+checksum = "8ab8966ac3ca27126141f7999361cc97dd6fb4b71da04c02044fa9045d98bb96"
 dependencies = [
  "ansi_term 0.12.1",
  "chrono",
@@ -10052,7 +10290,7 @@ dependencies = [
  "hash-db",
  "keccak-hasher",
  "memory-db",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "trie-db",
  "trie-root",
  "trie-standardmap",
@@ -10090,6 +10328,49 @@ dependencies = [
  "keccak-hasher",
 ]
 
+[[package]]
+name = "trust-dns-proto"
+version = "0.20.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8d57e219ba600dd96c2f6d82eb79645068e14edbc5c7e27514af40436b88150c"
+dependencies = [
+ "async-trait",
+ "cfg-if 1.0.0",
+ "data-encoding",
+ "enum-as-inner",
+ "futures-channel",
+ "futures-io",
+ "futures-util",
+ "idna 0.2.2",
+ "ipnet",
+ "lazy_static",
+ "log",
+ "rand 0.8.3",
+ "smallvec 1.6.1",
+ "thiserror",
+ "tinyvec",
+ "url 2.2.1",
+]
+
+[[package]]
+name = "trust-dns-resolver"
+version = "0.20.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b0437eea3a6da51acc1e946545ff53d5b8fb2611ff1c3bed58522dde100536ae"
+dependencies = [
+ "cfg-if 1.0.0",
+ "futures-util",
+ "ipconfig",
+ "lazy_static",
+ "log",
+ "lru-cache",
+ "parking_lot 0.11.1",
+ "resolv-conf",
+ "smallvec 1.6.1",
+ "thiserror",
+ "trust-dns-proto",
+]
+
 [[package]]
 name = "try-lock"
 version = "0.2.3"
@@ -10102,7 +10383,7 @@ version = "0.9.0"
 dependencies = [
  "frame-try-runtime",
  "log",
- "parity-scale-codec",
+ "parity-scale-codec 2.0.1",
  "remote-externalities",
  "sc-cli",
  "sc-client-api",
@@ -10119,9 +10400,9 @@ dependencies = [
 
 [[package]]
 name = "trybuild"
-version = "1.0.39"
+version = "1.0.41"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1c9594b802f041389d2baac680663573dde3103bb4a4926d61d6aba689465978"
+checksum = "99471a206425fba51842a9186315f32d91c56eadc21ea4c21f847b59cf778f8b"
 dependencies = [
  "dissimilar",
  "glob",
@@ -10187,9 +10468,9 @@ dependencies = [
 
 [[package]]
 name = "unicode-normalization"
-version = "0.1.16"
+version = "0.1.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a13e63ab62dbe32aeee58d1c5408d35c36c392bba5d9d3142287219721afe606"
+checksum = "07fbfce1c8a97d547e8b5334978438d9d6ec8c20e38f56d4a4374d181493eaef"
 dependencies = [
  "tinyvec",
 ]
@@ -10271,12 +10552,12 @@ dependencies = [
 
 [[package]]
 name = "url"
-version = "2.2.0"
+version = "2.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5909f2b0817350449ed73e8bcd81c8c3c8d9a7a5d8acba4b27db277f1868976e"
+checksum = "9ccd964113622c8e9322cfac19eb1004a07e636c545f325da085d5cdde6f1f8b"
 dependencies = [
  "form_urlencoded",
- "idna 0.2.0",
+ "idna 0.2.2",
  "matches",
  "percent-encoding 2.1.0",
 ]
@@ -10352,7 +10633,7 @@ version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b6395efa4784b027708f7451087e647ec73cc74f5d9bc2e418404248d679a230"
 dependencies = [
- "futures 0.1.30",
+ "futures 0.1.31",
  "log",
  "try-lock",
 ]
@@ -10381,9 +10662,9 @@ checksum = "1a143597ca7c7793eff794def352d41792a93c481eb1042423ff7ff72ba2c31f"
 
 [[package]]
 name = "wasm-bindgen"
-version = "0.2.70"
+version = "0.2.71"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "55c0f7123de74f0dab9b7d00fd614e7b19349cd1e2f5252bbe9b1754b59433be"
+checksum = "7ee1280240b7c461d6a0071313e08f34a60b0365f14260362e5a2b17d1d31aa7"
 dependencies = [
  "cfg-if 1.0.0",
  "serde",
@@ -10393,9 +10674,9 @@ dependencies = [
 
 [[package]]
 name = "wasm-bindgen-backend"
-version = "0.2.70"
+version = "0.2.71"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7bc45447f0d4573f3d65720f636bbcc3dd6ce920ed704670118650bcd47764c7"
+checksum = "5b7d8b6942b8bb3a9b0e73fc79b98095a27de6fa247615e59d096754a3bc2aa8"
 dependencies = [
  "bumpalo",
  "lazy_static",
@@ -10408,9 +10689,9 @@ dependencies = [
 
 [[package]]
 name = "wasm-bindgen-futures"
-version = "0.4.19"
+version = "0.4.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1fe9756085a84584ee9457a002b7cdfe0bfff169f45d2591d8be1345a6780e35"
+checksum = "3de431a2910c86679c34283a33f66f4e4abd7e0aec27b6669060148872aadf94"
 dependencies = [
  "cfg-if 1.0.0",
  "js-sys",
@@ -10420,9 +10701,9 @@ dependencies = [
 
 [[package]]
 name = "wasm-bindgen-macro"
-version = "0.2.70"
+version = "0.2.71"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3b8853882eef39593ad4174dd26fc9865a64e84026d223f63bb2c42affcbba2c"
+checksum = "e5ac38da8ef716661f0f36c0d8320b89028efe10c7c0afde65baffb496ce0d3b"
 dependencies = [
  "quote",
  "wasm-bindgen-macro-support",
@@ -10430,9 +10711,9 @@ dependencies = [
 
 [[package]]
 name = "wasm-bindgen-macro-support"
-version = "0.2.70"
+version = "0.2.71"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4133b5e7f2a531fa413b3a1695e925038a05a71cf67e87dafa295cb645a01385"
+checksum = "cc053ec74d454df287b9374ee8abb36ffd5acb95ba87da3ba5b7d3fe20eb401e"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -10443,15 +10724,15 @@ dependencies = [
 
 [[package]]
 name = "wasm-bindgen-shared"
-version = "0.2.70"
+version = "0.2.71"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dd4945e4943ae02d15c13962b38a5b1e81eadd4b71214eee75af64a4d6a4fd64"
+checksum = "7d6f8ec44822dd71f5f221a5847fb34acd9060535c1211b70a05844c0f6383b1"
 
 [[package]]
 name = "wasm-bindgen-test"
-version = "0.3.19"
+version = "0.3.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0355fa0c1f9b792a09b6dcb6a8be24d51e71e6d74972f9eb4a44c4c004d24a25"
+checksum = "f0d4da138503a4cf86801b94d95781ee3619faa8feca830569cc6b54997b8b5c"
 dependencies = [
  "console_error_panic_hook",
  "js-sys",
@@ -10463,9 +10744,9 @@ dependencies = [
 
 [[package]]
 name = "wasm-bindgen-test-macro"
-version = "0.3.19"
+version = "0.3.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "27e07b46b98024c2ba2f9e83a10c2ef0515f057f2da299c1762a2017de80438b"
+checksum = "c3199c33f06500c731d5544664c24d0c2b742b98debc6b1c6f0c6d6e8fb7c19b"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -10488,7 +10769,7 @@ version = "0.2.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "be0ecb0db480561e9a7642b5d3e4187c128914e58aa84330b9493e3eb68c5e7f"
 dependencies = [
- "futures 0.3.12",
+ "futures 0.3.13",
  "js-sys",
  "parking_lot 0.11.1",
  "pin-utils",
@@ -10748,9 +11029,9 @@ dependencies = [
 
 [[package]]
 name = "web-sys"
-version = "0.3.46"
+version = "0.3.47"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "222b1ef9334f92a21d3fb53dc3fd80f30836959a90f9274a626d7e06315ba3c3"
+checksum = "c40dc691fc48003eba817c38da7113c15698142da971298003cac3ef175680b3"
 dependencies = [
  "js-sys",
  "wasm-bindgen",
@@ -10803,6 +11084,12 @@ dependencies = [
  "thiserror",
 ]
 
+[[package]]
+name = "widestring"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c168940144dd21fd8046987c16a46a33d5fc84eec29ef9dcddc2ac9e31526b7c"
+
 [[package]]
 name = "winapi"
 version = "0.2.8"
@@ -10846,6 +11133,15 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
 
+[[package]]
+name = "winreg"
+version = "0.6.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b2986deb581c4fe11b621998a5e53361efe6b48a151178d0cd9eeffa4dc6acc9"
+dependencies = [
+ "winapi 0.3.9",
+]
+
 [[package]]
 name = "ws2_32-sys"
 version = "0.2.1"
@@ -10879,7 +11175,7 @@ version = "0.8.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1cc7bd8c983209ed5d527f44b01c41b7dc146fd960c61cf9e1d25399841dc271"
 dependencies = [
- "futures 0.3.12",
+ "futures 0.3.13",
  "log",
  "nohash-hasher",
  "parking_lot 0.11.1",
diff --git a/Cargo.toml b/Cargo.toml
index 4d8cfc3e9754d..3e4787770e053 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,4 +1,6 @@
 [workspace]
+resolver = "2"
+
 members = [
 	"bin/node-template/node",
 	"bin/node-template/pallets/template",
@@ -6,6 +8,7 @@ members = [
 	"bin/node/bench",
 	"bin/node/browser-testing",
 	"bin/node/cli",
+	"bin/node/test-runner-example",
 	"bin/node/executor",
 	"bin/node/primitives",
 	"bin/node/rpc",
@@ -76,6 +79,7 @@ members = [
 	"frame/try-runtime",
 	"frame/elections",
 	"frame/election-provider-multi-phase",
+	"frame/election-provider-support",
 	"frame/example",
 	"frame/example-offchain-worker",
 	"frame/example-parallel",
@@ -104,8 +108,8 @@ members = [
 	"frame/session/benchmarking",
 	"frame/society",
 	"frame/staking",
-	"frame/staking/fuzzer",
 	"frame/staking/reward-curve",
+	"frame/staking/reward-fn",
 	"frame/sudo",
 	"frame/support",
 	"frame/support/procedural",
@@ -145,7 +149,6 @@ members = [
 	"primitives/database",
 	"primitives/debug-derive",
 	"primitives/externalities",
-	"primitives/election-providers",
 	"primitives/finality-grandpa",
 	"primitives/inherents",
 	"primitives/io",
@@ -184,6 +187,7 @@ members = [
 	"test-utils/runtime",
 	"test-utils/runtime/client",
 	"test-utils/runtime/transaction-pool",
+	"test-utils/test-runner",
 	"test-utils/test-crate",
 	"utils/browser",
 	"utils/build-script-utils",
diff --git a/bin/node-template/.editorconfig b/bin/node-template/.editorconfig
new file mode 100644
index 0000000000000..5adac74ca24b3
--- /dev/null
+++ b/bin/node-template/.editorconfig
@@ -0,0 +1,16 @@
+root = true
+
+[*]
+indent_style=space
+indent_size=2
+tab_width=2
+end_of_line=lf
+charset=utf-8
+trim_trailing_whitespace=true
+insert_final_newline = true
+
+[*.{rs,toml}]
+indent_style=tab
+indent_size=tab
+tab_width=4
+max_line_length=100
diff --git a/bin/node-template/README.md b/bin/node-template/README.md
index 8c8b82a14bb86..cd977fac84493 100644
--- a/bin/node-template/README.md
+++ b/bin/node-template/README.md
@@ -1,97 +1,71 @@
 # Substrate Node Template
 
-A new FRAME-based Substrate node, ready for hacking :rocket:
+A fresh FRAME-based [Substrate](https://www.substrate.io/) node, ready for hacking :rocket:
 
-## Local Development
+## Getting Started
 
-Follow these steps to prepare a local Substrate development environment :hammer_and_wrench:
+Follow these steps to get started with the Node Template :hammer_and_wrench:
 
-### Simple Setup
+### Rust Setup
 
-Install all the required dependencies with a single command (be patient, this can take up to 30
-minutes).
+First, complete the [basic Rust setup instructions](./doc/rust-setup.md).
 
-```bash
-curl https://getsubstrate.io -sSf | bash -s -- --fast
-```
+### Run
 
-### Manual Setup
+Use Rust's native `cargo` command to build and launch the template node:
 
-Find manual setup instructions at the
-[Substrate Developer Hub](https://substrate.dev/docs/en/knowledgebase/getting-started/#manual-installation).
+```sh
+cargo run --release -- --dev --tmp
+```
 
 ### Build
 
-Once the development environment is set up, build the node template. This command will build the
-[Wasm](https://substrate.dev/docs/en/knowledgebase/advanced/executor#wasm-execution) and
-[native](https://substrate.dev/docs/en/knowledgebase/advanced/executor#native-execution) code:
+The `cargo run` command will perform an initial build. Use the following command to build the node
+without launching it:
 
-```bash
+```sh
 cargo build --release
 ```
 
-## Run
-
-### Single Node Development Chain
+### Embedded Docs
 
-Purge any existing dev chain state:
+Once the project has been built, the following command can be used to explore all parameters and
+subcommands:
 
-```bash
-./target/release/node-template purge-chain --dev
+```sh
+./target/release/node-template -h
 ```
 
-Start a dev chain:
+## Run
 
-```bash
-./target/release/node-template --dev
-```
+The provided `cargo run` command will launch a temporary node and its state will be discarded after
+you terminate the process. After the project has been built, there are other ways to launch the
+node.
+
+### Single-Node Development Chain
 
-Or, start a dev chain with detailed logging:
+This command will start the single-node development chain with persistent state:
 
 ```bash
-RUST_LOG=debug RUST_BACKTRACE=1 ./target/release/node-template -lruntime=debug --dev
+./target/release/node-template --dev
 ```
 
-### Multi-Node Local Testnet
-
-To see the multi-node consensus algorithm in action, run a local testnet with two validator nodes,
-Alice and Bob, that have been [configured](./node/src/chain_spec.rs) as the initial
-authorities of the `local` testnet chain and endowed with testnet units.
-
-Note: this will require two terminal sessions (one for each node).
-
-Start Alice's node first. The command below uses the default TCP port (30333) and specifies
-`/tmp/alice` as the chain database location. Alice's node ID will be
-`12D3KooWEyoppNCUx8Yx66oV9fJnriXwCcXwDDUA2kj6vnc6iDEp` (legacy representation:
-`QmRpheLN4JWdAnY7HGJfWFNbfkQCb6tFf4vvA6hgjMZKrR`); this is determined by the `node-key`.
+Purge the development chain's state:
 
 ```bash
-cargo run -- \
-  --base-path /tmp/alice \
-  --chain=local \
-  --alice \
-  --node-key 0000000000000000000000000000000000000000000000000000000000000001 \
-  --telemetry-url 'ws://telemetry.polkadot.io:1024 0' \
-  --validator
+./target/release/node-template purge-chain --dev
 ```
 
-In another terminal, use the following command to start Bob's node on a different TCP port (30334)
-and with a chain database location of `/tmp/bob`. The `--bootnodes` option will connect his node to
-Alice's on TCP port 30333:
+Start the development chain with detailed logging:
 
 ```bash
-cargo run -- \
-  --base-path /tmp/bob \
-  --bootnodes /ip4/127.0.0.1/tcp/30333/p2p/12D3KooWEyoppNCUx8Yx66oV9fJnriXwCcXwDDUA2kj6vnc6iDEp \
-  --chain=local \
-  --bob \
-  --port 30334 \
-  --ws-port 9945 \
-  --telemetry-url 'ws://telemetry.polkadot.io:1024 0' \
-  --validator
+RUST_BACKTRACE=1 ./target/release/node-template -ldebug --dev
 ```
 
-Execute `cargo run -- --help` to learn more about the template node's CLI options.
+### Multi-Node Local Testnet
+
+If you want to see the multi-node consensus algorithm in action, refer to
+[our Start a Private Network tutorial](https://substrate.dev/docs/en/tutorials/start-a-private-network/).
 
 ## Template Structure
 
@@ -184,24 +158,28 @@ A FRAME pallet is compromised of a number of blockchain primitives:
 -   Config: The `Config` configuration interface is used to define the types and parameters upon
     which a FRAME pallet depends.
 
-## Generate a Custom Node Template
+### Run in Docker
 
-Generate a Substrate node template based on a particular commit by running the following commands:
+First, install [Docker](https://docs.docker.com/get-docker/) and
+[Docker Compose](https://docs.docker.com/compose/install/).
+
+Then run the following command to start a single node development chain.
 
 ```bash
-# Clone from the main Substrate repo
-git clone https://github.com/paritytech/substrate.git
-cd substrate
+./scripts/docker_run.sh
+```
 
-# Switch to the branch or commit to base the template on
-git checkout <branch/tag/sha1>
+This command will firstly compile your code, and then start a local development network. You can
+also replace the default command (`cargo build --release && ./target/release/node-template --dev --ws-external`)
+by appending your own. A few useful ones are as follow.
 
-# Run the helper script to generate a node template. This script compiles Substrate, so it will take
-# a while to complete. It expects a single parameter: the location for the script's output expressed
-# as a relative path.
-.maintain/node-template-release.sh ../node-template.tar.gz
-```
+```bash
+# Run Substrate node without re-compiling
+./scripts/docker_run.sh ./target/release/node-template --dev --ws-external
+
+# Purge the local dev chain
+./scripts/docker_run.sh ./target/release/node-template purge-chain --dev
 
-Custom node templates are not supported. Please use a recently tagged version of the
-[Substrate Developer Node Template](https://github.com/substrate-developer-hub/substrate-node-template)
-in order to receive support.
+# Check whether the code is compilable
+./scripts/docker_run.sh cargo check
+```
diff --git a/bin/node-template/docker-compose.yml b/bin/node-template/docker-compose.yml
new file mode 100644
index 0000000000000..cfc4437bbae41
--- /dev/null
+++ b/bin/node-template/docker-compose.yml
@@ -0,0 +1,17 @@
+version: "3.2"
+
+services:
+  dev:
+    container_name: node-template
+    image: paritytech/ci-linux:974ba3ac-20201006
+    working_dir: /var/www/node-template
+    ports:
+      - "9944:9944"
+    environment:
+      - CARGO_HOME=/var/www/node-template/.cargo
+    volumes:
+      - .:/var/www/node-template
+      - type: bind
+        source: ./.local
+        target: /root/.local
+    command: bash -c "cargo build --release && ./target/release/node-template --dev --ws-external"
diff --git a/bin/node-template/docs/rust-setup.md b/bin/node-template/docs/rust-setup.md
new file mode 100644
index 0000000000000..34f6e43e7f0dd
--- /dev/null
+++ b/bin/node-template/docs/rust-setup.md
@@ -0,0 +1,81 @@
+---
+title: Installation
+---
+
+This page will guide you through the steps needed to prepare a computer for development with the
+Substrate Node Template. Since Substrate is built with
+[the Rust programming language](https://www.rust-lang.org/), the first thing you will need to do is
+prepare the computer for Rust development - these steps will vary based on the computer's operating
+system. Once Rust is configured, you will use its toolchains to interact with Rust projects; the
+commands for Rust's toolchains will be the same for all supported, Unix-based operating systems.
+
+## Unix-Based Operating Systems
+
+Substrate development is easiest on Unix-based operating systems like macOS or Linux. The examples
+in the Substrate [Tutorials](https://substrate.dev/tutorials) and [Recipes](https://substrate.dev/recipes/)
+use Unix-style terminals to demonstrate how to interact with Substrate from the command line.
+
+### macOS
+
+Open the Terminal application and execute the following commands:
+
+```bash
+# Install Homebrew if necessary https://brew.sh/
+/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install.sh)"
+
+# Make sure Homebrew is up-to-date, install openssl and cmake
+brew update
+brew install openssl cmake
+```
+
+### Ubuntu/Debian
+
+Use a terminal shell to execute the following commands:
+
+```bash
+sudo apt update
+# May prompt for location information
+sudo apt install -y cmake pkg-config libssl-dev git build-essential clang libclang-dev curl
+```
+
+### Arch Linux
+
+Run these commands from a terminal:
+
+```bash
+pacman -Syu --needed --noconfirm cmake gcc openssl-1.0 pkgconf git clang
+export OPENSSL_LIB_DIR="/usr/lib/openssl-1.0"
+export OPENSSL_INCLUDE_DIR="/usr/include/openssl-1.0"
+```
+
+### Fedora/RHEL/CentOS
+
+Use a terminal to run the following commands:
+
+```bash
+# Update
+sudo dnf update
+# Install packages
+sudo dnf install cmake pkgconfig rocksdb rocksdb-devel llvm git libcurl libcurl-devel curl-devel clang
+```
+
+## Rust Developer Environment
+
+This project uses [`rustup`](https://rustup.rs/) to help manage the Rust toolchain. First install
+and configure `rustup`:
+
+```bash
+# Install
+curl https://sh.rustup.rs -sSf | sh
+# Configure
+source ~/.cargo/env
+```
+
+Finally, configure the Rust toolchain:
+
+```bash
+rustup default stable
+rustup update nightly
+rustup update stable
+rustup target add wasm32-unknown-unknown --toolchain nightly
+```
diff --git a/bin/node-template/node/Cargo.toml b/bin/node-template/node/Cargo.toml
index 2d36d3c469083..e53320c940510 100644
--- a/bin/node-template/node/Cargo.toml
+++ b/bin/node-template/node/Cargo.toml
@@ -1,13 +1,13 @@
 [package]
 name = "node-template"
-version = "2.0.0"
-authors = ["Anonymous"]
-description = "A new FRAME-based Substrate node, ready for hacking."
+version = "3.0.0"
+authors = ["Substrate DevHub <https://github.com/substrate-developer-hub>"]
+description = "A fresh FRAME-based Substrate node, ready for hacking."
 edition = "2018"
 license = "Unlicense"
 build = "build.rs"
 homepage = "https://substrate.dev"
-repository = "https://github.com/paritytech/substrate/"
+repository = "https://github.com/substrate-developer-hub/substrate-node-template/"
 
 [package.metadata.docs.rs]
 targets = ["x86_64-unknown-linux-gnu"]
@@ -51,7 +51,7 @@ pallet-transaction-payment-rpc = { version = "3.0.0", path = "../../../frame/tra
 frame-benchmarking = { version = "3.1.0", path = "../../../frame/benchmarking" }
 frame-benchmarking-cli = { version = "3.0.0", path = "../../../utils/frame/benchmarking-cli" }
 
-node-template-runtime = { version = "2.0.0", path = "../runtime" }
+node-template-runtime = { version = "3.0.0", path = "../runtime" }
 
 [build-dependencies]
 substrate-build-script-utils = { version = "3.0.0", path = "../../../utils/build-script-utils" }
diff --git a/bin/node-template/pallets/template/Cargo.toml b/bin/node-template/pallets/template/Cargo.toml
index 9f0c6ee182670..df76d20a4a7e1 100644
--- a/bin/node-template/pallets/template/Cargo.toml
+++ b/bin/node-template/pallets/template/Cargo.toml
@@ -1,11 +1,11 @@
 [package]
-authors = ['Anonymous']
+authors = ['Substrate DevHub <https://github.com/substrate-developer-hub>']
 edition = '2018'
 name = 'pallet-template'
-version = "2.0.0"
+version = "3.0.0"
 license = "Unlicense"
 homepage = "https://substrate.dev"
-repository = "https://github.com/paritytech/substrate/"
+repository = "https://github.com/substrate-developer-hub/substrate-node-template/"
 description = "FRAME pallet template for defining custom runtime logic."
 readme = "README.md"
 
@@ -14,40 +14,15 @@ targets = ["x86_64-unknown-linux-gnu"]
 
 [dependencies]
 codec = { package = "parity-scale-codec", version = "2.0.0", default-features = false, features = ["derive"] }
-
-[dependencies.frame-support]
-default-features = false
-version = "3.0.0"
-path = "../../../../frame/support"
-
-[dependencies.frame-system]
-default-features = false
-version = "3.0.0"
-path = "../../../../frame/system"
-
-[dependencies.frame-benchmarking]
-default-features = false
-version = "3.1.0"
-path = "../../../../frame/benchmarking"
-optional = true
+frame-support = { default-features = false, version = "3.0.0", path = "../../../../frame/support" }
+frame-system = { default-features = false,  version = "3.0.0",  path = "../../../../frame/system" }
+frame-benchmarking = { default-features = false,  version = "3.1.0",  path = "../../../../frame/benchmarking", optional = true }
 
 [dev-dependencies]
-serde = { version = "1.0.101" }
-
-[dev-dependencies.sp-core]
-default-features = false
-version = "3.0.0"
-path = "../../../../primitives/core"
-
-[dev-dependencies.sp-io]
-default-features = false
-version = "3.0.0"
-path = "../../../../primitives/io"
-
-[dev-dependencies.sp-runtime]
-default-features = false
-version = "3.0.0"
-path = "../../../../primitives/runtime"
+serde = { version = "1.0.119" }
+sp-core = { default-features = false, version = "3.0.0", path = "../../../../primitives/core" }
+sp-io = { default-features = false, version = "3.0.0", path = "../../../../primitives/io" }
+sp-runtime = { default-features = false, version = "3.0.0", path = "../../../../primitives/runtime" }
 
 [features]
 default = ['std']
@@ -57,5 +32,6 @@ std = [
 	'frame-system/std',
 	'frame-benchmarking/std',
 ]
+
 runtime-benchmarks = ["frame-benchmarking"]
 try-runtime = ["frame-support/try-runtime"]
diff --git a/bin/node-template/pallets/template/src/benchmarking.rs b/bin/node-template/pallets/template/src/benchmarking.rs
index 5296ed7261d98..93d7fa395ad6b 100644
--- a/bin/node-template/pallets/template/src/benchmarking.rs
+++ b/bin/node-template/pallets/template/src/benchmarking.rs
@@ -5,7 +5,7 @@ use super::*;
 use frame_system::RawOrigin;
 use frame_benchmarking::{benchmarks, whitelisted_caller, impl_benchmark_test_suite};
 #[allow(unused)]
-use crate::Module as Template;
+use crate::Pallet as Template;
 
 benchmarks! {
 	do_something {
diff --git a/bin/node-template/pallets/template/src/lib.rs b/bin/node-template/pallets/template/src/lib.rs
index 99a285492c77f..7b986a5186692 100644
--- a/bin/node-template/pallets/template/src/lib.rs
+++ b/bin/node-template/pallets/template/src/lib.rs
@@ -17,7 +17,7 @@ mod benchmarking;
 
 #[frame_support::pallet]
 pub mod pallet {
-	use frame_support::{dispatch::DispatchResultWithPostInfo, pallet_prelude::*};
+	use frame_support::{dispatch::DispatchResult, pallet_prelude::*};
 	use frame_system::pallet_prelude::*;
 
 	/// Configure the pallet by specifying the parameters and types on which it depends.
@@ -70,7 +70,7 @@ pub mod pallet {
 		/// An example dispatchable that takes a singles value as a parameter, writes the value to
 		/// storage and emits an event. This function must be dispatched by a signed extrinsic.
 		#[pallet::weight(10_000 + T::DbWeight::get().writes(1))]
-		pub fn do_something(origin: OriginFor<T>, something: u32) -> DispatchResultWithPostInfo {
+		pub fn do_something(origin: OriginFor<T>, something: u32) -> DispatchResult {
 			// Check that the extrinsic was signed and get the signer.
 			// This function will return an error if the extrinsic is not signed.
 			// https://substrate.dev/docs/en/knowledgebase/runtime/origin
@@ -82,12 +82,12 @@ pub mod pallet {
 			// Emit an event.
 			Self::deposit_event(Event::SomethingStored(something, who));
 			// Return a successful DispatchResultWithPostInfo
-			Ok(().into())
+			Ok(())
 		}
 
 		/// An example dispatchable that may throw a custom error.
 		#[pallet::weight(10_000 + T::DbWeight::get().reads_writes(1,1))]
-		pub fn cause_error(origin: OriginFor<T>) -> DispatchResultWithPostInfo {
+		pub fn cause_error(origin: OriginFor<T>) -> DispatchResult {
 			let _who = ensure_signed(origin)?;
 
 			// Read a value from storage.
@@ -99,7 +99,7 @@ pub mod pallet {
 					let new = old.checked_add(1).ok_or(Error::<T>::StorageOverflow)?;
 					// Update the value in storage with the incremented result.
 					<Something<T>>::put(new);
-					Ok(().into())
+					Ok(())
 				},
 			}
 		}
diff --git a/bin/node-template/pallets/template/src/mock.rs b/bin/node-template/pallets/template/src/mock.rs
index d33670f2e9cb0..1ebe3bee6090c 100644
--- a/bin/node-template/pallets/template/src/mock.rs
+++ b/bin/node-template/pallets/template/src/mock.rs
@@ -7,7 +7,7 @@ use sp_runtime::{
 use frame_system as system;
 
 type UncheckedExtrinsic = frame_system::mocking::MockUncheckedExtrinsic<Test>;
-type Block = frame_system::mocking::MockBlock<Test>; 
+type Block = frame_system::mocking::MockBlock<Test>;
 
 // Configure a mock runtime to test the pallet.
 frame_support::construct_runtime!(
@@ -16,8 +16,8 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		TemplateModule: pallet_template::{Module, Call, Storage, Event<T>},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		TemplateModule: pallet_template::{Pallet, Call, Storage, Event<T>},
 	}
 );
 
diff --git a/bin/node-template/runtime/Cargo.toml b/bin/node-template/runtime/Cargo.toml
index d4e202d688c87..5bba2a4e970b0 100644
--- a/bin/node-template/runtime/Cargo.toml
+++ b/bin/node-template/runtime/Cargo.toml
@@ -1,11 +1,11 @@
 [package]
 name = "node-template-runtime"
-version = "2.0.0"
-authors = ["Anonymous"]
+version = "3.0.0"
+authors = ["Substrate DevHub <https://github.com/substrate-developer-hub>"]
 edition = "2018"
 license = "Unlicense"
 homepage = "https://substrate.dev"
-repository = "https://github.com/paritytech/substrate/"
+repository = "https://github.com/substrate-developer-hub/substrate-node-template/"
 
 [package.metadata.docs.rs]
 targets = ["x86_64-unknown-linux-gnu"]
@@ -45,7 +45,7 @@ frame-benchmarking = { version = "3.1.0", default-features = false, path = "../.
 frame-system-benchmarking = { version = "3.0.0", default-features = false, path = "../../../frame/system/benchmarking", optional = true }
 hex-literal = { version = "0.3.1", optional = true }
 
-template = { version = "2.0.0", default-features = false, path = "../pallets/template", package = "pallet-template" }
+pallet-template = { version = "3.0.0", default-features = false, path = "../pallets/template" }
 
 [build-dependencies]
 substrate-wasm-builder = { version = "4.0.0", path = "../../../utils/wasm-builder" }
@@ -56,14 +56,17 @@ std = [
 	"codec/std",
 	"frame-executive/std",
 	"frame-support/std",
+	"frame-system-rpc-runtime-api/std",
+	"frame-system/std",
 	"pallet-aura/std",
 	"pallet-balances/std",
 	"pallet-grandpa/std",
 	"pallet-randomness-collective-flip/std",
 	"pallet-sudo/std",
+	"pallet-template/std",
 	"pallet-timestamp/std",
-	"pallet-transaction-payment/std",
 	"pallet-transaction-payment-rpc-runtime-api/std",
+	"pallet-transaction-payment/std",
 	"serde",
 	"sp-api/std",
 	"sp-block-builder/std",
@@ -76,18 +79,15 @@ std = [
 	"sp-std/std",
 	"sp-transaction-pool/std",
 	"sp-version/std",
-	"frame-system/std",
-	"frame-system-rpc-runtime-api/std",
-	"template/std",
 ]
 runtime-benchmarks = [
-	"sp-runtime/runtime-benchmarks",
 	"frame-benchmarking",
 	"frame-support/runtime-benchmarks",
 	"frame-system-benchmarking",
-	"hex-literal",
 	"frame-system/runtime-benchmarks",
+	"hex-literal",
 	"pallet-balances/runtime-benchmarks",
+	"pallet-template/runtime-benchmarks",
 	"pallet-timestamp/runtime-benchmarks",
-	"template/runtime-benchmarks",
+	"sp-runtime/runtime-benchmarks",
 ]
diff --git a/bin/node-template/runtime/src/lib.rs b/bin/node-template/runtime/src/lib.rs
index 0f026db5735cc..1675b3d2a1cdc 100644
--- a/bin/node-template/runtime/src/lib.rs
+++ b/bin/node-template/runtime/src/lib.rs
@@ -40,7 +40,7 @@ pub use frame_support::{
 use pallet_transaction_payment::CurrencyAdapter;
 
 /// Import the template pallet.
-pub use template;
+pub use pallet_template;
 
 /// An index to a block.
 pub type BlockNumber = u32;
@@ -92,17 +92,24 @@ pub mod opaque {
 	}
 }
 
+// To learn more about runtime versioning and what each of the following value means:
+//   https://substrate.dev/docs/en/knowledgebase/runtime/upgrades#runtime-versioning
 pub const VERSION: RuntimeVersion = RuntimeVersion {
 	spec_name: create_runtime_str!("node-template"),
 	impl_name: create_runtime_str!("node-template"),
 	authoring_version: 1,
-	spec_version: 1,
+	// The version of the runtime specification. A full node will not attempt to use its native
+	//   runtime in substitute for the on-chain Wasm runtime unless all of `spec_name`,
+	//   `spec_version`, and `authoring_version` are the same between Wasm and native.
+	// This value is set to 100 to notify Polkadot-JS App (https://polkadot.js.org/apps) to use
+	//   the compatible custom types.
+	spec_version: 100,
 	impl_version: 1,
 	apis: RUNTIME_API_VERSIONS,
 	transaction_version: 1,
 };
 
-/// This determines the average expected block time that we are targetting.
+/// This determines the average expected block time that we are targeting.
 /// Blocks will be produced at a minimum duration defined by `SLOT_DURATION`.
 /// `SLOT_DURATION` is picked up by `pallet_timestamp` which is in turn picked
 /// up by `pallet_aura` to implement `fn slot_duration()`.
@@ -258,8 +265,8 @@ impl pallet_sudo::Config for Runtime {
 	type Call = Call;
 }
 
-/// Configure the pallet template in pallets/template.
-impl template::Config for Runtime {
+/// Configure the pallet-template in pallets/template.
+impl pallet_template::Config for Runtime {
 	type Event = Event;
 }
 
@@ -270,16 +277,16 @@ construct_runtime!(
 		NodeBlock = opaque::Block,
 		UncheckedExtrinsic = UncheckedExtrinsic
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		RandomnessCollectiveFlip: pallet_randomness_collective_flip::{Module, Call, Storage},
-		Timestamp: pallet_timestamp::{Module, Call, Storage, Inherent},
-		Aura: pallet_aura::{Module, Config<T>},
-		Grandpa: pallet_grandpa::{Module, Call, Storage, Config, Event},
-		Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
-		TransactionPayment: pallet_transaction_payment::{Module, Storage},
-		Sudo: pallet_sudo::{Module, Call, Config<T>, Storage, Event<T>},
-		// Include the custom logic from the template pallet in the runtime.
-		TemplateModule: template::{Module, Call, Storage, Event<T>},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		RandomnessCollectiveFlip: pallet_randomness_collective_flip::{Pallet, Call, Storage},
+		Timestamp: pallet_timestamp::{Pallet, Call, Storage, Inherent},
+		Aura: pallet_aura::{Pallet, Config<T>},
+		Grandpa: pallet_grandpa::{Pallet, Call, Storage, Config, Event},
+		Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
+		TransactionPayment: pallet_transaction_payment::{Pallet, Storage},
+		Sudo: pallet_sudo::{Pallet, Call, Config<T>, Storage, Event<T>},
+		// Include the custom logic from the pallet-template in the runtime.
+		TemplateModule: pallet_template::{Pallet, Call, Storage, Event<T>},
 	}
 );
 
@@ -313,7 +320,7 @@ pub type Executive = frame_executive::Executive<
 	Block,
 	frame_system::ChainContext<Runtime>,
 	Runtime,
-	AllModules,
+	AllPallets,
 >;
 
 impl_runtime_apis! {
@@ -378,8 +385,8 @@ impl_runtime_apis! {
 	}
 
 	impl sp_consensus_aura::AuraApi<Block, AuraId> for Runtime {
-		fn slot_duration() -> u64 {
-			Aura::slot_duration()
+		fn slot_duration() -> sp_consensus_aura::SlotDuration {
+			sp_consensus_aura::SlotDuration::from_millis(Aura::slot_duration())
 		}
 
 		fn authorities() -> Vec<AuraId> {
@@ -453,7 +460,7 @@ impl_runtime_apis! {
 		) -> Result<Vec<frame_benchmarking::BenchmarkBatch>, sp_runtime::RuntimeString> {
 			use frame_benchmarking::{Benchmarking, BenchmarkBatch, add_benchmark, TrackedStorageKey};
 
-			use frame_system_benchmarking::Module as SystemBench;
+			use frame_system_benchmarking::Pallet as SystemBench;
 			impl frame_system_benchmarking::Config for Runtime {}
 
 			let whitelist: Vec<TrackedStorageKey> = vec![
@@ -475,7 +482,7 @@ impl_runtime_apis! {
 			add_benchmark!(params, batches, frame_system, SystemBench::<Runtime>);
 			add_benchmark!(params, batches, pallet_balances, Balances);
 			add_benchmark!(params, batches, pallet_timestamp, Timestamp);
-			add_benchmark!(params, batches, template, TemplateModule);
+			add_benchmark!(params, batches, pallet_template, TemplateModule);
 
 			if batches.is_empty() { return Err("Benchmark not found for this pallet.".into()) }
 			Ok(batches)
diff --git a/bin/node-template/scripts/docker_run.sh b/bin/node-template/scripts/docker_run.sh
new file mode 100644
index 0000000000000..0bac44b4cfb3b
--- /dev/null
+++ b/bin/node-template/scripts/docker_run.sh
@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+# This script is meant to be run on Unix/Linux based systems
+set -e
+
+echo "*** Start Substrate node template ***"
+
+cd $(dirname ${BASH_SOURCE[0]})/..
+
+docker-compose down --remove-orphans
+docker-compose run --rm --service-ports dev $@
diff --git a/bin/node-template/scripts/init.sh b/bin/node-template/scripts/init.sh
index 1405a41ef333e..f976f7235d700 100755
--- a/bin/node-template/scripts/init.sh
+++ b/bin/node-template/scripts/init.sh
@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-
+# This script is meant to be run on Unix/Linux based systems
 set -e
 
 echo "*** Initializing WASM build environment"
diff --git a/bin/node/browser-testing/Cargo.toml b/bin/node/browser-testing/Cargo.toml
index fe83cc65ba632..292ee2cab6bf7 100644
--- a/bin/node/browser-testing/Cargo.toml
+++ b/bin/node/browser-testing/Cargo.toml
@@ -8,11 +8,11 @@ license = "Apache-2.0"
 
 [dependencies]
 futures-timer = "3.0.2"
-libp2p = { version = "0.35.1", default-features = false }
+libp2p = { version = "0.36.0", default-features = false }
 jsonrpc-core = "15.0.0"
 serde = "1.0.106"
 serde_json = "1.0.48"
-wasm-bindgen = { version = "=0.2.70", features = ["serde-serialize"] }
+wasm-bindgen = { version = "=0.2.71", features = ["serde-serialize"] }
 wasm-bindgen-futures = "0.4.18"
 wasm-bindgen-test = "0.3.18"
 futures = "0.3.9"
diff --git a/bin/node/cli/Cargo.toml b/bin/node/cli/Cargo.toml
index ebba2095e6be3..9449edfbf6e08 100644
--- a/bin/node/cli/Cargo.toml
+++ b/bin/node/cli/Cargo.toml
@@ -105,7 +105,7 @@ try-runtime-cli = { version = "0.9.0", optional = true, path = "../../../utils/f
 wasm-bindgen = { version = "0.2.57", optional = true }
 wasm-bindgen-futures = { version = "0.4.18", optional = true }
 browser-utils = { package = "substrate-browser-utils", path = "../../../utils/browser", optional = true, version = "0.9.0"}
-libp2p-wasm-ext = { version = "0.27", features = ["websocket"], optional = true }
+libp2p-wasm-ext = { version = "0.28", features = ["websocket"], optional = true }
 
 [target.'cfg(target_arch="x86_64")'.dependencies]
 node-executor = { version = "2.0.0", path = "../executor", features = [ "wasmtime" ] }
@@ -116,7 +116,7 @@ sp-trie = { version = "3.0.0", default-features = false, path = "../../../primit
 [dev-dependencies]
 sc-keystore = { version = "3.0.0", path = "../../../client/keystore" }
 sc-consensus = { version = "0.9.0", path = "../../../client/consensus/common" }
-sc-consensus-babe = { version = "0.9.0", features = ["test-helpers"], path = "../../../client/consensus/babe" }
+sc-consensus-babe = { version = "0.9.0", path = "../../../client/consensus/babe" }
 sc-consensus-epochs = { version = "0.9.0", path = "../../../client/consensus/epochs" }
 sc-service-test = { version = "2.0.0", path = "../../../client/service/test" }
 futures = "0.3.9"
diff --git a/bin/node/cli/src/chain_spec.rs b/bin/node/cli/src/chain_spec.rs
index ae1418981f167..c30710d236acc 100644
--- a/bin/node/cli/src/chain_spec.rs
+++ b/bin/node/cli/src/chain_spec.rs
@@ -295,10 +295,9 @@ pub fn testnet_genesis(
 			phantom: Default::default(),
 		},
 		pallet_contracts: ContractsConfig {
-			current_schedule: pallet_contracts::Schedule {
-				enable_println, // this should only be enabled on development chains
-				..Default::default()
-			},
+			// println should only be enabled on development chains
+			current_schedule: pallet_contracts::Schedule::default()
+				.enable_println(enable_println),
 		},
 		pallet_sudo: SudoConfig {
 			key: root_key,
diff --git a/bin/node/cli/src/service.rs b/bin/node/cli/src/service.rs
index 1351782315be7..ce0ffb2cecc0a 100644
--- a/bin/node/cli/src/service.rs
+++ b/bin/node/cli/src/service.rs
@@ -534,7 +534,7 @@ pub fn new_light(
 
 #[cfg(test)]
 mod tests {
-	use std::{sync::Arc, borrow::Cow, any::Any, convert::TryInto};
+	use std::{sync::Arc, borrow::Cow, convert::TryInto};
 	use sc_consensus_babe::{CompatibleDigestItem, BabeIntermediate, INTERMEDIATE_KEY};
 	use sc_consensus_epochs::descendent_query;
 	use sp_consensus::{
@@ -638,27 +638,34 @@ mod tests {
 					None,
 				);
 
-				let epoch_descriptor = babe_link.epoch_changes().lock().epoch_descriptor_for_child_of(
-					descendent_query(&*service.client()),
-					&parent_hash,
-					parent_number,
-					slot.into(),
-				).unwrap().unwrap();
-
 				let mut digest = Digest::<H256>::default();
 
 				// even though there's only one authority some slots might be empty,
 				// so we must keep trying the next slots until we can claim one.
-				let babe_pre_digest = loop {
-					inherent_data.replace_data(sp_timestamp::INHERENT_IDENTIFIER, &(slot * SLOT_DURATION));
-					if let Some(babe_pre_digest) = sc_consensus_babe::test_helpers::claim_slot(
+				let (babe_pre_digest, epoch_descriptor) = loop {
+					inherent_data.replace_data(
+						sp_timestamp::INHERENT_IDENTIFIER,
+						&(slot * SLOT_DURATION),
+					);
+
+					let epoch_descriptor = babe_link.epoch_changes().shared_data().epoch_descriptor_for_child_of(
+						descendent_query(&*service.client()),
+						&parent_hash,
+						parent_number,
+						slot.into(),
+					).unwrap().unwrap();
+
+					let epoch = babe_link.epoch_changes().shared_data().epoch_data(
+						&epoch_descriptor,
+						|slot| sc_consensus_babe::Epoch::genesis(&babe_link.config(), slot),
+					).unwrap();
+
+					if let Some(babe_pre_digest) = sc_consensus_babe::authorship::claim_slot(
 						slot.into(),
-						&parent_header,
-						&*service.client(),
-						keystore.clone(),
-						&babe_link,
-					) {
-						break babe_pre_digest;
+						&epoch,
+						&keystore,
+					).map(|(digest, _)| digest) {
+						break (babe_pre_digest, epoch_descriptor)
 					}
 
 					slot += 1;
@@ -696,11 +703,11 @@ mod tests {
 				params.body = Some(new_body);
 				params.intermediates.insert(
 					Cow::from(INTERMEDIATE_KEY),
-					Box::new(BabeIntermediate::<Block> { epoch_descriptor }) as Box<dyn Any>,
+					Box::new(BabeIntermediate::<Block> { epoch_descriptor }) as Box<_>,
 				);
 				params.fork_choice = Some(ForkChoiceStrategy::LongestChain);
 
-				block_import.import_block(params, Default::default())
+				futures::executor::block_on(block_import.import_block(params, Default::default()))
 					.expect("error importing test block");
 			},
 			|service, _| {
diff --git a/bin/node/executor/Cargo.toml b/bin/node/executor/Cargo.toml
index fb7fc9191141c..54a44d59c2591 100644
--- a/bin/node/executor/Cargo.toml
+++ b/bin/node/executor/Cargo.toml
@@ -44,6 +44,7 @@ sp-runtime = { version = "3.0.0", path = "../../../primitives/runtime" }
 sp-externalities = { version = "0.9.0", path = "../../../primitives/externalities" }
 substrate-test-client = { version = "2.0.0", path = "../../../test-utils/client" }
 wat = "1.0"
+futures = "0.3.9"
 
 [features]
 wasmtime = [
diff --git a/bin/node/executor/tests/basic.rs b/bin/node/executor/tests/basic.rs
index 279b6a776031a..fe3ae5f14cc37 100644
--- a/bin/node/executor/tests/basic.rs
+++ b/bin/node/executor/tests/basic.rs
@@ -600,13 +600,13 @@ fn deploying_wasm_contract_should_work() {
 	let transfer_code = wat::parse_str(CODE_TRANSFER).unwrap();
 	let transfer_ch = <Runtime as frame_system::Config>::Hashing::hash(&transfer_code);
 
-	let addr = pallet_contracts::Module::<Runtime>::contract_address(
+	let addr = pallet_contracts::Pallet::<Runtime>::contract_address(
 		&charlie(),
 		&transfer_ch,
 		&[],
 	);
 
-	let subsistence = pallet_contracts::Module::<Runtime>::subsistence_threshold();
+	let subsistence = pallet_contracts::Pallet::<Runtime>::subsistence_threshold();
 
 	let time = 42 * 1000;
 	let b = construct_block(
@@ -656,13 +656,10 @@ fn deploying_wasm_contract_should_work() {
 	).0.unwrap();
 
 	t.execute_with(|| {
-		// Verify that the contract constructor worked well and code of TRANSFER contract is actually deployed.
-		assert_eq!(
-			&pallet_contracts::ContractInfoOf::<Runtime>::get(addr)
-				.and_then(|c| c.get_alive())
-				.unwrap()
-				.code_hash,
-			&transfer_ch
+		// Verify that the contract does exist by querying some of its storage items
+		// It does not matter that the storage item itself does not exist.
+		assert!(
+			&pallet_contracts::Pallet::<Runtime>::get_storage(addr, Default::default()).is_ok()
 		);
 	});
 }
@@ -844,5 +841,5 @@ fn should_import_block_with_test_client() {
 	let block_data = block1.0;
 	let block = node_primitives::Block::decode(&mut &block_data[..]).unwrap();
 
-	client.import(BlockOrigin::Own, block).unwrap();
+	futures::executor::block_on(client.import(BlockOrigin::Own, block)).unwrap();
 }
diff --git a/bin/node/runtime/Cargo.toml b/bin/node/runtime/Cargo.toml
index 43ecca7e74456..f0cad60f2614d 100644
--- a/bin/node/runtime/Cargo.toml
+++ b/bin/node/runtime/Cargo.toml
@@ -36,6 +36,7 @@ sp-keyring = { version = "3.0.0", optional = true, path = "../../../primitives/k
 sp-session = { version = "3.0.0", default-features = false, path = "../../../primitives/session" }
 sp-transaction-pool = { version = "3.0.0", default-features = false, path = "../../../primitives/transaction-pool" }
 sp-version = { version = "3.0.0", default-features = false, path = "../../../primitives/version" }
+sp-npos-elections = { version = "3.0.0", default-features = false, path = "../../../primitives/npos-elections" }
 
 # frame dependencies
 frame-executive = { version = "3.0.0", default-features = false, path = "../../../frame/executive" }
@@ -159,6 +160,7 @@ std = [
 	"pallet-vesting/std",
 	"log/std",
 	"frame-try-runtime/std",
+	"sp-npos-elections/std",
 ]
 runtime-benchmarks = [
 	"frame-benchmarking",
diff --git a/bin/node/runtime/src/impls.rs b/bin/node/runtime/src/impls.rs
index c6a56e5ac0dab..416266119cb09 100644
--- a/bin/node/runtime/src/impls.rs
+++ b/bin/node/runtime/src/impls.rs
@@ -84,7 +84,7 @@ mod multiplier_tests {
 		let t1 = v * (s/m - ss/m);
 		let t2 = v.powi(2) * (s/m - ss/m).powi(2) / 2.0;
 		let next_float = previous_float * (1.0 + t1 + t2);
-		Multiplier::from_fraction(next_float)
+		Multiplier::from_float(next_float)
 	}
 
 	fn run_with_system_weight<F>(w: Weight, assertions: F) where F: Fn() -> () {
diff --git a/bin/node/runtime/src/lib.rs b/bin/node/runtime/src/lib.rs
index bb372f31c73b9..f790cf41a401b 100644
--- a/bin/node/runtime/src/lib.rs
+++ b/bin/node/runtime/src/lib.rs
@@ -114,7 +114,7 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
 	// implementation changes and behavior does not, then leave spec_version as
 	// is and increment impl_version.
 	spec_version: 265,
-	impl_version: 0,
+	impl_version: 1,
 	apis: RUNTIME_API_VERSIONS,
 	transaction_version: 2,
 };
@@ -379,7 +379,7 @@ impl pallet_balances::Config for Runtime {
 	type DustRemoval = ();
 	type Event = Event;
 	type ExistentialDeposit = ExistentialDeposit;
-	type AccountStore = frame_system::Module<Runtime>;
+	type AccountStore = frame_system::Pallet<Runtime>;
 	type WeightInfo = pallet_balances::weights::SubstrateWeight<Runtime>;
 }
 
@@ -468,17 +468,11 @@ parameter_types! {
 	pub const SlashDeferDuration: pallet_staking::EraIndex = 24 * 7; // 1/4 the bonding duration.
 	pub const RewardCurve: &'static PiecewiseLinear<'static> = &REWARD_CURVE;
 	pub const MaxNominatorRewardedPerValidator: u32 = 256;
-	pub const ElectionLookahead: BlockNumber = EPOCH_DURATION_IN_BLOCKS / 4;
-	pub const MaxIterations: u32 = 10;
-	// 0.05%. The higher the value, the more strict solution acceptance becomes.
-	pub MinSolutionScoreBump: Perbill = Perbill::from_rational_approximation(5u32, 10_000);
-	pub OffchainSolutionWeightLimit: Weight = RuntimeBlockWeights::get()
-		.get(DispatchClass::Normal)
-		.max_extrinsic.expect("Normal extrinsics have a weight limit configured; qed")
-		.saturating_sub(BlockExecutionWeight::get());
 }
 
 impl pallet_staking::Config for Runtime {
+	const MAX_NOMINATIONS: u32 =
+		<NposCompactSolution16 as sp_npos_elections::CompactSolution>::LIMIT as u32;
 	type Currency = Balances;
 	type UnixTime = Timestamp;
 	type CurrencyToVote = U128CurrencyToVote;
@@ -496,17 +490,9 @@ impl pallet_staking::Config for Runtime {
 		pallet_collective::EnsureProportionAtLeast<_3, _4, AccountId, CouncilCollective>
 	>;
 	type SessionInterface = Self;
-	type RewardCurve = RewardCurve;
+	type EraPayout = pallet_staking::ConvertCurve<RewardCurve>;
 	type NextNewSession = Session;
 	type MaxNominatorRewardedPerValidator = MaxNominatorRewardedPerValidator;
-	type ElectionLookahead = ElectionLookahead;
-	type Call = Call;
-	type MaxIterations = MaxIterations;
-	type MinSolutionScoreBump = MinSolutionScoreBump;
-	type UnsignedPriority = StakingUnsignedPriority;
-	// The unsigned solution weight targeted by the OCW. We set it to the maximum possible value of
-	// a single extrinsic.
-	type OffchainSolutionWeightLimit = OffchainSolutionWeightLimit;
 	type ElectionProvider = ElectionProviderMultiPhase;
 	type WeightInfo = pallet_staking::weights::SubstrateWeight<Runtime>;
 }
@@ -518,9 +504,9 @@ parameter_types! {
 
 	// fallback: no need to do on-chain phragmen initially.
 	pub const Fallback: pallet_election_provider_multi_phase::FallbackStrategy =
-		pallet_election_provider_multi_phase::FallbackStrategy::Nothing;
+		pallet_election_provider_multi_phase::FallbackStrategy::OnChain;
 
-	pub SolutionImprovementThreshold: Perbill = Perbill::from_rational_approximation(1u32, 10_000);
+	pub SolutionImprovementThreshold: Perbill = Perbill::from_rational(1u32, 10_000);
 
 	// miner configs
 	pub const MultiPhaseUnsignedPriority: TransactionPriority = StakingUnsignedPriority::get() - 1u64;
@@ -531,18 +517,27 @@ parameter_types! {
 		.saturating_sub(BlockExecutionWeight::get());
 }
 
+sp_npos_elections::generate_solution_type!(
+	#[compact]
+	pub struct NposCompactSolution16::<
+		VoterIndex = u32,
+		TargetIndex = u16,
+		Accuracy = sp_runtime::PerU16,
+	>(16)
+);
+
 impl pallet_election_provider_multi_phase::Config for Runtime {
 	type Event = Event;
 	type Currency = Balances;
 	type SignedPhase = SignedPhase;
 	type UnsignedPhase = UnsignedPhase;
-	type SolutionImprovementThreshold = MinSolutionScoreBump;
+	type SolutionImprovementThreshold = SolutionImprovementThreshold;
 	type MinerMaxIterations = MinerMaxIterations;
 	type MinerMaxWeight = MinerMaxWeight;
 	type MinerTxPriority = MultiPhaseUnsignedPriority;
 	type DataProvider = Staking;
 	type OnChainAccuracy = Perbill;
-	type CompactSolution = pallet_staking::CompactAssignments;
+	type CompactSolution = NposCompactSolution16;
 	type Fallback = Fallback;
 	type WeightInfo = pallet_election_provider_multi_phase::weights::SubstrateWeight<Runtime>;
 	type BenchmarkingConfig = ();
@@ -760,14 +755,14 @@ impl pallet_tips::Config for Runtime {
 }
 
 parameter_types! {
-	pub const TombstoneDeposit: Balance = deposit(
+	pub TombstoneDeposit: Balance = deposit(
 		1,
-		sp_std::mem::size_of::<pallet_contracts::ContractInfo<Runtime>>() as u32
+		<pallet_contracts::Pallet<Runtime>>::contract_info_size(),
 	);
-	pub const DepositPerContract: Balance = TombstoneDeposit::get();
+	pub DepositPerContract: Balance = TombstoneDeposit::get();
 	pub const DepositPerStorageByte: Balance = deposit(0, 1);
 	pub const DepositPerStorageItem: Balance = deposit(1, 0);
-	pub RentFraction: Perbill = Perbill::from_rational_approximation(1u32, 30 * DAYS);
+	pub RentFraction: Perbill = Perbill::from_rational(1u32, 30 * DAYS);
 	pub const SurchargeReward: Balance = 150 * MILLICENTS;
 	pub const SignedClaimHandicap: u32 = 2;
 	pub const MaxDepth: u32 = 32;
@@ -969,6 +964,7 @@ parameter_types! {
 	pub const PeriodSpend: Balance = 500 * DOLLARS;
 	pub const MaxLockDuration: BlockNumber = 36 * 30 * DAYS;
 	pub const ChallengePeriod: BlockNumber = 7 * DAYS;
+	pub const MaxCandidateIntake: u32 = 10;
 	pub const SocietyModuleId: ModuleId = ModuleId(*b"py/socie");
 }
 
@@ -986,6 +982,7 @@ impl pallet_society::Config for Runtime {
 	type MaxLockDuration = MaxLockDuration;
 	type FounderSetOrigin = pallet_collective::EnsureProportionMoreThan<_1, _2, AccountId, CouncilCollective>;
 	type SuspensionJudgementOrigin = pallet_society::EnsureFounder<Runtime>;
+	type MaxCandidateIntake = MaxCandidateIntake;
 	type ChallengePeriod = ChallengePeriod;
 }
 
@@ -1005,7 +1002,7 @@ impl pallet_mmr::Config for Runtime {
 	const INDEXING_PREFIX: &'static [u8] = b"mmr";
 	type Hashing = <Runtime as frame_system::Config>::Hashing;
 	type Hash = <Runtime as frame_system::Config>::Hash;
-	type LeafData = frame_system::Module<Self>;
+	type LeafData = frame_system::Pallet<Self>;
 	type OnNewRoot = ();
 	type WeightInfo = ();
 }
@@ -1048,6 +1045,8 @@ impl pallet_assets::Config for Runtime {
 	type MetadataDepositPerByte = MetadataDepositPerByte;
 	type ApprovalDeposit = ApprovalDeposit;
 	type StringLimit = StringLimit;
+	type Freezer = ();
+	type Extra = ();
 	type WeightInfo = pallet_assets::weights::SubstrateWeight<Runtime>;
 }
 
@@ -1065,6 +1064,7 @@ parameter_types! {
 impl pallet_gilt::Config for Runtime {
 	type Event = Event;
 	type Currency = Balances;
+	type CurrencyBalance = Balance;
 	type AdminOrigin = frame_system::EnsureRoot<AccountId>;
 	type Deficit = ();
 	type Surplus = ();
@@ -1085,44 +1085,44 @@ construct_runtime!(
 		NodeBlock = node_primitives::Block,
 		UncheckedExtrinsic = UncheckedExtrinsic
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Utility: pallet_utility::{Module, Call, Event},
-		Babe: pallet_babe::{Module, Call, Storage, Config, ValidateUnsigned},
-		Timestamp: pallet_timestamp::{Module, Call, Storage, Inherent},
-		Authorship: pallet_authorship::{Module, Call, Storage, Inherent},
-		Indices: pallet_indices::{Module, Call, Storage, Config<T>, Event<T>},
-		Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
-		TransactionPayment: pallet_transaction_payment::{Module, Storage},
-		ElectionProviderMultiPhase: pallet_election_provider_multi_phase::{Module, Call, Storage, Event<T>, ValidateUnsigned},
-		Staking: pallet_staking::{Module, Call, Config<T>, Storage, Event<T>, ValidateUnsigned},
-		Session: pallet_session::{Module, Call, Storage, Event, Config<T>},
-		Democracy: pallet_democracy::{Module, Call, Storage, Config, Event<T>},
-		Council: pallet_collective::<Instance1>::{Module, Call, Storage, Origin<T>, Event<T>, Config<T>},
-		TechnicalCommittee: pallet_collective::<Instance2>::{Module, Call, Storage, Origin<T>, Event<T>, Config<T>},
-		Elections: pallet_elections_phragmen::{Module, Call, Storage, Event<T>, Config<T>},
-		TechnicalMembership: pallet_membership::<Instance1>::{Module, Call, Storage, Event<T>, Config<T>},
-		Grandpa: pallet_grandpa::{Module, Call, Storage, Config, Event, ValidateUnsigned},
-		Treasury: pallet_treasury::{Module, Call, Storage, Config, Event<T>},
-		Contracts: pallet_contracts::{Module, Call, Config<T>, Storage, Event<T>},
-		Sudo: pallet_sudo::{Module, Call, Config<T>, Storage, Event<T>},
-		ImOnline: pallet_im_online::{Module, Call, Storage, Event<T>, ValidateUnsigned, Config<T>},
-		AuthorityDiscovery: pallet_authority_discovery::{Module, Call, Config},
-		Offences: pallet_offences::{Module, Call, Storage, Event},
-		Historical: pallet_session_historical::{Module},
-		RandomnessCollectiveFlip: pallet_randomness_collective_flip::{Module, Call, Storage},
-		Identity: pallet_identity::{Module, Call, Storage, Event<T>},
-		Society: pallet_society::{Module, Call, Storage, Event<T>, Config<T>},
-		Recovery: pallet_recovery::{Module, Call, Storage, Event<T>},
-		Vesting: pallet_vesting::{Module, Call, Storage, Event<T>, Config<T>},
-		Scheduler: pallet_scheduler::{Module, Call, Storage, Event<T>},
-		Proxy: pallet_proxy::{Module, Call, Storage, Event<T>},
-		Multisig: pallet_multisig::{Module, Call, Storage, Event<T>},
-		Bounties: pallet_bounties::{Module, Call, Storage, Event<T>},
-		Tips: pallet_tips::{Module, Call, Storage, Event<T>},
-		Assets: pallet_assets::{Module, Call, Storage, Event<T>},
-		Mmr: pallet_mmr::{Module, Storage},
-		Lottery: pallet_lottery::{Module, Call, Storage, Event<T>},
-		Gilt: pallet_gilt::{Module, Call, Storage, Event<T>, Config},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Utility: pallet_utility::{Pallet, Call, Event},
+		Babe: pallet_babe::{Pallet, Call, Storage, Config, ValidateUnsigned},
+		Timestamp: pallet_timestamp::{Pallet, Call, Storage, Inherent},
+		Authorship: pallet_authorship::{Pallet, Call, Storage, Inherent},
+		Indices: pallet_indices::{Pallet, Call, Storage, Config<T>, Event<T>},
+		Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
+		TransactionPayment: pallet_transaction_payment::{Pallet, Storage},
+		ElectionProviderMultiPhase: pallet_election_provider_multi_phase::{Pallet, Call, Storage, Event<T>, ValidateUnsigned},
+		Staking: pallet_staking::{Pallet, Call, Config<T>, Storage, Event<T>},
+		Session: pallet_session::{Pallet, Call, Storage, Event, Config<T>},
+		Democracy: pallet_democracy::{Pallet, Call, Storage, Config, Event<T>},
+		Council: pallet_collective::<Instance1>::{Pallet, Call, Storage, Origin<T>, Event<T>, Config<T>},
+		TechnicalCommittee: pallet_collective::<Instance2>::{Pallet, Call, Storage, Origin<T>, Event<T>, Config<T>},
+		Elections: pallet_elections_phragmen::{Pallet, Call, Storage, Event<T>, Config<T>},
+		TechnicalMembership: pallet_membership::<Instance1>::{Pallet, Call, Storage, Event<T>, Config<T>},
+		Grandpa: pallet_grandpa::{Pallet, Call, Storage, Config, Event, ValidateUnsigned},
+		Treasury: pallet_treasury::{Pallet, Call, Storage, Config, Event<T>},
+		Contracts: pallet_contracts::{Pallet, Call, Config<T>, Storage, Event<T>},
+		Sudo: pallet_sudo::{Pallet, Call, Config<T>, Storage, Event<T>},
+		ImOnline: pallet_im_online::{Pallet, Call, Storage, Event<T>, ValidateUnsigned, Config<T>},
+		AuthorityDiscovery: pallet_authority_discovery::{Pallet, Call, Config},
+		Offences: pallet_offences::{Pallet, Call, Storage, Event},
+		Historical: pallet_session_historical::{Pallet},
+		RandomnessCollectiveFlip: pallet_randomness_collective_flip::{Pallet, Call, Storage},
+		Identity: pallet_identity::{Pallet, Call, Storage, Event<T>},
+		Society: pallet_society::{Pallet, Call, Storage, Event<T>, Config<T>},
+		Recovery: pallet_recovery::{Pallet, Call, Storage, Event<T>},
+		Vesting: pallet_vesting::{Pallet, Call, Storage, Event<T>, Config<T>},
+		Scheduler: pallet_scheduler::{Pallet, Call, Storage, Event<T>},
+		Proxy: pallet_proxy::{Pallet, Call, Storage, Event<T>},
+		Multisig: pallet_multisig::{Pallet, Call, Storage, Event<T>},
+		Bounties: pallet_bounties::{Pallet, Call, Storage, Event<T>},
+		Tips: pallet_tips::{Pallet, Call, Storage, Event<T>},
+		Assets: pallet_assets::{Pallet, Call, Storage, Event<T>},
+		Mmr: pallet_mmr::{Pallet, Storage},
+		Lottery: pallet_lottery::{Pallet, Call, Storage, Event<T>},
+		Gilt: pallet_gilt::{Pallet, Call, Storage, Event<T>, Config},
 	}
 );
 
@@ -1162,7 +1162,7 @@ pub type Executive = frame_executive::Executive<
 	Block,
 	frame_system::ChainContext<Runtime>,
 	Runtime,
-	AllModules,
+	AllPallets,
 	(),
 >;
 
@@ -1434,9 +1434,9 @@ impl_runtime_apis! {
 			// Trying to add benchmarks directly to the Session Pallet caused cyclic dependency
 			// issues. To get around that, we separated the Session benchmarks into its own crate,
 			// which is why we need these two lines below.
-			use pallet_session_benchmarking::Module as SessionBench;
-			use pallet_offences_benchmarking::Module as OffencesBench;
-			use frame_system_benchmarking::Module as SystemBench;
+			use pallet_session_benchmarking::Pallet as SessionBench;
+			use pallet_offences_benchmarking::Pallet as OffencesBench;
+			use frame_system_benchmarking::Pallet as SystemBench;
 
 			impl pallet_session_benchmarking::Config for Runtime {}
 			impl pallet_offences_benchmarking::Config for Runtime {}
diff --git a/bin/node/test-runner-example/Cargo.toml b/bin/node/test-runner-example/Cargo.toml
new file mode 100644
index 0000000000000..f94575e8e621b
--- /dev/null
+++ b/bin/node/test-runner-example/Cargo.toml
@@ -0,0 +1,40 @@
+[package]
+name = "test-runner-example"
+version = "0.1.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+edition = "2018"
+publish = false
+
+[dependencies]
+test-runner = { path = "../../../test-utils/test-runner", version = "0.9.0" }
+
+frame-system = { version = "3.0.0", path = "../../../frame/system" }
+frame-support = { path = "../../../frame/support", version = "3.0.0" }
+frame-benchmarking = { path = "../../../frame/benchmarking", version = "3.0.0" }
+pallet-balances = { path = "../../../frame/balances", version = "3.0.0" }
+pallet-sudo = { path = "../../../frame/sudo", version = "3.0.0" }
+pallet-transaction-payment = { version = "3.0.0", path = "../../../frame/transaction-payment" }
+
+node-runtime = { path = "../runtime", version = "2.0.1" }
+node-primitives = { version = "2.0.0", path = "../primitives" }
+node-cli = { path = "../cli", version = "2.0.0" }
+
+grandpa = { version = "0.9.0", package = "sc-finality-grandpa", path = "../../../client/finality-grandpa" }
+sp-consensus-babe = { version = "0.9.0", path = "../../../primitives/consensus/babe" }
+sc-consensus-babe = { version = "0.9.0", path = "../../../client/consensus/babe" }
+sc-consensus-manual-seal = { version = "0.9.0", path = "../../../client/consensus/manual-seal" }
+sc-service = { version = "0.9.0", default-features = false, path = "../../../client/service" }
+sc-executor = { version = "0.9.0", path = "../../../client/executor" }
+sc-client-api = { version = "3.0.0", path = "../../../client/api" }
+sc-network = { version = "0.9.0", path = "../../../client/network" }
+sc-informant = { version = "0.9.0", path = "../../../client/informant" }
+sc-consensus = { version = "0.9.0", path = "../../../client/consensus/common" }
+
+sp-runtime = { path = "../../../primitives/runtime", version = "3.0.0" }
+sp-keyring = { version = "3.0.0", path = "../../../primitives/keyring" }
+sp-api = { version = "3.0.0",  path = "../../../primitives/api" }
+sp-inherents = { version = "3.0.0", path = "../../../primitives/inherents" }
+sp-keystore = { version = "0.9.0", path = "../../../primitives/keystore" }
+
+rand = "0.8.3"
+log = "0.4.14"
diff --git a/bin/node/test-runner-example/src/lib.rs b/bin/node/test-runner-example/src/lib.rs
new file mode 100644
index 0000000000000..22cfffa7f23a7
--- /dev/null
+++ b/bin/node/test-runner-example/src/lib.rs
@@ -0,0 +1,202 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Basic example of end to end runtime tests.
+
+use test_runner::{Node, ChainInfo, SignatureVerificationOverride};
+use grandpa::GrandpaBlockImport;
+use sc_service::{TFullBackend, TFullClient, Configuration, TaskManager, new_full_parts};
+use std::sync::Arc;
+use sp_inherents::InherentDataProviders;
+use sc_consensus_babe::BabeBlockImport;
+use sp_keystore::SyncCryptoStorePtr;
+use sp_keyring::sr25519::Keyring::Alice;
+use sp_consensus_babe::AuthorityId;
+use sc_consensus_manual_seal::{ConsensusDataProvider, consensus::babe::BabeConsensusDataProvider};
+use sp_runtime::{traits::IdentifyAccount, MultiSigner, generic::Era};
+
+type BlockImport<B, BE, C, SC> = BabeBlockImport<B, C, GrandpaBlockImport<BE, B, C, SC>>;
+
+sc_executor::native_executor_instance!(
+	pub Executor,
+	node_runtime::api::dispatch,
+	node_runtime::native_version,
+	(
+		frame_benchmarking::benchmarking::HostFunctions,
+		SignatureVerificationOverride,
+	)
+);
+
+/// ChainInfo implementation.
+struct NodeTemplateChainInfo;
+
+impl ChainInfo for NodeTemplateChainInfo {
+	type Block = node_primitives::Block;
+	type Executor = Executor;
+	type Runtime = node_runtime::Runtime;
+	type RuntimeApi = node_runtime::RuntimeApi;
+	type SelectChain = sc_consensus::LongestChain<TFullBackend<Self::Block>, Self::Block>;
+	type BlockImport = BlockImport<
+		Self::Block,
+		TFullBackend<Self::Block>,
+		TFullClient<Self::Block, Self::RuntimeApi, Self::Executor>,
+		Self::SelectChain,
+	>;
+	type SignedExtras = node_runtime::SignedExtra;
+
+	fn signed_extras(from: <Self::Runtime as frame_system::Config>::AccountId) -> Self::SignedExtras {
+		(
+			frame_system::CheckSpecVersion::<Self::Runtime>::new(),
+			frame_system::CheckTxVersion::<Self::Runtime>::new(),
+			frame_system::CheckGenesis::<Self::Runtime>::new(),
+			frame_system::CheckMortality::<Self::Runtime>::from(Era::Immortal),
+			frame_system::CheckNonce::<Self::Runtime>::from(frame_system::Pallet::<Self::Runtime>::account_nonce(from)),
+			frame_system::CheckWeight::<Self::Runtime>::new(),
+			pallet_transaction_payment::ChargeTransactionPayment::<Self::Runtime>::from(0),
+		)
+	}
+
+	fn create_client_parts(
+		config: &Configuration,
+	) -> Result<
+		(
+			Arc<TFullClient<Self::Block, Self::RuntimeApi, Self::Executor>>,
+			Arc<TFullBackend<Self::Block>>,
+			SyncCryptoStorePtr,
+			TaskManager,
+			InherentDataProviders,
+			Option<
+				Box<
+					dyn ConsensusDataProvider<
+						Self::Block,
+						Transaction = sp_api::TransactionFor<
+							TFullClient<Self::Block, Self::RuntimeApi, Self::Executor>,
+							Self::Block,
+						>,
+					>,
+				>,
+			>,
+			Self::SelectChain,
+			Self::BlockImport,
+		),
+		sc_service::Error,
+	> {
+		let (client, backend, keystore, task_manager) =
+			new_full_parts::<Self::Block, Self::RuntimeApi, Self::Executor>(config, None)?;
+		let client = Arc::new(client);
+
+		let inherent_providers = InherentDataProviders::new();
+		let select_chain = sc_consensus::LongestChain::new(backend.clone());
+
+		let (grandpa_block_import, ..) =
+			grandpa::block_import(
+				client.clone(),
+				&(client.clone() as Arc<_>),
+				select_chain.clone(),
+				None
+			)?;
+
+		let (block_import, babe_link) = sc_consensus_babe::block_import(
+			sc_consensus_babe::Config::get_or_compute(&*client)?,
+			grandpa_block_import,
+			client.clone(),
+		)?;
+
+		let consensus_data_provider = BabeConsensusDataProvider::new(
+			client.clone(),
+			keystore.sync_keystore(),
+			&inherent_providers,
+			babe_link.epoch_changes().clone(),
+			vec![(AuthorityId::from(Alice.public()), 1000)],
+		)
+			.expect("failed to create ConsensusDataProvider");
+
+		Ok((
+			client,
+			backend,
+			keystore.sync_keystore(),
+			task_manager,
+			inherent_providers,
+			Some(Box::new(consensus_data_provider)),
+			select_chain,
+			block_import,
+		))
+	}
+
+	fn dispatch_with_root(call: <Self::Runtime as frame_system::Config>::Call, node: &mut Node<Self>) {
+		let alice = MultiSigner::from(Alice.public()).into_account();
+		let call = pallet_sudo::Call::sudo(Box::new(call));
+		node.submit_extrinsic(call, alice);
+		node.seal_blocks(1);
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+	use test_runner::NodeConfig;
+	use log::LevelFilter;
+	use sc_client_api::execution_extensions::ExecutionStrategies;
+	use node_cli::chain_spec::development_config;
+
+	#[test]
+	fn test_runner() {
+		let config = NodeConfig {
+			execution_strategies: ExecutionStrategies {
+				syncing: sc_client_api::ExecutionStrategy::AlwaysWasm,
+				importing: sc_client_api::ExecutionStrategy::AlwaysWasm,
+				block_construction: sc_client_api::ExecutionStrategy::AlwaysWasm,
+				offchain_worker: sc_client_api::ExecutionStrategy::AlwaysWasm,
+				other: sc_client_api::ExecutionStrategy::AlwaysWasm,
+			},
+			chain_spec: Box::new(development_config()),
+			log_targets: vec![
+				("yamux", LevelFilter::Off),
+				("multistream_select", LevelFilter::Off),
+				("libp2p", LevelFilter::Off),
+				("jsonrpc_client_transports", LevelFilter::Off),
+				("sc_network", LevelFilter::Off),
+				("tokio_reactor", LevelFilter::Off),
+				("parity-db", LevelFilter::Off),
+				("sub-libp2p", LevelFilter::Off),
+				("sync", LevelFilter::Off),
+				("peerset", LevelFilter::Off),
+				("ws", LevelFilter::Off),
+				("sc_network", LevelFilter::Off),
+				("sc_service", LevelFilter::Off),
+				("sc_basic_authorship", LevelFilter::Off),
+				("telemetry-logger", LevelFilter::Off),
+				("sc_peerset", LevelFilter::Off),
+				("rpc", LevelFilter::Off),
+				("runtime", LevelFilter::Trace),
+				("babe", LevelFilter::Debug)
+			],
+		};
+		let mut node = Node::<NodeTemplateChainInfo>::new(config).unwrap();
+		// seals blocks
+		node.seal_blocks(1);
+		// submit extrinsics
+		let alice = MultiSigner::from(Alice.public()).into_account();
+		node.submit_extrinsic(frame_system::Call::remark((b"hello world").to_vec()), alice);
+
+		// look ma, I can read state.
+		let _events = node.with_state(|| frame_system::Pallet::<node_runtime::Runtime>::events());
+		// get access to the underlying client.
+		let _client = node.client();
+	}
+}
diff --git a/bin/node/testing/src/bench.rs b/bin/node/testing/src/bench.rs
index cc6d7587dd517..edb99c617771a 100644
--- a/bin/node/testing/src/bench.rs
+++ b/bin/node/testing/src/bench.rs
@@ -691,7 +691,7 @@ impl BenchContext {
 		assert_eq!(self.client.chain_info().best_number, 0);
 
 		assert_eq!(
-			self.client.import_block(import_params, Default::default())
+			futures::executor::block_on(self.client.import_block(import_params, Default::default()))
 				.expect("Failed to import block"),
 			ImportResult::Imported(
 				ImportedAux {
diff --git a/bin/utils/subkey/README.adoc b/bin/utils/subkey/README.adoc
index 5ce0d2d324470..b82213777e93a 100644
--- a/bin/utils/subkey/README.adoc
+++ b/bin/utils/subkey/README.adoc
@@ -12,7 +12,7 @@ Subkey is a commandline utility included with Substrate that generates or restor
 subkey generate
 ```
 
-Will output a mnemonic phrase and give you the seed, public key, and address of a new account. DO NOT SHARE your mnemonic or seed with ANYONE it will give them access to your funds. If someone is making a transfer to you they will only need your **Address**.
+Will output a secret phrase("mnemonic phrase") and give you the secret seed("Private Key"), public key("Account ID") and SS58 address("Public Address") of a new account. DO NOT SHARE your mnemonic phrase or secret seed with ANYONE it will give them access to your funds. If someone is making a transfer to you they will only need your **Public Address**.
 
 === Inspecting a key
 
@@ -80,4 +80,4 @@ Public Key URI `F3opxRbN5ZbjJNU511Kj2TLuzFcDq9BGduA9TgiECafpg29` is account:
   Public key (hex):   0x6d6f646c70792f74727372790000000000000000000000000000000000000000
   Account ID:         0x6d6f646c70792f74727372790000000000000000000000000000000000000000
   SS58 Address:       F3opxRbN5ZbjJNU511Kj2TLuzFcDq9BGduA9TgiECafpg29
-```
\ No newline at end of file
+```
diff --git a/client/api/src/backend.rs b/client/api/src/backend.rs
index e41b250269a11..14841d8d3e96f 100644
--- a/client/api/src/backend.rs
+++ b/client/api/src/backend.rs
@@ -22,11 +22,11 @@ use std::sync::Arc;
 use std::collections::{HashMap, HashSet};
 use sp_core::ChangesTrieConfigurationRange;
 use sp_core::offchain::OffchainStorage;
-use sp_runtime::{generic::BlockId, Justification, Storage};
+use sp_runtime::{generic::BlockId, Justification, Justifications, Storage};
 use sp_runtime::traits::{Block as BlockT, NumberFor, HashFor};
 use sp_state_machine::{
 	ChangesTrieState, ChangesTrieStorage as StateChangesTrieStorage, ChangesTrieTransaction,
-	StorageCollection, ChildStorageCollection, OffchainChangesCollection,
+	StorageCollection, ChildStorageCollection, OffchainChangesCollection, IndexOperation,
 };
 use sp_storage::{StorageData, StorageKey, PrefixedStorageKey, ChildInfo};
 use crate::{
@@ -148,7 +148,7 @@ pub trait BlockImportOperation<Block: BlockT> {
 		&mut self,
 		header: Block::Header,
 		body: Option<Vec<Block::Extrinsic>>,
-		justification: Option<Justification>,
+		justifications: Option<Justifications>,
 		state: NewBlockState,
 	) -> sp_blockchain::Result<()>;
 
@@ -197,9 +197,13 @@ pub trait BlockImportOperation<Block: BlockT> {
 		id: BlockId<Block>,
 		justification: Option<Justification>,
 	) -> sp_blockchain::Result<()>;
+
 	/// Mark a block as new head. If both block import and set head are specified, set head
 	/// overrides block import's best block rule.
 	fn mark_head(&mut self, id: BlockId<Block>) -> sp_blockchain::Result<()>;
+
+	/// Add a transaction index operation.
+	fn update_transaction_index(&mut self, index: Vec<IndexOperation>) -> sp_blockchain::Result<()>;
 }
 
 /// Interface for performing operations on the backend.
@@ -230,7 +234,6 @@ pub trait Finalizer<Block: BlockT, B: Backend<Block>> {
 		notify: bool,
 	) -> sp_blockchain::Result<()>;
 
-
 	/// Finalize a block.
 	///
 	/// This will implicitly finalize all blocks up to it and
@@ -250,7 +253,6 @@ pub trait Finalizer<Block: BlockT, B: Backend<Block>> {
 		justification: Option<Justification>,
 		notify: bool,
 	) -> sp_blockchain::Result<()>;
-
 }
 
 /// Provides access to an auxiliary database.
@@ -432,6 +434,15 @@ pub trait Backend<Block: BlockT>: AuxStore + Send + Sync {
 		justification: Option<Justification>,
 	) -> sp_blockchain::Result<()>;
 
+	/// Append justification to the block with the given Id.
+	///
+	/// This should only be called for blocks that are already finalized.
+	fn append_justification(
+		&self,
+		block: BlockId<Block>,
+		justification: Justification,
+	) -> sp_blockchain::Result<()>;
+
 	/// Returns reference to blockchain backend.
 	fn blockchain(&self) -> &Self::Blockchain;
 
diff --git a/client/api/src/client.rs b/client/api/src/client.rs
index 990a7908b62bb..4a0940b1f4bd3 100644
--- a/client/api/src/client.rs
+++ b/client/api/src/client.rs
@@ -23,7 +23,7 @@ use sp_core::storage::StorageKey;
 use sp_runtime::{
 	traits::{Block as BlockT, NumberFor},
 	generic::{BlockId, SignedBlock},
-	Justification,
+	Justifications,
 };
 use sp_consensus::BlockOrigin;
 
@@ -90,21 +90,24 @@ pub trait BlockBackend<Block: BlockT> {
 	/// Get block status.
 	fn block_status(&self, id: &BlockId<Block>) -> sp_blockchain::Result<sp_consensus::BlockStatus>;
 
-	/// Get block justification set by id.
-	fn justification(&self, id: &BlockId<Block>) -> sp_blockchain::Result<Option<Justification>>;
+	/// Get block justifications for the block with the given id.
+	fn justifications(&self, id: &BlockId<Block>) -> sp_blockchain::Result<Option<Justifications>>;
 
 	/// Get block hash by number.
 	fn block_hash(&self, number: NumberFor<Block>) -> sp_blockchain::Result<Option<Block::Hash>>;
 
-	/// Get single extrinsic by hash.
-	fn extrinsic(
+	/// Get single indexed transaction by content hash. 
+	///
+	/// Note that this will only fetch transactions
+	/// that are indexed by the runtime with `storage_index_transaction`.
+	fn indexed_transaction(
 		&self,
 		hash: &Block::Hash,
-	) -> sp_blockchain::Result<Option<<Block as BlockT>::Extrinsic>>;
+	) -> sp_blockchain::Result<Option<Vec<u8>>>;
 
-	/// Check if extrinsic exists.
-	fn have_extrinsic(&self, hash: &Block::Hash) -> sp_blockchain::Result<bool> {
-		Ok(self.extrinsic(hash)?.is_some())
+	/// Check if transaction index exists.
+	fn has_indexed_transaction(&self, hash: &Block::Hash) -> sp_blockchain::Result<bool> {
+		Ok(self.indexed_transaction(hash)?.is_some())
 	}
 }
 
diff --git a/client/api/src/in_mem.rs b/client/api/src/in_mem.rs
index b7060cf1d9b1b..930ae39c4b523 100644
--- a/client/api/src/in_mem.rs
+++ b/client/api/src/in_mem.rs
@@ -27,10 +27,10 @@ use sp_core::{
 };
 use sp_runtime::generic::BlockId;
 use sp_runtime::traits::{Block as BlockT, Header as HeaderT, Zero, NumberFor, HashFor};
-use sp_runtime::{Justification, Storage};
+use sp_runtime::{Justification, Justifications, Storage};
 use sp_state_machine::{
 	ChangesTrieTransaction, InMemoryBackend, Backend as StateBackend, StorageCollection,
-	ChildStorageCollection,
+	ChildStorageCollection, IndexOperation,
 };
 use sp_blockchain::{CachedHeaderMetadata, HeaderMetadata};
 
@@ -51,12 +51,12 @@ struct PendingBlock<B: BlockT> {
 
 #[derive(PartialEq, Eq, Clone)]
 enum StoredBlock<B: BlockT> {
-	Header(B::Header, Option<Justification>),
-	Full(B, Option<Justification>),
+	Header(B::Header, Option<Justifications>),
+	Full(B, Option<Justifications>),
 }
 
 impl<B: BlockT> StoredBlock<B> {
-	fn new(header: B::Header, body: Option<Vec<B::Extrinsic>>, just: Option<Justification>) -> Self {
+	fn new(header: B::Header, body: Option<Vec<B::Extrinsic>>, just: Option<Justifications>) -> Self {
 		match body {
 			Some(body) => StoredBlock::Full(B::new(header, body), just),
 			None => StoredBlock::Header(header, just),
@@ -70,7 +70,7 @@ impl<B: BlockT> StoredBlock<B> {
 		}
 	}
 
-	fn justification(&self) -> Option<&Justification> {
+	fn justifications(&self) -> Option<&Justifications> {
 		match *self {
 			StoredBlock::Header(_, ref j) | StoredBlock::Full(_, ref j) => j.as_ref()
 		}
@@ -83,7 +83,7 @@ impl<B: BlockT> StoredBlock<B> {
 		}
 	}
 
-	fn into_inner(self) -> (B::Header, Option<Vec<B::Extrinsic>>, Option<Justification>) {
+	fn into_inner(self) -> (B::Header, Option<Vec<B::Extrinsic>>, Option<Justifications>) {
 		match self {
 			StoredBlock::Header(header, just) => (header, None, just),
 			StoredBlock::Full(block, just) => {
@@ -164,7 +164,7 @@ impl<Block: BlockT> Blockchain<Block> {
 		&self,
 		hash: Block::Hash,
 		header: <Block as BlockT>::Header,
-		justification: Option<Justification>,
+		justifications: Option<Justifications>,
 		body: Option<Vec<<Block as BlockT>::Extrinsic>>,
 		new_state: NewBlockState,
 	) -> sp_blockchain::Result<()> {
@@ -176,7 +176,7 @@ impl<Block: BlockT> Blockchain<Block> {
 		{
 			let mut storage = self.storage.write();
 			storage.leaves.import(hash.clone(), number.clone(), header.parent_hash().clone());
-			storage.blocks.insert(hash.clone(), StoredBlock::new(header, body, justification));
+			storage.blocks.insert(hash.clone(), StoredBlock::new(header, body, justifications));
 
 			if let NewBlockState::Final = new_state {
 				storage.finalized_hash = hash;
@@ -285,16 +285,44 @@ impl<Block: BlockT> Blockchain<Block> {
 			let block = storage.blocks.get_mut(&hash)
 				.expect("hash was fetched from a block in the db; qed");
 
-			let block_justification = match block {
+			let block_justifications = match block {
 				StoredBlock::Header(_, ref mut j) | StoredBlock::Full(_, ref mut j) => j
 			};
 
-			*block_justification = justification;
+			*block_justifications = justification.map(Justifications::from);
 		}
 
 		Ok(())
 	}
 
+	fn append_justification(&self, id: BlockId<Block>, justification: Justification)
+		-> sp_blockchain::Result<()>
+	{
+		let hash = self.expect_block_hash_from_id(&id)?;
+		let mut storage = self.storage.write();
+
+		let block = storage
+			.blocks
+			.get_mut(&hash)
+			.expect("hash was fetched from a block in the db; qed");
+
+		let block_justifications = match block {
+			StoredBlock::Header(_, ref mut j) | StoredBlock::Full(_, ref mut j) => j
+		};
+
+		if let Some(stored_justifications) = block_justifications {
+			if !stored_justifications.append(justification) {
+				return Err(sp_blockchain::Error::BadJustification(
+					"Duplicate consensus engine ID".into()
+				));
+			}
+		} else {
+			*block_justifications = Some(Justifications::from(justification));
+		};
+
+		Ok(())
+	}
+
 	fn write_aux(&self, ops: Vec<(Vec<u8>, Option<Vec<u8>>)>) {
 		let mut storage = self.storage.write();
 		for (k, v) in ops {
@@ -365,9 +393,9 @@ impl<Block: BlockT> blockchain::Backend<Block> for Blockchain<Block> {
 		}))
 	}
 
-	fn justification(&self, id: BlockId<Block>) -> sp_blockchain::Result<Option<Justification>> {
+	fn justifications(&self, id: BlockId<Block>) -> sp_blockchain::Result<Option<Justifications>> {
 		Ok(self.id(id).and_then(|hash| self.storage.read().blocks.get(&hash).and_then(|b|
-			b.justification().map(|x| x.clone()))
+			b.justifications().map(|x| x.clone()))
 		))
 	}
 
@@ -387,10 +415,10 @@ impl<Block: BlockT> blockchain::Backend<Block> for Blockchain<Block> {
 		unimplemented!()
 	}
 
-	fn extrinsic(
+	fn indexed_transaction(
 		&self,
 		_hash: &Block::Hash,
-	) -> sp_blockchain::Result<Option<<Block as BlockT>::Extrinsic>> {
+	) -> sp_blockchain::Result<Option<Vec<u8>>> {
 		unimplemented!("Not supported by the in-mem backend.")
 	}
 }
@@ -508,12 +536,12 @@ impl<Block: BlockT> backend::BlockImportOperation<Block> for BlockImportOperatio
 		&mut self,
 		header: <Block as BlockT>::Header,
 		body: Option<Vec<<Block as BlockT>::Extrinsic>>,
-		justification: Option<Justification>,
+		justifications: Option<Justifications>,
 		state: NewBlockState,
 	) -> sp_blockchain::Result<()> {
 		assert!(self.pending_block.is_none(), "Only one block per operation is allowed");
 		self.pending_block = Some(PendingBlock {
-			block: StoredBlock::new(header, body, justification),
+			block: StoredBlock::new(header, body, justifications),
 			state,
 		});
 		Ok(())
@@ -585,6 +613,10 @@ impl<Block: BlockT> backend::BlockImportOperation<Block> for BlockImportOperatio
 		self.set_head = Some(block);
 		Ok(())
 	}
+
+	fn update_transaction_index(&mut self, _index: Vec<IndexOperation>) -> sp_blockchain::Result<()> {
+		Ok(())
+	}
 }
 
 /// In-memory backend. Keeps all states and blocks in memory.
@@ -696,6 +728,14 @@ impl<Block: BlockT> backend::Backend<Block> for Backend<Block> where Block::Hash
 		self.blockchain.finalize_header(block, justification)
 	}
 
+	fn append_justification(
+		&self,
+		block: BlockId<Block>,
+		justification: Justification,
+	) -> sp_blockchain::Result<()> {
+		self.blockchain.append_justification(block, justification)
+	}
+
 	fn blockchain(&self) -> &Self::Blockchain {
 		&self.blockchain
 	}
@@ -766,3 +806,64 @@ pub fn check_genesis_storage(storage: &Storage) -> sp_blockchain::Result<()> {
 
 	Ok(())
 }
+
+#[cfg(test)]
+mod tests {
+	use crate::{NewBlockState, in_mem::Blockchain};
+	use sp_api::{BlockId, HeaderT};
+	use sp_runtime::{ConsensusEngineId, Justifications};
+	use sp_blockchain::Backend;
+	use substrate_test_runtime::{Block, Header, H256};
+
+	pub const ID1: ConsensusEngineId = *b"TST1";
+	pub const ID2: ConsensusEngineId = *b"TST2";
+
+	fn header(number: u64) -> Header {
+		let parent_hash = match number {
+			0 => Default::default(),
+			_ => header(number - 1).hash(),
+		};
+		Header::new(number, H256::from_low_u64_be(0), H256::from_low_u64_be(0), parent_hash, Default::default())
+	}
+
+	fn test_blockchain() -> Blockchain<Block> {
+		let blockchain = Blockchain::<Block>::new();
+		let just0 = Some(Justifications::from((ID1, vec![0])));
+		let just1 = Some(Justifications::from((ID1, vec![1])));
+		let just2 = None;
+		let just3 = Some(Justifications::from((ID1, vec![3])));
+		blockchain.insert(header(0).hash(), header(0), just0, None, NewBlockState::Final).unwrap();
+		blockchain.insert(header(1).hash(), header(1), just1, None, NewBlockState::Final).unwrap();
+		blockchain.insert(header(2).hash(), header(2), just2, None, NewBlockState::Best).unwrap();
+		blockchain.insert(header(3).hash(), header(3), just3, None, NewBlockState::Final).unwrap();
+		blockchain
+	}
+
+	#[test]
+	fn append_and_retrieve_justifications() {
+		let blockchain = test_blockchain();
+		let last_finalized = blockchain.last_finalized().unwrap();
+		let block = BlockId::Hash(last_finalized);
+
+		blockchain.append_justification(block, (ID2, vec![4])).unwrap();
+		let justifications = {
+			let mut just = Justifications::from((ID1, vec![3]));
+			just.append((ID2, vec![4]));
+			just
+		};
+		assert_eq!(blockchain.justifications(block).unwrap(), Some(justifications));
+	}
+
+	#[test]
+	fn store_duplicate_justifications_is_forbidden() {
+		let blockchain = test_blockchain();
+		let last_finalized = blockchain.last_finalized().unwrap();
+		let block = BlockId::Hash(last_finalized);
+
+		blockchain.append_justification(block, (ID2, vec![0])).unwrap();
+		assert!(matches!(
+			blockchain.append_justification(block, (ID2, vec![1])),
+			Err(sp_blockchain::Error::BadJustification(_)),
+		));
+	}
+}
diff --git a/client/api/src/leaves.rs b/client/api/src/leaves.rs
index 1971012c6aabc..47cac8b186f4a 100644
--- a/client/api/src/leaves.rs
+++ b/client/api/src/leaves.rs
@@ -25,7 +25,7 @@ use sp_runtime::traits::AtLeast32Bit;
 use codec::{Encode, Decode};
 use sp_blockchain::{Error, Result};
 
-type DbHash = [u8; 32];
+type DbHash = sp_core::H256;
 
 #[derive(Debug, Clone, PartialEq, Eq)]
 struct LeafSetItem<H, N> {
@@ -55,6 +55,11 @@ impl<H, N: Ord> FinalizationDisplaced<H, N> {
 		// one transaction, then there will be no overlap in the keys.
 		self.leaves.append(&mut other.leaves);
 	}
+
+	/// Iterate over all displaced leaves.
+	pub fn leaves(&self) -> impl IntoIterator<Item=&H> {
+		self.leaves.values().flatten()
+	}
 }
 
 /// list of leaf hashes ordered by number (descending).
diff --git a/client/authority-discovery/Cargo.toml b/client/authority-discovery/Cargo.toml
index 4de6b5479066d..4a92186c444b7 100644
--- a/client/authority-discovery/Cargo.toml
+++ b/client/authority-discovery/Cargo.toml
@@ -23,7 +23,7 @@ derive_more = "0.99.2"
 either = "1.5.3"
 futures = "0.3.9"
 futures-timer = "3.0.1"
-libp2p = { version = "0.35.1", default-features = false, features = ["kad"] }
+libp2p = { version = "0.36.0", default-features = false, features = ["kad"] }
 log = "0.4.8"
 prometheus-endpoint = { package = "substrate-prometheus-endpoint", path = "../../utils/prometheus", version = "0.9.0"}
 prost = "0.7"
diff --git a/client/basic-authorship/src/basic_authorship.rs b/client/basic-authorship/src/basic_authorship.rs
index 93ee4fc1445de..910abfad5ae1e 100644
--- a/client/basic-authorship/src/basic_authorship.rs
+++ b/client/basic-authorship/src/basic_authorship.rs
@@ -420,6 +420,7 @@ mod tests {
 	use sp_blockchain::HeaderBackend;
 	use sp_runtime::traits::NumberFor;
 	use sc_client_api::Backend;
+	use futures::executor::block_on;
 
 	const SOURCE: TransactionSource = TransactionSource::External;
 
@@ -454,11 +455,11 @@ mod tests {
 			client.clone(),
 		);
 
-		futures::executor::block_on(
+		block_on(
 			txpool.submit_at(&BlockId::number(0), SOURCE, vec![extrinsic(0), extrinsic(1)])
 		).unwrap();
 
-		futures::executor::block_on(
+		block_on(
 			txpool.maintain(chain_event(
 				client.header(&BlockId::Number(0u64))
 					.expect("header get error")
@@ -492,7 +493,7 @@ mod tests {
 
 		// when
 		let deadline = time::Duration::from_secs(3);
-		let block = futures::executor::block_on(
+		let block = block_on(
 			proposer.propose(Default::default(), Default::default(), deadline)
 		).map(|r| r.block).unwrap();
 
@@ -538,7 +539,7 @@ mod tests {
 		);
 
 		let deadline = time::Duration::from_secs(1);
-		futures::executor::block_on(
+		block_on(
 			proposer.propose(Default::default(), Default::default(), deadline)
 		).map(|r| r.block).unwrap();
 	}
@@ -559,11 +560,11 @@ mod tests {
 		let genesis_hash = client.info().best_hash;
 		let block_id = BlockId::Hash(genesis_hash);
 
-		futures::executor::block_on(
+		block_on(
 			txpool.submit_at(&BlockId::number(0), SOURCE, vec![extrinsic(0)]),
 		).unwrap();
 
-		futures::executor::block_on(
+		block_on(
 			txpool.maintain(chain_event(
 				client.header(&BlockId::Number(0u64))
 					.expect("header get error")
@@ -585,7 +586,7 @@ mod tests {
 		);
 
 		let deadline = time::Duration::from_secs(9);
-		let proposal = futures::executor::block_on(
+		let proposal = block_on(
 			proposer.propose(Default::default(), Default::default(), deadline),
 		).unwrap();
 
@@ -625,7 +626,7 @@ mod tests {
 			client.clone(),
 		);
 
-		futures::executor::block_on(
+		block_on(
 			txpool.submit_at(&BlockId::number(0), SOURCE, vec![
 				extrinsic(0),
 				extrinsic(1),
@@ -667,7 +668,7 @@ mod tests {
 
 			// when
 			let deadline = time::Duration::from_secs(9);
-			let block = futures::executor::block_on(
+			let block = block_on(
 				proposer.propose(Default::default(), Default::default(), deadline)
 			).map(|r| r.block).unwrap();
 
@@ -679,7 +680,7 @@ mod tests {
 			block
 		};
 
-		futures::executor::block_on(
+		block_on(
 			txpool.maintain(chain_event(
 				client.header(&BlockId::Number(0u64))
 					.expect("header get error")
@@ -689,9 +690,9 @@ mod tests {
 
 		// let's create one block and import it
 		let block = propose_block(&client, 0, 2, 7);
-		client.import(BlockOrigin::Own, block).unwrap();
+		block_on(client.import(BlockOrigin::Own, block)).unwrap();
 
-		futures::executor::block_on(
+		block_on(
 			txpool.maintain(chain_event(
 				client.header(&BlockId::Number(1))
 					.expect("header get error")
@@ -701,6 +702,6 @@ mod tests {
 
 		// now let's make sure that we can still make some progress
 		let block = propose_block(&client, 1, 2, 5);
-		client.import(BlockOrigin::Own, block).unwrap();
+		block_on(client.import(BlockOrigin::Own, block)).unwrap();
 	}
 }
diff --git a/client/cli/Cargo.toml b/client/cli/Cargo.toml
index 4617c2d790ada..55748ffb3d903 100644
--- a/client/cli/Cargo.toml
+++ b/client/cli/Cargo.toml
@@ -18,7 +18,7 @@ regex = "1.4.2"
 tokio = { version = "0.2.21", features = [ "signal", "rt-core", "rt-threaded", "blocking" ] }
 futures = "0.3.9"
 fdlimit = "0.2.1"
-libp2p = "0.35.1"
+libp2p = "0.36.0"
 parity-scale-codec = "2.0.0"
 hex = "0.4.2"
 rand = "0.7.3"
diff --git a/client/consensus/aura/Cargo.toml b/client/consensus/aura/Cargo.toml
index 1465119c81d08..b2301fa9c5de5 100644
--- a/client/consensus/aura/Cargo.toml
+++ b/client/consensus/aura/Cargo.toml
@@ -26,7 +26,6 @@ futures = "0.3.9"
 futures-timer = "3.0.1"
 sp-inherents = { version = "3.0.0", path = "../../../primitives/inherents" }
 log = "0.4.8"
-parking_lot = "0.11.1"
 sp-core = { version = "3.0.0", path = "../../../primitives/core" }
 sp-blockchain = { version = "3.0.0", path = "../../../primitives/blockchain" }
 sp-io = { version = "3.0.0", path = "../../../primitives/io" }
@@ -38,6 +37,7 @@ sp-timestamp = { version = "3.0.0", path = "../../../primitives/timestamp" }
 sp-keystore = { version = "0.9.0", path = "../../../primitives/keystore" }
 sc-telemetry = { version = "3.0.0", path = "../../telemetry" }
 prometheus-endpoint = { package = "substrate-prometheus-endpoint", path = "../../../utils/prometheus", version = "0.9.0"}
+async-trait = "0.1.42"
 # We enable it only for web-wasm check
 # See https://docs.rs/getrandom/0.2.1/getrandom/#webassembly-support
 getrandom = { version = "0.2", features = ["js"], optional = true }
@@ -52,3 +52,4 @@ sc-network-test = { version = "0.8.0", path = "../../network/test" }
 sc-service = { version = "0.9.0", default-features = false, path = "../../service" }
 substrate-test-runtime-client = { version = "2.0.0", path = "../../../test-utils/runtime/client" }
 tempfile = "3.1.0"
+parking_lot = "0.11.1"
diff --git a/client/consensus/aura/src/import_queue.rs b/client/consensus/aura/src/import_queue.rs
index d3ed2bea3e115..736c89aff6b09 100644
--- a/client/consensus/aura/src/import_queue.rs
+++ b/client/consensus/aura/src/import_queue.rs
@@ -30,7 +30,7 @@ use log::{debug, info, trace};
 use prometheus_endpoint::Registry;
 use codec::{Encode, Decode, Codec};
 use sp_consensus::{
-	BlockImport, CanAuthorWith, ForkChoiceStrategy, BlockImportParams,
+	BlockImport, CanAuthorWith, ForkChoiceStrategy, BlockImportParams, SlotData,
 	BlockOrigin, Error as ConsensusError, BlockCheckParams, ImportResult,
 	import_queue::{
 		Verifier, BasicQueue, DefaultImportQueue, BoxJustificationImport,
@@ -39,7 +39,7 @@ use sp_consensus::{
 use sc_client_api::{backend::AuxStore, BlockOf};
 use sp_blockchain::{well_known_cache_keys::{self, Id as CacheKeyId}, ProvideCache, HeaderBackend};
 use sp_block_builder::BlockBuilder as BlockBuilderApi;
-use sp_runtime::{generic::{BlockId, OpaqueDigestItemId}, Justification};
+use sp_runtime::{generic::{BlockId, OpaqueDigestItemId}, Justifications};
 use sp_runtime::traits::{Block as BlockT, Header, DigestItemFor, Zero};
 use sp_api::ProvideRuntimeApi;
 use sp_core::crypto::Pair;
@@ -220,6 +220,7 @@ impl<C, P, CAW> AuraVerifier<C, P, CAW> where
 	}
 }
 
+#[async_trait::async_trait]
 impl<B: BlockT, C, P, CAW> Verifier<B> for AuraVerifier<C, P, CAW> where
 	C: ProvideRuntimeApi<B> +
 		Send +
@@ -234,11 +235,11 @@ impl<B: BlockT, C, P, CAW> Verifier<B> for AuraVerifier<C, P, CAW> where
 	P::Signature: Encode + Decode,
 	CAW: CanAuthorWith<B> + Send + Sync + 'static,
 {
-	fn verify(
+	async fn verify(
 		&mut self,
 		origin: BlockOrigin,
 		header: B::Header,
-		justification: Option<Justification>,
+		justifications: Option<Justifications>,
 		mut body: Option<Vec<B::Extrinsic>>,
 	) -> Result<(BlockImportParams<B, ()>, Option<Vec<(CacheKeyId, Vec<u8>)>>), String> {
 		let mut inherent_data = self.inherent_data_providers
@@ -284,7 +285,7 @@ impl<B: BlockT, C, P, CAW> Verifier<B> for AuraVerifier<C, P, CAW> where
 							block.clone(),
 							BlockId::Hash(parent_hash),
 							inherent_data,
-							timestamp_now,
+							*timestamp_now,
 						).map_err(|e| e.to_string())?;
 					}
 
@@ -317,7 +318,7 @@ impl<B: BlockT, C, P, CAW> Verifier<B> for AuraVerifier<C, P, CAW> where
 				let mut import_block = BlockImportParams::new(origin, pre_header);
 				import_block.post_digests.push(seal);
 				import_block.body = body;
-				import_block.justification = justification;
+				import_block.justifications = justifications;
 				import_block.fork_choice = Some(ForkChoiceStrategy::LongestChain);
 				import_block.post_hash = Some(hash);
 
@@ -405,6 +406,7 @@ impl<Block: BlockT, C, I: BlockImport<Block>, P> AuraBlockImport<Block, C, I, P>
 	}
 }
 
+#[async_trait::async_trait]
 impl<Block: BlockT, C, I, P> BlockImport<Block> for AuraBlockImport<Block, C, I, P> where
 	I: BlockImport<Block, Transaction = sp_api::TransactionFor<C, Block>> + Send + Sync,
 	I::Error: Into<ConsensusError>,
@@ -412,18 +414,19 @@ impl<Block: BlockT, C, I, P> BlockImport<Block> for AuraBlockImport<Block, C, I,
 	P: Pair + Send + Sync + 'static,
 	P::Public: Clone + Eq + Send + Sync + Hash + Debug + Encode + Decode,
 	P::Signature: Encode + Decode,
+	sp_api::TransactionFor<C, Block>: Send + 'static,
 {
 	type Error = ConsensusError;
 	type Transaction = sp_api::TransactionFor<C, Block>;
 
-	fn check_block(
+	async fn check_block(
 		&mut self,
 		block: BlockCheckParams<Block>,
 	) -> Result<ImportResult, Self::Error> {
-		self.inner.check_block(block).map_err(Into::into)
+		self.inner.check_block(block).await.map_err(Into::into)
 	}
 
-	fn import_block(
+	async fn import_block(
 		&mut self,
 		block: BlockImportParams<Block, Self::Transaction>,
 		new_cache: HashMap<CacheKeyId, Vec<u8>>,
@@ -453,7 +456,7 @@ impl<Block: BlockT, C, I, P> BlockImport<Block> for AuraBlockImport<Block, C, I,
 			);
 		}
 
-		self.inner.import_block(block, new_cache).map_err(Into::into)
+		self.inner.import_block(block, new_cache).await.map_err(Into::into)
 	}
 }
 
@@ -541,7 +544,7 @@ pub fn import_queue<'a, P, Block, I, C, S, CAW>(
 	S: sp_core::traits::SpawnEssentialNamed,
 	CAW: CanAuthorWith<Block> + Send + Sync + 'static,
 {
-	register_aura_inherent_data_provider(&inherent_data_providers, slot_duration.get())?;
+	register_aura_inherent_data_provider(&inherent_data_providers, slot_duration.slot_duration())?;
 	initialize_authorities_cache(&*client)?;
 
 	let verifier = AuraVerifier::<_, P, _>::new(
diff --git a/client/consensus/aura/src/lib.rs b/client/consensus/aura/src/lib.rs
index cce58304d0d02..77dac0f754487 100644
--- a/client/consensus/aura/src/lib.rs
+++ b/client/consensus/aura/src/lib.rs
@@ -35,7 +35,6 @@ use std::{
 };
 
 use futures::prelude::*;
-use parking_lot::Mutex;
 use log::{debug, trace};
 
 use codec::{Encode, Decode, Codec};
@@ -75,7 +74,7 @@ pub use sc_consensus_slots::SlotProportion;
 type AuthorityId<P> = <P as Pair>::Public;
 
 /// Slot duration type for Aura.
-pub type SlotDuration = sc_consensus_slots::SlotDuration<u64>;
+pub type SlotDuration = sc_consensus_slots::SlotDuration<sp_consensus_aura::SlotDuration>;
 
 /// Get type of `SlotDuration` for Aura.
 pub fn slot_duration<A, B, C>(client: &C) -> CResult<SlotDuration> where
@@ -111,12 +110,12 @@ impl SlotCompatible for AuraSlotCompatible {
 	fn extract_timestamp_and_slot(
 		&self,
 		data: &InherentData,
-	) -> Result<(u64, AuraInherent, std::time::Duration), sp_consensus::Error> {
+	) -> Result<(sp_timestamp::Timestamp, AuraInherent, std::time::Duration), sp_consensus::Error> {
 		data.timestamp_inherent_data()
 			.and_then(|t| data.aura_inherent_data().map(|a| (t, a)))
 			.map_err(Into::into)
 			.map_err(sp_consensus::Error::InherentData)
-			.map(|(x, y)| (*x, y, Default::default()))
+			.map(|(x, y)| (x, y, Default::default()))
 	}
 }
 
@@ -161,7 +160,7 @@ pub fn start_aura<P, B, C, SC, PF, I, SO, CAW, BS, Error>(
 		client,
 		select_chain,
 		block_import,
-		proposer_factory: env,
+		proposer_factory,
 		sync_oracle,
 		inherent_data_providers,
 		force_authoring,
@@ -187,22 +186,23 @@ pub fn start_aura<P, B, C, SC, PF, I, SO, CAW, BS, Error>(
 	CAW: CanAuthorWith<B> + Send,
 	BS: BackoffAuthoringBlocksStrategy<NumberFor<B>> + Send + 'static,
 {
-	let worker = AuraWorker {
+	let worker = build_aura_worker::<P, _, _, _, _, _, _, _>(BuildAuraWorkerParams {
 		client: client.clone(),
-		block_import: Arc::new(Mutex::new(block_import)),
-		env,
+		block_import,
+		proposer_factory,
 		keystore,
 		sync_oracle: sync_oracle.clone(),
 		force_authoring,
 		backoff_authoring_blocks,
 		telemetry,
-		_key_type: PhantomData::<P>,
 		block_proposal_slot_portion,
-	};
+	});
+
 	register_aura_inherent_data_provider(
 		&inherent_data_providers,
 		slot_duration.slot_duration()
 	)?;
+
 	Ok(sc_consensus_slots::start_slot_worker::<_, _, _, _, _, AuraSlotCompatible, _, _>(
 		slot_duration,
 		select_chain,
@@ -214,9 +214,78 @@ pub fn start_aura<P, B, C, SC, PF, I, SO, CAW, BS, Error>(
 	))
 }
 
+/// Parameters of [`build_aura_worker`].
+pub struct BuildAuraWorkerParams<C, I, PF, SO, BS> {
+	/// The client to interact with the chain.
+	pub client: Arc<C>,
+	/// The block import.
+	pub block_import: I,
+	/// The proposer factory to build proposer instances.
+	pub proposer_factory: PF,
+	/// The sync oracle that can give us the current sync status.
+	pub sync_oracle: SO,
+	/// Should we force the authoring of blocks?
+	pub force_authoring: bool,
+	/// The backoff strategy when we miss slots.
+	pub backoff_authoring_blocks: Option<BS>,
+	/// The keystore used by the node.
+	pub keystore: SyncCryptoStorePtr,
+	/// The proportion of the slot dedicated to proposing.
+	///
+	/// The block proposing will be limited to this proportion of the slot from the starting of the
+	/// slot. However, the proposing can still take longer when there is some lenience factor applied,
+	/// because there were no blocks produced for some slots.
+	pub block_proposal_slot_portion: SlotProportion,
+	/// Telemetry instance used to report telemetry metrics.
+	pub telemetry: Option<TelemetryHandle>,
+}
+
+/// Build the aura worker.
+///
+/// The caller is responsible for running this worker, otherwise it will do nothing.
+pub fn build_aura_worker<P, B, C, PF, I, SO, BS, Error>(
+	BuildAuraWorkerParams {
+		client,
+		block_import,
+		proposer_factory,
+		sync_oracle,
+		backoff_authoring_blocks,
+		keystore,
+		block_proposal_slot_portion,
+		telemetry,
+		force_authoring,
+	}: BuildAuraWorkerParams<C, I, PF, SO, BS>,
+) -> impl sc_consensus_slots::SlotWorker<B, <PF::Proposer as Proposer<B>>::Proof> where
+	B: BlockT,
+	C: ProvideRuntimeApi<B> + BlockOf + ProvideCache<B> + AuxStore + HeaderBackend<B> + Send + Sync,
+	C::Api: AuraApi<B, AuthorityId<P>>,
+	PF: Environment<B, Error = Error> + Send + Sync + 'static,
+	PF::Proposer: Proposer<B, Error = Error, Transaction = sp_api::TransactionFor<C, B>>,
+	P: Pair + Send + Sync,
+	P::Public: AppPublic + Hash + Member + Encode + Decode,
+	P::Signature: TryFrom<Vec<u8>> + Hash + Member + Encode + Decode,
+	I: BlockImport<B, Transaction = sp_api::TransactionFor<C, B>> + Send + Sync + 'static,
+	Error: std::error::Error + Send + From<sp_consensus::Error> + 'static,
+	SO: SyncOracle + Send + Sync + Clone,
+	BS: BackoffAuthoringBlocksStrategy<NumberFor<B>> + Send + 'static,
+{
+	AuraWorker {
+		client,
+		block_import,
+		env: proposer_factory,
+		keystore,
+		sync_oracle,
+		force_authoring,
+		backoff_authoring_blocks,
+		telemetry,
+		_key_type: PhantomData::<P>,
+		block_proposal_slot_portion,
+	}
+}
+
 struct AuraWorker<C, E, I, P, SO, BS> {
 	client: Arc<C>,
-	block_import: Arc<Mutex<I>>,
+	block_import: I,
 	env: E,
 	keystore: SyncCryptoStorePtr,
 	sync_oracle: SO,
@@ -256,8 +325,8 @@ where
 		"aura"
 	}
 
-	fn block_import(&self) -> Arc<Mutex<Self::BlockImport>> {
-		self.block_import.clone()
+	fn block_import(&mut self) -> &mut Self::BlockImport {
+		&mut self.block_import
 	}
 
 	fn epoch_data(
@@ -477,7 +546,7 @@ fn find_pre_digest<B: BlockT, Signature: Codec>(header: &B::Header) -> Result<Sl
 /// Register the aura inherent data provider, if not registered already.
 fn register_aura_inherent_data_provider(
 	inherent_data_providers: &InherentDataProviders,
-	slot_duration: u64,
+	slot_duration: std::time::Duration,
 ) -> Result<(), sp_consensus::Error> {
 	if !inherent_data_providers.has_provider(&INHERENT_IDENTIFIER) {
 		inherent_data_providers
@@ -511,6 +580,7 @@ mod tests {
 	use super::*;
 	use sp_consensus::{
 		NoNetwork as DummyOracle, Proposal, AlwaysCanAuthor, DisableProofRecording,
+		import_queue::BoxJustificationImport,
 	};
 	use sc_network_test::{Block as TestBlock, *};
 	use sp_runtime::traits::{Block as BlockT, DigestFor};
@@ -572,13 +642,17 @@ mod tests {
 
 	const SLOT_DURATION: u64 = 1000;
 
+	type AuraVerifier = import_queue::AuraVerifier<PeersFullClient, AuthorityPair, AlwaysCanAuthor>;
+	type AuraPeer = Peer<(), PeersClient>;
+
 	pub struct AuraTestNet {
-		peers: Vec<Peer<()>>,
+		peers: Vec<AuraPeer>,
 	}
 
 	impl TestNetFactory for AuraTestNet {
-		type Verifier = import_queue::AuraVerifier<PeersFullClient, AuthorityPair, AlwaysCanAuthor>;
+		type Verifier = AuraVerifier;
 		type PeerData = ();
+		type BlockImport = PeersClient;
 
 		/// Create new test network with peers and given config.
 		fn from_config(_config: &ProtocolConfig) -> Self {
@@ -596,10 +670,10 @@ mod tests {
 					let inherent_data_providers = InherentDataProviders::new();
 					register_aura_inherent_data_provider(
 						&inherent_data_providers,
-						slot_duration.get()
+						slot_duration.slot_duration()
 					).expect("Registers aura inherent data provider");
 
-					assert_eq!(slot_duration.get(), SLOT_DURATION);
+					assert_eq!(slot_duration.slot_duration().as_millis() as u64, SLOT_DURATION);
 					import_queue::AuraVerifier::new(
 						client,
 						inherent_data_providers,
@@ -612,14 +686,22 @@ mod tests {
 			}
 		}
 
-		fn peer(&mut self, i: usize) -> &mut Peer<Self::PeerData> {
+		fn make_block_import(&self, client: PeersClient) -> (
+			BlockImportAdapter<Self::BlockImport>,
+			Option<BoxJustificationImport<Block>>,
+			Self::PeerData,
+		) {
+			(client.as_block_import(), None, ())
+		}
+
+		fn peer(&mut self, i: usize) -> &mut AuraPeer {
 			&mut self.peers[i]
 		}
 
-		fn peers(&self) -> &Vec<Peer<Self::PeerData>> {
+		fn peers(&self) -> &Vec<AuraPeer> {
 			&self.peers
 		}
-		fn mut_peers<F: FnOnce(&mut Vec<Peer<Self::PeerData>>)>(&mut self, closure: F) {
+		fn mut_peers<F: FnOnce(&mut Vec<AuraPeer>)>(&mut self, closure: F) {
 			closure(&mut self.peers);
 		}
 	}
@@ -665,7 +747,7 @@ mod tests {
 
 			let inherent_data_providers = InherentDataProviders::new();
 			register_aura_inherent_data_provider(
-				&inherent_data_providers, slot_duration.get()
+				&inherent_data_providers, slot_duration.slot_duration()
 			).expect("Registers aura inherent data provider");
 
 			aura_futures.push(start_aura::<AuthorityPair, _, _, _, _, _, _, _, _, _>(StartAuraParams {
@@ -735,7 +817,7 @@ mod tests {
 
 		let worker = AuraWorker {
 			client: client.clone(),
-			block_import: Arc::new(Mutex::new(client)),
+			block_import: client,
 			env: environ,
 			keystore: keystore.into(),
 			sync_oracle: DummyOracle.clone(),
@@ -784,7 +866,7 @@ mod tests {
 
 		let mut worker = AuraWorker {
 			client: client.clone(),
-			block_import: Arc::new(Mutex::new(client.clone())),
+			block_import: client.clone(),
 			env: environ,
 			keystore: keystore.into(),
 			sync_oracle: DummyOracle.clone(),
@@ -801,7 +883,7 @@ mod tests {
 			head,
 			SlotInfo {
 				slot: 0.into(),
-				timestamp: 0,
+				timestamp: 0.into(),
 				ends_at: Instant::now() + Duration::from_secs(100),
 				inherent_data: InherentData::new(),
 				duration: Duration::from_millis(1000),
diff --git a/client/consensus/babe/Cargo.toml b/client/consensus/babe/Cargo.toml
index 14d48fba1bb57..b04caeb3ee9d7 100644
--- a/client/consensus/babe/Cargo.toml
+++ b/client/consensus/babe/Cargo.toml
@@ -53,6 +53,7 @@ merlin = "2.0"
 pdqselect = "0.1.0"
 derive_more = "0.99.2"
 retain_mut = "0.1.2"
+async-trait = "0.1.42"
 
 [dev-dependencies]
 sp-keyring = { version = "3.0.0", path = "../../../primitives/keyring" }
@@ -65,6 +66,3 @@ substrate-test-runtime-client = { version = "2.0.0", path = "../../../test-utils
 sc-block-builder = { version = "0.9.0", path = "../../block-builder" }
 rand_chacha = "0.2.2"
 tempfile = "3.1.0"
-
-[features]
-test-helpers = []
diff --git a/client/consensus/babe/rpc/src/lib.rs b/client/consensus/babe/rpc/src/lib.rs
index ca14a764eece5..6696a65040a5e 100644
--- a/client/consensus/babe/rpc/src/lib.rs
+++ b/client/consensus/babe/rpc/src/lib.rs
@@ -217,7 +217,7 @@ fn epoch_data<B, C, SC>(
 		SC: SelectChain<B>,
 {
 	let parent = select_chain.best_chain()?;
-	epoch_changes.lock().epoch_data_for_child_of(
+	epoch_changes.shared_data().epoch_data_for_child_of(
 		descendent_query(&**client),
 		&parent.hash(),
 		parent.number().clone(),
diff --git a/client/consensus/babe/src/aux_schema.rs b/client/consensus/babe/src/aux_schema.rs
index 7d5df77c92176..8b8804e3bfb02 100644
--- a/client/consensus/babe/src/aux_schema.rs
+++ b/client/consensus/babe/src/aux_schema.rs
@@ -18,8 +18,6 @@
 
 //! Schema for BABE epoch changes in the aux-db.
 
-use std::sync::Arc;
-use parking_lot::Mutex;
 use log::info;
 use codec::{Decode, Encode};
 
@@ -79,18 +77,19 @@ pub fn load_epoch_changes<Block: BlockT, B: AuxStore>(
 		},
 	};
 
-	let epoch_changes = Arc::new(Mutex::new(maybe_epoch_changes.unwrap_or_else(|| {
-		info!(target: "babe",
-			  "👶 Creating empty BABE epoch changes on what appears to be first startup."
+	let epoch_changes = SharedEpochChanges::<Block, Epoch>::new(maybe_epoch_changes.unwrap_or_else(|| {
+		info!(
+			target: "babe",
+			"👶 Creating empty BABE epoch changes on what appears to be first startup.",
 		);
 		EpochChangesFor::<Block, Epoch>::default()
-	})));
+	}));
 
 	// rebalance the tree after deserialization. this isn't strictly necessary
 	// since the tree is now rebalanced on every update operation. but since the
 	// tree wasn't rebalanced initially it's useful to temporarily leave it here
 	// to avoid having to wait until an import for rebalancing.
-	epoch_changes.lock().rebalance();
+	epoch_changes.shared_data().rebalance();
 
 	Ok(epoch_changes)
 }
@@ -189,7 +188,7 @@ mod test {
 		).unwrap();
 
 		assert!(
-			epoch_changes.lock()
+			epoch_changes.shared_data()
 				.tree()
 				.iter()
 				.map(|(_, _, epoch)| epoch.clone())
@@ -201,7 +200,7 @@ mod test {
 		); // PersistedEpochHeader does not implement Debug, so we use assert! directly.
 
 		write_epoch_changes::<TestBlock, _, _>(
-			&epoch_changes.lock(),
+			&epoch_changes.shared_data(),
 			|values| {
 				client.insert_aux(values, &[]).unwrap();
 			},
diff --git a/client/consensus/babe/src/lib.rs b/client/consensus/babe/src/lib.rs
index 3d72c436361c5..c3f1929c2ea8b 100644
--- a/client/consensus/babe/src/lib.rs
+++ b/client/consensus/babe/src/lib.rs
@@ -76,15 +76,15 @@ pub use sp_consensus_babe::{
 pub use sp_consensus::SyncOracle;
 pub use sc_consensus_slots::SlotProportion;
 use std::{
-	collections::HashMap, sync::Arc, u64, pin::Pin, time::{Instant, Duration},
-	any::Any, borrow::Cow, convert::TryInto,
+	collections::HashMap, sync::Arc, u64, pin::Pin, borrow::Cow, convert::TryInto,
+	time::{Duration, Instant},
 };
 use sp_consensus::{ImportResult, CanAuthorWith, import_queue::BoxJustificationImport};
 use sp_core::crypto::Public;
 use sp_application_crypto::AppKey;
 use sp_keystore::{SyncCryptoStorePtr, SyncCryptoStore};
 use sp_runtime::{
-	generic::{BlockId, OpaqueDigestItemId}, Justification,
+	generic::{BlockId, OpaqueDigestItemId}, Justifications,
 	traits::{Block as BlockT, Header, DigestItemFor, Zero},
 };
 use sp_api::{ProvideRuntimeApi, NumberFor};
@@ -345,8 +345,8 @@ impl Config {
 		}
 	}
 
-	/// Get the inner slot duration, in milliseconds.
-	pub fn slot_duration(&self) -> u64 {
+	/// Get the inner slot duration
+	pub fn slot_duration(&self) -> Duration {
 		self.0.slot_duration()
 	}
 }
@@ -438,7 +438,7 @@ pub fn start_babe<B, C, SC, E, I, SO, CAW, BS, Error>(BabeParams {
 		+ Sync + 'static,
 	Error: std::error::Error + Send + From<ConsensusError> + From<I::Error> + 'static,
 	SO: SyncOracle + Send + Sync + Clone + 'static,
-	CAW: CanAuthorWith<B> + Send + 'static,
+	CAW: CanAuthorWith<B> + Send + Sync + 'static,
 	BS: BackoffAuthoringBlocksStrategy<NumberFor<B>> + Send + 'static,
 {
 	const HANDLE_BUFFER_SIZE: usize = 1024;
@@ -448,7 +448,7 @@ pub fn start_babe<B, C, SC, E, I, SO, CAW, BS, Error>(BabeParams {
 
 	let worker = BabeSlotWorker {
 		client: client.clone(),
-		block_import: Arc::new(Mutex::new(block_import)),
+		block_import,
 		env,
 		sync_oracle: sync_oracle.clone(),
 		force_authoring,
@@ -502,7 +502,7 @@ async fn answer_requests<B: BlockT, C>(
 		match request {
 			BabeRequest::EpochForChild(parent_hash, parent_number, slot_number, response) => {
 				let lookup = || {
-					let epoch_changes =	epoch_changes.lock();
+					let epoch_changes = epoch_changes.shared_data();
 					let epoch_descriptor = epoch_changes.epoch_descriptor_for_child_of(
 						descendent_query(&*client),
 						&parent_hash,
@@ -605,7 +605,7 @@ type SlotNotificationSinks<B> = Arc<
 
 struct BabeSlotWorker<B: BlockT, C, E, I, SO, BS> {
 	client: Arc<C>,
-	block_import: Arc<Mutex<I>>,
+	block_import: I,
 	env: E,
 	sync_oracle: SO,
 	force_authoring: bool,
@@ -647,8 +647,8 @@ where
 		"babe"
 	}
 
-	fn block_import(&self) -> Arc<Mutex<Self::BlockImport>> {
-		self.block_import.clone()
+	fn block_import(&mut self) -> &mut Self::BlockImport {
+		&mut self.block_import
 	}
 
 	fn epoch_data(
@@ -656,7 +656,7 @@ where
 		parent: &B::Header,
 		slot: Slot,
 	) -> Result<Self::EpochData, ConsensusError> {
-		self.epoch_changes.lock().epoch_descriptor_for_child_of(
+		self.epoch_changes.shared_data().epoch_descriptor_for_child_of(
 			descendent_query(&*self.client),
 			&parent.hash(),
 			parent.number().clone(),
@@ -667,7 +667,8 @@ where
 	}
 
 	fn authorities_len(&self, epoch_descriptor: &Self::EpochData) -> Option<usize> {
-		self.epoch_changes.lock()
+		self.epoch_changes
+			.shared_data()
 			.viable_epoch(&epoch_descriptor, |slot| Epoch::genesis(&self.config, slot))
 			.map(|epoch| epoch.as_ref().authorities.len())
 	}
@@ -681,7 +682,7 @@ where
 		debug!(target: "babe", "Attempting to claim slot {}", slot);
 		let s = authorship::claim_slot(
 			slot,
-			self.epoch_changes.lock().viable_epoch(
+			self.epoch_changes.shared_data().viable_epoch(
 				&epoch_descriptor,
 				|slot| Epoch::genesis(&self.config, slot)
 			)?.as_ref(),
@@ -768,7 +769,7 @@ where
 			import_block.storage_changes = Some(storage_changes);
 			import_block.intermediates.insert(
 				Cow::from(INTERMEDIATE_KEY),
-				Box::new(BabeIntermediate::<B> { epoch_descriptor }) as Box<dyn Any>,
+				Box::new(BabeIntermediate::<B> { epoch_descriptor }) as Box<_>,
 			);
 
 			Ok(import_block)
@@ -919,13 +920,13 @@ impl SlotCompatible for TimeSource {
 	fn extract_timestamp_and_slot(
 		&self,
 		data: &InherentData,
-	) -> Result<(u64, Slot, std::time::Duration), sp_consensus::Error> {
+	) -> Result<(sp_timestamp::Timestamp, Slot, std::time::Duration), sp_consensus::Error> {
 		trace!(target: "babe", "extract timestamp");
 		data.timestamp_inherent_data()
 			.and_then(|t| data.babe_inherent_data().map(|a| (t, a)))
 			.map_err(Into::into)
 			.map_err(sp_consensus::Error::InherentData)
-			.map(|(x, y)| (*x, y, self.0.lock().0.take().unwrap_or_default()))
+			.map(|(x, y)| (x, y, self.0.lock().0.take().unwrap_or_default()))
 	}
 }
 
@@ -1083,6 +1084,7 @@ where
 	}
 }
 
+#[async_trait::async_trait]
 impl<Block, Client, SelectChain, CAW> Verifier<Block>
 	for BabeVerifier<Block, Client, SelectChain, CAW>
 where
@@ -1093,19 +1095,19 @@ where
 	SelectChain: sp_consensus::SelectChain<Block>,
 	CAW: CanAuthorWith<Block> + Send + Sync,
 {
-	fn verify(
+	async fn verify(
 		&mut self,
 		origin: BlockOrigin,
 		header: Block::Header,
-		justification: Option<Justification>,
+		justifications: Option<Justifications>,
 		mut body: Option<Vec<Block::Extrinsic>>,
 	) -> Result<(BlockImportParams<Block, ()>, Option<Vec<(CacheKeyId, Vec<u8>)>>), String> {
 		trace!(
 			target: "babe",
-			"Verifying origin: {:?} header: {:?} justification: {:?} body: {:?}",
+			"Verifying origin: {:?} header: {:?} justification(s): {:?} body: {:?}",
 			origin,
 			header,
-			justification,
+			justifications,
 			body,
 		);
 
@@ -1125,7 +1127,7 @@ where
 			.map_err(Error::<Block>::FetchParentHeader)?;
 
 		let pre_digest = find_pre_digest::<Block>(&header)?;
-		let epoch_changes = self.epoch_changes.lock();
+		let epoch_changes = self.epoch_changes.shared_data();
 		let epoch_descriptor = epoch_changes.epoch_descriptor_for_child_of(
 			descendent_query(&*self.client),
 			&parent_hash,
@@ -1189,15 +1191,16 @@ where
 					self.telemetry;
 					CONSENSUS_TRACE;
 					"babe.checked_and_importing";
-					"pre_header" => ?pre_header);
+					"pre_header" => ?pre_header,
+				);
 
 				let mut import_block = BlockImportParams::new(origin, pre_header);
 				import_block.post_digests.push(verified_info.seal);
 				import_block.body = body;
-				import_block.justification = justification;
+				import_block.justifications = justifications;
 				import_block.intermediates.insert(
 					Cow::from(INTERMEDIATE_KEY),
-					Box::new(BabeIntermediate::<Block> { epoch_descriptor }) as Box<dyn Any>,
+					Box::new(BabeIntermediate::<Block> { epoch_descriptor }) as Box<_>,
 				);
 				import_block.post_hash = Some(hash);
 
@@ -1220,7 +1223,7 @@ where
 /// Register the babe inherent data provider, if not registered already.
 pub fn register_babe_inherent_data_provider(
 	inherent_data_providers: &InherentDataProviders,
-	slot_duration: u64,
+	slot_duration: Duration,
 ) -> Result<(), sp_consensus::Error> {
 	debug!(target: "babe", "Registering");
 	if !inherent_data_providers.has_provider(&sp_consensus_babe::inherents::INHERENT_IDENTIFIER) {
@@ -1275,6 +1278,7 @@ impl<Block: BlockT, Client, I> BabeBlockImport<Block, Client, I> {
 	}
 }
 
+#[async_trait::async_trait]
 impl<Block, Client, Inner> BlockImport<Block> for BabeBlockImport<Block, Client, Inner> where
 	Block: BlockT,
 	Inner: BlockImport<Block, Transaction = sp_api::TransactionFor<Client, Block>> + Send + Sync,
@@ -1286,7 +1290,7 @@ impl<Block, Client, Inner> BlockImport<Block> for BabeBlockImport<Block, Client,
 	type Error = ConsensusError;
 	type Transaction = sp_api::TransactionFor<Client, Block>;
 
-	fn import_block(
+	async fn import_block(
 		&mut self,
 		mut block: BlockImportParams<Block, Self::Transaction>,
 		new_cache: HashMap<CacheKeyId, Vec<u8>>,
@@ -1328,202 +1332,209 @@ impl<Block, Client, Inner> BlockImport<Block> for BabeBlockImport<Block, Client,
 			);
 		}
 
-		let mut epoch_changes = self.epoch_changes.lock();
+		// if there's a pending epoch we'll save the previous epoch changes here
+		// this way we can revert it if there's any error
+		let mut old_epoch_changes = None;
 
-		// check if there's any epoch change expected to happen at this slot.
-		// `epoch` is the epoch to verify the block under, and `first_in_epoch` is true
-		// if this is the first block in its chain for that epoch.
-		//
-		// also provides the total weight of the chain, including the imported block.
-		let (epoch_descriptor, first_in_epoch, parent_weight) = {
-			let parent_weight = if *parent_header.number() == Zero::zero() {
-				0
-			} else {
-				aux_schema::load_block_weight(&*self.client, parent_hash)
-					.map_err(|e| ConsensusError::ClientImport(e.to_string()))?
+		// Use an extra scope to make the compiler happy, because otherwise he complains about the
+		// mutex, even if we dropped it...
+		let mut epoch_changes = {
+			let mut epoch_changes = self.epoch_changes.shared_data_locked();
+
+			// check if there's any epoch change expected to happen at this slot.
+			// `epoch` is the epoch to verify the block under, and `first_in_epoch` is true
+			// if this is the first block in its chain for that epoch.
+			//
+			// also provides the total weight of the chain, including the imported block.
+			let (epoch_descriptor, first_in_epoch, parent_weight) = {
+				let parent_weight = if *parent_header.number() == Zero::zero() {
+					0
+				} else {
+					aux_schema::load_block_weight(&*self.client, parent_hash)
+						.map_err(|e| ConsensusError::ClientImport(e.to_string()))?
 					.ok_or_else(|| ConsensusError::ClientImport(
 						babe_err(Error::<Block>::ParentBlockNoAssociatedWeight(hash)).into()
 					))?
-			};
+				};
 
-			let intermediate = block.take_intermediate::<BabeIntermediate<Block>>(
-				INTERMEDIATE_KEY
-			)?;
+				let intermediate = block.take_intermediate::<BabeIntermediate<Block>>(
+					INTERMEDIATE_KEY
+				)?;
 
-			let epoch_descriptor = intermediate.epoch_descriptor;
-			let first_in_epoch = parent_slot < epoch_descriptor.start_slot();
-			(epoch_descriptor, first_in_epoch, parent_weight)
-		};
+				let epoch_descriptor = intermediate.epoch_descriptor;
+				let first_in_epoch = parent_slot < epoch_descriptor.start_slot();
+				(epoch_descriptor, first_in_epoch, parent_weight)
+			};
 
-		let total_weight = parent_weight + pre_digest.added_weight();
-
-		// search for this all the time so we can reject unexpected announcements.
-		let next_epoch_digest = find_next_epoch_digest::<Block>(&block.header)
-			.map_err(|e| ConsensusError::ClientImport(e.to_string()))?;
-		let next_config_digest = find_next_config_digest::<Block>(&block.header)
-			.map_err(|e| ConsensusError::ClientImport(e.to_string()))?;
-
-		match (first_in_epoch, next_epoch_digest.is_some(), next_config_digest.is_some()) {
-			(true, true, _) => {},
-			(false, false, false) => {},
-			(false, false, true) => {
-				return Err(
-					ConsensusError::ClientImport(
-						babe_err(Error::<Block>::UnexpectedConfigChange).into(),
+			let total_weight = parent_weight + pre_digest.added_weight();
+
+			// search for this all the time so we can reject unexpected announcements.
+			let next_epoch_digest = find_next_epoch_digest::<Block>(&block.header)
+				.map_err(|e| ConsensusError::ClientImport(e.to_string()))?;
+			let next_config_digest = find_next_config_digest::<Block>(&block.header)
+				.map_err(|e| ConsensusError::ClientImport(e.to_string()))?;
+
+			match (first_in_epoch, next_epoch_digest.is_some(), next_config_digest.is_some()) {
+				(true, true, _) => {},
+				(false, false, false) => {},
+				(false, false, true) => {
+					return Err(
+						ConsensusError::ClientImport(
+							babe_err(Error::<Block>::UnexpectedConfigChange).into(),
+						)
 					)
-				)
-			},
-			(true, false, _) => {
-				return Err(
-					ConsensusError::ClientImport(
-						babe_err(Error::<Block>::ExpectedEpochChange(hash, slot)).into(),
+				},
+				(true, false, _) => {
+					return Err(
+						ConsensusError::ClientImport(
+							babe_err(Error::<Block>::ExpectedEpochChange(hash, slot)).into(),
+						)
 					)
-				)
-			},
-			(false, true, _) => {
-				return Err(
-					ConsensusError::ClientImport(
-						babe_err(Error::<Block>::UnexpectedEpochChange).into(),
+				},
+				(false, true, _) => {
+					return Err(
+						ConsensusError::ClientImport(
+							babe_err(Error::<Block>::UnexpectedEpochChange).into(),
+						)
 					)
-				)
-			},
-		}
+				},
+			}
 
-		// if there's a pending epoch we'll save the previous epoch changes here
-		// this way we can revert it if there's any error
-		let mut old_epoch_changes = None;
+			let info = self.client.info();
 
-		let info = self.client.info();
+			if let Some(next_epoch_descriptor) = next_epoch_digest {
+				old_epoch_changes = Some((*epoch_changes).clone());
 
-		if let Some(next_epoch_descriptor) = next_epoch_digest {
-			old_epoch_changes = Some(epoch_changes.clone());
+				let viable_epoch = epoch_changes.viable_epoch(
+					&epoch_descriptor,
+					|slot| Epoch::genesis(&self.config, slot)
+				).ok_or_else(|| {
+					ConsensusError::ClientImport(Error::<Block>::FetchEpoch(parent_hash).into())
+				})?;
 
-			let viable_epoch = epoch_changes.viable_epoch(
-				&epoch_descriptor,
-				|slot| Epoch::genesis(&self.config, slot)
-			).ok_or_else(|| {
-				ConsensusError::ClientImport(Error::<Block>::FetchEpoch(parent_hash).into())
-			})?;
+				let epoch_config = next_config_digest.map(Into::into).unwrap_or_else(
+					|| viable_epoch.as_ref().config.clone()
+				);
 
-			let epoch_config = next_config_digest.map(Into::into).unwrap_or_else(
-				|| viable_epoch.as_ref().config.clone()
-			);
+				// restrict info logging during initial sync to avoid spam
+				let log_level = if block.origin == BlockOrigin::NetworkInitialSync {
+					log::Level::Debug
+				} else {
+					log::Level::Info
+				};
 
-			// restrict info logging during initial sync to avoid spam
-			let log_level = if block.origin == BlockOrigin::NetworkInitialSync {
-				log::Level::Debug
-			} else {
-				log::Level::Info
-			};
+				log!(target: "babe",
+					 log_level,
+					 "👶 New epoch {} launching at block {} (block slot {} >= start slot {}).",
+					 viable_epoch.as_ref().epoch_index,
+					 hash,
+					 slot,
+					 viable_epoch.as_ref().start_slot,
+				);
 
-			log!(target: "babe",
-				log_level,
-				"👶 New epoch {} launching at block {} (block slot {} >= start slot {}).",
-				viable_epoch.as_ref().epoch_index,
-				hash,
-				slot,
-				viable_epoch.as_ref().start_slot,
-			);
+				let next_epoch = viable_epoch.increment((next_epoch_descriptor, epoch_config));
 
-			let next_epoch = viable_epoch.increment((next_epoch_descriptor, epoch_config));
+				log!(target: "babe",
+					 log_level,
+					 "👶 Next epoch starts at slot {}",
+					 next_epoch.as_ref().start_slot,
+				);
 
-			log!(target: "babe",
-				log_level,
-				"👶 Next epoch starts at slot {}",
-				next_epoch.as_ref().start_slot,
-			);
+				// prune the tree of epochs not part of the finalized chain or
+				// that are not live anymore, and then track the given epoch change
+				// in the tree.
+				// NOTE: it is important that these operations are done in this
+				// order, otherwise if pruning after import the `is_descendent_of`
+				// used by pruning may not know about the block that is being
+				// imported.
+				let prune_and_import = || {
+					prune_finalized(
+						self.client.clone(),
+						&mut epoch_changes,
+					)?;
 
-			// prune the tree of epochs not part of the finalized chain or
-			// that are not live anymore, and then track the given epoch change
-			// in the tree.
-			// NOTE: it is important that these operations are done in this
-			// order, otherwise if pruning after import the `is_descendent_of`
-			// used by pruning may not know about the block that is being
-			// imported.
-			let prune_and_import = || {
-				prune_finalized(
-					self.client.clone(),
-					&mut epoch_changes,
-				)?;
+					epoch_changes.import(
+						descendent_query(&*self.client),
+						hash,
+						number,
+						*block.header.parent_hash(),
+						next_epoch,
+					).map_err(|e| ConsensusError::ClientImport(format!("{:?}", e)))?;
 
-				epoch_changes.import(
-					descendent_query(&*self.client),
-					hash,
-					number,
-					*block.header.parent_hash(),
-					next_epoch,
-				).map_err(|e| ConsensusError::ClientImport(format!("{:?}", e)))?;
+					Ok(())
+				};
 
-				Ok(())
-			};
+				if let Err(e) = prune_and_import() {
+					debug!(target: "babe", "Failed to launch next epoch: {:?}", e);
+					*epoch_changes = old_epoch_changes.expect("set `Some` above and not taken; qed");
+					return Err(e);
+				}
 
-			if let Err(e) = prune_and_import() {
-				debug!(target: "babe", "Failed to launch next epoch: {:?}", e);
-				*epoch_changes = old_epoch_changes.expect("set `Some` above and not taken; qed");
-				return Err(e);
+				crate::aux_schema::write_epoch_changes::<Block, _, _>(
+					&*epoch_changes,
+					|insert| block.auxiliary.extend(
+						insert.iter().map(|(k, v)| (k.to_vec(), Some(v.to_vec())))
+					)
+				);
 			}
 
-			crate::aux_schema::write_epoch_changes::<Block, _, _>(
-				&*epoch_changes,
-				|insert| block.auxiliary.extend(
-					insert.iter().map(|(k, v)| (k.to_vec(), Some(v.to_vec())))
-				)
+			aux_schema::write_block_weight(
+				hash,
+				total_weight,
+				|values| block.auxiliary.extend(
+					values.iter().map(|(k, v)| (k.to_vec(), Some(v.to_vec())))
+				),
 			);
-		}
-
-		aux_schema::write_block_weight(
-			hash,
-			total_weight,
-			|values| block.auxiliary.extend(
-				values.iter().map(|(k, v)| (k.to_vec(), Some(v.to_vec())))
-			),
-		);
 
-		// The fork choice rule is that we pick the heaviest chain (i.e.
-		// more primary blocks), if there's a tie we go with the longest
-		// chain.
-		block.fork_choice = {
-			let (last_best, last_best_number) = (info.best_hash, info.best_number);
-
-			let last_best_weight = if &last_best == block.header.parent_hash() {
-				// the parent=genesis case is already covered for loading parent weight,
-				// so we don't need to cover again here.
-				parent_weight
-			} else {
-				aux_schema::load_block_weight(&*self.client, last_best)
-					.map_err(|e| ConsensusError::ChainLookup(format!("{:?}", e)))?
+			// The fork choice rule is that we pick the heaviest chain (i.e.
+			// more primary blocks), if there's a tie we go with the longest
+			// chain.
+			block.fork_choice = {
+				let (last_best, last_best_number) = (info.best_hash, info.best_number);
+
+				let last_best_weight = if &last_best == block.header.parent_hash() {
+					// the parent=genesis case is already covered for loading parent weight,
+					// so we don't need to cover again here.
+					parent_weight
+				} else {
+					aux_schema::load_block_weight(&*self.client, last_best)
+						.map_err(|e| ConsensusError::ChainLookup(format!("{:?}", e)))?
 					.ok_or_else(
 						|| ConsensusError::ChainLookup("No block weight for parent header.".to_string())
 					)?
+				};
+
+				Some(ForkChoiceStrategy::Custom(if total_weight > last_best_weight {
+					true
+				} else if total_weight == last_best_weight {
+					number > last_best_number
+				} else {
+					false
+				}))
 			};
 
-			Some(ForkChoiceStrategy::Custom(if total_weight > last_best_weight {
-				true
-			} else if total_weight == last_best_weight {
-				number > last_best_number
-			} else {
-				false
-			}))
+			// Release the mutex, but it stays locked
+			epoch_changes.release_mutex()
 		};
 
-		let import_result = self.inner.import_block(block, new_cache);
+		let import_result = self.inner.import_block(block, new_cache).await;
 
 		// revert to the original epoch changes in case there's an error
 		// importing the block
 		if import_result.is_err() {
 			if let Some(old_epoch_changes) = old_epoch_changes {
-				*epoch_changes = old_epoch_changes;
+				*epoch_changes.upgrade() = old_epoch_changes;
 			}
 		}
 
 		import_result.map_err(Into::into)
 	}
 
-	fn check_block(
+	async fn check_block(
 		&mut self,
 		block: BlockCheckParams<Block>,
 	) -> Result<ImportResult, Self::Error> {
-		self.inner.check_block(block).map_err(Into::into)
+		self.inner.check_block(block).await.map_err(Into::into)
 	}
 }
 
@@ -1583,7 +1594,7 @@ pub fn block_import<Client, Block: BlockT, I>(
 	// startup rather than waiting until importing the next epoch change block.
 	prune_finalized(
 		client.clone(),
-		&mut epoch_changes.lock(),
+		&mut epoch_changes.shared_data(),
 	)?;
 
 	let import = BabeBlockImport::new(
@@ -1626,7 +1637,7 @@ pub fn import_queue<Block: BlockT, Client, SelectChain, Inner, CAW>(
 	SelectChain: sp_consensus::SelectChain<Block> + 'static,
 	CAW: CanAuthorWith<Block> + Send + Sync + 'static,
 {
-	register_babe_inherent_data_provider(&inherent_data_providers, babe_link.config.slot_duration)?;
+	register_babe_inherent_data_provider(&inherent_data_providers, babe_link.config.slot_duration())?;
 
 	let verifier = BabeVerifier {
 		select_chain,
@@ -1647,41 +1658,3 @@ pub fn import_queue<Block: BlockT, Client, SelectChain, Inner, CAW>(
 		registry,
 	))
 }
-
-/// BABE test helpers. Utility methods for manually authoring blocks.
-#[cfg(feature = "test-helpers")]
-pub mod test_helpers {
-	use super::*;
-
-	/// Try to claim the given slot and return a `BabePreDigest` if
-	/// successful.
-	pub fn claim_slot<B, C>(
-		slot: Slot,
-		parent: &B::Header,
-		client: &C,
-		keystore: SyncCryptoStorePtr,
-		link: &BabeLink<B>,
-	) -> Option<PreDigest> where
-		B: BlockT,
-		C: ProvideRuntimeApi<B> +
-			ProvideCache<B> +
-			HeaderBackend<B> +
-			HeaderMetadata<B, Error = ClientError>,
-		C::Api: BabeApi<B>,
-	{
-		let epoch_changes = link.epoch_changes.lock();
-		let epoch = epoch_changes.epoch_data_for_child_of(
-			descendent_query(client),
-			&parent.hash(),
-			parent.number().clone(),
-			slot,
-			|slot| Epoch::genesis(&link.config, slot),
-		).unwrap().unwrap();
-
-		authorship::claim_slot(
-			slot,
-			&epoch,
-			&keystore,
-		).map(|(digest, _)| digest)
-	}
-}
diff --git a/client/consensus/babe/src/tests.rs b/client/consensus/babe/src/tests.rs
index d3e51b020326c..839d38b94a933 100644
--- a/client/consensus/babe/src/tests.rs
+++ b/client/consensus/babe/src/tests.rs
@@ -47,6 +47,7 @@ use rand_chacha::{
 };
 use sc_keystore::LocalKeystore;
 use sp_application_crypto::key_types::BABE;
+use futures::executor::block_on;
 
 type Item = DigestItem<Hash>;
 
@@ -67,6 +68,9 @@ enum Stage {
 
 type Mutator = Arc<dyn Fn(&mut TestHeader, Stage) + Send + Sync>;
 
+type BabeBlockImport =
+	PanickingBlockImport<crate::BabeBlockImport<TestBlock, TestClient, Arc<TestClient>>>;
+
 #[derive(Clone)]
 struct DummyFactory {
 	client: Arc<TestClient>,
@@ -134,7 +138,7 @@ impl DummyProposer {
 
 		// figure out if we should add a consensus digest, since the test runtime
 		// doesn't.
-		let epoch_changes = self.factory.epoch_changes.lock();
+		let epoch_changes = self.factory.epoch_changes.shared_data();
 		let epoch = epoch_changes.epoch_data_for_child_of(
 			descendent_query(&*self.factory.client),
 			&self.parent_hash,
@@ -188,30 +192,37 @@ thread_local! {
 }
 
 #[derive(Clone)]
-struct PanickingBlockImport<B>(B);
-
-impl<B: BlockImport<TestBlock>> BlockImport<TestBlock> for PanickingBlockImport<B> {
+pub struct PanickingBlockImport<B>(B);
+
+#[async_trait::async_trait]
+impl<B: BlockImport<TestBlock>> BlockImport<TestBlock> for PanickingBlockImport<B>
+	where
+		B::Transaction: Send,
+		B: Send,
+{
 	type Error = B::Error;
 	type Transaction = B::Transaction;
 
-	fn import_block(
+	async fn import_block(
 		&mut self,
 		block: BlockImportParams<TestBlock, Self::Transaction>,
 		new_cache: HashMap<CacheKeyId, Vec<u8>>,
 	) -> Result<ImportResult, Self::Error> {
-		Ok(self.0.import_block(block, new_cache).expect("importing block failed"))
+		Ok(self.0.import_block(block, new_cache).await.expect("importing block failed"))
 	}
 
-	fn check_block(
+	async fn check_block(
 		&mut self,
 		block: BlockCheckParams<TestBlock>,
 	) -> Result<ImportResult, Self::Error> {
-		Ok(self.0.check_block(block).expect("checking block failed"))
+		Ok(self.0.check_block(block).await.expect("checking block failed"))
 	}
 }
 
+type BabePeer = Peer<Option<PeerData>, BabeBlockImport>;
+
 pub struct BabeTestNet {
-	peers: Vec<Peer<Option<PeerData>>>,
+	peers: Vec<BabePeer>,
 }
 
 type TestHeader = <TestBlock as BlockT>::Header;
@@ -227,20 +238,21 @@ pub struct TestVerifier {
 	mutator: Mutator,
 }
 
+#[async_trait::async_trait]
 impl Verifier<TestBlock> for TestVerifier {
 	/// Verify the given data and return the BlockImportParams and an optional
 	/// new set of validators to import. If not, err with an Error-Message
 	/// presented to the User in the logs.
-	fn verify(
+	async fn verify(
 		&mut self,
 		origin: BlockOrigin,
 		mut header: TestHeader,
-		justification: Option<Justification>,
+		justifications: Option<Justifications>,
 		body: Option<Vec<TestExtrinsic>>,
 	) -> Result<(BlockImportParams<TestBlock, ()>, Option<Vec<(CacheKeyId, Vec<u8>)>>), String> {
 		// apply post-sealing mutations (i.e. stripping seal, if desired).
 		(self.mutator)(&mut header, Stage::PostSeal);
-		self.inner.verify(origin, header, justification, body)
+		self.inner.verify(dbg!(origin), header, justifications, body).await
 	}
 }
 
@@ -255,6 +267,7 @@ pub struct PeerData {
 impl TestNetFactory for BabeTestNet {
 	type Verifier = TestVerifier;
 	type PeerData = Option<PeerData>;
+	type BlockImport = BabeBlockImport;
 
 	/// Create new test network with peers and given config.
 	fn from_config(_config: &ProtocolConfig) -> Self {
@@ -264,9 +277,9 @@ impl TestNetFactory for BabeTestNet {
 		}
 	}
 
-	fn make_block_import<Transaction>(&self, client: PeersClient)
+	fn make_block_import(&self, client: PeersClient)
 		-> (
-			BlockImportAdapter<Transaction>,
+			BlockImportAdapter<Self::BlockImport>,
 			Option<BoxJustificationImport<Block>>,
 			Option<PeerData>,
 		)
@@ -287,7 +300,7 @@ impl TestNetFactory for BabeTestNet {
 			Some(Box::new(block_import.clone()) as BoxBlockImport<_, _>)
 		);
 		(
-			BlockImportAdapter::new_full(block_import),
+			BlockImportAdapter::new(block_import),
 			None,
 			Some(PeerData { link, inherent_data_providers, block_import: data_block_import }),
 		)
@@ -326,17 +339,17 @@ impl TestNetFactory for BabeTestNet {
 		}
 	}
 
-	fn peer(&mut self, i: usize) -> &mut Peer<Self::PeerData> {
+	fn peer(&mut self, i: usize) -> &mut BabePeer {
 		trace!(target: "babe", "Retrieving a peer");
 		&mut self.peers[i]
 	}
 
-	fn peers(&self) -> &Vec<Peer<Self::PeerData>> {
+	fn peers(&self) -> &Vec<BabePeer> {
 		trace!(target: "babe", "Retrieving peers");
 		&self.peers
 	}
 
-	fn mut_peers<F: FnOnce(&mut Vec<Peer<Self::PeerData>>)>(
+	fn mut_peers<F: FnOnce(&mut Vec<BabePeer>)>(
 		&mut self,
 		closure: F,
 	) {
@@ -436,7 +449,7 @@ fn run_one_test(
 			telemetry: None,
 		}).expect("Starts babe"));
 	}
-	futures::executor::block_on(future::select(
+	block_on(future::select(
 		futures::future::poll_fn(move |cx| {
 			let mut net = net.lock();
 			net.poll(cx);
@@ -567,7 +580,7 @@ fn can_author_block() {
 }
 
 // Propose and import a new BABE block on top of the given parent.
-fn propose_and_import_block<Transaction>(
+fn propose_and_import_block<Transaction: Send + 'static>(
 	parent: &TestHeader,
 	slot: Option<Slot>,
 	proposer_factory: &mut DummyFactory,
@@ -595,7 +608,7 @@ fn propose_and_import_block<Transaction>(
 
 	let mut block = futures::executor::block_on(proposer.propose_with(pre_digest)).unwrap().block;
 
-	let epoch_descriptor = proposer_factory.epoch_changes.lock().epoch_descriptor_for_child_of(
+	let epoch_descriptor = proposer_factory.epoch_changes.shared_data().epoch_descriptor_for_child_of(
 		descendent_query(&*proposer_factory.client),
 		&parent_hash,
 		*parent.number(),
@@ -623,10 +636,10 @@ fn propose_and_import_block<Transaction>(
 	import.body = Some(block.extrinsics);
 	import.intermediates.insert(
 		Cow::from(INTERMEDIATE_KEY),
-		Box::new(BabeIntermediate::<TestBlock> { epoch_descriptor }) as Box<dyn Any>,
+		Box::new(BabeIntermediate::<TestBlock> { epoch_descriptor }) as Box<_>,
 	);
 	import.fork_choice = Some(ForkChoiceStrategy::LongestChain);
-	let import_result = block_import.import_block(import, Default::default()).unwrap();
+	let import_result = block_on(block_import.import_block(import, Default::default())).unwrap();
 
 	match import_result {
 		ImportResult::Imported(_) => {},
@@ -664,7 +677,7 @@ fn importing_block_one_sets_genesis_epoch() {
 
 	let genesis_epoch = Epoch::genesis(&data.link.config, 999.into());
 
-	let epoch_changes = data.link.epoch_changes.lock();
+	let epoch_changes = data.link.epoch_changes.shared_data();
 	let epoch_for_second_block = epoch_changes.epoch_data_for_child_of(
 		descendent_query(&*client),
 		&block_hash,
@@ -739,13 +752,13 @@ fn importing_epoch_change_block_prunes_tree() {
 
 	// We should be tracking a total of 9 epochs in the fork tree
 	assert_eq!(
-		epoch_changes.lock().tree().iter().count(),
+		epoch_changes.shared_data().tree().iter().count(),
 		9,
 	);
 
 	// And only one root
 	assert_eq!(
-		epoch_changes.lock().tree().roots().count(),
+		epoch_changes.shared_data().tree().roots().count(),
 		1,
 	);
 
@@ -756,16 +769,16 @@ fn importing_epoch_change_block_prunes_tree() {
 
 	// at this point no hashes from the first fork must exist on the tree
 	assert!(
-		!epoch_changes.lock().tree().iter().map(|(h, _, _)| h).any(|h| fork_1.contains(h)),
+		!epoch_changes.shared_data().tree().iter().map(|(h, _, _)| h).any(|h| fork_1.contains(h)),
 	);
 
 	// but the epoch changes from the other forks must still exist
 	assert!(
-		epoch_changes.lock().tree().iter().map(|(h, _, _)| h).any(|h| fork_2.contains(h))
+		epoch_changes.shared_data().tree().iter().map(|(h, _, _)| h).any(|h| fork_2.contains(h))
 	);
 
 	assert!(
-		epoch_changes.lock().tree().iter().map(|(h, _, _)| h).any(|h| fork_3.contains(h)),
+		epoch_changes.shared_data().tree().iter().map(|(h, _, _)| h).any(|h| fork_3.contains(h)),
 	);
 
 	// finalizing block #25 from the canon chain should prune out the second fork
@@ -774,12 +787,12 @@ fn importing_epoch_change_block_prunes_tree() {
 
 	// at this point no hashes from the second fork must exist on the tree
 	assert!(
-		!epoch_changes.lock().tree().iter().map(|(h, _, _)| h).any(|h| fork_2.contains(h)),
+		!epoch_changes.shared_data().tree().iter().map(|(h, _, _)| h).any(|h| fork_2.contains(h)),
 	);
 
 	// while epoch changes from the last fork should still exist
 	assert!(
-		epoch_changes.lock().tree().iter().map(|(h, _, _)| h).any(|h| fork_3.contains(h)),
+		epoch_changes.shared_data().tree().iter().map(|(h, _, _)| h).any(|h| fork_3.contains(h)),
 	);
 }
 
diff --git a/client/consensus/common/Cargo.toml b/client/consensus/common/Cargo.toml
index 41c42866e7272..5762b9c998b67 100644
--- a/client/consensus/common/Cargo.toml
+++ b/client/consensus/common/Cargo.toml
@@ -17,3 +17,4 @@ sc-client-api = { version = "3.0.0", path = "../../api" }
 sp-blockchain = { version = "3.0.0", path = "../../../primitives/blockchain" }
 sp-runtime = { version = "3.0.0", path = "../../../primitives/runtime" }
 sp-consensus = { version = "0.9.0", path = "../../../primitives/consensus/common" }
+parking_lot = "0.11.1"
diff --git a/client/consensus/common/src/lib.rs b/client/consensus/common/src/lib.rs
index a53517c5c35ea..9b4d705769196 100644
--- a/client/consensus/common/src/lib.rs
+++ b/client/consensus/common/src/lib.rs
@@ -17,6 +17,8 @@
 // along with this program. If not, see <https://www.gnu.org/licenses/>.
 
 //! Collection of common consensus specific implementations
+
 mod longest_chain;
+pub mod shared_data;
 
 pub use longest_chain::LongestChain;
diff --git a/client/consensus/common/src/shared_data.rs b/client/consensus/common/src/shared_data.rs
new file mode 100644
index 0000000000000..d90fc6273e056
--- /dev/null
+++ b/client/consensus/common/src/shared_data.rs
@@ -0,0 +1,271 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Provides a generic wrapper around shared data. See [`SharedData`] for more information.
+
+use std::sync::Arc;
+use parking_lot::{Mutex, MappedMutexGuard, Condvar, MutexGuard};
+
+/// Created by [`SharedDataLocked::release_mutex`].
+///
+/// As long as the object isn't dropped, the shared data is locked. It is advised to drop this
+/// object when the shared data doesn't need to be locked anymore. To get access to the shared data
+/// [`Self::upgrade`] is provided.
+#[must_use = "Shared data will be unlocked on drop!"]
+pub struct SharedDataLockedUpgradable<T> {
+	shared_data: SharedData<T>,
+}
+
+impl<T> SharedDataLockedUpgradable<T> {
+	/// Upgrade to a *real* mutex guard that will give access to the inner data.
+	///
+	/// Every call to this function will reaquire the mutex again.
+	pub fn upgrade(&mut self) -> MappedMutexGuard<T> {
+		MutexGuard::map(self.shared_data.inner.lock(), |i| &mut i.shared_data)
+	}
+}
+
+impl<T> Drop for SharedDataLockedUpgradable<T> {
+	fn drop(&mut self) {
+		let mut inner = self.shared_data.inner.lock();
+		// It should not be locked anymore
+		inner.locked = false;
+
+		// Notify all waiting threads.
+		self.shared_data.cond_var.notify_all();
+	}
+}
+
+/// Created by [`SharedData::shared_data_locked`].
+///
+/// As long as this object isn't dropped, the shared data is held in a mutex guard and the shared
+/// data is tagged as locked. Access to the shared data is provided through [`Deref`] and
+/// [`DerefMut`]. The trick is to use [`Self::release_mutex`] to release the mutex, but still keep
+/// the shared data locked. This means every other thread trying to access the shared data in this
+/// time will need to wait until this lock is freed.
+///
+/// If this object is dropped without calling [`Self::release_mutex`], the lock will be dropped
+/// immediately.
+#[must_use = "Shared data will be unlocked on drop!"]
+pub struct SharedDataLocked<'a, T> {
+	/// The current active mutex guard holding the inner data.
+	inner: MutexGuard<'a, SharedDataInner<T>>,
+	/// The [`SharedData`] instance that created this instance.
+	///
+	/// This instance is only taken on drop or when calling [`Self::release_mutex`].
+	shared_data: Option<SharedData<T>>,
+}
+
+impl<'a, T> SharedDataLocked<'a, T> {
+	/// Release the mutex, but keep the shared data locked.
+	pub fn release_mutex(mut self) -> SharedDataLockedUpgradable<T> {
+		SharedDataLockedUpgradable {
+			shared_data: self.shared_data.take()
+				.expect("`shared_data` is only taken on drop; qed"),
+		}
+	}
+}
+
+impl<'a, T> Drop for SharedDataLocked<'a, T> {
+	fn drop(&mut self) {
+		if let Some(shared_data) = self.shared_data.take() {
+			// If the `shared_data` is still set, it means [`Self::release_mutex`] wasn't
+			// called and the lock should be released.
+			self.inner.locked = false;
+
+			// Notify all waiting threads about the released lock.
+			shared_data.cond_var.notify_all();
+		}
+	}
+}
+
+impl<'a, T> std::ops::Deref for SharedDataLocked<'a, T> {
+	type Target = T;
+
+	fn deref(&self) -> &Self::Target {
+		&self.inner.shared_data
+	}
+}
+
+impl<'a, T> std::ops::DerefMut for SharedDataLocked<'a, T> {
+	fn deref_mut(&mut self) -> &mut Self::Target {
+		&mut self.inner.shared_data
+	}
+}
+
+/// Holds the shared data and if the shared data is currently locked.
+///
+/// For more information see [`SharedData`].
+struct SharedDataInner<T> {
+	/// The actual shared data that is protected here against concurrent access.
+	shared_data: T,
+	/// Is `shared_data` currently locked and can not be accessed?
+	locked: bool,
+}
+
+/// Some shared data that provides support for locking this shared data for some time.
+///
+/// When working with consensus engines there is often data that needs to be shared between multiple
+/// parts of the system, like block production and block import. This struct provides an abstraction
+/// for this shared data in a generic way.
+///
+/// The pain point when sharing this data is often the usage of mutex guards in an async context as
+/// this doesn't work for most of them as these guards don't implement `Send`. This abstraction
+/// provides a way to lock the shared data, while not having the mutex locked. So, the data stays
+/// locked and we are still able to hold this lock over an `await` call.
+///
+/// # Example
+///
+/// ```
+///# use sc_consensus::shared_data::SharedData;
+///
+/// let shared_data = SharedData::new(String::from("hello world"));
+///
+/// let lock = shared_data.shared_data_locked();
+///
+/// let shared_data2 = shared_data.clone();
+/// let join_handle1 = std::thread::spawn(move || {
+///     // This will need to wait for the outer lock to be released before it can access the data.
+///     shared_data2.shared_data().push_str("1");
+/// });
+///
+/// assert_eq!(*lock, "hello world");
+///
+/// // Let us release the mutex, but we still keep it locked.
+/// // Now we could call `await` for example.
+/// let mut lock = lock.release_mutex();
+///
+/// let shared_data2 = shared_data.clone();
+/// let join_handle2 = std::thread::spawn(move || {
+///     shared_data2.shared_data().push_str("2");
+/// });
+///
+/// // We still have the lock and can upgrade it to access the data.
+/// assert_eq!(*lock.upgrade(), "hello world");
+/// lock.upgrade().push_str("3");
+///
+/// drop(lock);
+/// join_handle1.join().unwrap();
+/// join_handle2.join().unwrap();
+///
+/// let data = shared_data.shared_data();
+/// // As we don't know the order of the threads, we need to check for both combinations
+/// assert!(*data == "hello world321" || *data == "hello world312");
+/// ```
+pub struct SharedData<T> {
+	inner: Arc<Mutex<SharedDataInner<T>>>,
+	cond_var: Arc<Condvar>,
+}
+
+impl<T> Clone for SharedData<T> {
+	fn clone(&self) -> Self {
+		Self {
+			inner: self.inner.clone(),
+			cond_var: self.cond_var.clone(),
+		}
+	}
+}
+
+impl<T> SharedData<T> {
+	/// Create a new instance of [`SharedData`] to share the given `shared_data`.
+	pub fn new(shared_data: T) -> Self {
+		Self {
+			inner: Arc::new(Mutex::new(SharedDataInner { shared_data, locked: false })),
+			cond_var: Default::default(),
+		}
+	}
+
+	/// Acquire access to the shared data.
+	///
+	/// This will give mutable access to the shared data. After the returned mutex guard is dropped,
+	/// the shared data is accessible by other threads. So, this function should be used when
+	/// reading/writing of the shared data in a local context is required.
+	///
+	/// When requiring to lock shared data for some longer time, even with temporarily releasing the
+	/// lock, [`Self::shared_data_locked`] should be used.
+	pub fn shared_data(&self) -> MappedMutexGuard<T> {
+		let mut guard = self.inner.lock();
+
+		while guard.locked {
+			self.cond_var.wait(&mut guard);
+		}
+
+		debug_assert!(!guard.locked);
+
+		MutexGuard::map(guard, |i| &mut i.shared_data)
+	}
+
+	/// Acquire access to the shared data and lock it.
+	///
+	/// This will give mutable access to the shared data. The returned [`SharedDataLocked`]
+	/// provides the function [`SharedDataLocked::release_mutex`] to release the mutex, but
+	/// keeping the data locked. This is useful in async contexts for example where the data needs to
+	/// be locked, but a mutex guard can not be held.
+	///
+	/// For an example see [`SharedData`].
+	pub fn shared_data_locked(&self) -> SharedDataLocked<T> {
+		let mut guard = self.inner.lock();
+
+		while guard.locked {
+			self.cond_var.wait(&mut guard);
+		}
+
+		debug_assert!(!guard.locked);
+		guard.locked = true;
+
+		SharedDataLocked {
+			inner: guard,
+			shared_data: Some(self.clone()),
+		}
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+
+	#[test]
+	fn shared_data_locking_works() {
+		const THREADS: u32 = 100;
+		let shared_data = SharedData::new(0u32);
+
+		let lock = shared_data.shared_data_locked();
+
+		for i in 0..THREADS {
+			let data = shared_data.clone();
+			std::thread::spawn(move || {
+				if i % 2 == 1 {
+					*data.shared_data() += 1;
+				} else {
+					let mut lock = data.shared_data_locked().release_mutex();
+					// Give the other threads some time to wake up
+					std::thread::sleep(std::time::Duration::from_millis(10));
+					*lock.upgrade() += 1;
+				}
+			});
+		}
+
+		let lock = lock.release_mutex();
+		std::thread::sleep(std::time::Duration::from_millis(100));
+		drop(lock);
+
+		while *shared_data.shared_data() < THREADS {
+			std::thread::sleep(std::time::Duration::from_millis(100));
+		}
+	}
+}
diff --git a/client/consensus/epochs/Cargo.toml b/client/consensus/epochs/Cargo.toml
index bebe6979e694e..8e2fe77100967 100644
--- a/client/consensus/epochs/Cargo.toml
+++ b/client/consensus/epochs/Cargo.toml
@@ -14,8 +14,8 @@ targets = ["x86_64-unknown-linux-gnu"]
 
 [dependencies]
 codec = { package = "parity-scale-codec", version = "2.0.0", features = ["derive"] }
-parking_lot = "0.11.1"
 fork-tree = { version = "3.0.0", path = "../../../utils/fork-tree" }
 sp-runtime = {  path = "../../../primitives/runtime" , version = "3.0.0"}
 sp-blockchain = { version = "3.0.0", path = "../../../primitives/blockchain" }
 sc-client-api = { path = "../../api" , version = "3.0.0"}
+sc-consensus = { path = "../common" , version = "0.9.0"}
diff --git a/client/consensus/epochs/src/lib.rs b/client/consensus/epochs/src/lib.rs
index 5c5ef446993a2..98a3e83530510 100644
--- a/client/consensus/epochs/src/lib.rs
+++ b/client/consensus/epochs/src/lib.rs
@@ -20,8 +20,7 @@
 
 pub mod migration;
 
-use std::{sync::Arc, ops::Add, collections::BTreeMap, borrow::{Borrow, BorrowMut}};
-use parking_lot::Mutex;
+use std::{ops::Add, collections::BTreeMap, borrow::{Borrow, BorrowMut}};
 use codec::{Encode, Decode};
 use fork_tree::ForkTree;
 use sc_client_api::utils::is_descendent_of;
@@ -645,10 +644,12 @@ impl<Hash, Number, E: Epoch> EpochChanges<Hash, Number, E> where
 }
 
 /// Type alias to produce the epoch-changes tree from a block type.
-pub type EpochChangesFor<Block, Epoch> = EpochChanges<<Block as BlockT>::Hash, NumberFor<Block>, Epoch>;
+pub type EpochChangesFor<Block, Epoch> =
+	EpochChanges<<Block as BlockT>::Hash, NumberFor<Block>, Epoch>;
 
 /// A shared epoch changes tree.
-pub type SharedEpochChanges<Block, Epoch> = Arc<Mutex<EpochChangesFor<Block, Epoch>>>;
+pub type SharedEpochChanges<Block, Epoch> =
+	sc_consensus::shared_data::SharedData<EpochChangesFor<Block, Epoch>>;
 
 #[cfg(test)]
 mod tests {
diff --git a/client/consensus/manual-seal/Cargo.toml b/client/consensus/manual-seal/Cargo.toml
index 679fd5a3eb388..32cc89034fb1d 100644
--- a/client/consensus/manual-seal/Cargo.toml
+++ b/client/consensus/manual-seal/Cargo.toml
@@ -23,6 +23,7 @@ parking_lot = "0.11.1"
 codec = { package = "parity-scale-codec", version = "2.0.0" }
 serde = { version = "1.0", features=["derive"] }
 assert_matches = "1.3.0"
+async-trait = "0.1.42"
 
 sc-client-api = { path = "../../api", version = "3.0.0"}
 sc-consensus-babe = { path = "../../consensus/babe", version = "0.9.0"}
diff --git a/client/consensus/manual-seal/src/consensus/babe.rs b/client/consensus/manual-seal/src/consensus/babe.rs
index 7fe51c7b79ce5..d627ea2a25c3a 100644
--- a/client/consensus/manual-seal/src/consensus/babe.rs
+++ b/client/consensus/manual-seal/src/consensus/babe.rs
@@ -21,12 +21,7 @@
 use super::ConsensusDataProvider;
 use crate::Error;
 use codec::Encode;
-use std::{
-	any::Any,
-	borrow::Cow,
-	sync::{Arc, atomic},
-	time::SystemTime,
-};
+use std::{borrow::Cow, sync::{Arc, atomic}, time::SystemTime};
 use sc_client_api::AuxStore;
 use sc_consensus_babe::{
 	Config, Epoch, authorship, CompatibleDigestItem, BabeIntermediate,
@@ -90,7 +85,7 @@ impl<B, C> BabeConsensusDataProvider<B, C>
 		let timestamp_provider = SlotTimestampProvider::new(client.clone())?;
 
 		provider.register_provider(timestamp_provider)?;
-		register_babe_inherent_data_provider(provider, config.slot_duration)?;
+		register_babe_inherent_data_provider(provider, config.slot_duration())?;
 
 		Ok(Self {
 			config,
@@ -102,7 +97,7 @@ impl<B, C> BabeConsensusDataProvider<B, C>
 	}
 
 	fn epoch(&self, parent: &B::Header, slot: Slot) -> Result<Epoch, Error> {
-		let epoch_changes = self.epoch_changes.lock();
+		let epoch_changes = self.epoch_changes.shared_data();
 		let epoch_descriptor = epoch_changes
 			.epoch_descriptor_for_child_of(
 				descendent_query(&*self.client),
@@ -156,7 +151,7 @@ impl<B, C> ConsensusDataProvider<B> for BabeConsensusDataProvider<B, C>
 				authority_index: 0_u32,
 			});
 
-			let mut epoch_changes = self.epoch_changes.lock();
+			let mut epoch_changes = self.epoch_changes.shared_data();
 			let epoch_descriptor = epoch_changes
 				.epoch_descriptor_for_child_of(
 					descendent_query(&*self.client),
@@ -200,7 +195,7 @@ impl<B, C> ConsensusDataProvider<B> for BabeConsensusDataProvider<B, C>
 		inherents: &InherentData
 	) -> Result<(), Error> {
 		let slot = inherents.babe_inherent_data()?;
-		let epoch_changes = self.epoch_changes.lock();
+		let epoch_changes = self.epoch_changes.shared_data();
 		let mut epoch_descriptor = epoch_changes
 			.epoch_descriptor_for_child_of(
 				descendent_query(&*self.client),
@@ -239,7 +234,7 @@ impl<B, C> ConsensusDataProvider<B> for BabeConsensusDataProvider<B, C>
 
 		params.intermediates.insert(
 			Cow::from(INTERMEDIATE_KEY),
-			Box::new(BabeIntermediate::<B> { epoch_descriptor }) as Box<dyn Any>,
+			Box::new(BabeIntermediate::<B> { epoch_descriptor }) as Box<_>,
 		);
 
 		Ok(())
diff --git a/client/consensus/manual-seal/src/lib.rs b/client/consensus/manual-seal/src/lib.rs
index 64de70939503c..a5351c63bc3b4 100644
--- a/client/consensus/manual-seal/src/lib.rs
+++ b/client/consensus/manual-seal/src/lib.rs
@@ -27,7 +27,7 @@ use sp_consensus::{
 };
 use sp_blockchain::HeaderBackend;
 use sp_inherents::InherentDataProviders;
-use sp_runtime::{traits::Block as BlockT, Justification};
+use sp_runtime::{traits::Block as BlockT, Justifications, ConsensusEngineId};
 use sc_client_api::backend::{Backend as ClientBackend, Finalizer};
 use sc_transaction_pool::txpool;
 use std::{sync::Arc, marker::PhantomData};
@@ -49,19 +49,23 @@ pub use self::{
 };
 use sp_api::{ProvideRuntimeApi, TransactionFor};
 
+/// The `ConsensusEngineId` of Manual Seal.
+pub const MANUAL_SEAL_ENGINE_ID: ConsensusEngineId = [b'm', b'a', b'n', b'l'];
+
 /// The verifier for the manual seal engine; instantly finalizes.
 struct ManualSealVerifier;
 
+#[async_trait::async_trait]
 impl<B: BlockT> Verifier<B> for ManualSealVerifier {
-	fn verify(
+	async fn verify(
 		&mut self,
 		origin: BlockOrigin,
 		header: B::Header,
-		justification: Option<Justification>,
+		justifications: Option<Justifications>,
 		body: Option<Vec<B::Extrinsic>>,
 	) -> Result<(BlockImportParams<B, ()>, Option<Vec<(CacheKeyId, Vec<u8>)>>), String> {
 		let mut import_params = BlockImportParams::new(origin, header);
-		import_params.justification = justification;
+		import_params.justifications = justifications;
 		import_params.body = body;
 		import_params.finalized = false;
 		import_params.fork_choice = Some(ForkChoiceStrategy::LongestChain);
@@ -193,6 +197,7 @@ pub async fn run_manual_seal<B, BI, CB, E, C, A, SC, CS>(
 				).await;
 			}
 			EngineCommand::FinalizeBlock { hash, sender, justification } => {
+				let justification = justification.map(|j| (MANUAL_SEAL_ENGINE_ID, j));
 				finalize_block(
 					FinalizeBlockParams {
 						hash,
diff --git a/client/consensus/manual-seal/src/rpc.rs b/client/consensus/manual-seal/src/rpc.rs
index 293d4487a5d59..eb056f22fed8b 100644
--- a/client/consensus/manual-seal/src/rpc.rs
+++ b/client/consensus/manual-seal/src/rpc.rs
@@ -28,7 +28,7 @@ use futures::{
 	SinkExt
 };
 use serde::{Deserialize, Serialize};
-use sp_runtime::Justification;
+use sp_runtime::EncodedJustification;
 pub use self::gen_client::Client as ManualSealClient;
 
 /// Future's type for jsonrpc
@@ -62,7 +62,7 @@ pub enum EngineCommand<Hash> {
 		/// sender to report errors/success to the rpc.
 		sender: Sender<()>,
 		/// finalization justification
-		justification: Option<Justification>,
+		justification: Option<EncodedJustification>,
 	}
 }
 
@@ -83,7 +83,7 @@ pub trait ManualSealApi<Hash> {
 	fn finalize_block(
 		&self,
 		hash: Hash,
-		justification: Option<Justification>
+		justification: Option<EncodedJustification>
 	) -> FutureResult<bool>;
 }
 
@@ -131,7 +131,7 @@ impl<Hash: Send + 'static> ManualSealApi<Hash> for ManualSeal<Hash> {
 		Box::new(future.map_err(Error::from).compat())
 	}
 
-	fn finalize_block(&self, hash: Hash, justification: Option<Justification>) -> FutureResult<bool> {
+	fn finalize_block(&self, hash: Hash, justification: Option<EncodedJustification>) -> FutureResult<bool> {
 		let mut sink = self.import_block_channel.clone();
 		let future = async move {
 			let (sender, receiver) = oneshot::channel();
diff --git a/client/consensus/manual-seal/src/seal_block.rs b/client/consensus/manual-seal/src/seal_block.rs
index 2176973f3a298..23a560cebd54b 100644
--- a/client/consensus/manual-seal/src/seal_block.rs
+++ b/client/consensus/manual-seal/src/seal_block.rs
@@ -144,7 +144,7 @@ pub async fn seal_block<B, BI, SC, C, E, P>(
 			digest_provider.append_block_import(&parent, &mut params, &id)?;
 		}
 
-		match block_import.import_block(params, HashMap::new())? {
+		match block_import.import_block(params, HashMap::new()).await? {
 			ImportResult::Imported(aux) => {
 				Ok(CreatedBlock { hash: <B as BlockT>::Header::hash(&header), aux })
 			},
diff --git a/client/consensus/pow/Cargo.toml b/client/consensus/pow/Cargo.toml
index 8be43a8fa04bc..86b0b1df54e26 100644
--- a/client/consensus/pow/Cargo.toml
+++ b/client/consensus/pow/Cargo.toml
@@ -30,3 +30,4 @@ parking_lot = "0.11.1"
 sp-timestamp = { version = "3.0.0", path = "../../../primitives/timestamp" }
 derive_more = "0.99.2"
 prometheus-endpoint = { package = "substrate-prometheus-endpoint", path = "../../../utils/prometheus", version = "0.9.0"}
+async-trait = "0.1.42"
diff --git a/client/consensus/pow/src/lib.rs b/client/consensus/pow/src/lib.rs
index 482bc80170fe8..ea2e30afdc485 100644
--- a/client/consensus/pow/src/lib.rs
+++ b/client/consensus/pow/src/lib.rs
@@ -36,7 +36,7 @@ mod worker;
 pub use crate::worker::{MiningWorker, MiningMetadata, MiningBuild};
 
 use std::{
-	sync::Arc, any::Any, borrow::Cow, collections::HashMap, marker::PhantomData,
+	sync::Arc, borrow::Cow, collections::HashMap, marker::PhantomData,
 	cmp::Ordering, time::Duration,
 };
 use futures::{prelude::*, future::Either};
@@ -44,7 +44,7 @@ use parking_lot::Mutex;
 use sc_client_api::{BlockOf, backend::AuxStore, BlockchainEvents};
 use sp_blockchain::{HeaderBackend, ProvideCache, well_known_cache_keys::Id as CacheKeyId};
 use sp_block_builder::BlockBuilder as BlockBuilderApi;
-use sp_runtime::{Justification, RuntimeString};
+use sp_runtime::{Justifications, RuntimeString};
 use sp_runtime::generic::{BlockId, Digest, DigestItem};
 use sp_runtime::traits::{Block as BlockT, Header as HeaderT};
 use sp_api::ProvideRuntimeApi;
@@ -307,6 +307,7 @@ impl<B, I, C, S, Algorithm, CAW> PowBlockImport<B, I, C, S, Algorithm, CAW> wher
 	}
 }
 
+#[async_trait::async_trait]
 impl<B, I, C, S, Algorithm, CAW> BlockImport<B> for PowBlockImport<B, I, C, S, Algorithm, CAW> where
 	B: BlockT,
 	I: BlockImport<B, Transaction = sp_api::TransactionFor<C, B>> + Send + Sync,
@@ -314,21 +315,21 @@ impl<B, I, C, S, Algorithm, CAW> BlockImport<B> for PowBlockImport<B, I, C, S, A
 	S: SelectChain<B>,
 	C: ProvideRuntimeApi<B> + Send + Sync + HeaderBackend<B> + AuxStore + ProvideCache<B> + BlockOf,
 	C::Api: BlockBuilderApi<B>,
-	Algorithm: PowAlgorithm<B>,
-	Algorithm::Difficulty: 'static,
-	CAW: CanAuthorWith<B>,
+	Algorithm: PowAlgorithm<B> + Send,
+	Algorithm::Difficulty: 'static + Send,
+	CAW: CanAuthorWith<B> + Send,
 {
 	type Error = ConsensusError;
 	type Transaction = sp_api::TransactionFor<C, B>;
 
-	fn check_block(
+	async fn check_block(
 		&mut self,
 		block: BlockCheckParams<B>,
 	) -> Result<ImportResult, Self::Error> {
-		self.inner.check_block(block).map_err(Into::into)
+		self.inner.check_block(block).await.map_err(Into::into)
 	}
 
-	fn import_block(
+	async fn import_block(
 		&mut self,
 		mut block: BlockImportParams<B, Self::Transaction>,
 		new_cache: HashMap<CacheKeyId, Vec<u8>>,
@@ -403,7 +404,7 @@ impl<B, I, C, S, Algorithm, CAW> BlockImport<B> for PowBlockImport<B, I, C, S, A
 			));
 		}
 
-		self.inner.import_block(block, new_cache).map_err(Into::into)
+		self.inner.import_block(block, new_cache).await.map_err(Into::into)
 	}
 }
 
@@ -449,15 +450,16 @@ impl<B: BlockT, Algorithm> PowVerifier<B, Algorithm> {
 	}
 }
 
+#[async_trait::async_trait]
 impl<B: BlockT, Algorithm> Verifier<B> for PowVerifier<B, Algorithm> where
 	Algorithm: PowAlgorithm<B> + Send + Sync,
-	Algorithm::Difficulty: 'static,
+	Algorithm::Difficulty: 'static + Send,
 {
-	fn verify(
+	async fn verify(
 		&mut self,
 		origin: BlockOrigin,
 		header: B::Header,
-		justification: Option<Justification>,
+		justifications: Option<Justifications>,
 		body: Option<Vec<B::Extrinsic>>,
 	) -> Result<(BlockImportParams<B, ()>, Option<Vec<(CacheKeyId, Vec<u8>)>>), String> {
 		let hash = header.hash();
@@ -470,10 +472,10 @@ impl<B: BlockT, Algorithm> Verifier<B> for PowVerifier<B, Algorithm> where
 		let mut import_block = BlockImportParams::new(origin, checked_header);
 		import_block.post_digests.push(seal);
 		import_block.body = body;
-		import_block.justification = justification;
+		import_block.justifications = justifications;
 		import_block.intermediates.insert(
 			Cow::from(INTERMEDIATE_KEY),
-			Box::new(intermediate) as Box<dyn Any>
+			Box::new(intermediate) as Box<_>,
 		);
 		import_block.post_hash = Some(hash);
 
@@ -513,6 +515,7 @@ pub fn import_queue<B, Transaction, Algorithm>(
 	B: BlockT,
 	Transaction: Send + Sync + 'static,
 	Algorithm: PowAlgorithm<B> + Clone + Send + Sync + 'static,
+	Algorithm::Difficulty: Send,
 {
 	register_pow_inherent_data_provider(&inherent_data_providers)?;
 
@@ -556,7 +559,7 @@ pub fn start_mining_worker<Block, C, S, Algorithm, E, SO, CAW>(
 	C: ProvideRuntimeApi<Block> + BlockchainEvents<Block> + 'static,
 	S: SelectChain<Block> + 'static,
 	Algorithm: PowAlgorithm<Block> + Clone,
-	Algorithm::Difficulty: 'static,
+	Algorithm::Difficulty: Send + 'static,
 	E: Environment<Block> + Send + Sync + 'static,
 	E::Error: std::fmt::Debug,
 	E::Proposer: Proposer<Block, Transaction = sp_api::TransactionFor<C, Block>>,
diff --git a/client/consensus/pow/src/worker.rs b/client/consensus/pow/src/worker.rs
index d64596e48cf1a..18844e51ce418 100644
--- a/client/consensus/pow/src/worker.rs
+++ b/client/consensus/pow/src/worker.rs
@@ -16,7 +16,7 @@
 // You should have received a copy of the GNU General Public License
 // along with this program. If not, see <https://www.gnu.org/licenses/>.
 
-use std::{pin::Pin, time::Duration, collections::HashMap, any::Any, borrow::Cow};
+use std::{pin::Pin, time::Duration, collections::HashMap, borrow::Cow};
 use sc_client_api::ImportNotifications;
 use sp_runtime::{DigestItem, traits::Block as BlockT, generic::BlockId};
 use sp_consensus::{Proposal, BlockOrigin, BlockImportParams, import_queue::BoxBlockImport};
@@ -68,7 +68,8 @@ impl<Block, Algorithm, C, Proof> MiningWorker<Block, Algorithm, C, Proof> where
 	Block: BlockT,
 	C: sp_api::ProvideRuntimeApi<Block>,
 	Algorithm: PowAlgorithm<Block>,
-	Algorithm::Difficulty: 'static,
+	Algorithm::Difficulty: 'static + Send,
+	sp_api::TransactionFor<C, Block>: Send + 'static,
 {
 	/// Get the current best hash. `None` if the worker has just started or the client is doing
 	/// major syncing.
@@ -94,7 +95,7 @@ impl<Block, Algorithm, C, Proof> MiningWorker<Block, Algorithm, C, Proof> where
 
 	/// Submit a mined seal. The seal will be validated again. Returns true if the submission is
 	/// successful.
-	pub fn submit(&mut self, seal: Seal) -> bool {
+	pub async fn submit(&mut self, seal: Seal) -> bool {
 		if let Some(build) = self.build.take() {
 			match self.algorithm.verify(
 				&BlockId::Hash(build.metadata.best_hash),
@@ -135,10 +136,10 @@ impl<Block, Algorithm, C, Proof> MiningWorker<Block, Algorithm, C, Proof> where
 
 			import_block.intermediates.insert(
 				Cow::from(INTERMEDIATE_KEY),
-				Box::new(intermediate) as Box<dyn Any>
+				Box::new(intermediate) as Box<_>,
 			);
 
-			match self.block_import.import_block(import_block, HashMap::default()) {
+			match self.block_import.import_block(import_block, HashMap::default()).await {
 				Ok(_) => {
 					info!(
 						target: "pow",
diff --git a/client/consensus/slots/Cargo.toml b/client/consensus/slots/Cargo.toml
index 7ca413630e26e..64beea50fcf63 100644
--- a/client/consensus/slots/Cargo.toml
+++ b/client/consensus/slots/Cargo.toml
@@ -28,11 +28,12 @@ sp-api = { version = "3.0.0", path = "../../../primitives/api" }
 sc-telemetry = { version = "3.0.0", path = "../../telemetry" }
 sp-consensus = { version = "0.9.0", path = "../../../primitives/consensus/common" }
 sp-inherents = { version = "3.0.0", path = "../../../primitives/inherents" }
+sp-timestamp = { version = "3.0.0", path = "../../../primitives/timestamp" }
 futures = "0.3.9"
 futures-timer = "3.0.1"
-parking_lot = "0.11.1"
 log = "0.4.11"
 thiserror = "1.0.21"
+async-trait = "0.1.42"
 
 [dev-dependencies]
 substrate-test-runtime-client = { version = "2.0.0", path = "../../../test-utils/runtime/client" }
diff --git a/client/consensus/slots/src/lib.rs b/client/consensus/slots/src/lib.rs
index 037402260c0d3..c1f13fea1f9ef 100644
--- a/client/consensus/slots/src/lib.rs
+++ b/client/consensus/slots/src/lib.rs
@@ -32,12 +32,11 @@ pub use slots::SlotInfo;
 use slots::Slots;
 pub use aux_schema::{check_equivocation, MAX_SLOT_CAPACITY, PRUNING_BOUND};
 
-use std::{fmt::Debug, ops::Deref, pin::Pin, sync::Arc, time::Duration};
+use std::{fmt::Debug, ops::Deref, time::Duration};
 use codec::{Decode, Encode};
-use futures::{prelude::*, future::{self, Either}};
+use futures::{future::Either, Future, TryFutureExt};
 use futures_timer::Delay;
 use log::{debug, error, info, warn};
-use parking_lot::Mutex;
 use sp_api::{ProvideRuntimeApi, ApiRef};
 use sp_arithmetic::traits::BaseArithmetic;
 use sp_consensus::{BlockImport, Proposer, SyncOracle, SelectChain, CanAuthorWith, SlotData};
@@ -68,21 +67,23 @@ pub struct SlotResult<Block: BlockT, Proof> {
 ///
 /// The implementation should not make any assumptions of the slot being bound to the time or
 /// similar. The only valid assumption is that the slot number is always increasing.
+#[async_trait::async_trait]
 pub trait SlotWorker<B: BlockT, Proof> {
 	/// Called when a new slot is triggered.
 	///
 	/// Returns a future that resolves to a [`SlotResult`] iff a block was successfully built in
 	/// the slot. Otherwise `None` is returned.
-	fn on_slot(
+	async fn on_slot(
 		&mut self,
 		chain_head: B::Header,
 		slot_info: SlotInfo,
-	) -> Pin<Box<dyn Future<Output = Option<SlotResult<B, Proof>>> + Send>>;
+	) -> Option<SlotResult<B, Proof>>;
 }
 
 /// A skeleton implementation for `SlotWorker` which tries to claim a slot at
 /// its beginning and tries to produce a block if successfully claimed, timing
 /// out if block production takes too long.
+#[async_trait::async_trait]
 pub trait SimpleSlotWorker<B: BlockT> {
 	/// A handle to a `BlockImport`.
 	type BlockImport: BlockImport<B, Transaction = <Self::Proposer as Proposer<B>>::Transaction>
@@ -96,7 +97,7 @@ pub trait SimpleSlotWorker<B: BlockT> {
 		+ Send + Unpin + 'static;
 
 	/// The type of proposer to use to build blocks.
-	type Proposer: Proposer<B>;
+	type Proposer: Proposer<B> + Send;
 
 	/// Data associated with a slot claim.
 	type Claim: Send + 'static;
@@ -108,7 +109,7 @@ pub trait SimpleSlotWorker<B: BlockT> {
 	fn logging_target(&self) -> &'static str;
 
 	/// A handle to a `BlockImport`.
-	fn block_import(&self) -> Arc<Mutex<Self::BlockImport>>;
+	fn block_import(&mut self) -> &mut Self::BlockImport;
 
 	/// Returns the epoch data necessary for authoring. For time-dependent epochs,
 	/// use the provided slot number as a canonical source of time.
@@ -191,36 +192,38 @@ pub trait SimpleSlotWorker<B: BlockT> {
 	) -> Duration;
 
 	/// Implements [`SlotWorker::on_slot`].
-	fn on_slot(
+	async fn on_slot(
 		&mut self,
 		chain_head: B::Header,
 		slot_info: SlotInfo,
-	) -> Pin<Box<dyn Future<Output = Option<SlotResult<B, <Self::Proposer as Proposer<B>>::Proof>>> + Send>>
-	where
-		<Self::Proposer as Proposer<B>>::Proposal: Unpin + Send + 'static,
-	{
+	) -> Option<SlotResult<B, <Self::Proposer as Proposer<B>>::Proof>> {
 		let (timestamp, slot) = (slot_info.timestamp, slot_info.slot);
 		let telemetry = self.telemetry();
+		let logging_target = self.logging_target();
 
 		let proposing_remaining_duration = self.proposing_remaining_duration(&chain_head, &slot_info);
 
 		let proposing_remaining = if proposing_remaining_duration == Duration::default() {
 			debug!(
-				target: self.logging_target(),
+				target: logging_target,
 				"Skipping proposal slot {} since there's no time left to propose",
 				slot,
 			);
 
-			return Box::pin(future::ready(None));
+			return None
 		} else {
-			Box::new(Delay::new(proposing_remaining_duration))
-				as Box<dyn Future<Output = ()> + Unpin + Send>
+			Delay::new(proposing_remaining_duration)
 		};
 
 		let epoch_data = match self.epoch_data(&chain_head, slot) {
 			Ok(epoch_data) => epoch_data,
 			Err(err) => {
-				warn!("Unable to fetch epoch data at block {:?}: {:?}", chain_head.hash(), err);
+				warn!(
+					target: logging_target,
+					"Unable to fetch epoch data at block {:?}: {:?}",
+					chain_head.hash(),
+					err,
+				);
 
 				telemetry!(
 					telemetry;
@@ -230,7 +233,7 @@ pub trait SimpleSlotWorker<B: BlockT> {
 					"err" => ?err,
 				);
 
-				return Box::pin(future::ready(None));
+				return None;
 			}
 		};
 
@@ -242,7 +245,7 @@ pub trait SimpleSlotWorker<B: BlockT> {
 			self.sync_oracle().is_offline() &&
 			authorities_len.map(|a| a > 1).unwrap_or(false)
 		{
-			debug!(target: self.logging_target(), "Skipping proposal slot. Waiting for the network.");
+			debug!(target: logging_target, "Skipping proposal slot. Waiting for the network.");
 			telemetry!(
 				telemetry;
 				CONSENSUS_DEBUG;
@@ -250,16 +253,16 @@ pub trait SimpleSlotWorker<B: BlockT> {
 				"authorities_len" => authorities_len,
 			);
 
-			return Box::pin(future::ready(None));
+			return None;
 		}
 
 		let claim = match self.claim_slot(&chain_head, slot, &epoch_data) {
-			None => return Box::pin(future::ready(None)),
+			None => return None,
 			Some(claim) => claim,
 		};
 
 		if self.should_backoff(slot, &chain_head) {
-			return Box::pin(future::ready(None));
+			return None;
 		}
 
 		debug!(
@@ -274,13 +277,18 @@ pub trait SimpleSlotWorker<B: BlockT> {
 			CONSENSUS_DEBUG;
 			"slots.starting_authorship";
 			"slot_num" => *slot,
-			"timestamp" => timestamp,
+			"timestamp" => *timestamp,
 		);
 
-		let awaiting_proposer = {
-			let telemetry = telemetry.clone();
-			self.proposer(&chain_head).map_err(move |err| {
-				warn!("Unable to author block in slot {:?}: {:?}", slot, err);
+		let proposer = match self.proposer(&chain_head).await {
+			Ok(p) => p,
+			Err(err) => {
+				warn!(
+					target: logging_target,
+					"Unable to author block in slot {:?}: {:?}",
+					slot,
+					err,
+				);
 
 				telemetry!(
 					telemetry;
@@ -290,8 +298,8 @@ pub trait SimpleSlotWorker<B: BlockT> {
 					"err" => ?err
 				);
 
-				err
-			})
+				return None
+			}
 		};
 
 		let logs = self.pre_digest_data(slot, &claim);
@@ -299,106 +307,127 @@ pub trait SimpleSlotWorker<B: BlockT> {
 		// deadline our production to 98% of the total time left for proposing. As we deadline
 		// the proposing below to the same total time left, the 2% margin should be enough for
 		// the result to be returned.
-		let proposing = awaiting_proposer.and_then(move |proposer| proposer.propose(
+		let proposing = proposer.propose(
 			slot_info.inherent_data,
 			sp_runtime::generic::Digest {
 				logs,
 			},
 			proposing_remaining_duration.mul_f32(0.98),
-		).map_err(|e| sp_consensus::Error::ClientImport(format!("{:?}", e))));
-
-		let proposal_work = {
-			let telemetry = telemetry.clone();
-			futures::future::select(proposing, proposing_remaining).map(move |v| match v {
-				Either::Left((b, _)) => b.map(|b| (b, claim)),
-				Either::Right(_) => {
-					info!(
-						"⌛️ Discarding proposal for slot {}; block production took too long",
-						slot,
-					);
-					// If the node was compiled with debug, tell the user to use release optimizations.
-					#[cfg(build_type="debug")]
-					info!("👉 Recompile your node in `--release` mode to mitigate this problem.");
-					telemetry!(
-						telemetry;
-						CONSENSUS_INFO;
-						"slots.discarding_proposal_took_too_long";
-						"slot" => *slot,
-					);
+		).map_err(|e| sp_consensus::Error::ClientImport(format!("{:?}", e)));
 
-					Err(sp_consensus::Error::ClientImport("Timeout in the Slots proposer".into()))
-				},
-			})
+		let proposal = match futures::future::select(proposing, proposing_remaining).await {
+			Either::Left((Ok(p), _)) => p,
+			Either::Left((Err(err), _)) => {
+				warn!(
+					target: logging_target,
+					"Proposing failed: {:?}",
+					err,
+				);
+
+				return None
+			},
+			Either::Right(_) => {
+				info!(
+					target: logging_target,
+					"⌛️ Discarding proposal for slot {}; block production took too long",
+					slot,
+				);
+				// If the node was compiled with debug, tell the user to use release optimizations.
+				#[cfg(build_type="debug")]
+				info!(
+					target: logging_target,
+					"👉 Recompile your node in `--release` mode to mitigate this problem.",
+				);
+				telemetry!(
+					telemetry;
+					CONSENSUS_INFO;
+					"slots.discarding_proposal_took_too_long";
+					"slot" => *slot,
+				);
+
+				return None
+			},
 		};
 
 		let block_import_params_maker = self.block_import_params();
 		let block_import = self.block_import();
-		let logging_target = self.logging_target();
 
-		proposal_work.and_then(move |(proposal, claim)| async move {
-			let (block, storage_proof) = (proposal.block, proposal.proof);
-			let (header, body) = block.deconstruct();
-			let header_num = *header.number();
-			let header_hash = header.hash();
-			let parent_hash = *header.parent_hash();
-
-			let block_import_params = block_import_params_maker(
-				header,
-				&header_hash,
-				body.clone(),
-				proposal.storage_changes,
-				claim,
-				epoch_data,
-			)?;
-
-			info!(
-				"🔖 Pre-sealed block for proposal at {}. Hash now {:?}, previously {:?}.",
-				header_num,
-				block_import_params.post_hash(),
-				header_hash,
-			);
-
-			telemetry!(
-				telemetry;
-				CONSENSUS_INFO;
-				"slots.pre_sealed_block";
-				"header_num" => ?header_num,
-				"hash_now" => ?block_import_params.post_hash(),
-				"hash_previously" => ?header_hash,
-			);
-
-			let header = block_import_params.post_header();
-			if let Err(err) = block_import.lock().import_block(block_import_params, Default::default()) {
+		let (block, storage_proof) = (proposal.block, proposal.proof);
+		let (header, body) = block.deconstruct();
+		let header_num = *header.number();
+		let header_hash = header.hash();
+		let parent_hash = *header.parent_hash();
+
+		let block_import_params = match block_import_params_maker(
+			header,
+			&header_hash,
+			body.clone(),
+			proposal.storage_changes,
+			claim,
+			epoch_data,
+		) {
+			Ok(bi) => bi,
+			Err(err) => {
 				warn!(
 					target: logging_target,
-					"Error with block built on {:?}: {:?}",
-					parent_hash,
+					"Failed to create block import params: {:?}",
 					err,
 				);
 
-				telemetry!(
-					telemetry;
-					CONSENSUS_WARN;
-					"slots.err_with_block_built_on";
-					"hash" => ?parent_hash,
-					"err" => ?err,
-				);
+				return None
 			}
+		};
 
-			Ok(SlotResult { block: B::new(header, body), storage_proof })
-		}).then(|r| async move {
-			r.map_err(|e| warn!(target: "slots", "Encountered consensus error: {:?}", e)).ok()
-		}).boxed()
+		info!(
+			target: logging_target,
+			"🔖 Pre-sealed block for proposal at {}. Hash now {:?}, previously {:?}.",
+			header_num,
+			block_import_params.post_hash(),
+			header_hash,
+		);
+
+		telemetry!(
+			telemetry;
+			CONSENSUS_INFO;
+			"slots.pre_sealed_block";
+			"header_num" => ?header_num,
+			"hash_now" => ?block_import_params.post_hash(),
+			"hash_previously" => ?header_hash,
+		);
+
+		let header = block_import_params.post_header();
+		if let Err(err) = block_import
+			.import_block(block_import_params, Default::default())
+			.await
+		{
+			warn!(
+				target: logging_target,
+				"Error with block built on {:?}: {:?}",
+				parent_hash,
+				err,
+			);
+
+			telemetry!(
+				telemetry;
+				CONSENSUS_WARN;
+				"slots.err_with_block_built_on";
+				"hash" => ?parent_hash,
+				"err" => ?err,
+			);
+		}
+
+		Some(SlotResult { block: B::new(header, body), storage_proof })
 	}
 }
 
-impl<B: BlockT, T: SimpleSlotWorker<B>> SlotWorker<B, <T::Proposer as Proposer<B>>::Proof> for T {
-	fn on_slot(
+#[async_trait::async_trait]
+impl<B: BlockT, T: SimpleSlotWorker<B> + Send> SlotWorker<B, <T::Proposer as Proposer<B>>::Proof> for T {
+	async fn on_slot(
 		&mut self,
 		chain_head: B::Header,
 		slot_info: SlotInfo,
-	) -> Pin<Box<dyn Future<Output = Option<SlotResult<B, <T::Proposer as Proposer<B>>::Proof>>> + Send>> {
-		SimpleSlotWorker::on_slot(self, chain_head, slot_info)
+	) -> Option<SlotResult<B, <T::Proposer as Proposer<B>>::Proof>> {
+		SimpleSlotWorker::on_slot(self, chain_head, slot_info).await
 	}
 }
 
@@ -408,7 +437,7 @@ pub trait SlotCompatible {
 	fn extract_timestamp_and_slot(
 		&self,
 		inherent: &InherentData,
-	) -> Result<(u64, Slot, std::time::Duration), sp_consensus::Error>;
+	) -> Result<(sp_timestamp::Timestamp, Slot, std::time::Duration), sp_consensus::Error>;
 }
 
 /// Start a new slot worker.
@@ -436,25 +465,39 @@ where
 	let SlotDuration(slot_duration) = slot_duration;
 
 	// rather than use a timer interval, we schedule our waits ourselves
-	Slots::<SC>::new(
+	let mut slots = Slots::<SC>::new(
 		slot_duration.slot_duration(),
 		inherent_data_providers,
 		timestamp_extractor,
-	).inspect_err(|e| debug!(target: "slots", "Faulty timer: {:?}", e))
-		.try_for_each(move |slot_info| {
+	);
+
+	async move {
+		loop {
+			let slot_info = match slots.next_slot().await {
+				Ok(slot) => slot,
+				Err(err) => {
+					debug!(target: "slots", "Faulty timer: {:?}", err);
+					return
+				},
+			};
+
 			// only propose when we are not syncing.
 			if sync_oracle.is_major_syncing() {
 				debug!(target: "slots", "Skipping proposal slot due to sync.");
-				return Either::Right(future::ready(Ok(())));
+				continue;
 			}
 
 			let slot = slot_info.slot;
 			let chain_head = match client.best_chain() {
 				Ok(x) => x,
 				Err(e) => {
-					warn!(target: "slots", "Unable to author block in slot {}. \
-					no best block header: {:?}", slot, e);
-					return Either::Right(future::ready(Ok(())));
+					warn!(
+						target: "slots",
+						"Unable to author block in slot {}. No best block header: {:?}",
+						slot,
+						e,
+					);
+					continue;
 				}
 			};
 
@@ -466,19 +509,11 @@ where
 					slot,
 					err,
 				);
-				Either::Right(future::ready(Ok(())))
 			} else {
-				Either::Left(
-					worker.on_slot(chain_head, slot_info)
-						.then(|_| future::ready(Ok(())))
-				)
+				worker.on_slot(chain_head, slot_info).await;
 			}
-		}).then(|res| {
-			if let Err(err) = res {
-				warn!(target: "slots", "Slots stream terminated with an error: {:?}", err);
-			}
-			future::ready(())
-		})
+		}
+	}
 }
 
 /// A header which has been checked
@@ -514,10 +549,7 @@ impl<T> Deref for SlotDuration<T> {
 }
 
 impl<T: SlotData> SlotData for SlotDuration<T> {
-	/// Get the slot duration in milliseconds.
-	fn slot_duration(&self) -> u64
-		where T: SlotData,
-	{
+	fn slot_duration(&self) -> std::time::Duration {
 		self.0.slot_duration()
 	}
 
@@ -562,7 +594,7 @@ impl<T: Clone + Send + Sync + 'static> SlotDuration<T> {
 			}
 		}?;
 
-		if slot_duration.slot_duration() == 0u64 {
+		if slot_duration.slot_duration() == Default::default() {
 			return Err(sp_blockchain::Error::Application(Box::new(Error::SlotDurationInvalid(slot_duration))))
 		}
 
diff --git a/client/consensus/slots/src/slots.rs b/client/consensus/slots/src/slots.rs
index b23d676035696..d7ed1eda64c09 100644
--- a/client/consensus/slots/src/slots.rs
+++ b/client/consensus/slots/src/slots.rs
@@ -22,10 +22,9 @@
 
 use super::{SlotCompatible, Slot};
 use sp_consensus::Error;
-use futures::{prelude::*, task::Context, task::Poll};
 use sp_inherents::{InherentData, InherentDataProviders};
 
-use std::{pin::Pin, time::{Duration, Instant}};
+use std::time::{Duration, Instant};
 use futures_timer::Delay;
 
 /// Returns current duration since unix epoch.
@@ -52,7 +51,7 @@ pub struct SlotInfo {
 	/// The slot number.
 	pub slot: Slot,
 	/// Current timestamp.
-	pub timestamp: u64,
+	pub timestamp: sp_timestamp::Timestamp,
 	/// The instant at which the slot ends.
 	pub ends_at: Instant,
 	/// The inherent data.
@@ -61,6 +60,26 @@ pub struct SlotInfo {
 	pub duration: Duration,
 }
 
+impl SlotInfo {
+	/// Create a new [`SlotInfo`].
+	///
+	/// `ends_at` is calculated using `timestamp` and `duration`.
+	pub fn new(
+		slot: Slot,
+		timestamp: sp_timestamp::Timestamp,
+		inherent_data: InherentData,
+		duration: Duration,
+	) -> Self {
+		Self {
+			slot,
+			timestamp,
+			inherent_data,
+			duration,
+			ends_at: Instant::now() + time_until_next(timestamp.as_duration(), duration),
+		}
+	}
+}
+
 /// A stream that returns every time there is a new slot.
 pub(crate) struct Slots<SC> {
 	last_slot: Slot,
@@ -73,13 +92,13 @@ pub(crate) struct Slots<SC> {
 impl<SC> Slots<SC> {
 	/// Create a new `Slots` stream.
 	pub fn new(
-		slot_duration: u64,
+		slot_duration: Duration,
 		inherent_data_providers: InherentDataProviders,
 		timestamp_extractor: SC,
 	) -> Self {
 		Slots {
 			last_slot: 0.into(),
-			slot_duration: Duration::from_millis(slot_duration),
+			slot_duration,
 			inner_delay: None,
 			inherent_data_providers,
 			timestamp_extractor,
@@ -87,59 +106,49 @@ impl<SC> Slots<SC> {
 	}
 }
 
-impl<SC: SlotCompatible> Stream for Slots<SC> {
-	type Item = Result<SlotInfo, Error>;
-
-	fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Option<Self::Item>> {
+impl<SC: SlotCompatible> Slots<SC> {
+	/// Returns a future that fires when the next slot starts.
+	pub async fn next_slot(&mut self) -> Result<SlotInfo, Error> {
 		loop {
-			let slot_duration = self.slot_duration;
 			self.inner_delay = match self.inner_delay.take() {
 				None => {
 					// schedule wait.
-					let wait_dur = time_until_next(duration_now(), slot_duration);
+					let wait_dur = time_until_next(duration_now(), self.slot_duration);
 					Some(Delay::new(wait_dur))
 				}
 				Some(d) => Some(d),
 			};
 
-			if let Some(ref mut inner_delay) = self.inner_delay {
-				match Future::poll(Pin::new(inner_delay), cx) {
-					Poll::Pending => return Poll::Pending,
-					Poll::Ready(()) => {}
-				}
+			if let Some(inner_delay) = self.inner_delay.take() {
+				inner_delay.await;
 			}
-
 			// timeout has fired.
 
 			let inherent_data = match self.inherent_data_providers.create_inherent_data() {
 				Ok(id) => id,
-				Err(err) => return Poll::Ready(Some(Err(sp_consensus::Error::InherentData(err)))),
+				Err(err) => return Err(sp_consensus::Error::InherentData(err)),
 			};
 			let result = self.timestamp_extractor.extract_timestamp_and_slot(&inherent_data);
 			let (timestamp, slot, offset) = match result {
 				Ok(v) => v,
-				Err(err) => return Poll::Ready(Some(Err(err))),
+				Err(err) => return Err(err),
 			};
 			// reschedule delay for next slot.
 			let ends_in = offset +
-				time_until_next(Duration::from_millis(timestamp), slot_duration);
-			let ends_at = Instant::now() + ends_in;
+				time_until_next(timestamp.as_duration(), self.slot_duration);
 			self.inner_delay = Some(Delay::new(ends_in));
 
 			// never yield the same slot twice.
 			if slot > self.last_slot {
 				self.last_slot = slot;
 
-				break Poll::Ready(Some(Ok(SlotInfo {
+				break Ok(SlotInfo::new(
 					slot,
-					duration: self.slot_duration,
 					timestamp,
-					ends_at,
 					inherent_data,
-				})))
+					self.slot_duration,
+				))
 			}
 		}
 	}
 }
-
-impl<SC> Unpin for Slots<SC> {}
diff --git a/client/db/Cargo.toml b/client/db/Cargo.toml
index 72c26fead1c1c..e5e52494c2db6 100644
--- a/client/db/Cargo.toml
+++ b/client/db/Cargo.toml
@@ -35,7 +35,7 @@ sp-trie = { version = "3.0.0", path = "../../primitives/trie" }
 sp-consensus = { version = "0.9.0", path = "../../primitives/consensus/common" }
 sp-blockchain = { version = "3.0.0", path = "../../primitives/blockchain" }
 sp-database = { version = "3.0.0", path = "../../primitives/database" }
-parity-db = { version = "0.2.2", optional = true }
+parity-db = { version = "0.2.3", optional = true }
 prometheus-endpoint = { package = "substrate-prometheus-endpoint", version = "0.9.0", path = "../../utils/prometheus" }
 
 [dev-dependencies]
diff --git a/client/db/src/changes_tries_storage.rs b/client/db/src/changes_tries_storage.rs
index 6233eab3ea396..8051adc1832bc 100644
--- a/client/db/src/changes_tries_storage.rs
+++ b/client/db/src/changes_tries_storage.rs
@@ -955,7 +955,8 @@ mod tests {
 		let block0 = insert_header_with_configuration_change(&backend, 0, Default::default(), None, config0);
 		let config1 = Some(ChangesTrieConfiguration::new(2, 6));
 		let block1 = insert_header_with_configuration_change(&backend, 1, block0, changes(0), config1);
-		backend.finalize_block(BlockId::Number(1), Some(vec![42])).unwrap();
+		let just1 = Some((*b"TEST", vec![42]));
+		backend.finalize_block(BlockId::Number(1), just1).unwrap();
 		let config2 = Some(ChangesTrieConfiguration::new(2, 7));
 		let block2 = insert_header_with_configuration_change(&backend, 2, block1, changes(1), config2);
 		let config2_1 = Some(ChangesTrieConfiguration::new(2, 8));
diff --git a/client/db/src/lib.rs b/client/db/src/lib.rs
index 6654083939dae..03a6ce2200957 100644
--- a/client/db/src/lib.rs
+++ b/client/db/src/lib.rs
@@ -57,10 +57,11 @@ use sc_client_api::{
 	UsageInfo, MemoryInfo, IoInfo, MemorySize,
 	backend::{NewBlockState, PrunableStateChangesTrieStorage, ProvideChtRoots},
 	leaves::{LeafSet, FinalizationDisplaced}, cht,
+	utils::is_descendent_of,
 };
 use sp_blockchain::{
 	Result as ClientResult, Error as ClientError,
-	well_known_cache_keys, HeaderBackend,
+	well_known_cache_keys, Backend as _, HeaderBackend,
 };
 use codec::{Decode, Encode};
 use hash_db::Prefix;
@@ -70,14 +71,14 @@ use sp_core::{Hasher, ChangesTrieConfiguration};
 use sp_core::offchain::OffchainOverlayedChange;
 use sp_core::storage::{well_known_keys, ChildInfo};
 use sp_arithmetic::traits::Saturating;
-use sp_runtime::{generic::{DigestItem, BlockId}, Justification, Storage};
+use sp_runtime::{generic::{DigestItem, BlockId}, Justification, Justifications, Storage};
 use sp_runtime::traits::{
 	Block as BlockT, Header as HeaderT, NumberFor, Zero, One, SaturatedConversion, HashFor,
 };
 use sp_state_machine::{
 	DBValue, ChangesTrieTransaction, ChangesTrieCacheAction, UsageInfo as StateUsageInfo,
 	StorageCollection, ChildStorageCollection, OffchainChangesCollection,
-	backend::Backend as StateBackend, StateMachineStats,
+	backend::Backend as StateBackend, StateMachineStats, IndexOperation,
 };
 use crate::utils::{DatabaseType, Meta, meta_keys, read_db, read_meta};
 use crate::changes_tries_storage::{DbChangesTrieStorage, DbChangesTrieStorageTransaction};
@@ -106,7 +107,16 @@ pub type DbState<B> = sp_state_machine::TrieBackend<
 
 const DB_HASH_LEN: usize = 32;
 /// Hash type that this backend uses for the database.
-pub type DbHash = [u8; DB_HASH_LEN];
+pub type DbHash = sp_core::H256;
+
+/// This is used as block body when storage-chain mode is enabled.
+#[derive(Debug, Encode, Decode)]
+struct ExtrinsicHeader {
+	/// Hash of the indexed part
+	indexed_hash: DbHash, // Zero hash if there's no indexed data
+	/// The rest of the data.
+	data: Vec<u8>,
+}
 
 /// A reference tracking state.
 ///
@@ -351,7 +361,7 @@ pub(crate) mod columns {
 	pub const KEY_LOOKUP: u32 = 3;
 	pub const HEADER: u32 = 4;
 	pub const BODY: u32 = 5;
-	pub const JUSTIFICATION: u32 = 6;
+	pub const JUSTIFICATIONS: u32 = 6;
 	pub const CHANGES_TRIE: u32 = 7;
 	pub const AUX: u32 = 8;
 	/// Offchain workers local storage
@@ -363,7 +373,7 @@ pub(crate) mod columns {
 
 struct PendingBlock<Block: BlockT> {
 	header: Block::Header,
-	justification: Option<Justification>,
+	justifications: Option<Justifications>,
 	body: Option<Vec<Block::Extrinsic>>,
 	leaf_state: NewBlockState,
 }
@@ -505,42 +515,56 @@ impl<Block: BlockT> sc_client_api::blockchain::HeaderBackend<Block> for Blockcha
 
 impl<Block: BlockT> sc_client_api::blockchain::Backend<Block> for BlockchainDb<Block> {
 	fn body(&self, id: BlockId<Block>) -> ClientResult<Option<Vec<Block::Extrinsic>>> {
-		match read_db(&*self.db, columns::KEY_LOOKUP, columns::BODY, id)? {
-			Some(body) => {
-				match self.transaction_storage {
-					TransactionStorageMode::BlockBody => match Decode::decode(&mut &body[..]) {
-						Ok(body) => Ok(Some(body)),
-						Err(err) => return Err(sp_blockchain::Error::Backend(
-							format!("Error decoding body: {}", err)
-						)),
-					},
-					TransactionStorageMode::StorageChain => {
-						match Vec::<Block::Hash>::decode(&mut &body[..]) {
-							Ok(hashes) => {
-								let extrinsics: ClientResult<Vec<Block::Extrinsic>> = hashes.into_iter().map(
-									|h| self.extrinsic(&h).and_then(|maybe_ex| maybe_ex.ok_or_else(
-										|| sp_blockchain::Error::Backend(
-											format!("Missing transaction: {}", h))))
-								).collect();
-								Ok(Some(extrinsics?))
+		let body = match read_db(&*self.db, columns::KEY_LOOKUP, columns::BODY, id)? {
+			Some(body) => body,
+			None => return Ok(None),
+		};
+		match self.transaction_storage {
+			TransactionStorageMode::BlockBody => match Decode::decode(&mut &body[..]) {
+				Ok(body) => Ok(Some(body)),
+				Err(err) => return Err(sp_blockchain::Error::Backend(
+					format!("Error decoding body: {}", err)
+				)),
+			},
+			TransactionStorageMode::StorageChain => {
+				match Vec::<ExtrinsicHeader>::decode(&mut &body[..]) {
+					Ok(index) => {
+						let extrinsics: ClientResult<Vec<Block::Extrinsic>> = index.into_iter().map(
+							| ExtrinsicHeader { indexed_hash, data } | {
+								let decode_result = if indexed_hash != Default::default() {
+									match self.db.get(columns::TRANSACTION, indexed_hash.as_ref()) {
+										Some(t) => {
+											let mut input = utils::join_input(data.as_ref(), t.as_ref());
+											Block::Extrinsic::decode(&mut input)
+										},
+										None => return Err(sp_blockchain::Error::Backend(
+											format!("Missing indexed transaction {:?}", indexed_hash))
+										)
+									}
+								} else {
+									Block::Extrinsic::decode(&mut data.as_ref())
+								};
+								decode_result.map_err(|err| sp_blockchain::Error::Backend(
+									format!("Error decoding extrinsic: {}", err))
+								)
 							}
-							Err(err) => return Err(sp_blockchain::Error::Backend(
-								format!("Error decoding body list: {}", err)
-							)),
-						}
+						).collect();
+						Ok(Some(extrinsics?))
 					}
+					Err(err) => return Err(sp_blockchain::Error::Backend(
+						format!("Error decoding body list: {}", err)
+					)),
 				}
 			}
-			None => Ok(None),
 		}
 	}
 
-	fn justification(&self, id: BlockId<Block>) -> ClientResult<Option<Justification>> {
-		match read_db(&*self.db, columns::KEY_LOOKUP, columns::JUSTIFICATION, id)? {
-			Some(justification) => match Decode::decode(&mut &justification[..]) {
-				Ok(justification) => Ok(Some(justification)),
+	fn justifications(&self, id: BlockId<Block>) -> ClientResult<Option<Justifications>> {
+		match read_db(&*self.db, columns::KEY_LOOKUP, columns::JUSTIFICATIONS, id)? {
+			Some(justifications) => match Decode::decode(&mut &justifications[..]) {
+				Ok(justifications) => Ok(Some(justifications)),
 				Err(err) => return Err(sp_blockchain::Error::Backend(
-					format!("Error decoding justification: {}", err)
+					format!("Error decoding justifications: {}", err)
 				)),
 			}
 			None => Ok(None),
@@ -563,21 +587,11 @@ impl<Block: BlockT> sc_client_api::blockchain::Backend<Block> for BlockchainDb<B
 		children::read_children(&*self.db, columns::META, meta_keys::CHILDREN_PREFIX, parent_hash)
 	}
 
-	fn extrinsic(&self, hash: &Block::Hash) -> ClientResult<Option<Block::Extrinsic>> {
-		match self.db.get(columns::TRANSACTION, hash.as_ref()) {
-			Some(ex) => {
-				match Decode::decode(&mut &ex[..]) {
-					Ok(ex) => Ok(Some(ex)),
-					Err(err) => Err(sp_blockchain::Error::Backend(
-							format!("Error decoding extrinsic {}: {}", hash, err)
-					)),
-				}
-			},
-			None => Ok(None),
-		}
+	fn indexed_transaction(&self, hash: &Block::Hash) -> ClientResult<Option<Vec<u8>>> {
+		Ok(self.db.get(columns::TRANSACTION, hash.as_ref()))
 	}
 
-	fn have_extrinsic(&self, hash: &Block::Hash) -> ClientResult<bool> {
+	fn has_indexed_transaction(&self, hash: &Block::Hash) -> ClientResult<bool> {
 		Ok(self.db.contains(columns::TRANSACTION, hash.as_ref()))
 	}
 }
@@ -680,6 +694,7 @@ pub struct BlockImportOperation<Block: BlockT> {
 	finalized_blocks: Vec<(BlockId<Block>, Option<Justification>)>,
 	set_head: Option<BlockId<Block>>,
 	commit_state: bool,
+	index_ops: Vec<IndexOperation>,
 }
 
 impl<Block: BlockT> BlockImportOperation<Block> {
@@ -716,7 +731,7 @@ impl<Block: BlockT> sc_client_api::backend::BlockImportOperation<Block> for Bloc
 		&mut self,
 		header: Block::Header,
 		body: Option<Vec<Block::Extrinsic>>,
-		justification: Option<Justification>,
+		justifications: Option<Justifications>,
 		leaf_state: NewBlockState,
 	) -> ClientResult<()> {
 		assert!(self.pending_block.is_none(), "Only one block per operation is allowed");
@@ -726,7 +741,7 @@ impl<Block: BlockT> sc_client_api::backend::BlockImportOperation<Block> for Bloc
 		self.pending_block = Some(PendingBlock {
 			header,
 			body,
-			justification,
+			justifications,
 			leaf_state,
 		});
 		Ok(())
@@ -822,6 +837,11 @@ impl<Block: BlockT> sc_client_api::backend::BlockImportOperation<Block> for Bloc
 		self.set_head = Some(block);
 		Ok(())
 	}
+
+	fn update_transaction_index(&mut self, index_ops: Vec<IndexOperation>) -> ClientResult<()> {
+		self.index_ops = index_ops;
+		Ok(())
+	}
 }
 
 struct StorageDb<Block: BlockT> {
@@ -1130,9 +1150,9 @@ impl<Block: BlockT> Backend<Block> {
 
 		if let Some(justification) = justification {
 			transaction.set_from_vec(
-				columns::JUSTIFICATION,
+				columns::JUSTIFICATIONS,
 				&utils::number_and_hash_to_lookup_key(number, hash)?,
-				justification.encode(),
+				Justifications::from(justification).encode(),
 			);
 		}
 		Ok((*hash, number, false, true))
@@ -1154,21 +1174,21 @@ impl<Block: BlockT> Backend<Block> {
 			if new_canonical <= self.storage.state_db.best_canonical().unwrap_or(0) {
 				return Ok(())
 			}
-
 			let hash = if new_canonical == number_u64 {
 				hash
 			} else {
-				::sc_client_api::blockchain::HeaderBackend::hash(&self.blockchain, new_canonical.saturated_into())?
-					.expect("existence of block with number `new_canonical` \
-						implies existence of blocks with all numbers before it; qed")
+				sc_client_api::blockchain::HeaderBackend::hash(
+					&self.blockchain,
+					new_canonical.saturated_into(),
+				)?.expect("existence of block with number `new_canonical` \
+					implies existence of blocks with all numbers before it; qed")
 			};
 
 			trace!(target: "db", "Canonicalize block #{} ({:?})", new_canonical, hash);
 			let commit = self.storage.state_db.canonicalize_block(&hash)
 				.map_err(|e: sc_state_db::Error<io::Error>| sp_blockchain::Error::from_state_db(e))?;
 			apply_state_commit(transaction, commit);
-		};
-
+		}
 		Ok(())
 	}
 
@@ -1224,25 +1244,19 @@ impl<Block: BlockT> Backend<Block> {
 			)?;
 
 			transaction.set_from_vec(columns::HEADER, &lookup_key, pending_block.header.encode());
-			if let Some(body) = &pending_block.body {
+			if let Some(body) = pending_block.body {
 				match self.transaction_storage {
 					TransactionStorageMode::BlockBody => {
 						transaction.set_from_vec(columns::BODY, &lookup_key, body.encode());
 					},
 					TransactionStorageMode::StorageChain => {
-						let mut hashes = Vec::with_capacity(body.len());
-						for extrinsic in body {
-							let extrinsic = extrinsic.encode();
-							let hash = HashFor::<Block>::hash(&extrinsic);
-							transaction.set(columns::TRANSACTION, &hash.as_ref(), &extrinsic);
-							hashes.push(hash);
-						}
-						transaction.set_from_vec(columns::BODY, &lookup_key, hashes.encode());
+						let body = apply_index_ops::<Block>(&mut transaction, body, operation.index_ops);
+						transaction.set_from_vec(columns::BODY, &lookup_key, body);
 					},
 				}
 			}
-			if let Some(justification) = pending_block.justification {
-				transaction.set_from_vec(columns::JUSTIFICATION, &lookup_key, justification.encode());
+			if let Some(justifications) = pending_block.justifications {
+				transaction.set_from_vec(columns::JUSTIFICATIONS, &lookup_key, justifications.encode());
 			}
 
 			if number.is_zero() {
@@ -1409,7 +1423,7 @@ impl<Block: BlockT> Backend<Block> {
 
 		self.storage.db.commit(transaction)?;
 
-		// Apply all in-memory state shanges.
+		// Apply all in-memory state changes.
 		// Code beyond this point can't fail.
 
 		if let Some((
@@ -1490,8 +1504,8 @@ impl<Block: BlockT> Backend<Block> {
 			}
 		}
 
-		self.prune_blocks(transaction, f_num)?;
 		let new_displaced = self.blockchain.leaves.write().finalize_height(f_num);
+		self.prune_blocks(transaction, f_num, &new_displaced)?;
 		match displaced {
 			x @ &mut None => *x = Some(new_displaced),
 			&mut Some(ref mut displaced) => displaced.merge(new_displaced),
@@ -1504,47 +1518,83 @@ impl<Block: BlockT> Backend<Block> {
 		&self,
 		transaction: &mut Transaction<DbHash>,
 		finalized: NumberFor<Block>,
+		displaced: &FinalizationDisplaced<Block::Hash, NumberFor<Block>>,
 	) -> ClientResult<()> {
 		if let KeepBlocks::Some(keep_blocks) = self.keep_blocks {
 			// Always keep the last finalized block
 			let keep = std::cmp::max(keep_blocks, 1);
-			if finalized < keep.into() {
-				return Ok(())
+			if finalized >= keep.into() {
+				let number = finalized.saturating_sub(keep.into());
+				self.prune_block(transaction, BlockId::<Block>::number(number))?;
 			}
-			let number = finalized.saturating_sub(keep.into());
-			match read_db(&*self.storage.db, columns::KEY_LOOKUP, columns::BODY, BlockId::<Block>::number(number))? {
-				Some(body) => {
-					debug!(target: "db", "Removing block #{}", number);
-					utils::remove_from_db(
-						transaction,
-						&*self.storage.db,
-						columns::KEY_LOOKUP,
-						columns::BODY,
-						BlockId::<Block>::number(number),
-					)?;
-					match self.transaction_storage {
-						TransactionStorageMode::BlockBody => {},
-						TransactionStorageMode::StorageChain => {
-							match Vec::<Block::Hash>::decode(&mut &body[..]) {
-								Ok(hashes) => {
-									for h in hashes {
-										transaction.remove(columns::TRANSACTION, h.as_ref());
+
+			// Also discard all blocks from displaced branches
+			for h in displaced.leaves() {
+				let mut number = finalized;
+				let mut hash = h.clone();
+				// Follow displaced chains back until we reach a finalized block.
+				// Since leaves are discarded due to finality, they can't have parents
+				// that are canonical, but not yet finalized. So we stop deletig as soon as
+				// we reach canonical chain.
+				while self.blockchain.hash(number)? != Some(hash.clone()) {
+					let id = BlockId::<Block>::hash(hash.clone());
+					match self.blockchain.header(id)? {
+						Some(header) => {
+							self.prune_block(transaction, id)?;
+							number = header.number().saturating_sub(One::one());
+							hash = header.parent_hash().clone();
+						},
+						None => break,
+					}
+				}
+			}
+		}
+		Ok(())
+	}
+
+	fn prune_block(
+		&self,
+		transaction: &mut Transaction<DbHash>,
+		id: BlockId<Block>,
+	) -> ClientResult<()> {
+		match read_db(&*self.storage.db, columns::KEY_LOOKUP, columns::BODY, id)? {
+			Some(body) => {
+				debug!(target: "db", "Removing block #{}", id);
+				utils::remove_from_db(
+					transaction,
+					&*self.storage.db,
+					columns::KEY_LOOKUP,
+					columns::BODY,
+					id,
+				)?;
+				match self.transaction_storage {
+					TransactionStorageMode::BlockBody => {},
+					TransactionStorageMode::StorageChain => {
+						match Vec::<ExtrinsicHeader>::decode(&mut &body[..]) {
+							Ok(body) => {
+								for ExtrinsicHeader { indexed_hash, .. } in body {
+									if indexed_hash != Default::default() {
+										transaction.release(
+											columns::TRANSACTION,
+											indexed_hash,
+										);
 									}
 								}
-								Err(err) => return Err(sp_blockchain::Error::Backend(
-									format!("Error decoding body list: {}", err)
-								)),
 							}
+							Err(err) => return Err(sp_blockchain::Error::Backend(
+									format!("Error decoding body list: {}", err)
+							)),
 						}
 					}
 				}
-				None => return Ok(()),
 			}
+			None => return Ok(()),
 		}
 		Ok(())
 	}
 }
 
+
 fn apply_state_commit(transaction: &mut Transaction<DbHash>, commit: sc_state_db::CommitSet<Vec<u8>>) {
 	for (key, val) in commit.data.inserted.into_iter() {
 		transaction.set_from_vec(columns::STATE, &key[..], val);
@@ -1560,6 +1610,67 @@ fn apply_state_commit(transaction: &mut Transaction<DbHash>, commit: sc_state_db
 	}
 }
 
+fn apply_index_ops<Block: BlockT>(
+	transaction: &mut Transaction<DbHash>,
+	body: Vec<Block::Extrinsic>,
+	ops: Vec<IndexOperation>,
+) -> Vec<u8> {
+	let mut extrinsic_headers: Vec<ExtrinsicHeader> = Vec::with_capacity(body.len());
+	let mut index_map = HashMap::new();
+	let mut renewed_map = HashMap::new();
+	for op in ops {
+		match op {
+			IndexOperation::Insert { extrinsic, offset } => {
+				index_map.insert(extrinsic, offset);
+			}
+			IndexOperation::Renew { extrinsic, hash, .. } => {
+				renewed_map.insert(extrinsic, DbHash::from_slice(hash.as_ref()));
+			}
+		}
+	}
+	for (index, extrinsic) in body.into_iter().enumerate() {
+		let extrinsic = extrinsic.encode();
+		let extrinsic_header = if let Some(hash) = renewed_map.get(&(index as u32)) {
+			// Bump ref counter
+			transaction.reference(columns::TRANSACTION, DbHash::from_slice(hash.as_ref()));
+			ExtrinsicHeader {
+				indexed_hash: hash.clone(),
+				data: extrinsic,
+			}
+		} else {
+			match index_map.get(&(index as u32)) {
+				Some(offset) if *offset as usize <= extrinsic.len() => {
+					let offset = *offset as usize;
+					let hash = HashFor::<Block>::hash(&extrinsic[offset..]);
+					transaction.store(
+						columns::TRANSACTION,
+						DbHash::from_slice(hash.as_ref()),
+						extrinsic[offset..].to_vec(),
+					);
+					ExtrinsicHeader {
+						indexed_hash: DbHash::from_slice(hash.as_ref()),
+						data: extrinsic[..offset].to_vec(),
+					}
+				},
+				_ => {
+					ExtrinsicHeader {
+						indexed_hash: Default::default(),
+						data: extrinsic,
+					}
+				}
+			}
+		};
+		extrinsic_headers.push(extrinsic_header);
+	}
+	debug!(
+		target: "db",
+		"DB transaction index: {} inserted, {} renewed",
+		index_map.len(),
+		renewed_map.len()
+	);
+	extrinsic_headers.encode()
+}
+
 impl<Block> sc_client_api::backend::AuxStore for Backend<Block> where Block: BlockT {
 	fn insert_aux<
 		'a,
@@ -1608,6 +1719,7 @@ impl<Block: BlockT> sc_client_api::backend::Backend<Block> for Backend<Block> {
 			finalized_blocks: Vec::new(),
 			set_head: None,
 			commit_state: false,
+			index_ops: Default::default(),
 		})
 	}
 
@@ -1668,6 +1780,50 @@ impl<Block: BlockT> sc_client_api::backend::Backend<Block> for Backend<Block> {
 		Ok(())
 	}
 
+	fn append_justification(
+		&self,
+		block: BlockId<Block>,
+		justification: Justification,
+	) -> ClientResult<()> {
+		let mut transaction: Transaction<DbHash> = Transaction::new();
+		let hash = self.blockchain.expect_block_hash_from_id(&block)?;
+		let header = self.blockchain.expect_header(block)?;
+		let number = *header.number();
+
+		// Check if the block is finalized first.
+		let is_descendent_of = is_descendent_of(&self.blockchain, None);
+		let last_finalized = self.blockchain.last_finalized()?;
+
+		// We can do a quick check first, before doing a proper but more expensive check
+		if number > self.blockchain.info().finalized_number
+			|| (hash != last_finalized && !is_descendent_of(&hash, &last_finalized)?)
+		{
+			return Err(ClientError::NotInFinalizedChain);
+		}
+
+		let justifications =
+			if let Some(mut stored_justifications) = self.blockchain.justifications(block)? {
+				if !stored_justifications.append(justification) {
+					return Err(ClientError::BadJustification(
+						"Duplicate consensus engine ID".into()
+					));
+				}
+				stored_justifications
+			} else {
+				Justifications::from(justification)
+			};
+
+		transaction.set_from_vec(
+			columns::JUSTIFICATIONS,
+			&utils::number_and_hash_to_lookup_key(number, hash)?,
+			justifications.encode(),
+		);
+
+		self.storage.db.commit(transaction)?;
+
+		Ok(())
+	}
+
 	fn changes_trie_storage(&self) -> Option<&dyn PrunableStateChangesTrieStorage<Block>> {
 		Some(&self.changes_tries_storage)
 	}
@@ -1918,12 +2074,16 @@ pub(crate) mod tests {
 	use sp_core::H256;
 	use sc_client_api::backend::{Backend as BTrait, BlockImportOperation as Op};
 	use sc_client_api::blockchain::Backend as BLBTrait;
+	use sp_runtime::ConsensusEngineId;
 	use sp_runtime::testing::{Header, Block as RawBlock, ExtrinsicWrapper};
 	use sp_runtime::traits::{Hash, BlakeTwo256};
 	use sp_runtime::generic::DigestItem;
 	use sp_state_machine::{TrieMut, TrieDBMut};
 	use sp_blockchain::{lowest_common_ancestor, tree_route};
 
+	const CONS0_ENGINE_ID: ConsensusEngineId = *b"CON0";
+	const CONS1_ENGINE_ID: ConsensusEngineId = *b"CON1";
+
 	pub(crate) type Block = RawBlock<ExtrinsicWrapper<u64>>;
 
 	pub fn prepare_changes(changes: Vec<(Vec<u8>, Vec<u8>)>) -> (H256, MemoryDB<BlakeTwo256>) {
@@ -1949,7 +2109,7 @@ pub(crate) mod tests {
 		changes: Option<Vec<(Vec<u8>, Vec<u8>)>>,
 		extrinsics_root: H256,
 	) -> H256 {
-		insert_block(backend, number, parent_hash, changes, extrinsics_root, Vec::new())
+		insert_block(backend, number, parent_hash, changes, extrinsics_root, Vec::new(), None)
 	}
 
 	pub fn insert_block(
@@ -1959,6 +2119,7 @@ pub(crate) mod tests {
 		changes: Option<Vec<(Vec<u8>, Vec<u8>)>>,
 		extrinsics_root: H256,
 		body: Vec<ExtrinsicWrapper<u64>>,
+		transaction_index: Option<Vec<IndexOperation>>,
 	) -> H256 {
 		use sp_runtime::testing::Digest;
 
@@ -1986,6 +2147,9 @@ pub(crate) mod tests {
 		let mut op = backend.begin_operation().unwrap();
 		backend.begin_state_operation(&mut op, block_id).unwrap();
 		op.set_block_data(header, Some(body), None, NewBlockState::Best).unwrap();
+		if let Some(index) = transaction_index {
+			op.update_transaction_index(index).unwrap();
+		}
 		op.update_changes_trie((changes_trie_update, ChangesTrieCacheAction::Clear)).unwrap();
 		backend.commit_operation(op).unwrap();
 
@@ -2511,12 +2675,47 @@ pub(crate) mod tests {
 		let block0 = insert_header(&backend, 0, Default::default(), None, Default::default());
 		let _ = insert_header(&backend, 1, block0, None, Default::default());
 
-		let justification = Some(vec![1, 2, 3]);
+		let justification = Some((CONS0_ENGINE_ID, vec![1, 2, 3]));
 		backend.finalize_block(BlockId::Number(1), justification.clone()).unwrap();
 
 		assert_eq!(
-			backend.blockchain().justification(BlockId::Number(1)).unwrap(),
-			justification,
+			backend.blockchain().justifications(BlockId::Number(1)).unwrap(),
+			justification.map(Justifications::from),
+		);
+	}
+
+	#[test]
+	fn test_append_justification_to_finalized_block() {
+		use sc_client_api::blockchain::{Backend as BlockChainBackend};
+
+		let backend = Backend::<Block>::new_test(10, 10);
+
+		let block0 = insert_header(&backend, 0, Default::default(), None, Default::default());
+		let _ = insert_header(&backend, 1, block0, None, Default::default());
+
+		let just0 = (CONS0_ENGINE_ID, vec![1, 2, 3]);
+		backend.finalize_block(
+			BlockId::Number(1),
+			Some(just0.clone().into()),
+		).unwrap();
+
+		let just1 = (CONS1_ENGINE_ID, vec![4, 5]);
+		backend.append_justification(BlockId::Number(1), just1.clone()).unwrap();
+
+		let just2 = (CONS1_ENGINE_ID, vec![6, 7]);
+		assert!(matches!(
+			backend.append_justification(BlockId::Number(1), just2),
+			Err(ClientError::BadJustification(_))
+		));
+
+		let justifications = {
+			let mut just = Justifications::from(just0);
+			just.append(just1);
+			just
+		};
+		assert_eq!(
+			backend.blockchain().justifications(BlockId::Number(1)).unwrap(),
+			Some(justifications),
 		);
 	}
 
@@ -2592,7 +2791,7 @@ pub(crate) mod tests {
 			let mut blocks = Vec::new();
 			let mut prev_hash = Default::default();
 			for i in 0 .. 5 {
-				let hash = insert_block(&backend, i, prev_hash, None, Default::default(), vec![i.into()]);
+				let hash = insert_block(&backend, i, prev_hash, None, Default::default(), vec![i.into()], None);
 				blocks.push(hash);
 				prev_hash = hash;
 			}
@@ -2613,4 +2812,100 @@ pub(crate) mod tests {
 			assert_eq!(Some(vec![4.into()]), bc.body(BlockId::hash(blocks[4])).unwrap());
 		}
 	}
+
+	#[test]
+	fn prune_blocks_on_finalize_with_fork() {
+		let backend = Backend::<Block>::new_test_with_tx_storage(
+			2,
+			10,
+			TransactionStorageMode::StorageChain
+		);
+		let mut blocks = Vec::new();
+		let mut prev_hash = Default::default();
+		for i in 0 .. 5 {
+			let hash = insert_block(&backend, i, prev_hash, None, Default::default(), vec![i.into()], None);
+			blocks.push(hash);
+			prev_hash = hash;
+		}
+
+		// insert a fork at block 2
+		let fork_hash_root = insert_block(
+			&backend,
+			2,
+			blocks[1],
+			None,
+			sp_core::H256::random(),
+			vec![2.into()],
+			None
+		);
+		insert_block(&backend, 3, fork_hash_root, None, H256::random(), vec![3.into(), 11.into()], None);
+		let mut op = backend.begin_operation().unwrap();
+		backend.begin_state_operation(&mut op, BlockId::Hash(blocks[4])).unwrap();
+		op.mark_head(BlockId::Hash(blocks[4])).unwrap();
+		backend.commit_operation(op).unwrap();
+
+		for i in 1 .. 5 {
+			let mut op = backend.begin_operation().unwrap();
+			backend.begin_state_operation(&mut op, BlockId::Hash(blocks[4])).unwrap();
+			op.mark_finalized(BlockId::Hash(blocks[i]), None).unwrap();
+			backend.commit_operation(op).unwrap();
+		}
+
+		let bc = backend.blockchain();
+		assert_eq!(None, bc.body(BlockId::hash(blocks[0])).unwrap());
+		assert_eq!(None, bc.body(BlockId::hash(blocks[1])).unwrap());
+		assert_eq!(None, bc.body(BlockId::hash(blocks[2])).unwrap());
+		assert_eq!(Some(vec![3.into()]), bc.body(BlockId::hash(blocks[3])).unwrap());
+		assert_eq!(Some(vec![4.into()]), bc.body(BlockId::hash(blocks[4])).unwrap());
+	}
+
+	#[test]
+	fn renew_transaction_storage() {
+		let backend = Backend::<Block>::new_test_with_tx_storage(
+			2,
+			10,
+			TransactionStorageMode::StorageChain
+		);
+		let mut blocks = Vec::new();
+		let mut prev_hash = Default::default();
+		let x1 = ExtrinsicWrapper::from(0u64).encode();
+		let x1_hash = <HashFor::<Block> as sp_core::Hasher>::hash(&x1[1..]);
+		for i in 0 .. 10 {
+			let mut index = Vec::new();
+			if i == 0 {
+				index.push(IndexOperation::Insert { extrinsic: 0, offset: 1 });
+			} else if i < 5 {
+				// keep renewing 1st
+				index.push(IndexOperation::Renew {
+					extrinsic: 0,
+					hash: x1_hash.as_ref().to_vec(),
+					size: (x1.len() - 1) as u32,
+				});
+			} // else stop renewing
+			let hash = insert_block(
+				&backend,
+				i,
+				prev_hash,
+				None,
+				Default::default(),
+				vec![i.into()],
+				Some(index)
+			);
+			blocks.push(hash);
+			prev_hash = hash;
+		}
+
+		for i in 1 .. 10 {
+			let mut op = backend.begin_operation().unwrap();
+			backend.begin_state_operation(&mut op, BlockId::Hash(blocks[4])).unwrap();
+			op.mark_finalized(BlockId::Hash(blocks[i]), None).unwrap();
+			backend.commit_operation(op).unwrap();
+			let bc = backend.blockchain();
+			if i < 6 {
+				assert!(bc.indexed_transaction(&x1_hash).unwrap().is_some());
+			} else {
+				assert!(bc.indexed_transaction(&x1_hash).unwrap().is_none());
+			}
+		}
+	}
 }
diff --git a/client/db/src/light.rs b/client/db/src/light.rs
index 91f37dd374d9f..bf24197c5b5d9 100644
--- a/client/db/src/light.rs
+++ b/client/db/src/light.rs
@@ -756,7 +756,7 @@ pub(crate) mod tests {
 	#[test]
 	fn finalized_ancient_headers_are_replaced_with_cht() {
 		fn insert_headers<F: Fn(&Hash, u64) -> Header>(header_producer: F) ->
-			(Arc<sp_database::MemDb<DbHash>>, LightStorage<Block>)
+			(Arc<sp_database::MemDb>, LightStorage<Block>)
 		{
 			let raw_db = Arc::new(sp_database::MemDb::default());
 			let db = LightStorage::from_kvdb(raw_db.clone()).unwrap();
diff --git a/client/db/src/parity_db.rs b/client/db/src/parity_db.rs
index 71cc5117f19ee..ed39c1e9f669f 100644
--- a/client/db/src/parity_db.rs
+++ b/client/db/src/parity_db.rs
@@ -33,7 +33,7 @@ fn handle_err<T>(result: parity_db::Result<T>) -> T {
 }
 
 /// Wrap parity-db database into a trait object that implements `sp_database::Database`
-pub fn open<H: Clone>(path: &std::path::Path, db_type: DatabaseType)
+pub fn open<H: Clone + AsRef<[u8]>>(path: &std::path::Path, db_type: DatabaseType)
 	-> parity_db::Result<std::sync::Arc<dyn Database<H>>>
 {
 	let mut config = parity_db::Options::with_columns(path, NUM_COLUMNS as u8);
@@ -48,7 +48,7 @@ pub fn open<H: Clone>(path: &std::path::Path, db_type: DatabaseType)
 	Ok(std::sync::Arc::new(DbAdapter(db)))
 }
 
-impl<H: Clone> Database<H> for DbAdapter {
+impl<H: Clone + AsRef<[u8]>> Database<H> for DbAdapter {
 	fn commit(&self, transaction: Transaction<H>) -> Result<(), DatabaseError> {
 		handle_err(self.0.commit(transaction.0.into_iter().map(|change|
 			match change {
@@ -65,7 +65,11 @@ impl<H: Clone> Database<H> for DbAdapter {
 		handle_err(self.0.get(col as u8, key))
 	}
 
-	fn lookup(&self, _hash: &H) -> Option<Vec<u8>> {
-		unimplemented!();
+	fn contains(&self, col: ColumnId, key: &[u8]) -> bool {
+		handle_err(self.0.get_size(col as u8, key)).is_some()
+	}
+
+	fn value_size(&self, col: ColumnId, key: &[u8]) -> Option<usize> {
+		handle_err(self.0.get_size(col as u8, key)).map(|s| s as usize)
 	}
 }
diff --git a/client/db/src/upgrade.rs b/client/db/src/upgrade.rs
index b6e49edba1978..ea91b8253e1d8 100644
--- a/client/db/src/upgrade.rs
+++ b/client/db/src/upgrade.rs
@@ -23,17 +23,19 @@ use std::io::{Read, Write, ErrorKind};
 use std::path::{Path, PathBuf};
 
 use sp_runtime::traits::Block as BlockT;
-use crate::utils::DatabaseType;
+use crate::{columns, utils::DatabaseType};
 use kvdb_rocksdb::{Database, DatabaseConfig};
+use codec::{Decode, Encode};
 
 /// Version file name.
 const VERSION_FILE_NAME: &'static str = "db_version";
 
 /// Current db version.
-const CURRENT_VERSION: u32 = 2;
+const CURRENT_VERSION: u32 = 3;
 
 /// Number of columns in v1.
 const V1_NUM_COLUMNS: u32 = 11;
+const V2_NUM_COLUMNS: u32 = 12;
 
 /// Upgrade database to current version.
 pub fn upgrade_db<Block: BlockT>(db_path: &Path, db_type: DatabaseType) -> sp_blockchain::Result<()> {
@@ -42,7 +44,11 @@ pub fn upgrade_db<Block: BlockT>(db_path: &Path, db_type: DatabaseType) -> sp_bl
 		let db_version = current_version(db_path)?;
 		match db_version {
 			0 => Err(sp_blockchain::Error::Backend(format!("Unsupported database version: {}", db_version)))?,
-			1 => migrate_1_to_2::<Block>(db_path, db_type)?,
+			1 => {
+				migrate_1_to_2::<Block>(db_path, db_type)?;
+				migrate_2_to_3::<Block>(db_path, db_type)?
+			},
+			2 => migrate_2_to_3::<Block>(db_path, db_type)?,
 			CURRENT_VERSION => (),
 			_ => Err(sp_blockchain::Error::Backend(format!("Future database version: {}", db_version)))?,
 		}
@@ -62,6 +68,36 @@ fn migrate_1_to_2<Block: BlockT>(db_path: &Path, _db_type: DatabaseType) -> sp_b
 	db.add_column().map_err(db_err)
 }
 
+/// Migration from version2 to version3:
+/// - The format of the stored Justification changed to support multiple Justifications.
+fn migrate_2_to_3<Block: BlockT>(db_path: &Path, _db_type: DatabaseType) -> sp_blockchain::Result<()> {
+	let db_path = db_path.to_str()
+		.ok_or_else(|| sp_blockchain::Error::Backend("Invalid database path".into()))?;
+	let db_cfg = DatabaseConfig::with_columns(V2_NUM_COLUMNS);
+	let db = Database::open(&db_cfg, db_path).map_err(db_err)?;
+
+	// Get all the keys we need to update
+	let keys: Vec<_> = db.iter(columns::JUSTIFICATIONS).map(|entry| entry.0).collect();
+
+	// Read and update each entry
+	let mut transaction = db.transaction();
+	for key in keys {
+		if let Some(justification) = db.get(columns::JUSTIFICATIONS, &key).map_err(db_err)? {
+			// Tag each justification with the hardcoded ID for GRANDPA to avoid the dependency on
+			// the GRANDPA crate.
+			// NOTE: when storing justifications the previous API would get a `Vec<u8>` and still
+			// call encode on it.
+			let justification = Vec::<u8>::decode(&mut &justification[..])
+				.map_err(|_| sp_blockchain::Error::Backend("Invalid justification blob".into()))?;
+			let justifications = sp_runtime::Justifications::from((*b"FRNK", justification));
+			transaction.put_vec(columns::JUSTIFICATIONS, &key, justifications.encode());
+		}
+	}
+	db.write(transaction).map_err(db_err)?;
+
+	Ok(())
+}
+
 /// Reads current database version from the file at given path.
 /// If the file does not exist returns 0.
 fn current_version(path: &Path) -> sp_blockchain::Result<u32> {
@@ -141,8 +177,8 @@ mod tests {
 	}
 
 	#[test]
-	fn upgrade_from_1_to_2_works() {
-		for version_from_file in &[None, Some(1)] {
+	fn upgrade_to_3_works() {
+		for version_from_file in &[None, Some(1), Some(2)] {
 			let db_dir = tempfile::TempDir::new().unwrap();
 			let db_path = db_dir.path();
 			create_db(db_path, *version_from_file);
diff --git a/client/db/src/utils.rs b/client/db/src/utils.rs
index cd9b2a6f56d41..590b994d50e87 100644
--- a/client/db/src/utils.rs
+++ b/client/db/src/utils.rs
@@ -278,7 +278,7 @@ pub fn open_database<Block: BlockT>(
 		#[cfg(feature = "with-parity-db")]
 		DatabaseSettingsSrc::ParityDb { path } => {
 			crate::parity_db::open(&path, db_type)
-				.map_err(|e| sp_blockchain::Error::Backend(format!("{:?}", e)))?
+				.map_err(|e| sp_blockchain::Error::Backend(format!("{}", e)))?
 		},
 		#[cfg(not(feature = "with-parity-db"))]
 		DatabaseSettingsSrc::ParityDb { .. } => {
@@ -449,10 +449,35 @@ impl DatabaseType {
 	}
 }
 
+pub(crate) struct JoinInput<'a, 'b>(&'a [u8], &'b [u8]);
+
+pub(crate) fn join_input<'a, 'b>(i1: &'a[u8], i2: &'b [u8]) -> JoinInput<'a, 'b> {
+	JoinInput(i1, i2)
+}
+
+impl<'a, 'b> codec::Input for JoinInput<'a, 'b> {
+	fn remaining_len(&mut self) -> Result<Option<usize>, codec::Error> {
+		Ok(Some(self.0.len() + self.1.len()))
+	}
+
+	fn read(&mut self, into: &mut [u8]) -> Result<(), codec::Error> {
+		let mut read = 0;
+		if self.0.len() > 0 {
+			read = std::cmp::min(self.0.len(), into.len());
+			self.0.read(&mut into[..read])?;
+		}
+		if read < into.len() {
+			self.1.read(&mut into[read..])?;
+		}
+		Ok(())
+	}
+}
+
 #[cfg(test)]
 mod tests {
 	use super::*;
 	use sp_runtime::testing::{Block as RawBlock, ExtrinsicWrapper};
+	use codec::Input;
 	type Block = RawBlock<ExtrinsicWrapper<u32>>;
 
 	#[test]
@@ -469,4 +494,25 @@ mod tests {
 		assert_eq!(DatabaseType::Full.as_str(), "full");
 		assert_eq!(DatabaseType::Light.as_str(), "light");
 	}
+
+	#[test]
+	fn join_input_works() {
+		let buf1 = [1, 2, 3, 4];
+		let buf2 = [5, 6, 7, 8];
+		let mut test = [0, 0, 0];
+		let mut joined = join_input(buf1.as_ref(), buf2.as_ref());
+		assert_eq!(joined.remaining_len().unwrap(), Some(8));
+
+		joined.read(&mut test).unwrap();
+		assert_eq!(test, [1, 2, 3]);
+		assert_eq!(joined.remaining_len().unwrap(), Some(5));
+
+		joined.read(&mut test).unwrap();
+		assert_eq!(test, [4, 5, 6]);
+		assert_eq!(joined.remaining_len().unwrap(), Some(2));
+
+		joined.read(&mut test[0..2]).unwrap();
+		assert_eq!(test, [7, 8, 6]);
+		assert_eq!(joined.remaining_len().unwrap(), Some(0));
+	}
 }
diff --git a/client/executor/src/native_executor.rs b/client/executor/src/native_executor.rs
index 42a7950593ccf..6df651e1b776c 100644
--- a/client/executor/src/native_executor.rs
+++ b/client/executor/src/native_executor.rs
@@ -274,10 +274,20 @@ impl<D: NativeExecutionDispatch> NativeExecutor<D> {
 		default_heap_pages: Option<u64>,
 		max_runtime_instances: usize,
 	) -> Self {
-		let mut host_functions = D::ExtendHostFunctions::host_functions();
+		let extended =  D::ExtendHostFunctions::host_functions();
+		let mut host_functions = sp_io::SubstrateHostFunctions::host_functions()
+			.into_iter()
+			// filter out any host function overrides provided.
+			.filter(|host_fn| {
+				extended.iter()
+					.find(|ext_host_fn| host_fn.name() == ext_host_fn.name())
+					.is_none()
+			})
+			.collect::<Vec<_>>();
+
 
 		// Add the custom host functions provided by the user.
-		host_functions.extend(sp_io::SubstrateHostFunctions::host_functions());
+		host_functions.extend(extended);
 		let wasm_executor = WasmExecutor::new(
 			fallback_method,
 			default_heap_pages,
diff --git a/client/finality-grandpa-warp-sync/src/proof.rs b/client/finality-grandpa-warp-sync/src/proof.rs
index 1b447d2ef720c..4677d2401e835 100644
--- a/client/finality-grandpa-warp-sync/src/proof.rs
+++ b/client/finality-grandpa-warp-sync/src/proof.rs
@@ -20,7 +20,7 @@ use sc_finality_grandpa::{
 	find_scheduled_change, AuthoritySetChanges, BlockNumberOps, GrandpaJustification,
 };
 use sp_blockchain::Backend as BlockchainBackend;
-use sp_finality_grandpa::{AuthorityList, SetId};
+use sp_finality_grandpa::{AuthorityList, SetId, GRANDPA_ENGINE_ID};
 use sp_runtime::{
 	generic::BlockId,
 	traits::{Block as BlockT, NumberFor},
@@ -108,11 +108,14 @@ impl<Block: BlockT> WarpSyncProof<Block> {
 				break;
 			}
 
-			let justification = backend.justification(BlockId::Number(*last_block))?.expect(
-				"header is last in set and contains standard change signal; \
-				 must have justification; \
-				 qed.",
-			);
+			let justification = backend
+				.justifications(BlockId::Number(*last_block))?
+				.and_then(|just| just.into_justification(GRANDPA_ENGINE_ID))
+				.expect(
+					"header is last in set and contains standard change signal; \
+					must have justification; \
+					qed.",
+				);
 
 			let justification = GrandpaJustification::<Block>::decode(&mut &justification[..])?;
 
@@ -171,6 +174,7 @@ mod tests {
 	use sc_finality_grandpa::{AuthoritySetChanges, GrandpaJustification};
 	use sp_blockchain::HeaderBackend;
 	use sp_consensus::BlockOrigin;
+	use sp_finality_grandpa::GRANDPA_ENGINE_ID;
 	use sp_keyring::Ed25519Keyring;
 	use sp_runtime::{generic::BlockId, traits::Header as _};
 	use std::sync::Arc;
@@ -233,7 +237,7 @@ mod tests {
 				block.header.digest_mut().logs.push(digest);
 			}
 
-			client.import(BlockOrigin::Own, block).unwrap();
+			futures::executor::block_on(client.import(BlockOrigin::Own, block)).unwrap();
 
 			if let Some(new_authorities) = new_authorities {
 				// generate a justification for this block, finalize it and note the authority set
@@ -272,7 +276,10 @@ mod tests {
 				let justification = GrandpaJustification::from_commit(&client, 42, commit).unwrap();
 
 				client
-					.finalize_block(BlockId::Hash(target_hash), Some(justification.encode()))
+					.finalize_block(
+						BlockId::Hash(target_hash),
+						Some((GRANDPA_ENGINE_ID, justification.encode()))
+					)
 					.unwrap();
 
 				authority_set_changes.push((current_set_id, n));
diff --git a/client/finality-grandpa/Cargo.toml b/client/finality-grandpa/Cargo.toml
index 7ae5666c7bc84..1f21f454491b3 100644
--- a/client/finality-grandpa/Cargo.toml
+++ b/client/finality-grandpa/Cargo.toml
@@ -47,6 +47,7 @@ sc-block-builder = { version = "0.9.0", path = "../block-builder" }
 finality-grandpa = { version = "0.14.0", features = ["derive-codec"] }
 pin-project = "1.0.4"
 linked-hash-map = "0.5.2"
+async-trait = "0.1.42"
 
 [dev-dependencies]
 assert_matches = "1.3.0"
diff --git a/client/finality-grandpa/src/authorities.rs b/client/finality-grandpa/src/authorities.rs
index 1854a33d29f1f..056460ac9ed80 100644
--- a/client/finality-grandpa/src/authorities.rs
+++ b/client/finality-grandpa/src/authorities.rs
@@ -19,17 +19,17 @@
 //! Utilities for dealing with authorities, authority sets, and handoffs.
 
 use fork_tree::ForkTree;
-use parking_lot::RwLock;
+use parking_lot::MappedMutexGuard;
 use finality_grandpa::voter_set::VoterSet;
 use parity_scale_codec::{Encode, Decode};
 use log::debug;
 use sc_telemetry::{telemetry, TelemetryHandle, CONSENSUS_INFO};
 use sp_finality_grandpa::{AuthorityId, AuthorityList};
+use sc_consensus::shared_data::{SharedData, SharedDataLocked};
 
 use std::cmp::Ord;
 use std::fmt::Debug;
 use std::ops::Add;
-use std::sync::Arc;
 
 /// Error type returned on operations on the `AuthoritySet`.
 #[derive(Debug, derive_more::Display)]
@@ -70,19 +70,30 @@ impl<N, E: std::error::Error> From<E> for Error<N, E> {
 
 /// A shared authority set.
 pub struct SharedAuthoritySet<H, N> {
-	inner: Arc<RwLock<AuthoritySet<H, N>>>,
+	inner: SharedData<AuthoritySet<H, N>>,
 }
 
 impl<H, N> Clone for SharedAuthoritySet<H, N> {
 	fn clone(&self) -> Self {
-		SharedAuthoritySet { inner: self.inner.clone() }
+		SharedAuthoritySet {
+			inner: self.inner.clone(),
+		}
 	}
 }
 
 impl<H, N> SharedAuthoritySet<H, N> {
-	/// Acquire a reference to the inner read-write lock.
-	pub(crate) fn inner(&self) -> &RwLock<AuthoritySet<H, N>> {
-		&*self.inner
+	/// Returns access to the [`AuthoritySet`].
+	pub(crate) fn inner(&self) -> MappedMutexGuard<AuthoritySet<H, N>> {
+		self.inner.shared_data()
+	}
+
+	/// Returns access to the [`AuthoritySet`] and locks it.
+	///
+	/// For more information see [`SharedDataLocked`].
+	pub(crate) fn inner_locked(
+		&self,
+	) -> SharedDataLocked<AuthoritySet<H, N>> {
+		self.inner.shared_data_locked()
 	}
 }
 
@@ -93,17 +104,17 @@ where N: Add<Output=N> + Ord + Clone + Debug,
 	/// Get the earliest limit-block number that's higher or equal to the given
 	/// min number, if any.
 	pub(crate) fn current_limit(&self, min: N) -> Option<N> {
-		self.inner.read().current_limit(min)
+		self.inner().current_limit(min)
 	}
 
 	/// Get the current set ID. This is incremented every time the set changes.
 	pub fn set_id(&self) -> u64 {
-		self.inner.read().set_id
+		self.inner().set_id
 	}
 
 	/// Get the current authorities and their weights (for the current set ID).
 	pub fn current_authorities(&self) -> VoterSet<AuthorityId> {
-		VoterSet::new(self.inner.read().current_authorities.iter().cloned()).expect(
+		VoterSet::new(self.inner().current_authorities.iter().cloned()).expect(
 			"current_authorities is non-empty and weights are non-zero; \
 			 constructor and all mutating operations on `AuthoritySet` ensure this; \
 			 qed.",
@@ -112,18 +123,20 @@ where N: Add<Output=N> + Ord + Clone + Debug,
 
 	/// Clone the inner `AuthoritySet`.
 	pub fn clone_inner(&self) -> AuthoritySet<H, N> {
-		self.inner.read().clone()
+		self.inner().clone()
 	}
 
 	/// Clone the inner `AuthoritySetChanges`.
 	pub fn authority_set_changes(&self) -> AuthoritySetChanges<N> {
-		self.inner.read().authority_set_changes.clone()
+		self.inner().authority_set_changes.clone()
 	}
 }
 
 impl<H, N> From<AuthoritySet<H, N>> for SharedAuthoritySet<H, N> {
 	fn from(set: AuthoritySet<H, N>) -> Self {
-		SharedAuthoritySet { inner: Arc::new(RwLock::new(set)) }
+		SharedAuthoritySet {
+			inner: SharedData::new(set),
+		}
 	}
 }
 
diff --git a/client/finality-grandpa/src/aux_schema.rs b/client/finality-grandpa/src/aux_schema.rs
index 43c45b9f10ae1..8ecfae40f68c7 100644
--- a/client/finality-grandpa/src/aux_schema.rs
+++ b/client/finality-grandpa/src/aux_schema.rs
@@ -592,7 +592,7 @@ mod test {
 		).unwrap();
 
 		assert_eq!(
-			*authority_set.inner().read(),
+			*authority_set.inner(),
 			AuthoritySet::new(
 				authorities.clone(),
 				set_id,
@@ -616,7 +616,7 @@ mod test {
 						votes: vec![],
 					},
 					set_id,
-					&*authority_set.inner().read(),
+					&*authority_set.inner(),
 				),
 				current_rounds,
 			},
@@ -688,7 +688,7 @@ mod test {
 		).unwrap();
 
 		assert_eq!(
-			*authority_set.inner().read(),
+			*authority_set.inner(),
 			AuthoritySet::new(
 				authorities.clone(),
 				set_id,
@@ -712,7 +712,7 @@ mod test {
 						votes: vec![],
 					},
 					set_id,
-					&*authority_set.inner().read(),
+					&*authority_set.inner(),
 				),
 				current_rounds,
 			},
@@ -781,7 +781,7 @@ mod test {
 		).unwrap();
 
 		assert_eq!(
-			*authority_set.inner().read(),
+			*authority_set.inner(),
 			AuthoritySet::new(
 				authorities.clone(),
 				set_id,
diff --git a/client/finality-grandpa/src/environment.rs b/client/finality-grandpa/src/environment.rs
index 5bb525549b18c..3786355d2db4e 100644
--- a/client/finality-grandpa/src/environment.rs
+++ b/client/finality-grandpa/src/environment.rs
@@ -55,7 +55,7 @@ use crate::justification::GrandpaJustification;
 use crate::until_imported::UntilVoteTargetImported;
 use crate::voting_rule::VotingRule;
 use sp_finality_grandpa::{
-	AuthorityId, AuthoritySignature, Equivocation, EquivocationProof,
+	AuthorityId, AuthoritySignature, Equivocation, EquivocationProof, GRANDPA_ENGINE_ID,
 	GrandpaApi, RoundNumber, SetId,
 };
 use prometheus_endpoint::{register, Counter, Gauge, PrometheusError, U64};
@@ -508,7 +508,7 @@ where
 			.best_chain()
 			.map_err(|e| Error::Blockchain(e.to_string()))?;
 
-		let authority_set = self.authority_set.inner().read();
+		let authority_set = self.authority_set.inner();
 
 		// block hash and number of the next pending authority set change in the
 		// given best chain.
@@ -1228,7 +1228,7 @@ where
 	// NOTE: lock must be held through writing to DB to avoid race. this lock
 	//       also implicitly synchronizes the check for last finalized number
 	//       below.
-	let mut authority_set = authority_set.inner().write();
+	let mut authority_set = authority_set.inner();
 
 	let status = client.info();
 
@@ -1326,10 +1326,13 @@ where
 
 		// ideally some handle to a synchronization oracle would be used
 		// to avoid unconditionally notifying.
-		client.apply_finality(import_op, BlockId::Hash(hash), justification, true).map_err(|e| {
-			warn!(target: "afg", "Error applying finality to block {:?}: {:?}", (hash, number), e);
-			e
-		})?;
+		let justification = justification.map(|j| (GRANDPA_ENGINE_ID, j.clone()));
+		client
+			.apply_finality(import_op, BlockId::Hash(hash), justification, true)
+			.map_err(|e| {
+				warn!(target: "afg", "Error applying finality to block {:?}: {:?}", (hash, number), e);
+				e
+			})?;
 		telemetry!(
 			telemetry;
 			CONSENSUS_INFO;
diff --git a/client/finality-grandpa/src/finality_proof.rs b/client/finality-grandpa/src/finality_proof.rs
index b79b3190739d6..80ba8cee9101e 100644
--- a/client/finality-grandpa/src/finality_proof.rs
+++ b/client/finality-grandpa/src/finality_proof.rs
@@ -43,11 +43,11 @@ use finality_grandpa::BlockNumberOps;
 use parity_scale_codec::{Encode, Decode};
 use sp_blockchain::{Backend as BlockchainBackend, Error as ClientError, Result as ClientResult};
 use sp_runtime::{
-	Justification, generic::BlockId,
+	EncodedJustification, generic::BlockId,
 	traits::{NumberFor, Block as BlockT, Header as HeaderT, One},
 };
 use sc_client_api::backend::Backend;
-use sp_finality_grandpa::AuthorityId;
+use sp_finality_grandpa::{AuthorityId, GRANDPA_ENGINE_ID};
 
 use crate::authorities::AuthoritySetChanges;
 use crate::justification::GrandpaJustification;
@@ -190,8 +190,10 @@ where
 	// Get the Justification stored at the last block of the set
 	let last_block_for_set_id = BlockId::Number(last_block_for_set);
 	let justification =
-		if let Some(justification) = blockchain.justification(last_block_for_set_id)? {
-			justification
+		if let Some(grandpa_justification) = blockchain.justifications(last_block_for_set_id)?
+			.and_then(|justifications| justifications.into_justification(GRANDPA_ENGINE_ID))
+		{
+			grandpa_justification
 		} else {
 			trace!(
 				target: "afg",
@@ -257,7 +259,7 @@ pub trait ProvableJustification<Header: HeaderT>: Encode + Decode {
 
 	/// Decode and verify justification.
 	fn decode_and_verify(
-		justification: &Justification,
+		justification: &EncodedJustification,
 		set_id: u64,
 		authorities: &[(AuthorityId, u64)],
 	) -> ClientResult<Self> {
@@ -286,6 +288,7 @@ pub(crate) mod tests {
 	use super::*;
 	use crate::authorities::AuthoritySetChanges;
 	use sp_core::crypto::Public;
+	use sp_runtime::Justifications;
 	use sp_finality_grandpa::AuthorityList;
 	use sc_client_api::NewBlockState;
 	use sc_client_api::in_mem::Blockchain as InMemoryBlockchain;
@@ -330,31 +333,27 @@ pub(crate) mod tests {
 	}
 
 	fn test_blockchain() -> InMemoryBlockchain<Block> {
+		use sp_finality_grandpa::GRANDPA_ENGINE_ID as ID;
 		let blockchain = InMemoryBlockchain::<Block>::new();
-		blockchain
-			.insert(header(0).hash(), header(0), Some(vec![0]), None, NewBlockState::Final)
-			.unwrap();
-		blockchain
-			.insert(header(1).hash(), header(1), Some(vec![1]), None, NewBlockState::Final)
-			.unwrap();
-		blockchain
-			.insert(header(2).hash(), header(2), None, None, NewBlockState::Best)
-			.unwrap();
-		blockchain
-			.insert(header(3).hash(), header(3), Some(vec![3]), None, NewBlockState::Final)
-			.unwrap();
+		let just0 = Some(Justifications::from((ID, vec![0])));
+		let just1 = Some(Justifications::from((ID, vec![1])));
+		let just2 = None;
+		let just3 = Some(Justifications::from((ID, vec![3])));
+		blockchain.insert(header(0).hash(), header(0), just0, None, NewBlockState::Final).unwrap();
+		blockchain.insert(header(1).hash(), header(1), just1, None, NewBlockState::Final).unwrap();
+		blockchain.insert(header(2).hash(), header(2), just2, None, NewBlockState::Best).unwrap();
+		blockchain.insert(header(3).hash(), header(3), just3, None, NewBlockState::Final).unwrap();
 		blockchain
 	}
 
 	#[test]
 	fn finality_proof_fails_if_no_more_last_finalized_blocks() {
+		use sp_finality_grandpa::GRANDPA_ENGINE_ID as ID;
 		let blockchain = test_blockchain();
-		blockchain
-			.insert(header(4).hash(), header(4), Some(vec![1]), None, NewBlockState::Best)
-			.unwrap();
-		blockchain
-			.insert(header(5).hash(), header(5), Some(vec![2]), None, NewBlockState::Best)
-			.unwrap();
+		let just1 = Some(Justifications::from((ID, vec![1])));
+		let just2 = Some(Justifications::from((ID, vec![2])));
+		blockchain.insert(header(4).hash(), header(4), just1, None, NewBlockState::Best).unwrap();
+		blockchain.insert(header(5).hash(), header(5), just2, None, NewBlockState::Best).unwrap();
 
 		let mut authority_set_changes = AuthoritySetChanges::empty();
 		authority_set_changes.append(0, 5);
@@ -430,22 +429,17 @@ pub(crate) mod tests {
 
 	#[test]
 	fn finality_proof_using_authority_set_changes_fails_with_undefined_start() {
+		use sp_finality_grandpa::GRANDPA_ENGINE_ID as ID;
 		let blockchain = test_blockchain();
 		let auth = vec![(AuthorityId::from_slice(&[1u8; 32]), 1u64)];
-		let just4 = TestJustification((0, auth.clone()), vec![4]).encode();
-		let just7 = TestJustification((1, auth.clone()), vec![7]).encode();
-		blockchain
-			.insert(header(4).hash(), header(4), Some(just4), None, NewBlockState::Final)
-			.unwrap();
-		blockchain
-			.insert(header(5).hash(), header(5), None, None, NewBlockState::Final)
-			.unwrap();
-		blockchain
-			.insert(header(6).hash(), header(6), None, None, NewBlockState::Final)
-			.unwrap();
-		blockchain
-			.insert(header(7).hash(), header(7), Some(just7.clone()), None, NewBlockState::Final)
-			.unwrap();
+		let grandpa_just4 = TestJustification((0, auth.clone()), vec![4]).encode();
+		let grandpa_just7 = TestJustification((1, auth.clone()), vec![7]).encode();
+		let just4 = Some(Justifications::from((ID, grandpa_just4)));
+		let just7 = Some(Justifications::from((ID, grandpa_just7)));
+		blockchain.insert(header(4).hash(), header(4), just4, None, NewBlockState::Final).unwrap();
+		blockchain.insert(header(5).hash(), header(5), None, None, NewBlockState::Final).unwrap();
+		blockchain.insert(header(6).hash(), header(6), None, None, NewBlockState::Final).unwrap();
+		blockchain.insert(header(7).hash(), header(7), just7, None, NewBlockState::Final).unwrap();
 
 		// We have stored the correct block number for the relevant set, but as we are missing the
 		// block for the preceding set the start is not well-defined.
@@ -462,22 +456,17 @@ pub(crate) mod tests {
 
 	#[test]
 	fn finality_proof_using_authority_set_changes_works() {
+		use sp_finality_grandpa::GRANDPA_ENGINE_ID as ID;
 		let blockchain = test_blockchain();
 		let auth = vec![(AuthorityId::from_slice(&[1u8; 32]), 1u64)];
-		let just4 = TestJustification((0, auth.clone()), vec![4]).encode();
-		let just7 = TestJustification((1, auth.clone()), vec![7]).encode();
-		blockchain
-			.insert(header(4).hash(), header(4), Some(just4), None, NewBlockState::Final)
-			.unwrap();
-		blockchain
-			.insert(header(5).hash(), header(5), None, None, NewBlockState::Final)
-			.unwrap();
-		blockchain
-			.insert(header(6).hash(), header(6), None, None, NewBlockState::Final)
-			.unwrap();
-		blockchain
-			.insert(header(7).hash(), header(7), Some(just7.clone()), None, NewBlockState::Final)
-			.unwrap();
+		let grandpa_just4 = TestJustification((0, auth.clone()), vec![4]).encode();
+		let grandpa_just7 = TestJustification((1, auth.clone()), vec![7]).encode();
+		let just4 = Some(Justifications::from((ID, grandpa_just4)));
+		let just7 = Some(Justifications::from((ID, grandpa_just7.clone())));
+		blockchain.insert(header(4).hash(), header(4), just4, None, NewBlockState::Final) .unwrap();
+		blockchain.insert(header(5).hash(), header(5), None, None, NewBlockState::Final) .unwrap();
+		blockchain.insert(header(6).hash(), header(6), None, None, NewBlockState::Final).unwrap();
+		blockchain.insert(header(7).hash(), header(7), just7, None, NewBlockState::Final).unwrap();
 
 		let mut authority_set_changes = AuthoritySetChanges::empty();
 		authority_set_changes.append(0, 4);
@@ -497,7 +486,7 @@ pub(crate) mod tests {
 			proof_of_5,
 			FinalityProof {
 				block: header(7).hash(),
-				justification: just7,
+				justification: grandpa_just7,
 				unknown_headers: vec![header(6)],
 			}
 		);
diff --git a/client/finality-grandpa/src/import.rs b/client/finality-grandpa/src/import.rs
index 22d7b7fd5bcc8..b2fcca019bcb1 100644
--- a/client/finality-grandpa/src/import.rs
+++ b/client/finality-grandpa/src/import.rs
@@ -20,13 +20,13 @@ use std::{sync::Arc, collections::HashMap};
 
 use log::debug;
 use parity_scale_codec::Encode;
-use parking_lot::RwLockWriteGuard;
 
 use sp_blockchain::{BlockStatus, well_known_cache_keys};
 use sc_client_api::{backend::Backend, utils::is_descendent_of};
 use sc_telemetry::TelemetryHandle;
 use sp_utils::mpsc::TracingUnboundedSender;
 use sp_api::TransactionFor;
+use sc_consensus::shared_data::{SharedDataLockedUpgradable, SharedDataLocked};
 
 use sp_consensus::{
 	BlockImport, Error as ConsensusError,
@@ -99,7 +99,7 @@ impl<BE, Block: BlockT, Client, SC> JustificationImport<Block>
 		let chain_info = self.inner.info();
 
 		// request justifications for all pending changes for which change blocks have already been imported
-		let authorities = self.authority_set.inner().read();
+		let authorities = self.authority_set.inner();
 		for pending_change in authorities.pending_changes() {
 			if pending_change.delay_kind == DelayKind::Finalized &&
 				pending_change.effective_number() > chain_info.finalized_number &&
@@ -157,30 +157,30 @@ impl<H, N> AppliedChanges<H, N> {
 	}
 }
 
-struct PendingSetChanges<'a, Block: 'a + BlockT> {
+struct PendingSetChanges<Block: BlockT> {
 	just_in_case: Option<(
 		AuthoritySet<Block::Hash, NumberFor<Block>>,
-		RwLockWriteGuard<'a, AuthoritySet<Block::Hash, NumberFor<Block>>>,
+		SharedDataLockedUpgradable<AuthoritySet<Block::Hash, NumberFor<Block>>>,
 	)>,
 	applied_changes: AppliedChanges<Block::Hash, NumberFor<Block>>,
 	do_pause: bool,
 }
 
-impl<'a, Block: 'a + BlockT> PendingSetChanges<'a, Block> {
+impl<Block: BlockT> PendingSetChanges<Block> {
 	// revert the pending set change explicitly.
-	fn revert(self) { }
+	fn revert(self) {}
 
 	fn defuse(mut self) -> (AppliedChanges<Block::Hash, NumberFor<Block>>, bool) {
 		self.just_in_case = None;
-		let applied_changes = ::std::mem::replace(&mut self.applied_changes, AppliedChanges::None);
+		let applied_changes = std::mem::replace(&mut self.applied_changes, AppliedChanges::None);
 		(applied_changes, self.do_pause)
 	}
 }
 
-impl<'a, Block: 'a + BlockT> Drop for PendingSetChanges<'a, Block> {
+impl<Block: BlockT> Drop for PendingSetChanges<Block> {
 	fn drop(&mut self) {
 		if let Some((old_set, mut authorities)) = self.just_in_case.take() {
-			*authorities = old_set;
+			*authorities.upgrade() = old_set;
 		}
 	}
 }
@@ -269,33 +269,38 @@ where
 		// when we update the authorities, we need to hold the lock
 		// until the block is written to prevent a race if we need to restore
 		// the old authority set on error or panic.
-		struct InnerGuard<'a, T: 'a> {
-			old: Option<T>,
-			guard: Option<RwLockWriteGuard<'a, T>>,
+		struct InnerGuard<'a, H, N> {
+			old: Option<AuthoritySet<H, N>>,
+			guard: Option<SharedDataLocked<'a, AuthoritySet<H, N>>>,
 		}
 
-		impl<'a, T: 'a> InnerGuard<'a, T> {
-			fn as_mut(&mut self) -> &mut T {
+		impl<'a, H, N> InnerGuard<'a, H, N> {
+			fn as_mut(&mut self) -> &mut AuthoritySet<H, N> {
 				&mut **self.guard.as_mut().expect("only taken on deconstruction; qed")
 			}
 
-			fn set_old(&mut self, old: T) {
+			fn set_old(&mut self, old: AuthoritySet<H, N>) {
 				if self.old.is_none() {
 					// ignore "newer" old changes.
 					self.old = Some(old);
 				}
 			}
 
-			fn consume(mut self) -> Option<(T, RwLockWriteGuard<'a, T>)> {
+			fn consume(
+				mut self,
+			) -> Option<(AuthoritySet<H, N>, SharedDataLocked<'a, AuthoritySet<H, N>>)> {
 				if let Some(old) = self.old.take() {
-					Some((old, self.guard.take().expect("only taken on deconstruction; qed")))
+					Some((
+						old,
+						self.guard.take().expect("only taken on deconstruction; qed"),
+					))
 				} else {
 					None
 				}
 			}
 		}
 
-		impl<'a, T: 'a> Drop for InnerGuard<'a, T> {
+		impl<'a, H, N> Drop for InnerGuard<'a, H, N> {
 			fn drop(&mut self) {
 				if let (Some(mut guard), Some(old)) = (self.guard.take(), self.old.take()) {
 					*guard = old;
@@ -315,7 +320,7 @@ where
 		let is_descendent_of = is_descendent_of(&*self.inner, Some((hash, parent_hash)));
 
 		let mut guard = InnerGuard {
-			guard: Some(self.authority_set.inner().write()),
+			guard: Some(self.authority_set.inner_locked()),
 			old: None,
 		};
 
@@ -413,10 +418,13 @@ where
 			);
 		}
 
+		let just_in_case = just_in_case.map(|(o, i)| (o, i.release_mutex()));
+
 		Ok(PendingSetChanges { just_in_case, applied_changes, do_pause })
 	}
 }
 
+#[async_trait::async_trait]
 impl<BE, Block: BlockT, Client, SC> BlockImport<Block>
 	for GrandpaBlockImport<BE, Block, Client, SC> where
 		NumberFor<Block>: finality_grandpa::BlockNumberOps,
@@ -425,11 +433,13 @@ impl<BE, Block: BlockT, Client, SC> BlockImport<Block>
 		Client: crate::ClientForGrandpa<Block, BE>,
 		for<'a> &'a Client:
 			BlockImport<Block, Error = ConsensusError, Transaction = TransactionFor<Client, Block>>,
+		TransactionFor<Client, Block>: Send + 'static,
+		SC: Send,
 {
 	type Error = ConsensusError;
 	type Transaction = TransactionFor<Client, Block>;
 
-	fn import_block(
+	async fn import_block(
 		&mut self,
 		mut block: BlockImportParams<Block, Self::Transaction>,
 		new_cache: HashMap<well_known_cache_keys::Id, Vec<u8>>,
@@ -451,8 +461,8 @@ impl<BE, Block: BlockT, Client, SC> BlockImport<Block>
 		let pending_changes = self.make_authorities_changes(&mut block, hash, initial_sync)?;
 
 		// we don't want to finalize on `inner.import_block`
-		let mut justification = block.justification.take();
-		let import_result = (&*self.inner).import_block(block, new_cache);
+		let mut justifications = block.justifications.take();
+		let import_result = (&*self.inner).import_block(block, new_cache).await;
 
 		let mut imported_aux = {
 			match import_result {
@@ -513,17 +523,20 @@ impl<BE, Block: BlockT, Client, SC> BlockImport<Block>
 				// need to apply first, drop any justification that might have been provided with
 				// the block to make sure we request them from `sync` which will ensure they'll be
 				// applied in-order.
-				justification.take();
+				justifications.take();
 			},
 			_ => {},
 		}
 
-		match justification {
+		let grandpa_justification = justifications
+			.and_then(|just| just.into_justification(GRANDPA_ENGINE_ID));
+
+		match grandpa_justification {
 			Some(justification) => {
 				let import_res = self.import_justification(
 					hash,
 					number,
-					justification,
+					(GRANDPA_ENGINE_ID, justification),
 					needs_justification,
 					initial_sync,
 				);
@@ -553,11 +566,11 @@ impl<BE, Block: BlockT, Client, SC> BlockImport<Block>
 		Ok(ImportResult::Imported(imported_aux))
 	}
 
-	fn check_block(
+	async fn check_block(
 		&mut self,
 		block: BlockCheckParams<Block>,
 	) -> Result<ImportResult, Self::Error> {
-		self.inner.check_block(block)
+		self.inner.check_block(block).await
 	}
 }
 
@@ -577,8 +590,7 @@ impl<Backend, Block: BlockT, Client, SC> GrandpaBlockImport<Backend, Block, Clie
 			.iter()
 			.find(|(set_id, _)| *set_id == authority_set.set_id())
 		{
-			let mut authority_set = authority_set.inner().write();
-			authority_set.current_authorities = change.next_authorities.clone();
+			authority_set.inner().current_authorities = change.next_authorities.clone();
 		}
 
 		// index authority set hard forks by block hash so that they can be used
@@ -593,7 +605,7 @@ impl<Backend, Block: BlockT, Client, SC> GrandpaBlockImport<Backend, Block, Clie
 		// any *pending* standard changes, checking by the block hash at which
 		// they were announced.
 		{
-			let mut authority_set = authority_set.inner().write();
+			let mut authority_set = authority_set.inner();
 
 			authority_set.pending_standard_changes = authority_set
 				.pending_standard_changes
@@ -637,8 +649,14 @@ where
 		enacts_change: bool,
 		initial_sync: bool,
 	) -> Result<(), ConsensusError> {
+		if justification.0 != GRANDPA_ENGINE_ID {
+			return Err(ConsensusError::ClientImport(
+				"GRANDPA can only import GRANDPA Justifications.".into(),
+			));
+		}
+
 		let justification = GrandpaJustification::decode_and_verify_finalizes(
-			&justification,
+			&justification.1,
 			(hash, number),
 			self.authority_set.set_id(),
 			&self.authority_set.current_authorities(),
diff --git a/client/finality-grandpa/src/lib.rs b/client/finality-grandpa/src/lib.rs
index c6c2a39674b8c..9a8939660473b 100644
--- a/client/finality-grandpa/src/lib.rs
+++ b/client/finality-grandpa/src/lib.rs
@@ -1019,7 +1019,7 @@ where
 					// set changed (not where the signal happened!) as the base.
 					let set_state = VoterSetState::live(
 						new.set_id,
-						&*self.env.authority_set.inner().read(),
+						&*self.env.authority_set.inner(),
 						(new.canon_hash, new.canon_number),
 					);
 
diff --git a/client/finality-grandpa/src/observer.rs b/client/finality-grandpa/src/observer.rs
index c0eab15e4f455..827a7388d6033 100644
--- a/client/finality-grandpa/src/observer.rs
+++ b/client/finality-grandpa/src/observer.rs
@@ -326,7 +326,7 @@ where
 				// set changed (not where the signal happened!) as the base.
 				let set_state = VoterSetState::live(
 					new.set_id,
-					&*self.persistent_data.authority_set.inner().read(),
+					&*self.persistent_data.authority_set.inner(),
 					(new.canon_hash, new.canon_number),
 				);
 
diff --git a/client/finality-grandpa/src/tests.rs b/client/finality-grandpa/src/tests.rs
index 6824a8ed04273..b87bbefc11375 100644
--- a/client/finality-grandpa/src/tests.rs
+++ b/client/finality-grandpa/src/tests.rs
@@ -28,9 +28,9 @@ use sc_network_test::{
 use sc_network::config::ProtocolConfig;
 use parking_lot::{RwLock, Mutex};
 use futures_timer::Delay;
+use futures::executor::block_on;
 use tokio::runtime::{Runtime, Handle};
 use sp_keyring::Ed25519Keyring;
-use sc_client_api::backend::TransactionFor;
 use sp_blockchain::Result;
 use sp_api::{ApiRef, ProvideRuntimeApi};
 use substrate_test_runtime_client::runtime::BlockNumber;
@@ -39,11 +39,13 @@ use sp_consensus::{
 	import_queue::BoxJustificationImport,
 };
 use std::{collections::{HashMap, HashSet}, pin::Pin};
-use sp_runtime::traits::{Block as BlockT, Header as HeaderT};
+use sp_runtime::{Justifications, traits::{Block as BlockT, Header as HeaderT}};
 use sp_runtime::generic::{BlockId, DigestItem};
 use sp_core::H256;
 use sp_keystore::{SyncCryptoStorePtr, SyncCryptoStore};
-use sp_finality_grandpa::{GRANDPA_ENGINE_ID, AuthorityList, EquivocationProof, GrandpaApi, OpaqueKeyOwnershipProof};
+use sp_finality_grandpa::{
+	GRANDPA_ENGINE_ID, AuthorityList, EquivocationProof, GrandpaApi, OpaqueKeyOwnershipProof,
+};
 
 use authorities::AuthoritySet;
 use sc_block_builder::BlockBuilderProvider;
@@ -54,7 +56,13 @@ use sp_application_crypto::key_types::GRANDPA;
 type TestLinkHalf =
 	LinkHalf<Block, PeersFullClient, LongestChain<substrate_test_runtime_client::Backend, Block>>;
 type PeerData = Mutex<Option<TestLinkHalf>>;
-type GrandpaPeer = Peer<PeerData>;
+type GrandpaPeer = Peer<PeerData, GrandpaBlockImport>;
+type GrandpaBlockImport = crate::GrandpaBlockImport<
+	substrate_test_runtime_client::Backend,
+	Block,
+	PeersFullClient,
+	LongestChain<substrate_test_runtime_client::Backend, Block>
+>;
 
 struct GrandpaTestNet {
 	peers: Vec<GrandpaPeer>,
@@ -62,21 +70,38 @@ struct GrandpaTestNet {
 }
 
 impl GrandpaTestNet {
-	fn new(test_config: TestApi, n_peers: usize) -> Self {
+	fn new(test_config: TestApi, n_authority: usize, n_full: usize) -> Self {
 		let mut net = GrandpaTestNet {
-			peers: Vec::with_capacity(n_peers),
+			peers: Vec::with_capacity(n_authority + n_full),
 			test_config,
 		};
-		for _ in 0..n_peers {
+
+		for _ in 0..n_authority {
+			net.add_authority_peer();
+		}
+
+		for _ in 0..n_full {
 			net.add_full_peer();
 		}
+
 		net
 	}
 }
 
+impl GrandpaTestNet {
+	fn add_authority_peer(&mut self) {
+		self.add_full_peer_with_config(FullPeerConfig {
+			notifications_protocols: vec![communication::GRANDPA_PROTOCOL_NAME.into()],
+			is_authority: true,
+			..Default::default()
+		})
+	}
+}
+
 impl TestNetFactory for GrandpaTestNet {
 	type Verifier = PassThroughVerifier;
 	type PeerData = PeerData;
+	type BlockImport = GrandpaBlockImport;
 
 	/// Create new test network with peers and given config.
 	fn from_config(_config: &ProtocolConfig) -> Self {
@@ -94,6 +119,7 @@ impl TestNetFactory for GrandpaTestNet {
 	fn add_full_peer(&mut self) {
 		self.add_full_peer_with_config(FullPeerConfig {
 			notifications_protocols: vec![communication::GRANDPA_PROTOCOL_NAME.into()],
+			is_authority: false,
 			..Default::default()
 		})
 	}
@@ -107,9 +133,9 @@ impl TestNetFactory for GrandpaTestNet {
 		PassThroughVerifier::new(false) // use non-instant finality.
 	}
 
-	fn make_block_import<Transaction>(&self, client: PeersClient)
+	fn make_block_import(&self, client: PeersClient)
 		-> (
-			BlockImportAdapter<Transaction>,
+			BlockImportAdapter<Self::BlockImport>,
 			Option<BoxJustificationImport<Block>>,
 			PeerData,
 		)
@@ -124,7 +150,7 @@ impl TestNetFactory for GrandpaTestNet {
 				).expect("Could not create block import for fresh peer.");
 				let justification_import = Box::new(import.clone());
 				(
-					BlockImportAdapter::new_full(import),
+					BlockImportAdapter::new(import),
 					Some(justification_import),
 					Mutex::new(Some(link)),
 				)
@@ -354,7 +380,7 @@ fn finalize_3_voters_no_observers() {
 	let peers = &[Ed25519Keyring::Alice, Ed25519Keyring::Bob, Ed25519Keyring::Charlie];
 	let voters = make_ids(peers);
 
-	let mut net = GrandpaTestNet::new(TestApi::new(voters), 3);
+	let mut net = GrandpaTestNet::new(TestApi::new(voters), 3, 0);
 	runtime.spawn(initialize_grandpa(&mut net, peers));
 	net.peer(0).push_blocks(20, false);
 	net.block_until_sync();
@@ -369,7 +395,7 @@ fn finalize_3_voters_no_observers() {
 
 	// normally there's no justification for finalized blocks
 	assert!(
-		net.lock().peer(0).client().justification(&BlockId::Number(20)).unwrap().is_none(),
+		net.lock().peer(0).client().justifications(&BlockId::Number(20)).unwrap().is_none(),
 		"Extra justification for block#1",
 	);
 }
@@ -381,7 +407,7 @@ fn finalize_3_voters_1_full_observer() {
 	let peers = &[Ed25519Keyring::Alice, Ed25519Keyring::Bob, Ed25519Keyring::Charlie];
 	let voters = make_ids(peers);
 
-	let mut net = GrandpaTestNet::new(TestApi::new(voters), 4);
+	let mut net = GrandpaTestNet::new(TestApi::new(voters), 3, 1);
 	runtime.spawn(initialize_grandpa(&mut net, peers));
 
 	runtime.spawn({
@@ -464,7 +490,7 @@ fn transition_3_voters_twice_1_full_observer() {
 	let genesis_voters = make_ids(peers_a);
 
 	let api = TestApi::new(genesis_voters);
-	let net = Arc::new(Mutex::new(GrandpaTestNet::new(api, 8)));
+	let net = Arc::new(Mutex::new(GrandpaTestNet::new(api, 8, 1)));
 
 	let mut runtime = Runtime::new().unwrap();
 
@@ -602,7 +628,7 @@ fn justification_is_generated_periodically() {
 	let peers = &[Ed25519Keyring::Alice, Ed25519Keyring::Bob, Ed25519Keyring::Charlie];
 	let voters = make_ids(peers);
 
-	let mut net = GrandpaTestNet::new(TestApi::new(voters), 3);
+	let mut net = GrandpaTestNet::new(TestApi::new(voters), 3, 0);
 	runtime.spawn(initialize_grandpa(&mut net, peers));
 	net.peer(0).push_blocks(32, false);
 	net.block_until_sync();
@@ -613,7 +639,7 @@ fn justification_is_generated_periodically() {
 	// when block#32 (justification_period) is finalized, justification
 	// is required => generated
 	for i in 0..3 {
-		assert!(net.lock().peer(i).client().justification(&BlockId::Number(32)).unwrap().is_some());
+		assert!(net.lock().peer(i).client().justifications(&BlockId::Number(32)).unwrap().is_some());
 	}
 }
 
@@ -626,7 +652,7 @@ fn sync_justifications_on_change_blocks() {
 
 	// 4 peers, 3 of them are authorities and participate in grandpa
 	let api = TestApi::new(voters);
-	let mut net = GrandpaTestNet::new(api, 4);
+	let mut net = GrandpaTestNet::new(api, 3, 1);
 	let voters = initialize_grandpa(&mut net, peers_a);
 
 	// add 20 blocks
@@ -658,12 +684,12 @@ fn sync_justifications_on_change_blocks() {
 	// the first 3 peers are grandpa voters and therefore have already finalized
 	// block 21 and stored a justification
 	for i in 0..3 {
-		assert!(net.lock().peer(i).client().justification(&BlockId::Number(21)).unwrap().is_some());
+		assert!(net.lock().peer(i).client().justifications(&BlockId::Number(21)).unwrap().is_some());
 	}
 
 	// the last peer should get the justification by syncing from other peers
 	futures::executor::block_on(futures::future::poll_fn(move |cx| {
-		if net.lock().peer(3).client().justification(&BlockId::Number(21)).unwrap().is_none() {
+		if net.lock().peer(3).client().justifications(&BlockId::Number(21)).unwrap().is_none() {
 			net.lock().poll(cx);
 			Poll::Pending
 		} else {
@@ -688,8 +714,10 @@ fn finalizes_multiple_pending_changes_in_order() {
 	let genesis_voters = make_ids(peers_a);
 
 	// 6 peers, 3 of them are authorities and participate in grandpa from genesis
+	// but all of them will be part of the voter set eventually so they should be
+	// all added to the network as authorities
 	let api = TestApi::new(genesis_voters);
-	let mut net = GrandpaTestNet::new(api, 6);
+	let mut net = GrandpaTestNet::new(api, 6, 0);
 	runtime.spawn(initialize_grandpa(&mut net, all_peers));
 
 	// add 20 blocks
@@ -749,7 +777,7 @@ fn force_change_to_new_set() {
 	let api = TestApi::new(make_ids(genesis_authorities));
 
 	let voters = make_ids(peers_a);
-	let mut net = GrandpaTestNet::new(api, 3);
+	let mut net = GrandpaTestNet::new(api, 3, 0);
 	let voters_future = initialize_grandpa(&mut net, peers_a);
 	let net = Arc::new(Mutex::new(net));
 
@@ -798,14 +826,10 @@ fn allows_reimporting_change_blocks() {
 	let peers_b = &[Ed25519Keyring::Alice, Ed25519Keyring::Bob];
 	let voters = make_ids(peers_a);
 	let api = TestApi::new(voters);
-	let mut net = GrandpaTestNet::new(api.clone(), 3);
+	let mut net = GrandpaTestNet::new(api.clone(), 3, 0);
 
 	let client = net.peer(0).client().clone();
-	let (mut block_import, ..) = net.make_block_import::<
-		TransactionFor<substrate_test_runtime_client::Backend, Block>
-	>(
-		client.clone(),
-	);
+	let (mut block_import, ..) = net.make_block_import(client.clone());
 
 	let full_client = client.as_full().unwrap();
 	let builder = full_client.new_block_at(&BlockId::Number(0), Default::default(), false).unwrap();
@@ -825,7 +849,7 @@ fn allows_reimporting_change_blocks() {
 	};
 
 	assert_eq!(
-		block_import.import_block(block(), HashMap::new()).unwrap(),
+		block_on(block_import.import_block(block(), HashMap::new())).unwrap(),
 		ImportResult::Imported(ImportedAux {
 			needs_justification: true,
 			clear_justification_requests: false,
@@ -836,7 +860,7 @@ fn allows_reimporting_change_blocks() {
 	);
 
 	assert_eq!(
-		block_import.import_block(block(), HashMap::new()).unwrap(),
+		block_on(block_import.import_block(block(), HashMap::new())).unwrap(),
 		ImportResult::AlreadyInChain
 	);
 }
@@ -847,14 +871,10 @@ fn test_bad_justification() {
 	let peers_b = &[Ed25519Keyring::Alice, Ed25519Keyring::Bob];
 	let voters = make_ids(peers_a);
 	let api = TestApi::new(voters);
-	let mut net = GrandpaTestNet::new(api.clone(), 3);
+	let mut net = GrandpaTestNet::new(api.clone(), 3, 0);
 
 	let client = net.peer(0).client().clone();
-	let (mut block_import, ..) = net.make_block_import::<
-		TransactionFor<substrate_test_runtime_client::Backend, Block>
-	>(
-		client.clone(),
-	);
+	let (mut block_import, ..) = net.make_block_import(client.clone());
 
 	let full_client = client.as_full().expect("only full clients are used in test");
 	let builder = full_client.new_block_at(&BlockId::Number(0), Default::default(), false).unwrap();
@@ -868,7 +888,7 @@ fn test_bad_justification() {
 	let block = || {
 		let block = block.clone();
 		let mut import = BlockImportParams::new(BlockOrigin::File, block.header);
-		import.justification = Some(Vec::new());
+		import.justifications = Some(Justifications::from((GRANDPA_ENGINE_ID, Vec::new())));
 		import.body = Some(block.extrinsics);
 		import.fork_choice = Some(ForkChoiceStrategy::LongestChain);
 
@@ -876,7 +896,7 @@ fn test_bad_justification() {
 	};
 
 	assert_eq!(
-		block_import.import_block(block(), HashMap::new()).unwrap(),
+		block_on(block_import.import_block(block(), HashMap::new())).unwrap(),
 		ImportResult::Imported(ImportedAux {
 			needs_justification: true,
 			clear_justification_requests: false,
@@ -887,7 +907,7 @@ fn test_bad_justification() {
 	);
 
 	assert_eq!(
-		block_import.import_block(block(), HashMap::new()).unwrap(),
+		block_on(block_import.import_block(block(), HashMap::new())).unwrap(),
 		ImportResult::AlreadyInChain
 	);
 }
@@ -907,7 +927,7 @@ fn voter_persists_its_votes() {
 	let voters = make_ids(peers);
 
 	// alice has a chain with 20 blocks
-	let mut net = GrandpaTestNet::new(TestApi::new(voters.clone()), 2);
+	let mut net = GrandpaTestNet::new(TestApi::new(voters.clone()), 2, 0);
 
 	// create the communication layer for bob, but don't start any
 	// voter. instead we'll listen for the prevote that alice casts
@@ -931,9 +951,7 @@ fn voter_persists_its_votes() {
 		let set_state = {
 			let bob_client = net.peer(1).client().clone();
 			let (_, _, link) = net
-				.make_block_import::<
-					TransactionFor<substrate_test_runtime_client::Backend, Block>
-				>(bob_client);
+				.make_block_import(bob_client);
 			let LinkHalf { persistent_data, .. } = link.lock().take().unwrap();
 			let PersistentData { set_state, .. } = persistent_data;
 			set_state
@@ -992,7 +1010,7 @@ fn voter_persists_its_votes() {
 
 		// we add a new peer to the test network and we'll use
 		// the network service of this new peer
-		net.add_full_peer();
+		net.add_authority_peer();
 		let net_service = net.peers[2].network_service().clone();
 		// but we'll reuse the client from the first peer (alice_voter1)
 		// since we want to share the same database, so that we can
@@ -1000,9 +1018,7 @@ fn voter_persists_its_votes() {
 		let alice_client = net.peer(0).client().clone();
 
 		let (_block_import, _, link) = net
-			.make_block_import::<
-				TransactionFor<substrate_test_runtime_client::Backend, Block>
-			>(alice_client);
+			.make_block_import(alice_client);
 		let link = link.lock().take().unwrap();
 
 		let grandpa_params = GrandpaParams {
@@ -1163,7 +1179,7 @@ fn finalize_3_voters_1_light_observer() {
 	let authorities = &[Ed25519Keyring::Alice, Ed25519Keyring::Bob, Ed25519Keyring::Charlie];
 	let voters = make_ids(authorities);
 
-	let mut net = GrandpaTestNet::new(TestApi::new(voters), 4);
+	let mut net = GrandpaTestNet::new(TestApi::new(voters), 3, 1);
 	let voters = initialize_grandpa(&mut net, authorities);
 	let observer = observer::run_grandpa_observer(
 		Config {
@@ -1201,7 +1217,7 @@ fn voter_catches_up_to_latest_round_when_behind() {
 	let peers = &[Ed25519Keyring::Alice, Ed25519Keyring::Bob];
 	let voters = make_ids(peers);
 
-	let net = GrandpaTestNet::new(TestApi::new(voters), 2);
+	let net = GrandpaTestNet::new(TestApi::new(voters), 2, 0);
 
 	let net = Arc::new(Mutex::new(net));
 	let mut finality_notifications = Vec::new();
@@ -1269,7 +1285,7 @@ fn voter_catches_up_to_latest_round_when_behind() {
 		let runtime = runtime.handle().clone();
 
 		wait_for_finality.then(move |_| {
-			net.lock().add_full_peer();
+			net.lock().add_authority_peer();
 
 			let link = {
 				let net = net.lock();
@@ -1373,7 +1389,7 @@ fn grandpa_environment_respects_voting_rules() {
 	let peers = &[Ed25519Keyring::Alice];
 	let voters = make_ids(peers);
 
-	let mut net = GrandpaTestNet::new(TestApi::new(voters), 1);
+	let mut net = GrandpaTestNet::new(TestApi::new(voters), 1, 0);
 	let peer = net.peer(0);
 	let network_service = peer.network_service().clone();
 	let link = peer.data.lock().take().unwrap();
@@ -1403,7 +1419,7 @@ fn grandpa_environment_respects_voting_rules() {
 
 	// the unrestricted environment should just return the best block
 	assert_eq!(
-		futures::executor::block_on(unrestricted_env.best_chain_containing(
+		block_on(unrestricted_env.best_chain_containing(
 			peer.client().info().finalized_hash
 		)).unwrap().unwrap().1,
 		21,
@@ -1412,14 +1428,14 @@ fn grandpa_environment_respects_voting_rules() {
 	// both the other environments should return block 16, which is 3/4 of the
 	// way in the unfinalized chain
 	assert_eq!(
-		futures::executor::block_on(three_quarters_env.best_chain_containing(
+		block_on(three_quarters_env.best_chain_containing(
 			peer.client().info().finalized_hash
 		)).unwrap().unwrap().1,
 		16,
 	);
 
 	assert_eq!(
-		futures::executor::block_on(default_env.best_chain_containing(
+		block_on(default_env.best_chain_containing(
 			peer.client().info().finalized_hash
 		)).unwrap().unwrap().1,
 		16,
@@ -1430,7 +1446,7 @@ fn grandpa_environment_respects_voting_rules() {
 
 	// the 3/4 environment should propose block 21 for voting
 	assert_eq!(
-		futures::executor::block_on(three_quarters_env.best_chain_containing(
+		block_on(three_quarters_env.best_chain_containing(
 			peer.client().info().finalized_hash
 		)).unwrap().unwrap().1,
 		21,
@@ -1439,7 +1455,7 @@ fn grandpa_environment_respects_voting_rules() {
 	// while the default environment will always still make sure we don't vote
 	// on the best block (2 behind)
 	assert_eq!(
-		futures::executor::block_on(default_env.best_chain_containing(
+		block_on(default_env.best_chain_containing(
 			peer.client().info().finalized_hash
 		)).unwrap().unwrap().1,
 		19,
@@ -1452,7 +1468,7 @@ fn grandpa_environment_respects_voting_rules() {
 	// best block, there's a hard rule that we can't cast any votes lower than
 	// the given base (#21).
 	assert_eq!(
-		futures::executor::block_on(default_env.best_chain_containing(
+		block_on(default_env.best_chain_containing(
 			peer.client().info().finalized_hash
 		)).unwrap().unwrap().1,
 		21,
@@ -1466,7 +1482,7 @@ fn grandpa_environment_never_overwrites_round_voter_state() {
 	let peers = &[Ed25519Keyring::Alice];
 	let voters = make_ids(peers);
 
-	let mut net = GrandpaTestNet::new(TestApi::new(voters), 1);
+	let mut net = GrandpaTestNet::new(TestApi::new(voters), 1, 0);
 	let peer = net.peer(0);
 	let network_service = peer.network_service().clone();
 	let link = peer.data.lock().take().unwrap();
@@ -1535,12 +1551,10 @@ fn imports_justification_for_regular_blocks_on_import() {
 	let peers = &[Ed25519Keyring::Alice];
 	let voters = make_ids(peers);
 	let api = TestApi::new(voters);
-	let mut net = GrandpaTestNet::new(api.clone(), 1);
+	let mut net = GrandpaTestNet::new(api.clone(), 1, 0);
 
 	let client = net.peer(0).client().clone();
-	let (mut block_import, ..) = net.make_block_import::<
-		TransactionFor<substrate_test_runtime_client::Backend, Block>
-	>(client.clone());
+	let (mut block_import, ..) = net.make_block_import(client.clone());
 
 	let full_client = client.as_full().expect("only full clients are used in test");
 	let builder = full_client.new_block_at(&BlockId::Number(0), Default::default(), false).unwrap();
@@ -1583,12 +1597,12 @@ fn imports_justification_for_regular_blocks_on_import() {
 
 	// we import the block with justification attached
 	let mut import = BlockImportParams::new(BlockOrigin::File, block.header);
-	import.justification = Some(justification.encode());
+	import.justifications = Some((GRANDPA_ENGINE_ID, justification.encode()).into());
 	import.body = Some(block.extrinsics);
 	import.fork_choice = Some(ForkChoiceStrategy::LongestChain);
 
 	assert_eq!(
-		block_import.import_block(import, HashMap::new()).unwrap(),
+		block_on(block_import.import_block(import, HashMap::new())).unwrap(),
 		ImportResult::Imported(ImportedAux {
 			needs_justification: false,
 			clear_justification_requests: false,
@@ -1600,7 +1614,7 @@ fn imports_justification_for_regular_blocks_on_import() {
 
 	// the justification should be imported and available from the client
 	assert!(
-		client.justification(&BlockId::Hash(block_hash)).unwrap().is_some(),
+		client.justifications(&BlockId::Hash(block_hash)).unwrap().is_some(),
 	);
 }
 
@@ -1612,7 +1626,7 @@ fn grandpa_environment_doesnt_send_equivocation_reports_for_itself() {
 	let voters = make_ids(&[alice]);
 
 	let environment = {
-		let mut net = GrandpaTestNet::new(TestApi::new(voters), 1);
+		let mut net = GrandpaTestNet::new(TestApi::new(voters), 1, 0);
 		let peer = net.peer(0);
 		let network_service = peer.network_service().clone();
 		let link = peer.data.lock().take().unwrap();
diff --git a/client/finality-grandpa/src/until_imported.rs b/client/finality-grandpa/src/until_imported.rs
index c27eab5351562..bcde68d2fb338 100644
--- a/client/finality-grandpa/src/until_imported.rs
+++ b/client/finality-grandpa/src/until_imported.rs
@@ -987,7 +987,7 @@ mod tests {
 		threads_pool.spawn_ok(until_imported.into_future().map(|_| ()));
 
 		// assert that we will make sync requests
-		let assert = futures::future::poll_fn(|_| {
+		let assert = futures::future::poll_fn(|ctx| {
 			let block_sync_requests = block_sync_requester.requests.lock();
 
 			// we request blocks targeted by the precommits that aren't imported
@@ -997,6 +997,11 @@ mod tests {
 				return Poll::Ready(());
 			}
 
+			// NOTE: nothing in this function is future-aware (i.e nothing gets registered to wake
+			// up this future), we manually wake up this task to avoid having to wait until the
+			// timeout below triggers.
+			ctx.waker().wake_by_ref();
+
 			Poll::Pending
 		});
 
diff --git a/client/finality-grandpa/src/voting_rule.rs b/client/finality-grandpa/src/voting_rule.rs
index 9b3fb9b328560..3ede7649a1387 100644
--- a/client/finality-grandpa/src/voting_rule.rs
+++ b/client/finality-grandpa/src/voting_rule.rs
@@ -372,7 +372,7 @@ mod tests {
 				.unwrap()
 				.block;
 
-			client.import(BlockOrigin::Own, block).unwrap();
+			futures::executor::block_on(client.import(BlockOrigin::Own, block)).unwrap();
 		}
 
 		let genesis = client
diff --git a/client/light/src/backend.rs b/client/light/src/backend.rs
index 27e0754eb552e..621ada13ff61d 100644
--- a/client/light/src/backend.rs
+++ b/client/light/src/backend.rs
@@ -30,9 +30,9 @@ use sp_core::storage::{well_known_keys, ChildInfo};
 use sp_core::offchain::storage::InMemOffchainStorage;
 use sp_state_machine::{
 	Backend as StateBackend, TrieBackend, InMemoryBackend, ChangesTrieTransaction,
-	StorageCollection, ChildStorageCollection,
+	StorageCollection, ChildStorageCollection, IndexOperation,
 };
-use sp_runtime::{generic::BlockId, Justification, Storage};
+use sp_runtime::{generic::BlockId, Justification, Justifications, Storage};
 use sp_runtime::traits::{Block as BlockT, NumberFor, Zero, Header, HashFor};
 use sp_blockchain::{Error as ClientError, Result as ClientResult};
 use sc_client_api::{
@@ -199,6 +199,14 @@ impl<S, Block> ClientBackend<Block> for Backend<S, HashFor<Block>>
 		self.blockchain.storage().finalize_header(block)
 	}
 
+	fn append_justification(
+		&self,
+		_block: BlockId<Block>,
+		_justification: Justification,
+	) -> ClientResult<()> {
+		Ok(())
+	}
+
 	fn blockchain(&self) -> &Blockchain<S> {
 		&self.blockchain
 	}
@@ -278,7 +286,7 @@ impl<S, Block> BlockImportOperation<Block> for ImportOperation<Block, S>
 		&mut self,
 		header: Block::Header,
 		_body: Option<Vec<Block::Extrinsic>>,
-		_justification: Option<Justification>,
+		_justifications: Option<Justifications>,
 		state: NewBlockState,
 	) -> ClientResult<()> {
 		self.leaf_state = state;
@@ -356,7 +364,7 @@ impl<S, Block> BlockImportOperation<Block> for ImportOperation<Block, S>
 	fn mark_finalized(
 		&mut self,
 		block: BlockId<Block>,
-		_justification: Option<Justification>,
+		_justifications: Option<Justification>,
 	) -> ClientResult<()> {
 		self.finalized_blocks.push(block);
 		Ok(())
@@ -366,6 +374,11 @@ impl<S, Block> BlockImportOperation<Block> for ImportOperation<Block, S>
 		self.set_head = Some(block);
 		Ok(())
 	}
+
+	fn update_transaction_index(&mut self, _index: Vec<IndexOperation>) -> sp_blockchain::Result<()> {
+		// noop for the light client
+		Ok(())
+	}
 }
 
 impl<H: Hasher> std::fmt::Debug for GenesisOrUnavailableState<H> {
diff --git a/client/light/src/blockchain.rs b/client/light/src/blockchain.rs
index bcabc365676a5..3349adf7ac693 100644
--- a/client/light/src/blockchain.rs
+++ b/client/light/src/blockchain.rs
@@ -21,7 +21,7 @@
 
 use std::sync::Arc;
 
-use sp_runtime::{Justification, generic::BlockId};
+use sp_runtime::{Justifications, generic::BlockId};
 use sp_runtime::traits::{Block as BlockT, Header as HeaderT, NumberFor, Zero};
 
 use sp_blockchain::{
@@ -109,7 +109,7 @@ impl<S, Block> BlockchainBackend<Block> for Blockchain<S> where Block: BlockT, S
 		Err(ClientError::NotAvailableOnLightClient)
 	}
 
-	fn justification(&self, _id: BlockId<Block>) -> ClientResult<Option<Justification>> {
+	fn justifications(&self, _id: BlockId<Block>) -> ClientResult<Option<Justifications>> {
 		Err(ClientError::NotAvailableOnLightClient)
 	}
 
@@ -129,10 +129,10 @@ impl<S, Block> BlockchainBackend<Block> for Blockchain<S> where Block: BlockT, S
 		Err(ClientError::NotAvailableOnLightClient)
 	}
 
-	fn extrinsic(
+	fn indexed_transaction(
 		&self,
 		_hash: &Block::Hash,
-	) -> ClientResult<Option<<Block as BlockT>::Extrinsic>> {
+	) -> ClientResult<Option<Vec<u8>>> {
 		Err(ClientError::NotAvailableOnLightClient)
 	}
 }
diff --git a/client/network-gossip/Cargo.toml b/client/network-gossip/Cargo.toml
index b5f3b754af030..a72e65ab3f572 100644
--- a/client/network-gossip/Cargo.toml
+++ b/client/network-gossip/Cargo.toml
@@ -17,13 +17,14 @@ targets = ["x86_64-unknown-linux-gnu"]
 [dependencies]
 futures = "0.3.9"
 futures-timer = "3.0.1"
-libp2p = { version = "0.35.1", default-features = false }
+libp2p = { version = "0.36.0", default-features = false }
 log = "0.4.8"
 lru = "0.6.5"
 prometheus-endpoint = { package = "substrate-prometheus-endpoint", version = "0.9.0", path = "../../utils/prometheus" }
 sc-network = { version = "0.9.0", path = "../network" }
 sp-runtime = { version = "3.0.0", path = "../../primitives/runtime" }
 wasm-timer = "0.2"
+tracing = "0.1.25"
 
 [dev-dependencies]
 async-std = "1.6.5"
diff --git a/client/network-gossip/src/state_machine.rs b/client/network-gossip/src/state_machine.rs
index a58432d8c2476..4c006f288f011 100644
--- a/client/network-gossip/src/state_machine.rs
+++ b/client/network-gossip/src/state_machine.rs
@@ -23,7 +23,6 @@ use std::collections::{HashMap, HashSet};
 use std::sync::Arc;
 use std::iter;
 use std::time;
-use log::{debug, error, trace};
 use lru::LruCache;
 use libp2p::PeerId;
 use prometheus_endpoint::{register, Counter, PrometheusError, Registry, U64};
@@ -146,7 +145,13 @@ fn propagate<'a, B: BlockT, I>(
 
 			peer.known_messages.insert(message_hash.clone());
 
-			trace!(target: "gossip", "Propagating to {}: {:?}", id, message);
+			tracing::trace!(
+				target: "gossip",
+				to = %id,
+				%protocol,
+				?message,
+				"Propagating message",
+			);
 			network.write_notification(id.clone(), protocol.clone(), message.clone());
 		}
 	}
@@ -173,7 +178,7 @@ impl<B: BlockT> ConsensusGossip<B> {
 		let metrics = match metrics_registry.map(Metrics::register) {
 			Some(Ok(metrics)) => Some(metrics),
 			Some(Err(e)) => {
-				debug!(target: "gossip", "Failed to register metrics: {:?}", e);
+				tracing::debug!(target: "gossip", "Failed to register metrics: {:?}", e);
 				None
 			}
 			None => None,
@@ -197,7 +202,13 @@ impl<B: BlockT> ConsensusGossip<B> {
 			return;
 		}
 
-		trace!(target:"gossip", "Registering {:?} {}", role, who);
+		tracing::trace!(
+			target:"gossip",
+			%who,
+			protocol = %self.protocol,
+			?role,
+			"Registering peer",
+		);
 		self.peers.insert(who.clone(), PeerConsensus {
 			known_messages: HashSet::new(),
 		});
@@ -301,7 +312,10 @@ impl<B: BlockT> ConsensusGossip<B> {
 			metrics.expired_messages.inc_by(expired_messages as u64)
 		}
 
-		trace!(target: "gossip", "Cleaned up {} stale messages, {} left ({} known)",
+		tracing::trace!(
+			target: "gossip",
+			protocol = %self.protocol,
+			"Cleaned up {} stale messages, {} left ({} known)",
 			expired_messages,
 			self.messages.len(),
 			known_messages.len(),
@@ -331,14 +345,25 @@ impl<B: BlockT> ConsensusGossip<B> {
 		let mut to_forward = vec![];
 
 		if !messages.is_empty() {
-			trace!(target: "gossip", "Received {} messages from peer {}", messages.len(), who);
+			tracing::trace!(
+				target: "gossip",
+				messages_num = %messages.len(),
+				%who,
+				protocol = %self.protocol,
+				"Received messages from peer",
+			);
 		}
 
 		for message in messages {
 			let message_hash = HashFor::<B>::hash(&message[..]);
 
 			if self.known_messages.contains(&message_hash) {
-				trace!(target:"gossip", "Ignored already known message from {}", who);
+				tracing::trace!(
+					target: "gossip",
+					%who,
+					protocol = %self.protocol,
+					"Ignored already known message",
+				);
 				network.report_peer(who.clone(), rep::DUPLICATE_GOSSIP);
 				continue;
 			}
@@ -354,7 +379,12 @@ impl<B: BlockT> ConsensusGossip<B> {
 				ValidationResult::ProcessAndKeep(topic) => (topic, true),
 				ValidationResult::ProcessAndDiscard(topic) => (topic, false),
 				ValidationResult::Discard => {
-					trace!(target:"gossip", "Discard message from peer {}", who);
+					tracing::trace!(
+						target: "gossip",
+						%who,
+						protocol = %self.protocol,
+						"Discard message from peer",
+					);
 					continue;
 				},
 			};
@@ -362,7 +392,12 @@ impl<B: BlockT> ConsensusGossip<B> {
 			let peer = match self.peers.get_mut(&who) {
 				Some(peer) => peer,
 				None => {
-					error!(target:"gossip", "Got message from unregistered peer {}", who);
+					tracing::error!(
+						target: "gossip",
+						%who,
+						protocol = %self.protocol,
+						"Got message from unregistered peer",
+					);
 					continue;
 				}
 			};
@@ -415,7 +450,13 @@ impl<B: BlockT> ConsensusGossip<B> {
 
 				peer.known_messages.insert(entry.message_hash.clone());
 
-				trace!(target: "gossip", "Sending topic message to {}: {:?}", who, entry.message);
+				tracing::trace!(
+					target: "gossip",
+					to = %who,
+					protocol = %self.protocol,
+					?entry.message,
+					"Sending topic message",
+				);
 				network.write_notification(who.clone(), self.protocol.clone(), entry.message.clone());
 			}
 		}
@@ -457,7 +498,13 @@ impl<B: BlockT> ConsensusGossip<B> {
 
 		let message_hash = HashFor::<B>::hash(&message);
 
-		trace!(target: "gossip", "Sending direct to {}: {:?}", who, message);
+		tracing::trace!(
+			target: "gossip",
+			to = %who,
+			protocol = %self.protocol,
+			?message,
+			"Sending direct message",
+		);
 
 		peer.known_messages.insert(message_hash);
 		network.write_notification(who.clone(), self.protocol.clone(), message);
diff --git a/client/network/Cargo.toml b/client/network/Cargo.toml
index 3d8c33eae0f25..604165d10074d 100644
--- a/client/network/Cargo.toml
+++ b/client/network/Cargo.toml
@@ -63,17 +63,17 @@ wasm-timer = "0.2"
 zeroize = "1.2.0"
 
 [dependencies.libp2p]
-version = "0.35.1"
+version = "0.36.0"
 
 [target.'cfg(target_os = "unknown")'.dependencies.libp2p]
-version = "0.35.1"
+version = "0.36.0"
 default-features = false
 features = ["identify", "kad", "mdns", "mplex", "noise", "ping", "request-response", "tcp-async-io", "websocket", "yamux"]
 
 
 [dev-dependencies]
 assert_matches = "1.3"
-libp2p = { version = "0.35.1", default-features = false }
+libp2p = { version = "0.36.0", default-features = false }
 quickcheck = "1.0.3"
 rand = "0.7.2"
 sp-keyring = { version = "3.0.0", path = "../../primitives/keyring" }
diff --git a/client/network/src/behaviour.rs b/client/network/src/behaviour.rs
index 0eebd1713cc81..a73685ed3bf32 100644
--- a/client/network/src/behaviour.rs
+++ b/client/network/src/behaviour.rs
@@ -37,7 +37,7 @@ use libp2p::swarm::{
 use log::debug;
 use prost::Message;
 use sp_consensus::{BlockOrigin, import_queue::{IncomingBlock, Origin}};
-use sp_runtime::{traits::{Block as BlockT, NumberFor}, Justification};
+use sp_runtime::{traits::{Block as BlockT, NumberFor}, Justifications};
 use std::{
 	borrow::Cow,
 	collections::{HashSet, VecDeque},
@@ -84,7 +84,7 @@ pub struct Behaviour<B: BlockT> {
 /// Event generated by `Behaviour`.
 pub enum BehaviourOut<B: BlockT> {
 	BlockImport(BlockOrigin, Vec<IncomingBlock<B>>),
-	JustificationImport(Origin, B::Hash, NumberFor<B>, Justification),
+	JustificationImport(Origin, B::Hash, NumberFor<B>, Justifications),
 
 	/// Started a random iterative Kademlia discovery query.
 	RandomKademliaStarted(ProtocolId),
diff --git a/client/network/src/bitswap.rs b/client/network/src/bitswap.rs
index 7129f3dbe07b1..aea2b8420cb2c 100644
--- a/client/network/src/bitswap.rs
+++ b/client/network/src/bitswap.rs
@@ -25,7 +25,6 @@ use std::io;
 use std::sync::Arc;
 use std::task::{Context, Poll};
 use cid::Version;
-use codec::Encode;
 use core::pin::Pin;
 use futures::Future;
 use futures::io::{AsyncRead, AsyncWrite};
@@ -257,15 +256,15 @@ impl<B: BlockT> NetworkBehaviour for Bitswap<B> {
 			}
 			let mut hash = B::Hash::default();
 			hash.as_mut().copy_from_slice(&cid.hash().digest()[0..32]);
-			let extrinsic = match self.client.extrinsic(&hash) {
+			let transaction = match self.client.indexed_transaction(&hash) {
 				Ok(ex) => ex,
 				Err(e) => {
-					error!(target: LOG_TARGET, "Error retrieving extrinsic {}: {}", hash, e);
+					error!(target: LOG_TARGET, "Error retrieving transaction {}: {}", hash, e);
 					None
 				}
 			};
-			match extrinsic {
-				Some(extrinsic) => {
+			match transaction {
+				Some(transaction) => {
 					trace!(target: LOG_TARGET, "Found CID {:?}, hash {:?}", cid, hash);
 					if entry.want_type == WantType::Block as i32 {
 						let prefix = Prefix {
@@ -276,7 +275,7 @@ impl<B: BlockT> NetworkBehaviour for Bitswap<B> {
 						};
 						response.payload.push(MessageBlock {
 							prefix: prefix.to_bytes(),
-							data: extrinsic.encode(),
+							data: transaction,
 						});
 					} else {
 						response.block_presences.push(BlockPresence {
diff --git a/client/network/src/block_request_handler.rs b/client/network/src/block_request_handler.rs
index 148bc01302f7f..2cc888c220f62 100644
--- a/client/network/src/block_request_handler.rs
+++ b/client/network/src/block_request_handler.rs
@@ -275,12 +275,28 @@ impl<B: BlockT> BlockRequestHandler<B> {
 			let number = *header.number();
 			let hash = header.hash();
 			let parent_hash = *header.parent_hash();
-			let justification = if get_justification {
-				self.client.justification(&BlockId::Hash(hash))?
+			let justifications = if get_justification {
+				self.client.justifications(&BlockId::Hash(hash))?
 			} else {
 				None
 			};
-			let is_empty_justification = justification.as_ref().map(|j| j.is_empty()).unwrap_or(false);
+
+			// TODO: In a follow up PR tracked by https://github.com/paritytech/substrate/issues/8172
+			// we want to send/receive all justifications.
+			// For now we keep compatibility by selecting precisely the GRANDPA one, and not just
+			// the first one. When sending we could have just taken the first one, since we don't
+			// expect there to be any other kind currently, but when receiving we need to add the
+			// engine ID tag.
+			// The ID tag is hardcoded here to avoid depending on the GRANDPA crate, and will be
+			// removed when resolving the above issue.
+			let justification = justifications.and_then(|just| just.into_justification(*b"FRNK"));
+
+			let is_empty_justification = justification
+				.as_ref()
+				.map(|j| j.is_empty())
+				.unwrap_or(false);
+
+			let justification = justification.unwrap_or_default();
 
 			let body = if get_body {
 				match self.client.block_body(&BlockId::Hash(hash))? {
@@ -306,7 +322,7 @@ impl<B: BlockT> BlockRequestHandler<B> {
 				body,
 				receipt: Vec::new(),
 				message_queue: Vec::new(),
-				justification: justification.unwrap_or_default(),
+				justification,
 				is_empty_justification,
 			};
 
diff --git a/client/network/src/discovery.rs b/client/network/src/discovery.rs
index 87b533ef77dc1..b7c791e392676 100644
--- a/client/network/src/discovery.rs
+++ b/client/network/src/discovery.rs
@@ -61,7 +61,7 @@ use libp2p::kad::handler::KademliaHandlerProto;
 use libp2p::kad::QueryId;
 use libp2p::kad::record::{self, store::{MemoryStore, RecordStore}};
 #[cfg(not(target_os = "unknown"))]
-use libp2p::mdns::{Mdns, MdnsEvent};
+use libp2p::mdns::{Mdns, MdnsConfig, MdnsEvent};
 use libp2p::multiaddr::Protocol;
 use log::{debug, info, trace, warn};
 use std::{cmp, collections::{HashMap, HashSet, VecDeque}, io, num::NonZeroUsize, time::Duration};
@@ -220,7 +220,7 @@ impl DiscoveryConfig {
 			discovery_only_if_under_num,
 			#[cfg(not(target_os = "unknown"))]
 			mdns: if enable_mdns {
-				MdnsWrapper::Instantiating(Mdns::new().boxed())
+				MdnsWrapper::Instantiating(Mdns::new(MdnsConfig::default()).boxed())
 			} else {
 				MdnsWrapper::Disabled
 			},
diff --git a/client/network/src/gossip/tests.rs b/client/network/src/gossip/tests.rs
index 89ad5fcf047dc..b000cf575ddb3 100644
--- a/client/network/src/gossip/tests.rs
+++ b/client/network/src/gossip/tests.rs
@@ -47,12 +47,14 @@ fn build_test_full_node(network_config: config::NetworkConfiguration)
 
 	#[derive(Clone)]
 	struct PassThroughVerifier(bool);
+
+	#[async_trait::async_trait]
 	impl<B: BlockT> sp_consensus::import_queue::Verifier<B> for PassThroughVerifier {
-		fn verify(
+		async fn verify(
 			&mut self,
 			origin: sp_consensus::BlockOrigin,
 			header: B::Header,
-			justification: Option<sp_runtime::Justification>,
+			justifications: Option<sp_runtime::Justifications>,
 			body: Option<Vec<B::Extrinsic>>,
 		) -> Result<
 			(
@@ -79,7 +81,7 @@ fn build_test_full_node(network_config: config::NetworkConfiguration)
 			let mut import = sp_consensus::BlockImportParams::new(origin, header);
 			import.body = body;
 			import.finalized = self.0;
-			import.justification = justification;
+			import.justifications = justifications;
 			import.fork_choice = Some(sp_consensus::ForkChoiceStrategy::LongestChain);
 			Ok((import, maybe_keys))
 		}
diff --git a/client/network/src/protocol.rs b/client/network/src/protocol.rs
index 7f321775b160e..84b5285b38ada 100644
--- a/client/network/src/protocol.rs
+++ b/client/network/src/protocol.rs
@@ -27,7 +27,7 @@ use crate::{
 use bytes::Bytes;
 use codec::{Decode, DecodeAll, Encode};
 use futures::{channel::oneshot, prelude::*};
-use generic_proto::{GenericProto, GenericProtoOut};
+use notifications::{Notifications, NotificationsOut};
 use libp2p::core::{ConnectedPoint, connection::{ConnectionId, ListenerId}};
 use libp2p::request_response::OutboundFailure;
 use libp2p::swarm::{NetworkBehaviour, NetworkBehaviourAction, PollParameters};
@@ -43,9 +43,10 @@ use sp_consensus::{
 	block_validation::BlockAnnounceValidator,
 	import_queue::{BlockImportResult, BlockImportError, IncomingBlock, Origin}
 };
-use sp_runtime::{generic::BlockId, Justification};
-use sp_runtime::traits::{
-	Block as BlockT, Header as HeaderT, NumberFor, Zero, CheckedSub
+use sp_runtime::{
+	Justifications,
+	generic::BlockId,
+	traits::{Block as BlockT, Header as HeaderT, NumberFor, Zero, CheckedSub},
 };
 use sp_arithmetic::traits::SaturatedConversion;
 use sync::{ChainSync, SyncState};
@@ -55,13 +56,13 @@ use std::collections::{HashMap, HashSet, VecDeque};
 use std::sync::Arc;
 use std::{io, iter, num::NonZeroUsize, pin::Pin, task::Poll, time};
 
-mod generic_proto;
+mod notifications;
 
 pub mod message;
 pub mod event;
 pub mod sync;
 
-pub use generic_proto::{NotificationsSink, Ready, NotifsHandlerError};
+pub use notifications::{NotificationsSink, Ready, NotifsHandlerError};
 
 /// Interval at which we perform time based maintenance
 const TICK_TIMEOUT: time::Duration = time::Duration::from_millis(1100);
@@ -160,7 +161,7 @@ pub struct Protocol<B: BlockT> {
 	/// Used to report reputation changes.
 	peerset_handle: sc_peerset::PeersetHandle,
 	/// Handles opening the unique substream and sending and receiving raw messages.
-	behaviour: GenericProto,
+	behaviour: Notifications,
 	/// List of notifications protocols that have been registered.
 	notification_protocols: Vec<Cow<'static, str>>,
 	/// If we receive a new "substream open" event that contains an invalid handshake, we ask the
@@ -361,7 +362,7 @@ impl<B: BlockT> Protocol<B> {
 				genesis_hash,
 			).encode();
 
-			GenericProto::new(
+			Notifications::new(
 				peerset,
 				iter::once((block_announces_protocol, block_announces_handshake, MAX_BLOCK_ANNOUNCE_SIZE))
 					.chain(network_config.extra_sets.iter()
@@ -612,8 +613,8 @@ impl<B: BlockT> Protocol<B> {
 		if request.fields == message::BlockAttributes::JUSTIFICATION {
 			match self.sync.on_block_justification(peer_id, block_response) {
 				Ok(sync::OnBlockJustification::Nothing) => CustomMessageOutcome::None,
-				Ok(sync::OnBlockJustification::Import { peer, hash, number, justification }) =>
-					CustomMessageOutcome::JustificationImport(peer, hash, number, justification),
+				Ok(sync::OnBlockJustification::Import { peer, hash, number, justifications }) =>
+					CustomMessageOutcome::JustificationImport(peer, hash, number, justifications),
 				Err(sync::BadPeer(id, repu)) => {
 					self.behaviour.disconnect_peer(&id, HARDCODED_PEERSETS_SYNC);
 					self.peerset_handle.report_peer(id, repu);
@@ -664,7 +665,7 @@ impl<B: BlockT> Protocol<B> {
 		if status.genesis_hash != self.genesis_hash {
 			log!(
 				target: "sync",
-				if self.important_peers.contains(&who) { Level::Warn } else { Level::Trace },
+				if self.important_peers.contains(&who) { Level::Warn } else { Level::Debug },
 				"Peer is on different chain (our genesis: {} theirs: {})",
 				self.genesis_hash, status.genesis_hash
 			);
@@ -1134,7 +1135,7 @@ fn prepare_block_request<B: BlockT>(
 #[must_use]
 pub enum CustomMessageOutcome<B: BlockT> {
 	BlockImport(BlockOrigin, Vec<IncomingBlock<B>>),
-	JustificationImport(Origin, B::Hash, NumberFor<B>, Justification),
+	JustificationImport(Origin, B::Hash, NumberFor<B>, Justifications),
 	/// Notification protocols have been opened with a remote.
 	NotificationStreamOpened {
 		remote: PeerId,
@@ -1168,7 +1169,7 @@ pub enum CustomMessageOutcome<B: BlockT> {
 }
 
 impl<B: BlockT> NetworkBehaviour for Protocol<B> {
-	type ProtocolsHandler = <GenericProto as NetworkBehaviour>::ProtocolsHandler;
+	type ProtocolsHandler = <Notifications as NetworkBehaviour>::ProtocolsHandler;
 	type OutEvent = CustomMessageOutcome<B>;
 
 	fn new_handler(&mut self) -> Self::ProtocolsHandler {
@@ -1331,7 +1332,7 @@ impl<B: BlockT> NetworkBehaviour for Protocol<B> {
 		};
 
 		let outcome = match event {
-			GenericProtoOut::CustomProtocolOpen { peer_id, set_id, received_handshake, notifications_sink, .. } => {
+			NotificationsOut::CustomProtocolOpen { peer_id, set_id, received_handshake, notifications_sink, .. } => {
 				// Set number 0 is hardcoded the default set of peers we sync from.
 				if set_id == HARDCODED_PEERSETS_SYNC {
 					// `received_handshake` can be either a `Status` message if received from the
@@ -1418,7 +1419,7 @@ impl<B: BlockT> NetworkBehaviour for Protocol<B> {
 					}
 				}
 			}
-			GenericProtoOut::CustomProtocolReplaced { peer_id, notifications_sink, set_id } => {
+			NotificationsOut::CustomProtocolReplaced { peer_id, notifications_sink, set_id } => {
 				if set_id == HARDCODED_PEERSETS_SYNC {
 					CustomMessageOutcome::None
 				} else if self.bad_handshake_substreams.contains(&(peer_id.clone(), set_id)) {
@@ -1431,7 +1432,7 @@ impl<B: BlockT> NetworkBehaviour for Protocol<B> {
 					}
 				}
 			},
-			GenericProtoOut::CustomProtocolClosed { peer_id, set_id } => {
+			NotificationsOut::CustomProtocolClosed { peer_id, set_id } => {
 				// Set number 0 is hardcoded the default set of peers we sync from.
 				if set_id == HARDCODED_PEERSETS_SYNC {
 					if self.on_sync_peer_disconnected(peer_id.clone()).is_ok() {
@@ -1456,7 +1457,7 @@ impl<B: BlockT> NetworkBehaviour for Protocol<B> {
 					}
 				}
 			},
-			GenericProtoOut::Notification { peer_id, set_id, message } =>
+			NotificationsOut::Notification { peer_id, set_id, message } =>
 				match set_id {
 					HARDCODED_PEERSETS_SYNC if self.peers.contains_key(&peer_id) => {
 						if let Ok(announce) = message::BlockAnnounce::decode(&mut message.as_ref()) {
diff --git a/client/network/src/protocol/message.rs b/client/network/src/protocol/message.rs
index ed2721032801c..01e9a5d7215af 100644
--- a/client/network/src/protocol/message.rs
+++ b/client/network/src/protocol/message.rs
@@ -148,7 +148,7 @@ pub struct RemoteReadResponse {
 pub mod generic {
 	use bitflags::bitflags;
 	use codec::{Encode, Decode, Input, Output};
-	use sp_runtime::Justification;
+	use sp_runtime::EncodedJustification;
 	use super::{
 		RemoteReadResponse, Transactions, Direction,
 		RequestId, BlockAttributes, RemoteCallResponse, ConsensusEngineId,
@@ -233,7 +233,7 @@ pub mod generic {
 		/// Block message queue if requested.
 		pub message_queue: Option<Vec<u8>>,
 		/// Justification if requested.
-		pub justification: Option<Justification>,
+		pub justification: Option<EncodedJustification>,
 	}
 
 	/// Identifies starting point of a block sequence.
diff --git a/client/network/src/protocol/generic_proto.rs b/client/network/src/protocol/notifications.rs
similarity index 71%
rename from client/network/src/protocol/generic_proto.rs
rename to client/network/src/protocol/notifications.rs
index a305fc1f5ea5f..ef25795758b80 100644
--- a/client/network/src/protocol/generic_proto.rs
+++ b/client/network/src/protocol/notifications.rs
@@ -16,13 +16,10 @@
 // You should have received a copy of the GNU General Public License
 // along with this program. If not, see <https://www.gnu.org/licenses/>.
 
-//! Implementation of libp2p's `NetworkBehaviour` trait that opens a single substream with the
-//! remote and then allows any communication with them.
-//!
-//! The `Protocol` struct uses `GenericProto` in order to open substreams with the rest of the
-//! network, then performs the Substrate protocol handling on top.
+//! Implementation of libp2p's `NetworkBehaviour` trait that establishes communications and opens
+//! notifications substreams.
 
-pub use self::behaviour::{GenericProto, GenericProtoOut};
+pub use self::behaviour::{Notifications, NotificationsOut};
 pub use self::handler::{NotifsHandlerError, NotificationsSink, Ready};
 
 mod behaviour;
diff --git a/client/network/src/protocol/generic_proto/behaviour.rs b/client/network/src/protocol/notifications/behaviour.rs
similarity index 98%
rename from client/network/src/protocol/generic_proto/behaviour.rs
rename to client/network/src/protocol/notifications/behaviour.rs
index 05247dc6f0e68..08c4ec5d4f7b3 100644
--- a/client/network/src/protocol/generic_proto/behaviour.rs
+++ b/client/network/src/protocol/notifications/behaviour.rs
@@ -16,7 +16,7 @@
 // You should have received a copy of the GNU General Public License
 // along with this program. If not, see <https://www.gnu.org/licenses/>.
 
-use crate::protocol::generic_proto::{
+use crate::protocol::notifications::{
 	handler::{NotificationsSink, NotifsHandlerProto, NotifsHandlerOut, NotifsHandlerIn}
 };
 
@@ -44,7 +44,7 @@ use wasm_timer::Instant;
 ///
 /// # How it works
 ///
-/// The role of the `GenericProto` is to synchronize the following components:
+/// The role of the `Notifications` is to synchronize the following components:
 ///
 /// - The libp2p swarm that opens new connections and reports disconnects.
 /// - The connection handler (see `group.rs`) that handles individual connections.
@@ -83,9 +83,9 @@ use wasm_timer::Instant;
 ///      different than a single connection failing and being re-established
 ///      in terms of potential reordering and dropped messages. Messages can
 ///      be received on any connection.
-///   3. The behaviour reports `GenericProtoOut::CustomProtocolOpen` when the
+///   3. The behaviour reports `NotificationsOut::CustomProtocolOpen` when the
 ///      first connection reports `NotifsHandlerOut::OpenResultOk`.
-///   4. The behaviour reports `GenericProtoOut::CustomProtocolClosed` when the
+///   4. The behaviour reports `NotificationsOut::CustomProtocolClosed` when the
 ///      last connection reports `NotifsHandlerOut::ClosedResult`.
 ///
 /// In this way, the number of actual established connections to the peer is
@@ -94,7 +94,7 @@ use wasm_timer::Instant;
 /// and only as a result of simultaneous dialing. However, the implementation
 /// accommodates for any number of connections.
 ///
-pub struct GenericProto {
+pub struct Notifications {
 	/// Notification protocols. Entries are only ever added and not removed.
 	/// Contains, for each protocol, the protocol name and the message to send as part of the
 	/// initial handshake.
@@ -127,7 +127,7 @@ pub struct GenericProto {
 	next_incoming_index: sc_peerset::IncomingIndex,
 
 	/// Events to produce from `poll()`.
-	events: VecDeque<NetworkBehaviourAction<NotifsHandlerIn, GenericProtoOut>>,
+	events: VecDeque<NetworkBehaviourAction<NotifsHandlerIn, NotificationsOut>>,
 }
 
 /// Identifier for a delay firing.
@@ -302,9 +302,9 @@ struct IncomingPeer {
 	incoming_id: sc_peerset::IncomingIndex,
 }
 
-/// Event that can be emitted by the `GenericProto`.
+/// Event that can be emitted by the `Notifications`.
 #[derive(Debug)]
-pub enum GenericProtoOut {
+pub enum NotificationsOut {
 	/// Opened a custom protocol with the remote.
 	CustomProtocolOpen {
 		/// Id of the peer we are connected to.
@@ -354,7 +354,7 @@ pub enum GenericProtoOut {
 	},
 }
 
-impl GenericProto {
+impl Notifications {
 	/// Creates a `CustomProtos`.
 	pub fn new(
 		peerset: sc_peerset::Peerset,
@@ -366,7 +366,7 @@ impl GenericProto {
 
 		assert!(!notif_protocols.is_empty());
 
-		GenericProto {
+		Notifications {
 			notif_protocols,
 			peerset,
 			peers: FnvHashMap::default(),
@@ -462,7 +462,7 @@ impl GenericProto {
 
 				if connections.iter().any(|(_, s)| matches!(s, ConnectionState::Open(_))) {
 					debug!(target: "sub-libp2p", "External API <= Closed({}, {:?})", peer_id, set_id);
-					let event = GenericProtoOut::CustomProtocolClosed {
+					let event = NotificationsOut::CustomProtocolClosed {
 						peer_id: peer_id.clone(),
 						set_id,
 					};
@@ -828,7 +828,7 @@ impl GenericProto {
 
 				if connections.iter().any(|(_, s)| matches!(s, ConnectionState::Open(_))) {
 					debug!(target: "sub-libp2p", "External API <= Closed({}, {:?})", entry.key().0, set_id);
-					let event = GenericProtoOut::CustomProtocolClosed {
+					let event = NotificationsOut::CustomProtocolClosed {
 						peer_id: entry.key().0.clone(),
 						set_id,
 					};
@@ -1013,9 +1013,9 @@ impl GenericProto {
 	}
 }
 
-impl NetworkBehaviour for GenericProto {
+impl NetworkBehaviour for Notifications {
 	type ProtocolsHandler = NotifsHandlerProto;
-	type OutEvent = GenericProtoOut;
+	type OutEvent = NotificationsOut;
 
 	fn new_handler(&mut self) -> Self::ProtocolsHandler {
 		NotifsHandlerProto::new(self.notif_protocols.clone())
@@ -1265,7 +1265,7 @@ impl NetworkBehaviour for GenericProto {
 										"External API <= Sink replaced({}, {:?})",
 										peer_id, set_id
 									);
-									let event = GenericProtoOut::CustomProtocolReplaced {
+									let event = NotificationsOut::CustomProtocolReplaced {
 										peer_id: peer_id.clone(),
 										set_id,
 										notifications_sink: replacement_sink,
@@ -1277,7 +1277,7 @@ impl NetworkBehaviour for GenericProto {
 									target: "sub-libp2p", "External API <= Closed({}, {:?})",
 									peer_id, set_id
 								);
-								let event = GenericProtoOut::CustomProtocolClosed {
+								let event = NotificationsOut::CustomProtocolClosed {
 									peer_id: peer_id.clone(),
 									set_id,
 								};
@@ -1642,7 +1642,7 @@ impl NetworkBehaviour for GenericProto {
 						{
 							if pos <= replacement_pos {
 								debug!(target: "sub-libp2p", "External API <= Sink replaced({:?})", source);
-								let event = GenericProtoOut::CustomProtocolReplaced {
+								let event = NotificationsOut::CustomProtocolReplaced {
 									peer_id: source,
 									set_id,
 									notifications_sink: replacement_sink,
@@ -1665,7 +1665,7 @@ impl NetworkBehaviour for GenericProto {
 							}
 
 							debug!(target: "sub-libp2p", "External API <= Closed({}, {:?})", source, set_id);
-							let event = GenericProtoOut::CustomProtocolClosed {
+							let event = NotificationsOut::CustomProtocolClosed {
 								peer_id: source,
 								set_id,
 							};
@@ -1739,7 +1739,7 @@ impl NetworkBehaviour for GenericProto {
 						{
 							if !any_open {
 								debug!(target: "sub-libp2p", "External API <= Open({:?})", source);
-								let event = GenericProtoOut::CustomProtocolOpen {
+								let event = NotificationsOut::CustomProtocolOpen {
 									peer_id: source,
 									set_id,
 									received_handshake,
@@ -1876,7 +1876,7 @@ impl NetworkBehaviour for GenericProto {
 					);
 					trace!(target: "sub-libp2p", "External API <= Message({}, {:?})",
 						source, set_id);
-					let event = GenericProtoOut::Notification {
+					let event = NotificationsOut::Notification {
 						peer_id: source,
 						set_id,
 						message,
diff --git a/client/network/src/protocol/generic_proto/handler.rs b/client/network/src/protocol/notifications/handler.rs
similarity index 92%
rename from client/network/src/protocol/generic_proto/handler.rs
rename to client/network/src/protocol/notifications/handler.rs
index 0db249f90a8b7..99677cc45e54e 100644
--- a/client/network/src/protocol/generic_proto/handler.rs
+++ b/client/network/src/protocol/notifications/handler.rs
@@ -57,7 +57,7 @@
 //! It is illegal to send a [`NotifsHandlerIn::Open`] before a previously-emitted
 //! [`NotifsHandlerIn::Open`] has gotten an answer.
 
-use crate::protocol::generic_proto::{
+use crate::protocol::notifications::{
 	upgrade::{
 		NotificationsIn, NotificationsOut, NotificationsInSubstream, NotificationsOutSubstream,
 		NotificationsHandshakeError, UpgradeCollec
@@ -188,10 +188,10 @@ enum State {
 		/// We use two different channels in order to have two different channel sizes, but from
 		/// the receiving point of view, the two channels are the same.
 		/// The receivers are fused in case the user drops the [`NotificationsSink`] entirely.
-		notifications_sink_rx: stream::Select<
+		notifications_sink_rx: stream::Peekable<stream::Select<
 			stream::Fuse<mpsc::Receiver<NotificationsSinkMessage>>,
 			stream::Fuse<mpsc::Receiver<NotificationsSinkMessage>>
-		>,
+		>>,
 
 		/// Outbound substream that has been accepted by the remote.
 		///
@@ -552,7 +552,7 @@ impl ProtocolsHandler for NotifsHandler {
 				};
 
 				self.protocols[protocol_index].state = State::Open {
-					notifications_sink_rx: stream::select(async_rx.fuse(), sync_rx.fuse()),
+					notifications_sink_rx: stream::select(async_rx.fuse(), sync_rx.fuse()).peekable(),
 					out_substream: Some(substream),
 					in_substream: in_substream.take(),
 				};
@@ -716,8 +716,80 @@ impl ProtocolsHandler for NotifsHandler {
 			return Poll::Ready(ev);
 		}
 
+		// For each open substream, try send messages from `notifications_sink_rx` to the
+		// substream.
+		for protocol_index in 0..self.protocols.len() {
+			if let State::Open { notifications_sink_rx, out_substream: Some(out_substream), .. }
+				= &mut self.protocols[protocol_index].state
+			{
+				loop {
+					// Only proceed with `out_substream.poll_ready_unpin` if there is an element
+					// available in `notifications_sink_rx`. This avoids waking up the task when
+					// a substream is ready to send if there isn't actually something to send.
+					match Pin::new(&mut *notifications_sink_rx).as_mut().poll_peek(cx) {
+						Poll::Ready(Some(&NotificationsSinkMessage::ForceClose)) => {
+							return Poll::Ready(
+								ProtocolsHandlerEvent::Close(NotifsHandlerError::SyncNotificationsClogged)
+							);
+						},
+						Poll::Ready(Some(&NotificationsSinkMessage::Notification { .. })) => {},
+						Poll::Ready(None) | Poll::Pending => break,
+					}
+
+					// Before we extract the element from `notifications_sink_rx`, check that the
+					// substream is ready to accept a message.
+					match out_substream.poll_ready_unpin(cx) {
+						Poll::Ready(_) => {},
+						Poll::Pending => break
+					}
+
+					// Now that the substream is ready for a message, grab what to send.
+					let message = match notifications_sink_rx.poll_next_unpin(cx) {
+						Poll::Ready(Some(NotificationsSinkMessage::Notification { message })) => message,
+						Poll::Ready(Some(NotificationsSinkMessage::ForceClose))
+						| Poll::Ready(None)
+						| Poll::Pending => {
+							// Should never be reached, as per `poll_peek` above.
+							debug_assert!(false);
+							break;
+						}
+					};
+
+					let _ = out_substream.start_send_unpin(message);
+					// Note that flushing is performed later down this function.
+				}
+			}
+		}
+
+		// Flush all outbound substreams.
+		// When `poll` returns `Poll::Ready`, the libp2p `Swarm` may decide to no longer call
+		// `poll` again before it is ready to accept more events.
+		// In order to make sure that substreams are flushed as soon as possible, the flush is
+		// performed before the code paths that can produce `Ready` (with some rare exceptions).
+		// Importantly, however, the flush is performed *after* notifications are queued with
+		// `Sink::start_send`.
+		for protocol_index in 0..self.protocols.len() {
+			match &mut self.protocols[protocol_index].state {
+				State::Open { out_substream: out_substream @ Some(_), .. } => {
+					match Sink::poll_flush(Pin::new(out_substream.as_mut().unwrap()), cx) {
+						Poll::Pending | Poll::Ready(Ok(())) => {},
+						Poll::Ready(Err(_)) => {
+							*out_substream = None;
+							let event = NotifsHandlerOut::CloseDesired { protocol_index };
+							return Poll::Ready(ProtocolsHandlerEvent::Custom(event));
+						}
+					};
+				}
+
+				State::Closed { .. } |
+				State::Opening { .. } |
+				State::Open { out_substream: None, .. } |
+				State::OpenDesiredByRemote { .. } => {}
+			}
+		}
+
+		// Poll inbound substreams.
 		for protocol_index in 0..self.protocols.len() {
-			// Poll inbound substreams.
 			// Inbound substreams being closed is always tolerated, except for the
 			// `OpenDesiredByRemote` state which might need to be switched back to `Closed`.
 			match &mut self.protocols[protocol_index].state {
@@ -763,68 +835,11 @@ impl ProtocolsHandler for NotifsHandler {
 					}
 				}
 			}
-
-			// Poll outbound substream.
-			match &mut self.protocols[protocol_index].state {
-				State::Open { out_substream: out_substream @ Some(_), .. } => {
-					match Sink::poll_flush(Pin::new(out_substream.as_mut().unwrap()), cx) {
-						Poll::Pending | Poll::Ready(Ok(())) => {},
-						Poll::Ready(Err(_)) => {
-							*out_substream = None;
-							let event = NotifsHandlerOut::CloseDesired { protocol_index };
-							return Poll::Ready(ProtocolsHandlerEvent::Custom(event));
-						}
-					};
-				}
-
-				State::Closed { .. } |
-				State::Opening { .. } |
-				State::Open { out_substream: None, .. } |
-				State::OpenDesiredByRemote { .. } => {}
-			}
-
-			if let State::Open { notifications_sink_rx, out_substream: Some(out_substream), .. }
-				= &mut self.protocols[protocol_index].state
-			{
-				loop {
-					// Before we poll the notifications sink receiver, check that the substream
-					// is ready to accept a message.
-					match out_substream.poll_ready_unpin(cx) {
-						Poll::Ready(_) => {},
-						Poll::Pending => break
-					}
-
-					// Now that all substreams are ready for a message, grab what to send.
-					let message = match notifications_sink_rx.poll_next_unpin(cx) {
-						Poll::Ready(Some(msg)) => msg,
-						Poll::Ready(None) | Poll::Pending => break,
-					};
-
-					match message {
-						NotificationsSinkMessage::Notification { message } => {
-							let _ = out_substream.start_send_unpin(message);
-
-							// Calling `start_send_unpin` only queues the message. Actually
-							// emitting the message is done with `poll_flush`. In order to
-							// not introduce too much complexity, this flushing is done earlier
-							// in the body of this `poll()` method. As such, we schedule a task
-							// wake-up now in order to guarantee that `poll()` will be called
-							// again and the flush happening.
-							// At the time of the writing of this comment, a rewrite of this
-							// code is being planned. If you find this comment in the wild and
-							// the rewrite didn't happen, please consider a refactor.
-							cx.waker().wake_by_ref();
-						}
-						NotificationsSinkMessage::ForceClose => {
-							return Poll::Ready(
-								ProtocolsHandlerEvent::Close(NotifsHandlerError::SyncNotificationsClogged)
-							);
-						}
-					}
-				}
-			}
 		}
 
+		// This is the only place in this method that can return `Pending`.
+		// By putting it at the very bottom, we are guaranteed that everything has been properly
+		// polled.
 		Poll::Pending
 	}
 }
diff --git a/client/network/src/protocol/generic_proto/tests.rs b/client/network/src/protocol/notifications/tests.rs
similarity index 92%
rename from client/network/src/protocol/generic_proto/tests.rs
rename to client/network/src/protocol/notifications/tests.rs
index 2c80fe8523ac3..f159a8e631782 100644
--- a/client/network/src/protocol/generic_proto/tests.rs
+++ b/client/network/src/protocol/notifications/tests.rs
@@ -18,7 +18,7 @@
 
 #![cfg(test)]
 
-use crate::protocol::generic_proto::{GenericProto, GenericProtoOut};
+use crate::protocol::notifications::{Notifications, NotificationsOut};
 
 use futures::prelude::*;
 use libp2p::{PeerId, Multiaddr, Transport};
@@ -80,7 +80,7 @@ fn build_nodes() -> (Swarm<CustomProtoWithAddr>, Swarm<CustomProtoWithAddr>) {
 		});
 
 		let behaviour = CustomProtoWithAddr {
-			inner: GenericProto::new(peerset, iter::once(("/foo".into(), Vec::new(), 1024 * 1024))),
+			inner: Notifications::new(peerset, iter::once(("/foo".into(), Vec::new(), 1024 * 1024))),
 			addrs: addrs
 				.iter()
 				.enumerate()
@@ -110,12 +110,12 @@ fn build_nodes() -> (Swarm<CustomProtoWithAddr>, Swarm<CustomProtoWithAddr>) {
 
 /// Wraps around the `CustomBehaviour` network behaviour, and adds hardcoded node addresses to it.
 struct CustomProtoWithAddr {
-	inner: GenericProto,
+	inner: Notifications,
 	addrs: Vec<(PeerId, Multiaddr)>,
 }
 
 impl std::ops::Deref for CustomProtoWithAddr {
-	type Target = GenericProto;
+	type Target = Notifications;
 
 	fn deref(&self) -> &Self::Target {
 		&self.inner
@@ -129,8 +129,8 @@ impl std::ops::DerefMut for CustomProtoWithAddr {
 }
 
 impl NetworkBehaviour for CustomProtoWithAddr {
-	type ProtocolsHandler = <GenericProto as NetworkBehaviour>::ProtocolsHandler;
-	type OutEvent = <GenericProto as NetworkBehaviour>::OutEvent;
+	type ProtocolsHandler = <Notifications as NetworkBehaviour>::ProtocolsHandler;
+	type OutEvent = <Notifications as NetworkBehaviour>::OutEvent;
 
 	fn new_handler(&mut self) -> Self::ProtocolsHandler {
 		self.inner.new_handler()
@@ -240,7 +240,7 @@ fn reconnect_after_disconnect() {
 			};
 
 			match event {
-				future::Either::Left(GenericProtoOut::CustomProtocolOpen { .. }) => {
+				future::Either::Left(NotificationsOut::CustomProtocolOpen { .. }) => {
 					match service1_state {
 						ServiceState::NotConnected => {
 							service1_state = ServiceState::FirstConnec;
@@ -255,14 +255,14 @@ fn reconnect_after_disconnect() {
 						ServiceState::FirstConnec | ServiceState::ConnectedAgain => panic!(),
 					}
 				},
-				future::Either::Left(GenericProtoOut::CustomProtocolClosed { .. }) => {
+				future::Either::Left(NotificationsOut::CustomProtocolClosed { .. }) => {
 					match service1_state {
 						ServiceState::FirstConnec => service1_state = ServiceState::Disconnected,
 						ServiceState::ConnectedAgain| ServiceState::NotConnected |
 						ServiceState::Disconnected => panic!(),
 					}
 				},
-				future::Either::Right(GenericProtoOut::CustomProtocolOpen { .. }) => {
+				future::Either::Right(NotificationsOut::CustomProtocolOpen { .. }) => {
 					match service2_state {
 						ServiceState::NotConnected => {
 							service2_state = ServiceState::FirstConnec;
@@ -277,7 +277,7 @@ fn reconnect_after_disconnect() {
 						ServiceState::FirstConnec | ServiceState::ConnectedAgain => panic!(),
 					}
 				},
-				future::Either::Right(GenericProtoOut::CustomProtocolClosed { .. }) => {
+				future::Either::Right(NotificationsOut::CustomProtocolClosed { .. }) => {
 					match service2_state {
 						ServiceState::FirstConnec => service2_state = ServiceState::Disconnected,
 						ServiceState::ConnectedAgain| ServiceState::NotConnected |
@@ -310,8 +310,8 @@ fn reconnect_after_disconnect() {
 			};
 
 			match event {
-				GenericProtoOut::CustomProtocolOpen { .. } |
-				GenericProtoOut::CustomProtocolClosed { .. } => panic!(),
+				NotificationsOut::CustomProtocolOpen { .. } |
+				NotificationsOut::CustomProtocolClosed { .. } => panic!(),
 				_ => {}
 			}
 		}
diff --git a/client/network/src/protocol/generic_proto/upgrade.rs b/client/network/src/protocol/notifications/upgrade.rs
similarity index 100%
rename from client/network/src/protocol/generic_proto/upgrade.rs
rename to client/network/src/protocol/notifications/upgrade.rs
diff --git a/client/network/src/protocol/generic_proto/upgrade/collec.rs b/client/network/src/protocol/notifications/upgrade/collec.rs
similarity index 100%
rename from client/network/src/protocol/generic_proto/upgrade/collec.rs
rename to client/network/src/protocol/notifications/upgrade/collec.rs
diff --git a/client/network/src/protocol/generic_proto/upgrade/notifications.rs b/client/network/src/protocol/notifications/upgrade/notifications.rs
similarity index 100%
rename from client/network/src/protocol/generic_proto/upgrade/notifications.rs
rename to client/network/src/protocol/notifications/upgrade/notifications.rs
diff --git a/client/network/src/protocol/sync.rs b/client/network/src/protocol/sync.rs
index 35f840152217f..d7d0f66750b6f 100644
--- a/client/network/src/protocol/sync.rs
+++ b/client/network/src/protocol/sync.rs
@@ -44,7 +44,7 @@ use extra_requests::ExtraRequests;
 use libp2p::PeerId;
 use log::{debug, trace, warn, info, error};
 use sp_runtime::{
-	Justification,
+	EncodedJustification, Justifications,
 	generic::BlockId,
 	traits::{
 		Block as BlockT, Header as HeaderT, NumberFor, Zero, One, CheckedSub, SaturatedConversion,
@@ -425,7 +425,7 @@ pub enum OnBlockJustification<B: BlockT> {
 		peer: PeerId,
 		hash: B::Hash,
 		number: NumberFor<B>,
-		justification: Justification
+		justifications: Justifications
 	}
 }
 
@@ -823,11 +823,13 @@ impl<B: BlockT> ChainSync<B> {
 								.drain(self.best_queued_number + One::one())
 								.into_iter()
 								.map(|block_data| {
+									let justifications =
+										legacy_justification_mapping(block_data.block.justification);
 									IncomingBlock {
 										hash: block_data.block.hash,
 										header: block_data.block.header,
 										body: block_data.block.body,
-										justification: block_data.block.justification,
+										justifications,
 										origin: block_data.origin,
 										allow_missing_state: true,
 										import_existing: false,
@@ -846,7 +848,7 @@ impl<B: BlockT> ChainSync<B> {
 									hash: b.hash,
 									header: b.header,
 									body: b.body,
-									justification: b.justification,
+									justifications: legacy_justification_mapping(b.justification),
 									origin: Some(who.clone()),
 									allow_missing_state: true,
 									import_existing: false,
@@ -955,7 +957,7 @@ impl<B: BlockT> ChainSync<B> {
 							hash: b.hash,
 							header: b.header,
 							body: b.body,
-							justification: b.justification,
+							justifications: legacy_justification_mapping(b.justification),
 							origin: Some(who.clone()),
 							allow_missing_state: true,
 							import_existing: false,
@@ -1039,8 +1041,11 @@ impl<B: BlockT> ChainSync<B> {
 				None
 			};
 
-			if let Some((peer, hash, number, j)) = self.extra_justifications.on_response(who, justification) {
-				return Ok(OnBlockJustification::Import { peer, hash, number, justification: j })
+			if let Some((peer, hash, number, j)) = self
+				.extra_justifications
+				.on_response(who, legacy_justification_mapping(justification))
+			{
+				return Ok(OnBlockJustification::Import { peer, hash, number, justifications: j })
 			}
 		}
 
@@ -1547,11 +1552,13 @@ impl<B: BlockT> ChainSync<B> {
 		debug!(target:"sync", "Restarted with {} ({})", self.best_queued_number, self.best_queued_hash);
 		let old_peers = std::mem::take(&mut self.peers);
 
-		old_peers.into_iter().filter_map(move |(id, p)| {
+		old_peers.into_iter().filter_map(move |(id, mut p)| {
 			// peers that were downloading justifications
 			// should be kept in that state.
 			match p.state {
 				PeerSyncState::DownloadingJustification(_) => {
+					// We make sure our commmon number is at least something we have.
+					p.common_number = info.best_number;
 					self.peers.insert(id, p);
 					return None;
 				}
@@ -1597,6 +1604,14 @@ impl<B: BlockT> ChainSync<B> {
 	}
 }
 
+// This is purely during a backwards compatible transitionary period and should be removed
+// once we can assume all nodes can send and receive multiple Justifications
+// The ID tag is hardcoded here to avoid depending on the GRANDPA crate.
+// TODO: https://github.com/paritytech/substrate/issues/8172
+fn legacy_justification_mapping(justification: Option<EncodedJustification>) -> Option<Justifications> {
+	justification.map(|just| (*b"FRNK", just).into())
+}
+
 #[derive(Debug)]
 pub(crate) struct Metrics {
 	pub(crate) queued_blocks: u32,
@@ -2003,7 +2018,7 @@ mod test {
 		let mut new_blocks = |n| {
 			for _ in 0..n {
 				let block = client.new_block(Default::default()).unwrap().build().unwrap().block;
-				client.import(BlockOrigin::Own, block.clone()).unwrap();
+				block_on(client.import(BlockOrigin::Own, block.clone())).unwrap();
 			}
 
 			let info = client.info();
@@ -2051,6 +2066,14 @@ mod test {
 			sync.peers.get(&peer_id3).unwrap().state,
 			PeerSyncState::DownloadingJustification(b1_hash),
 		);
+
+		// Set common block to something that we don't have (e.g. failed import)
+		sync.peers.get_mut(&peer_id3).unwrap().common_number = 100;
+		let _ = sync.restart().count();
+		assert_eq!(
+			sync.peers.get(&peer_id3).unwrap().common_number,
+			50
+		);
 	}
 
 	/// Send a block annoucnement for the given `header`.
@@ -2134,7 +2157,7 @@ mod test {
 
 		let block = block_builder.build().unwrap().block;
 
-		client.import(BlockOrigin::Own, block.clone()).unwrap();
+		block_on(client.import(BlockOrigin::Own, block.clone())).unwrap();
 		block
 	}
 
@@ -2175,7 +2198,7 @@ mod test {
 			let block = block_builder.build().unwrap().block;
 
 			if import {
-				client2.import(BlockOrigin::Own, block.clone()).unwrap();
+				block_on(client2.import(BlockOrigin::Own, block.clone())).unwrap();
 			}
 
 			block
@@ -2200,7 +2223,7 @@ mod test {
 		send_block_announce(block3_fork.header().clone(), &peer_id2, &mut sync);
 
 		// Import and tell sync that we now have the fork.
-		client.import(BlockOrigin::Own, block3_fork.clone()).unwrap();
+		block_on(client.import(BlockOrigin::Own, block3_fork.clone())).unwrap();
 		sync.update_chain_info(&block3_fork.hash(), 3);
 
 		let block4 = build_block_at(block3_fork.hash(), false);
@@ -2312,7 +2335,7 @@ mod test {
 
 			resp_blocks.into_iter()
 					.rev()
-					.for_each(|b| client.import_as_final(BlockOrigin::Own, b).unwrap());
+					.for_each(|b| block_on(client.import_as_final(BlockOrigin::Own, b)).unwrap());
 		}
 
 		// Let peer2 announce that it finished syncing
@@ -2375,7 +2398,7 @@ mod test {
 			let mut client = Arc::new(TestClientBuilder::new().build());
 			let fork_blocks = blocks[..MAX_BLOCKS_TO_LOOK_BACKWARDS as usize * 2]
 				.into_iter()
-				.inspect(|b| client.import(BlockOrigin::Own, (*b).clone()).unwrap())
+				.inspect(|b| block_on(client.import(BlockOrigin::Own, (*b).clone())).unwrap())
 				.cloned()
 				.collect::<Vec<_>>();
 
@@ -2396,7 +2419,8 @@ mod test {
 		);
 
 		let finalized_block = blocks[MAX_BLOCKS_TO_LOOK_BACKWARDS as usize * 2 - 1].clone();
-		client.finalize_block(BlockId::Hash(finalized_block.hash()), Some(Vec::new())).unwrap();
+		let just = (*b"TEST", Vec::new());
+		client.finalize_block(BlockId::Hash(finalized_block.hash()), Some(just)).unwrap();
 		sync.update_chain_info(&info.best_hash, info.best_number);
 
 		let peer_id1 = PeerId::random();
@@ -2478,7 +2502,7 @@ mod test {
 
 			resp_blocks.into_iter()
 				.rev()
-				.for_each(|b| client.import(BlockOrigin::Own, b).unwrap());
+				.for_each(|b| block_on(client.import(BlockOrigin::Own, b)).unwrap());
 		}
 
 		// Request the tip
diff --git a/client/network/src/service.rs b/client/network/src/service.rs
index 74ce9316fc41c..7ea66799bad35 100644
--- a/client/network/src/service.rs
+++ b/client/network/src/service.rs
@@ -647,6 +647,13 @@ impl<B: BlockT + 'static, H: ExHashT> NetworkService<B, H> {
 			.unbounded_send(ServiceToWorkerMsg::SetReservedOnly(reserved_only));
 	}
 
+	/// Adds an address known to a node.
+	pub fn add_known_address(&self, peer_id: PeerId, addr: Multiaddr) {
+		let _ = self
+			.to_worker
+			.unbounded_send(ServiceToWorkerMsg::AddKnownAddress(peer_id, addr));
+	}
+
 	/// Appends a notification to the buffer of pending outgoing notifications with the given peer.
 	/// Has no effect if the notifications channel with this protocol name is not open.
 	///
@@ -1452,11 +1459,11 @@ impl<B: BlockT + 'static, H: ExHashT> Future for NetworkWorker<B, H> {
 					}
 					this.import_queue.import_blocks(origin, blocks);
 				},
-				Poll::Ready(SwarmEvent::Behaviour(BehaviourOut::JustificationImport(origin, hash, nb, justification))) => {
+				Poll::Ready(SwarmEvent::Behaviour(BehaviourOut::JustificationImport(origin, hash, nb, justifications))) => {
 					if let Some(metrics) = this.metrics.as_ref() {
 						metrics.import_queue_justifications_submitted.inc();
 					}
-					this.import_queue.import_justification(origin, hash, nb, justification);
+					this.import_queue.import_justifications(origin, hash, nb, justifications);
 				},
 				Poll::Ready(SwarmEvent::Behaviour(BehaviourOut::InboundRequest { protocol, result, .. })) => {
 					if let Some(metrics) = this.metrics.as_ref() {
diff --git a/client/network/src/service/tests.rs b/client/network/src/service/tests.rs
index 660eac82c4c60..dd4a0597cbcbc 100644
--- a/client/network/src/service/tests.rs
+++ b/client/network/src/service/tests.rs
@@ -47,12 +47,14 @@ fn build_test_full_node(config: config::NetworkConfiguration)
 
 	#[derive(Clone)]
 	struct PassThroughVerifier(bool);
+
+	#[async_trait::async_trait]
 	impl<B: BlockT> sp_consensus::import_queue::Verifier<B> for PassThroughVerifier {
-		fn verify(
+		async fn verify(
 			&mut self,
 			origin: sp_consensus::BlockOrigin,
 			header: B::Header,
-			justification: Option<sp_runtime::Justification>,
+			justifications: Option<sp_runtime::Justifications>,
 			body: Option<Vec<B::Extrinsic>>,
 		) -> Result<
 			(
@@ -79,7 +81,7 @@ fn build_test_full_node(config: config::NetworkConfiguration)
 			let mut import = sp_consensus::BlockImportParams::new(origin, header);
 			import.body = body;
 			import.finalized = self.0;
-			import.justification = justification;
+			import.justifications = justifications;
 			import.fork_choice = Some(sp_consensus::ForkChoiceStrategy::LongestChain);
 			Ok((import, maybe_keys))
 		}
diff --git a/client/network/src/transport.rs b/client/network/src/transport.rs
index 12c82c0fcefd0..ab587e01a875b 100644
--- a/client/network/src/transport.rs
+++ b/client/network/src/transport.rs
@@ -63,10 +63,11 @@ pub fn build_transport(
 		let desktop_trans = tcp::TcpConfig::new().nodelay(true);
 		let desktop_trans = websocket::WsConfig::new(desktop_trans.clone())
 			.or_transport(desktop_trans);
-		OptionalTransport::some(if let Ok(dns) = dns::DnsConfig::new(desktop_trans.clone()) {
+		let dns_init = futures::executor::block_on(dns::DnsConfig::system(desktop_trans.clone()));
+		OptionalTransport::some(if let Ok(dns) = dns_init {
 			EitherTransport::Left(dns)
 		} else {
-			EitherTransport::Right(desktop_trans.map_err(dns::DnsErr::Underlying))
+			EitherTransport::Right(desktop_trans.map_err(dns::DnsErr::Transport))
 		})
 	} else {
 		OptionalTransport::none()
diff --git a/client/network/test/Cargo.toml b/client/network/test/Cargo.toml
index 009315084cc32..4fc1aa740040d 100644
--- a/client/network/test/Cargo.toml
+++ b/client/network/test/Cargo.toml
@@ -20,7 +20,7 @@ parking_lot = "0.11.1"
 futures = "0.3.9"
 futures-timer = "3.0.1"
 rand = "0.7.2"
-libp2p = { version = "0.35.1", default-features = false }
+libp2p = { version = "0.36.0", default-features = false }
 sp-consensus = { version = "0.9.0", path = "../../../primitives/consensus/common" }
 sc-consensus = { version = "0.9.0", path = "../../consensus/common" }
 sc-client-api = { version = "3.0.0", path = "../../api" }
@@ -34,3 +34,4 @@ substrate-test-runtime = { version = "2.0.0", path = "../../../test-utils/runtim
 tempfile = "3.1.0"
 sp-tracing = { version = "3.0.0", path = "../../../primitives/tracing" }
 sc-service = { version = "0.9.0", default-features = false, features = ["test-helpers"],  path = "../../service" }
+async-trait = "0.1.42"
diff --git a/client/network/test/src/block_import.rs b/client/network/test/src/block_import.rs
index 4000e53420b4a..b3641d4b41214 100644
--- a/client/network/test/src/block_import.rs
+++ b/client/network/test/src/block_import.rs
@@ -26,22 +26,23 @@ use substrate_test_runtime_client::{self, prelude::*};
 use substrate_test_runtime_client::runtime::{Block, Hash};
 use sp_runtime::generic::BlockId;
 use sc_block_builder::BlockBuilderProvider;
+use futures::executor::block_on;
 use super::*;
 
 fn prepare_good_block() -> (TestClient, Hash, u64, PeerId, IncomingBlock<Block>) {
 	let mut client = substrate_test_runtime_client::new();
 	let block = client.new_block(Default::default()).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::File, block).unwrap();
+	block_on(client.import(BlockOrigin::File, block)).unwrap();
 
 	let (hash, number) = (client.block_hash(1).unwrap().unwrap(), 1);
 	let header = client.header(&BlockId::Number(1)).unwrap();
-	let justification = client.justification(&BlockId::Number(1)).unwrap();
+	let justifications = client.justifications(&BlockId::Number(1)).unwrap();
 	let peer_id = PeerId::random();
 	(client, hash, number, peer_id.clone(), IncomingBlock {
 		hash,
 		header,
 		body: Some(Vec::new()),
-		justification,
+		justifications,
 		origin: Some(peer_id.clone()),
 		allow_missing_state: false,
 		import_existing: false,
@@ -55,12 +56,12 @@ fn import_single_good_block_works() {
 	let mut expected_aux = ImportedAux::default();
 	expected_aux.is_new_best = true;
 
-	match import_single_block(
+	match block_on(import_single_block(
 		&mut substrate_test_runtime_client::new(),
 		BlockOrigin::File,
 		block,
 		&mut PassThroughVerifier::new(true)
-	) {
+	)) {
 		Ok(BlockImportResult::ImportedUnknown(ref num, ref aux, ref org))
 			if *num == number && *aux == expected_aux && *org == Some(peer_id) => {}
 		r @ _ => panic!("{:?}", r)
@@ -70,12 +71,12 @@ fn import_single_good_block_works() {
 #[test]
 fn import_single_good_known_block_is_ignored() {
 	let (mut client, _hash, number, _, block) = prepare_good_block();
-	match import_single_block(
+	match block_on(import_single_block(
 		&mut client,
 		BlockOrigin::File,
 		block,
 		&mut PassThroughVerifier::new(true)
-	) {
+	)) {
 		Ok(BlockImportResult::ImportedKnown(ref n, _)) if *n == number => {}
 		_ => panic!()
 	}
@@ -85,12 +86,12 @@ fn import_single_good_known_block_is_ignored() {
 fn import_single_good_block_without_header_fails() {
 	let (_, _, _, peer_id, mut block) = prepare_good_block();
 	block.header = None;
-	match import_single_block(
+	match block_on(import_single_block(
 		&mut substrate_test_runtime_client::new(),
 		BlockOrigin::File,
 		block,
 		&mut PassThroughVerifier::new(true)
-	) {
+	)) {
 		Err(BlockImportError::IncompleteHeader(ref org)) if *org == Some(peer_id) => {}
 		_ => panic!()
 	}
diff --git a/client/network/test/src/lib.rs b/client/network/test/src/lib.rs
index c8b442d0dd563..5e05f57175490 100644
--- a/client/network/test/src/lib.rs
+++ b/client/network/test/src/lib.rs
@@ -23,8 +23,7 @@ mod block_import;
 mod sync;
 
 use std::{
-	borrow::Cow, collections::HashMap, pin::Pin, sync::Arc, marker::PhantomData,
-	task::{Poll, Context as FutureContext}
+	borrow::Cow, collections::HashMap, pin::Pin, sync::Arc, task::{Poll, Context as FutureContext}
 };
 
 use libp2p::build_multiaddr;
@@ -63,8 +62,8 @@ use sp_core::H256;
 use sc_network::config::ProtocolConfig;
 use sp_runtime::generic::{BlockId, OpaqueDigestItemId};
 use sp_runtime::traits::{Block as BlockT, Header as HeaderT, NumberFor};
-use sp_runtime::Justification;
-use substrate_test_runtime_client::{self, AccountKeyring};
+use sp_runtime::{Justification, Justifications};
+use substrate_test_runtime_client::AccountKeyring;
 use sc_service::client::Client;
 pub use sc_network::config::EmptyTransactionPool;
 pub use substrate_test_runtime_client::runtime::{Block, Extrinsic, Hash, Transfer};
@@ -104,12 +103,13 @@ impl PassThroughVerifier {
 }
 
 /// This `Verifier` accepts all data as valid.
+#[async_trait::async_trait]
 impl<B: BlockT> Verifier<B> for PassThroughVerifier {
-	fn verify(
+	async fn verify(
 		&mut self,
 		origin: BlockOrigin,
 		header: B::Header,
-		justification: Option<Justification>,
+		justifications: Option<Justifications>,
 		body: Option<Vec<B::Extrinsic>>
 	) -> Result<(BlockImportParams<B, ()>, Option<Vec<(CacheKeyId, Vec<u8>)>>), String> {
 		let maybe_keys = header.digest()
@@ -120,7 +120,7 @@ impl<B: BlockT> Verifier<B> for PassThroughVerifier {
 		let mut import = BlockImportParams::new(origin, header);
 		import.body = body;
 		import.finalized = self.finalized;
-		import.justification = justification;
+		import.justifications = justifications;
 		import.fork_choice = Some(self.fork_choice.clone());
 
 		Ok((import, maybe_keys))
@@ -154,13 +154,8 @@ impl PeersClient {
 		}
 	}
 
-	pub fn as_block_import<Transaction>(&self) -> BlockImportAdapter<Transaction> {
-		match *self {
-			PeersClient::Full(ref client, ref _backend) =>
-				BlockImportAdapter::new_full(client.clone()),
-			PeersClient::Light(ref client, ref _backend) =>
-				BlockImportAdapter::Light(Arc::new(Mutex::new(client.clone())), PhantomData),
-		}
+	pub fn as_block_import(&self) -> BlockImportAdapter<Self> {
+		BlockImportAdapter::new(self.clone())
 	}
 
 	pub fn get_aux(&self, key: &[u8]) -> ClientResult<Option<Vec<u8>>> {
@@ -184,10 +179,10 @@ impl PeersClient {
 		}
 	}
 
-	pub fn justification(&self, block: &BlockId<Block>) -> ClientResult<Option<Justification>> {
+	pub fn justifications(&self, block: &BlockId<Block>) -> ClientResult<Option<Justifications>> {
 		match *self {
-			PeersClient::Full(ref client, ref _backend) => client.justification(block),
-			PeersClient::Light(ref client, ref _backend) => client.justification(block),
+			PeersClient::Full(ref client, ref _backend) => client.justifications(block),
+			PeersClient::Light(ref client, ref _backend) => client.justifications(block),
 		}
 	}
 
@@ -218,7 +213,36 @@ impl PeersClient {
 	}
 }
 
-pub struct Peer<D> {
+#[async_trait::async_trait]
+impl BlockImport<Block> for PeersClient {
+	type Error = ConsensusError;
+	type Transaction = ();
+
+	async fn check_block(
+		&mut self,
+		block: BlockCheckParams<Block>,
+	) -> Result<ImportResult, Self::Error> {
+		match self {
+			PeersClient::Full(client, _) => client.check_block(block).await,
+			PeersClient::Light(client, _) => client.check_block(block).await,
+		}
+	}
+
+	async fn import_block(
+		&mut self,
+		block: BlockImportParams<Block, ()>,
+		cache: HashMap<well_known_cache_keys::Id, Vec<u8>>,
+	) -> Result<ImportResult, Self::Error> {
+		match self {
+			PeersClient::Full(client, _) =>
+				client.import_block(block.convert_transaction(), cache).await,
+			PeersClient::Light(client, _) =>
+				client.import_block(block.convert_transaction(), cache).await,
+		}
+	}
+}
+
+pub struct Peer<D, BlockImport> {
 	pub data: D,
 	client: PeersClient,
 	/// We keep a copy of the verifier so that we can invoke it for locally-generated blocks,
@@ -226,7 +250,7 @@ pub struct Peer<D> {
 	verifier: VerifierAdapter<Block>,
 	/// We keep a copy of the block_import so that we can invoke it for locally-generated blocks,
 	/// instead of going through the import queue.
-	block_import: BlockImportAdapter<()>,
+	block_import: BlockImportAdapter<BlockImport>,
 	select_chain: Option<LongestChain<substrate_test_runtime_client::Backend, Block>>,
 	backend: Option<Arc<substrate_test_runtime_client::Backend>>,
 	network: NetworkWorker<Block, <Block as BlockT>::Hash>,
@@ -235,7 +259,10 @@ pub struct Peer<D> {
 	listen_addr: Multiaddr,
 }
 
-impl<D> Peer<D> {
+impl<D, B> Peer<D, B> where
+	B: BlockImport<Block, Error = ConsensusError> + Send + Sync,
+	B::Transaction: Send,
+{
 	/// Get this peer ID.
 	pub fn id(&self) -> PeerId {
 		self.network.service().local_peer_id().clone()
@@ -277,13 +304,24 @@ impl<D> Peer<D> {
 	}
 
 	/// Request explicit fork sync.
-	pub fn set_sync_fork_request(&self, peers: Vec<PeerId>, hash: <Block as BlockT>::Hash, number: NumberFor<Block>) {
+	pub fn set_sync_fork_request(
+		&self,
+		peers: Vec<PeerId>,
+		hash: <Block as BlockT>::Hash,
+		number: NumberFor<Block>,
+	) {
 		self.network.service().set_sync_fork_request(peers, hash, number);
 	}
 
 	/// Add blocks to the peer -- edit the block before adding
-	pub fn generate_blocks<F>(&mut self, count: usize, origin: BlockOrigin, edit_block: F) -> H256
-		where F: FnMut(BlockBuilder<Block, PeersFullClient, substrate_test_runtime_client::Backend>) -> Block
+	pub fn generate_blocks<F>(
+		&mut self,
+		count: usize,
+		origin: BlockOrigin,
+		edit_block: F,
+	) -> H256
+		where
+			F: FnMut(BlockBuilder<Block, PeersFullClient, substrate_test_runtime_client::Backend>) -> Block
 	{
 		let best_hash = self.client.info().best_hash;
 		self.generate_blocks_at(BlockId::Hash(best_hash), count, origin, edit_block, false, true, true)
@@ -320,19 +358,21 @@ impl<D> Peer<D> {
 				block.header.parent_hash,
 			);
 			let header = block.header.clone();
-			let (import_block, cache) = self.verifier.verify(
+			let (import_block, cache) = futures::executor::block_on(self.verifier.verify(
 				origin,
 				header.clone(),
 				None,
 				if headers_only { None } else { Some(block.extrinsics) },
-			).unwrap();
+			)).unwrap();
 			let cache = if let Some(cache) = cache {
 				cache.into_iter().collect()
 			} else {
 				Default::default()
 			};
 
-			self.block_import.import_block(import_block, cache).expect("block_import failed");
+			futures::executor::block_on(
+				self.block_import.import_block(import_block, cache)
+			).expect("block_import failed");
 			if announce_block {
 				self.network.service().announce_block(hash, None);
 			}
@@ -478,120 +518,107 @@ impl<D> Peer<D> {
 	}
 }
 
+pub trait BlockImportAdapterFull:
+	BlockImport<
+		Block,
+		Transaction = TransactionFor<substrate_test_runtime_client::Backend, Block>,
+		Error = ConsensusError,
+	> +
+	Send +
+	Sync +
+	Clone
+{}
+
+impl<T> BlockImportAdapterFull for T where
+	T: BlockImport<
+		Block,
+		Transaction = TransactionFor<substrate_test_runtime_client::Backend, Block>,
+		Error = ConsensusError,
+	> +
+	Send +
+	Sync +
+	Clone
+{}
+
 /// Implements `BlockImport` for any `Transaction`. Internally the transaction is
 /// "converted", aka the field is set to `None`.
 ///
 /// This is required as the `TestNetFactory` trait does not distinguish between
 /// full and light nodes.
-pub enum BlockImportAdapter<Transaction> {
-	Full(
-		Arc<Mutex<dyn BlockImport<
-			Block,
-			Transaction = TransactionFor<substrate_test_runtime_client::Backend, Block>,
-			Error = ConsensusError
-		> + Send>>,
-		PhantomData<Transaction>,
-	),
-	Light(
-		Arc<Mutex<dyn BlockImport<
-			Block,
-			Transaction = TransactionFor<substrate_test_runtime_client::LightBackend, Block>,
-			Error = ConsensusError
-		> + Send>>,
-		PhantomData<Transaction>,
-	),
+#[derive(Clone)]
+pub struct BlockImportAdapter<I> {
+	inner: I,
 }
 
-impl<Transaction> BlockImportAdapter<Transaction> {
+impl<I> BlockImportAdapter<I> {
 	/// Create a new instance of `Self::Full`.
-	pub fn new_full(
-		full: impl BlockImport<
-			Block,
-			Transaction = TransactionFor<substrate_test_runtime_client::Backend, Block>,
-			Error = ConsensusError
-		>
-		+ 'static
-		+ Send
-	) -> Self {
-		Self::Full(Arc::new(Mutex::new(full)), PhantomData)
-	}
-
-	/// Create a new instance of `Self::Light`.
-	pub fn new_light(
-		light: impl BlockImport<
-			Block,
-			Transaction = TransactionFor<substrate_test_runtime_client::LightBackend, Block>,
-			Error = ConsensusError
-		>
-		+ 'static
-		+ Send
-	) -> Self {
-		Self::Light(Arc::new(Mutex::new(light)), PhantomData)
-	}
-}
-
-impl<Transaction> Clone for BlockImportAdapter<Transaction> {
-	fn clone(&self) -> Self {
-		match self {
-			Self::Full(full, _) => Self::Full(full.clone(), PhantomData),
-			Self::Light(light, _) => Self::Light(light.clone(), PhantomData),
+	pub fn new(inner: I) -> Self {
+		Self {
+			inner,
 		}
 	}
 }
 
-impl<Transaction> BlockImport<Block> for BlockImportAdapter<Transaction> {
+#[async_trait::async_trait]
+impl<I> BlockImport<Block> for BlockImportAdapter<I> where
+	I: BlockImport<Block, Error = ConsensusError> + Send + Sync,
+	I::Transaction: Send,
+{
 	type Error = ConsensusError;
-	type Transaction = Transaction;
+	type Transaction = ();
 
-	fn check_block(
+	async fn check_block(
 		&mut self,
 		block: BlockCheckParams<Block>,
 	) -> Result<ImportResult, Self::Error> {
-		match self {
-			Self::Full(full, _) => full.lock().check_block(block),
-			Self::Light(light, _) => light.lock().check_block(block),
-		}
+		self.inner.check_block(block).await
 	}
 
-	fn import_block(
+	async fn import_block(
 		&mut self,
-		block: BlockImportParams<Block, Transaction>,
+		block: BlockImportParams<Block, ()>,
 		cache: HashMap<well_known_cache_keys::Id, Vec<u8>>,
 	) -> Result<ImportResult, Self::Error> {
-		match self {
-			Self::Full(full, _) => full.lock().import_block(block.convert_transaction(), cache),
-			Self::Light(light, _) => light.lock().import_block(block.convert_transaction(), cache),
-		}
+		self.inner.import_block(block.convert_transaction(), cache).await
 	}
 }
 
-/// Implements `Verifier` on an `Arc<Mutex<impl Verifier>>`. Used internally.
-#[derive(Clone)]
+/// Implements `Verifier` and keeps track of failed verifications.
 struct VerifierAdapter<B: BlockT> {
-	verifier: Arc<Mutex<Box<dyn Verifier<B>>>>,
+	verifier: Arc<futures::lock::Mutex<Box<dyn Verifier<B>>>>,
 	failed_verifications: Arc<Mutex<HashMap<B::Hash, String>>>,
 }
 
+#[async_trait::async_trait]
 impl<B: BlockT> Verifier<B> for VerifierAdapter<B> {
-	fn verify(
+	async fn verify(
 		&mut self,
 		origin: BlockOrigin,
 		header: B::Header,
-		justification: Option<Justification>,
+		justifications: Option<Justifications>,
 		body: Option<Vec<B::Extrinsic>>
 	) -> Result<(BlockImportParams<B, ()>, Option<Vec<(CacheKeyId, Vec<u8>)>>), String> {
 		let hash = header.hash();
-		self.verifier.lock().verify(origin, header, justification, body).map_err(|e| {
+		self.verifier.lock().await.verify(origin, header, justifications, body).await.map_err(|e| {
 			self.failed_verifications.lock().insert(hash, e.clone());
 			e
 		})
 	}
 }
 
+impl<B: BlockT> Clone for VerifierAdapter<B> {
+	fn clone(&self) -> Self {
+		Self {
+			verifier: self.verifier.clone(),
+			failed_verifications: self.failed_verifications.clone(),
+		}
+	}
+}
+
 impl<B: BlockT> VerifierAdapter<B> {
-	fn new(verifier: Arc<Mutex<Box<dyn Verifier<B>>>>) -> VerifierAdapter<B> {
+	fn new(verifier: impl Verifier<B> + 'static) -> Self {
 		VerifierAdapter {
-			verifier,
+			verifier: Arc::new(futures::lock::Mutex::new(Box::new(verifier))),
 			failed_verifications: Default::default(),
 		}
 	}
@@ -610,10 +637,13 @@ pub struct FullPeerConfig {
 	///
 	/// If `None`, it will be connected to all other peers.
 	pub connect_to_peers: Option<Vec<usize>>,
+	/// Whether the full peer should have the authority role.
+	pub is_authority: bool,
 }
 
-pub trait TestNetFactory: Sized {
+pub trait TestNetFactory: Sized where <Self::BlockImport as BlockImport<Block>>::Transaction: Send {
 	type Verifier: 'static + Verifier<Block>;
+	type BlockImport: BlockImport<Block, Error = ConsensusError> + Clone + Send + Sync + 'static;
 	type PeerData: Default;
 
 	/// These two need to be implemented!
@@ -626,23 +656,20 @@ pub trait TestNetFactory: Sized {
 	) -> Self::Verifier;
 
 	/// Get reference to peer.
-	fn peer(&mut self, i: usize) -> &mut Peer<Self::PeerData>;
-	fn peers(&self) -> &Vec<Peer<Self::PeerData>>;
-	fn mut_peers<F: FnOnce(&mut Vec<Peer<Self::PeerData>>)>(
+	fn peer(&mut self, i: usize) -> &mut Peer<Self::PeerData, Self::BlockImport>;
+	fn peers(&self) -> &Vec<Peer<Self::PeerData, Self::BlockImport>>;
+	fn mut_peers<F: FnOnce(&mut Vec<Peer<Self::PeerData, Self::BlockImport>>)>(
 		&mut self,
 		closure: F,
 	);
 
 	/// Get custom block import handle for fresh client, along with peer data.
-	fn make_block_import<Transaction>(&self, client: PeersClient)
+	fn make_block_import(&self, client: PeersClient)
 		-> (
-			BlockImportAdapter<Transaction>,
+			BlockImportAdapter<Self::BlockImport>,
 			Option<BoxJustificationImport<Block>>,
 			Self::PeerData,
-		)
-	{
-		(client.as_block_import(), None, Default::default())
-	}
+		);
 
 	fn default_config() -> ProtocolConfig {
 		ProtocolConfig::default()
@@ -686,7 +713,7 @@ pub trait TestNetFactory: Sized {
 			&Default::default(),
 			&data,
 		);
-		let verifier = VerifierAdapter::new(Arc::new(Mutex::new(Box::new(verifier) as Box<_>)));
+		let verifier = VerifierAdapter::new(verifier);
 
 		let import_queue = Box::new(BasicQueue::new(
 			verifier.clone(),
@@ -743,7 +770,7 @@ pub trait TestNetFactory: Sized {
 		};
 
 		let network = NetworkWorker::new(sc_network::config::Params {
-			role: Role::Full,
+			role: if config.is_authority { Role::Authority } else { Role::Full },
 			executor: None,
 			transactions_handler_executor: Box::new(|task| { async_std::task::spawn(task); }),
 			network_config,
@@ -774,7 +801,7 @@ pub trait TestNetFactory: Sized {
 
 			peers.push(Peer {
 				data,
-				client: PeersClient::Full(client, backend.clone()),
+				client: PeersClient::Full(client.clone(), backend.clone()),
 				select_chain: Some(longest_chain),
 				backend: Some(backend),
 				imported_blocks_stream,
@@ -802,7 +829,7 @@ pub trait TestNetFactory: Sized {
 			&Default::default(),
 			&data,
 		);
-		let verifier = VerifierAdapter::new(Arc::new(Mutex::new(Box::new(verifier) as Box<_>)));
+		let verifier = VerifierAdapter::new(verifier);
 
 		let import_queue = Box::new(BasicQueue::new(
 			verifier.clone(),
@@ -984,7 +1011,7 @@ pub trait TestNetFactory: Sized {
 }
 
 pub struct TestNet {
-	peers: Vec<Peer<()>>,
+	peers: Vec<Peer<(), PeersClient>>,
 	fork_choice: ForkChoiceStrategy,
 }
 
@@ -1001,6 +1028,7 @@ impl TestNet {
 impl TestNetFactory for TestNet {
 	type Verifier = PassThroughVerifier;
 	type PeerData = ();
+	type BlockImport = PeersClient;
 
 	/// Create new test network with peers and given config.
 	fn from_config(_config: &ProtocolConfig) -> Self {
@@ -1016,15 +1044,25 @@ impl TestNetFactory for TestNet {
 		PassThroughVerifier::new_with_fork_choice(false, self.fork_choice.clone())
 	}
 
-	fn peer(&mut self, i: usize) -> &mut Peer<()> {
+	fn make_block_import(&self, client: PeersClient)
+		-> (
+			BlockImportAdapter<Self::BlockImport>,
+			Option<BoxJustificationImport<Block>>,
+			Self::PeerData,
+		)
+	{
+		(client.as_block_import(), None, ())
+	}
+
+	fn peer(&mut self, i: usize) -> &mut Peer<(), Self::BlockImport> {
 		&mut self.peers[i]
 	}
 
-	fn peers(&self) -> &Vec<Peer<()>> {
+	fn peers(&self) -> &Vec<Peer<(), Self::BlockImport>> {
 		&self.peers
 	}
 
-	fn mut_peers<F: FnOnce(&mut Vec<Peer<()>>)>(&mut self, closure: F) {
+	fn mut_peers<F: FnOnce(&mut Vec<Peer<(), Self::BlockImport>>)>(&mut self, closure: F) {
 		closure(&mut self.peers);
 	}
 }
@@ -1050,6 +1088,7 @@ pub struct JustificationTestNet(TestNet);
 impl TestNetFactory for JustificationTestNet {
 	type Verifier = PassThroughVerifier;
 	type PeerData = ();
+	type BlockImport = PeersClient;
 
 	fn from_config(config: &ProtocolConfig) -> Self {
 		JustificationTestNet(TestNet::from_config(config))
@@ -1059,23 +1098,23 @@ impl TestNetFactory for JustificationTestNet {
 		self.0.make_verifier(client, config, peer_data)
 	}
 
-	fn peer(&mut self, i: usize) -> &mut Peer<Self::PeerData> {
+	fn peer(&mut self, i: usize) -> &mut Peer<Self::PeerData, Self::BlockImport> {
 		self.0.peer(i)
 	}
 
-	fn peers(&self) -> &Vec<Peer<Self::PeerData>> {
+	fn peers(&self) -> &Vec<Peer<Self::PeerData, Self::BlockImport>> {
 		self.0.peers()
 	}
 
 	fn mut_peers<F: FnOnce(
-		&mut Vec<Peer<Self::PeerData>>,
+		&mut Vec<Peer<Self::PeerData, Self::BlockImport>>,
 	)>(&mut self, closure: F) {
 		self.0.mut_peers(closure)
 	}
 
-	fn make_block_import<Transaction>(&self, client: PeersClient)
+	fn make_block_import(&self, client: PeersClient)
 		-> (
-			BlockImportAdapter<Transaction>,
+			BlockImportAdapter<Self::BlockImport>,
 			Option<BoxJustificationImport<Block>>,
 			Self::PeerData,
 		)
diff --git a/client/network/test/src/sync.rs b/client/network/test/src/sync.rs
index b11dbaca75e14..953639dcc0e22 100644
--- a/client/network/test/src/sync.rs
+++ b/client/network/test/src/sync.rs
@@ -22,6 +22,7 @@ use futures::{Future, executor::block_on};
 use super::*;
 use sp_consensus::block_validation::Validation;
 use substrate_test_runtime::Header;
+use sp_runtime::Justifications;
 
 fn test_ancestor_search_when_common_is(n: usize) {
 	sp_tracing::try_init_simple();
@@ -248,13 +249,14 @@ fn sync_justifications() {
 	net.block_until_sync();
 
 	// there's currently no justification for block #10
-	assert_eq!(net.peer(0).client().justification(&BlockId::Number(10)).unwrap(), None);
-	assert_eq!(net.peer(1).client().justification(&BlockId::Number(10)).unwrap(), None);
+	assert_eq!(net.peer(0).client().justifications(&BlockId::Number(10)).unwrap(), None);
+	assert_eq!(net.peer(1).client().justifications(&BlockId::Number(10)).unwrap(), None);
 
 	// we finalize block #10, #15 and #20 for peer 0 with a justification
-	net.peer(0).client().finalize_block(BlockId::Number(10), Some(Vec::new()), true).unwrap();
-	net.peer(0).client().finalize_block(BlockId::Number(15), Some(Vec::new()), true).unwrap();
-	net.peer(0).client().finalize_block(BlockId::Number(20), Some(Vec::new()), true).unwrap();
+	let just = (*b"FRNK", Vec::new());
+	net.peer(0).client().finalize_block(BlockId::Number(10), Some(just.clone()), true).unwrap();
+	net.peer(0).client().finalize_block(BlockId::Number(15), Some(just.clone()), true).unwrap();
+	net.peer(0).client().finalize_block(BlockId::Number(20), Some(just.clone()), true).unwrap();
 
 	let h1 = net.peer(1).client().header(&BlockId::Number(10)).unwrap().unwrap();
 	let h2 = net.peer(1).client().header(&BlockId::Number(15)).unwrap().unwrap();
@@ -269,10 +271,20 @@ fn sync_justifications() {
 		net.poll(cx);
 
 		for height in (10..21).step_by(5) {
-			if net.peer(0).client().justification(&BlockId::Number(height)).unwrap() != Some(Vec::new()) {
+			if net
+				.peer(0)
+				.client()
+				.justifications(&BlockId::Number(height))
+				.unwrap() != Some(Justifications::from((*b"FRNK", Vec::new())))
+			{
 				return Poll::Pending;
 			}
-			if net.peer(1).client().justification(&BlockId::Number(height)).unwrap() != Some(Vec::new()) {
+			if net
+				.peer(1)
+				.client()
+				.justifications(&BlockId::Number(height))
+				.unwrap() != Some(Justifications::from((*b"FRNK", Vec::new())))
+			{
 				return Poll::Pending;
 			}
 		}
@@ -295,7 +307,8 @@ fn sync_justifications_across_forks() {
 	// for both and finalize the small fork instead.
 	net.block_until_sync();
 
-	net.peer(0).client().finalize_block(BlockId::Hash(f1_best), Some(Vec::new()), true).unwrap();
+	let just = (*b"FRNK", Vec::new());
+	net.peer(0).client().finalize_block(BlockId::Hash(f1_best), Some(just), true).unwrap();
 
 	net.peer(1).request_justification(&f1_best, 10);
 	net.peer(1).request_justification(&f2_best, 11);
@@ -303,8 +316,16 @@ fn sync_justifications_across_forks() {
 	block_on(futures::future::poll_fn::<(), _>(|cx| {
 		net.poll(cx);
 
-		if net.peer(0).client().justification(&BlockId::Number(10)).unwrap() == Some(Vec::new()) &&
-			net.peer(1).client().justification(&BlockId::Number(10)).unwrap() == Some(Vec::new())
+		if net
+			.peer(0)
+			.client()
+			.justifications(&BlockId::Number(10))
+			.unwrap() == Some(Justifications::from((*b"FRNK", Vec::new())))
+			&& net
+				.peer(1)
+				.client()
+				.justifications(&BlockId::Number(10))
+				.unwrap() == Some(Justifications::from((*b"FRNK", Vec::new())))
 		{
 			Poll::Ready(())
 		} else {
@@ -696,8 +717,9 @@ fn can_sync_to_peers_with_wrong_common_block() {
 	net.block_until_connected();
 
 	// both peers re-org to the same fork without notifying each other
-	net.peer(0).client().finalize_block(BlockId::Hash(fork_hash), Some(Vec::new()), true).unwrap();
-	net.peer(1).client().finalize_block(BlockId::Hash(fork_hash), Some(Vec::new()), true).unwrap();
+	let just = Some((*b"FRNK", Vec::new()));
+	net.peer(0).client().finalize_block(BlockId::Hash(fork_hash), just.clone(), true).unwrap();
+	net.peer(1).client().finalize_block(BlockId::Hash(fork_hash), just, true).unwrap();
 	let final_hash = net.peer(0).push_blocks(1, false);
 
 	net.block_until_sync();
@@ -948,8 +970,8 @@ fn multiple_requests_are_accepted_as_long_as_they_are_not_fulfilled() {
 	net.block_until_sync();
 
 	// there's currently no justification for block #10
-	assert_eq!(net.peer(0).client().justification(&BlockId::Number(10)).unwrap(), None);
-	assert_eq!(net.peer(1).client().justification(&BlockId::Number(10)).unwrap(), None);
+	assert_eq!(net.peer(0).client().justifications(&BlockId::Number(10)).unwrap(), None);
+	assert_eq!(net.peer(1).client().justifications(&BlockId::Number(10)).unwrap(), None);
 
 	let h1 = net.peer(1).client().header(&BlockId::Number(10)).unwrap().unwrap();
 
@@ -967,12 +989,21 @@ fn multiple_requests_are_accepted_as_long_as_they_are_not_fulfilled() {
 	}
 
 	// Finalize the block and make the justification available.
-	net.peer(0).client().finalize_block(BlockId::Number(10), Some(Vec::new()), true).unwrap();
+	net.peer(0).client().finalize_block(
+		BlockId::Number(10),
+		Some((*b"FRNK", Vec::new())),
+		true,
+	).unwrap();
 
 	block_on(futures::future::poll_fn::<(), _>(|cx| {
 		net.poll(cx);
 
-		if net.peer(1).client().justification(&BlockId::Number(10)).unwrap() != Some(Vec::new()) {
+		if net
+			.peer(1)
+			.client()
+			.justifications(&BlockId::Number(10))
+			.unwrap() != Some(Justifications::from((*b"FRNK", Vec::new())))
+		{
 			return Poll::Pending;
 		}
 
diff --git a/client/offchain/src/lib.rs b/client/offchain/src/lib.rs
index 717f02eccd5dc..26975edbd6b63 100644
--- a/client/offchain/src/lib.rs
+++ b/client/offchain/src/lib.rs
@@ -240,6 +240,7 @@ mod tests {
 	use sp_consensus::BlockOrigin;
 	use sc_client_api::Backend as _;
 	use sc_block_builder::BlockBuilderProvider as _;
+	use futures::executor::block_on;
 
 	struct TestNetwork();
 
@@ -331,7 +332,7 @@ mod tests {
 		).unwrap();
 
 		let block = block_builder.build().unwrap().block;
-		client.import(BlockOrigin::Own, block).unwrap();
+		block_on(client.import(BlockOrigin::Own, block)).unwrap();
 
 		assert_eq!(value, &offchain_db.get(sp_offchain::STORAGE_PREFIX, &key).unwrap());
 
@@ -341,7 +342,7 @@ mod tests {
 		).unwrap();
 
 		let block = block_builder.build().unwrap().block;
-		client.import(BlockOrigin::Own, block).unwrap();
+		block_on(client.import(BlockOrigin::Own, block)).unwrap();
 
 		assert!(offchain_db.get(sp_offchain::STORAGE_PREFIX, &key).is_none());
 	}
diff --git a/client/peerset/Cargo.toml b/client/peerset/Cargo.toml
index 536ec6b681753..984bfc5e835ff 100644
--- a/client/peerset/Cargo.toml
+++ b/client/peerset/Cargo.toml
@@ -16,7 +16,7 @@ targets = ["x86_64-unknown-linux-gnu"]
 
 [dependencies]
 futures = "0.3.9"
-libp2p = { version = "0.35.1", default-features = false }
+libp2p = { version = "0.36.0", default-features = false }
 sp-utils = { version = "3.0.0", path = "../../primitives/utils"}
 log = "0.4.8"
 serde_json = "1.0.41"
diff --git a/client/peerset/src/lib.rs b/client/peerset/src/lib.rs
index 31162930efc67..153e097dc8b46 100644
--- a/client/peerset/src/lib.rs
+++ b/client/peerset/src/lib.rs
@@ -296,7 +296,10 @@ impl Peerset {
 			}
 		}
 
-		peerset.alloc_slots();
+		for set_index in 0..peerset.data.num_sets() {
+			peerset.alloc_slots(SetId(set_index));
+		}
+
 		(peerset, handle)
 	}
 
@@ -307,7 +310,7 @@ impl Peerset {
 		}
 
 		self.data.add_no_slot_node(set_id.0, peer_id);
-		self.alloc_slots();
+		self.alloc_slots(set_id);
 	}
 
 	fn on_remove_reserved_peer(&mut self, set_id: SetId, peer_id: PeerId) {
@@ -372,7 +375,7 @@ impl Peerset {
 			}
 
 		} else {
-			self.alloc_slots();
+			self.alloc_slots(set_id);
 		}
 	}
 
@@ -383,7 +386,7 @@ impl Peerset {
 	pub fn add_to_peers_set(&mut self, set_id: SetId, peer_id: PeerId) {
 		if let peersstate::Peer::Unknown(entry) = self.data.peer(set_id.0, &peer_id) {
 			entry.discover();
-			self.alloc_slots();
+			self.alloc_slots(set_id);
 		}
 	}
 
@@ -500,59 +503,68 @@ impl Peerset {
 		}
 	}
 
-	/// Try to fill available out slots with nodes.
-	fn alloc_slots(&mut self) {
+	/// Try to fill available out slots with nodes for the given set.
+	fn alloc_slots(&mut self, set_id: SetId) {
 		self.update_time();
 
 		// Try to connect to all the reserved nodes that we are not connected to.
-		for set_index in 0..self.data.num_sets() {
-			for reserved_node in &self.reserved_nodes[set_index].0 {
-				let entry = match self.data.peer(set_index, reserved_node) {
-					peersstate::Peer::Unknown(n) => n.discover(),
-					peersstate::Peer::NotConnected(n) => n,
-					peersstate::Peer::Connected(_) => continue,
-				};
-
-				match entry.try_outgoing() {
-					Ok(conn) => self.message_queue.push_back(Message::Connect {
-						set_id: SetId(set_index),
-						peer_id: conn.into_peer_id()
-					}),
-					Err(_) => {
-						// An error is returned only if no slot is available. Reserved nodes are
-						// marked in the state machine with a flag saying "doesn't occupy a slot",
-						// and as such this should never happen.
-						debug_assert!(false);
-						log::error!(
-							target: "peerset",
-							"Not enough slots to connect to reserved node"
-						);
-					}
+		for reserved_node in &self.reserved_nodes[set_id.0].0 {
+			let entry = match self.data.peer(set_id.0, reserved_node) {
+				peersstate::Peer::Unknown(n) => n.discover(),
+				peersstate::Peer::NotConnected(n) => n,
+				peersstate::Peer::Connected(_) => continue,
+			};
+
+			match entry.try_outgoing() {
+				Ok(conn) => self.message_queue.push_back(Message::Connect {
+					set_id,
+					peer_id: conn.into_peer_id()
+				}),
+				Err(_) => {
+					// An error is returned only if no slot is available. Reserved nodes are
+					// marked in the state machine with a flag saying "doesn't occupy a slot",
+					// and as such this should never happen.
+					debug_assert!(false);
+					log::error!(
+						target: "peerset",
+						"Not enough slots to connect to reserved node"
+					);
 				}
 			}
 		}
 
 		// Now, we try to connect to other nodes.
-		for set_index in 0..self.data.num_sets() {
-			// Nothing more to do if we're in reserved mode.
-			if self.reserved_nodes[set_index].1 {
-				continue;
+
+		// Nothing more to do if we're in reserved mode.
+		if self.reserved_nodes[set_id.0].1 {
+			return;
+		}
+
+		// Try to grab the next node to attempt to connect to.
+		// Since `highest_not_connected_peer` is rather expensive to call, check beforehand
+		// whether we have an available slot.
+		while self.data.has_free_outgoing_slot(set_id.0) {
+			let next = match self.data.highest_not_connected_peer(set_id.0) {
+				Some(n) => n,
+				None => break
+			};
+
+			// Don't connect to nodes with an abysmal reputation.
+			if next.reputation() < BANNED_THRESHOLD {
+				break;
 			}
 
-			// Try to grab the next node to attempt to connect to.
-			while let Some(next) = self.data.highest_not_connected_peer(set_index) {
-				// Don't connect to nodes with an abysmal reputation.
-				if next.reputation() < BANNED_THRESHOLD {
+			match next.try_outgoing() {
+				Ok(conn) => self.message_queue.push_back(Message::Connect {
+					set_id,
+					peer_id: conn.into_peer_id()
+				}),
+				Err(_) => {
+					// This branch can only be entered if there is no free slot, which is
+					// checked above.
+					debug_assert!(false);
 					break;
 				}
-
-				match next.try_outgoing() {
-					Ok(conn) => self.message_queue.push_back(Message::Connect {
-						set_id: SetId(set_index),
-						peer_id: conn.into_peer_id()
-					}),
-					Err(_) => break,	// No more slots available.
-				}
 			}
 		}
 	}
@@ -624,7 +636,7 @@ impl Peerset {
 			self.on_remove_from_peers_set(set_id, peer_id);
 		}
 
-		self.alloc_slots();
+		self.alloc_slots(set_id);
 	}
 
 	/// Reports an adjustment to the reputation of the given peer.
diff --git a/client/peerset/src/peersstate.rs b/client/peerset/src/peersstate.rs
index c79dac5e10a7b..c200d2729e16c 100644
--- a/client/peerset/src/peersstate.rs
+++ b/client/peerset/src/peersstate.rs
@@ -283,6 +283,11 @@ impl PeersState {
 		}
 	}
 
+	/// Returns `true` if there is a free outgoing slot available related to this set.
+	pub fn has_free_outgoing_slot(&self, set: usize) -> bool {
+		self.sets[set].num_out < self.sets[set].max_out
+	}
+
 	/// Add a node to the list of nodes that don't occupy slots.
 	///
 	/// Has no effect if the node was already in the group.
@@ -506,9 +511,7 @@ impl<'a> NotConnectedPeer<'a> {
 
 		// Note that it is possible for num_out to be strictly superior to the max, in case we were
 		// connected to reserved node then marked them as not reserved.
-		if self.state.sets[self.set].num_out >= self.state.sets[self.set].max_out
-			&& !is_no_slot_occupy
-		{
+		if !self.state.has_free_outgoing_slot(self.set) && !is_no_slot_occupy {
 			return Err(self);
 		}
 
diff --git a/client/rpc/src/chain/chain_light.rs b/client/rpc/src/chain/chain_light.rs
index 41d4d02e33c9d..a3f3db9b7116c 100644
--- a/client/rpc/src/chain/chain_light.rs
+++ b/client/rpc/src/chain/chain_light.rs
@@ -106,7 +106,7 @@ impl<Block, Client, F> ChainBackend<Client, Block> for LightChain<Block, Client,
 					.compat()
 					.map(move |body| Some(SignedBlock {
 						block: Block::new(header, body),
-						justification: None,
+						justifications: None,
 					}))
 					.map_err(client_err)
 				),
diff --git a/client/rpc/src/chain/tests.rs b/client/rpc/src/chain/tests.rs
index 80b990a9fbf03..bb673d65ea0f2 100644
--- a/client/rpc/src/chain/tests.rs
+++ b/client/rpc/src/chain/tests.rs
@@ -67,12 +67,12 @@ fn should_return_a_block() {
 
 	let block = client.new_block(Default::default()).unwrap().build().unwrap().block;
 	let block_hash = block.hash();
-	client.import(BlockOrigin::Own, block).unwrap();
+	executor::block_on(client.import(BlockOrigin::Own, block)).unwrap();
 
 	// Genesis block is not justified
 	assert_matches!(
 		api.block(Some(client.genesis_hash()).into()).wait(),
-		Ok(Some(SignedBlock { justification: None, .. }))
+		Ok(Some(SignedBlock { justifications: None, .. }))
 	);
 
 	assert_matches!(
@@ -133,7 +133,7 @@ fn should_return_block_hash() {
 	);
 
 	let block = client.new_block(Default::default()).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, block.clone()).unwrap();
+	executor::block_on(client.import(BlockOrigin::Own, block.clone())).unwrap();
 
 	assert_matches!(
 		api.block_hash(Some(ListOrValue::Value(0u64.into())).into()),
@@ -167,7 +167,7 @@ fn should_return_finalized_hash() {
 
 	// import new block
 	let block = client.new_block(Default::default()).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, block).unwrap();
+	executor::block_on(client.import(BlockOrigin::Own, block)).unwrap();
 	// no finalization yet
 	assert_matches!(
 		api.finalized_head(),
@@ -199,7 +199,7 @@ fn should_notify_about_latest_block() {
 		));
 
 		let block = client.new_block(Default::default()).unwrap().build().unwrap().block;
-		client.import(BlockOrigin::Own, block).unwrap();
+		executor::block_on(client.import(BlockOrigin::Own, block)).unwrap();
 	}
 
 	// assert initial head sent.
@@ -229,7 +229,7 @@ fn should_notify_about_best_block() {
 		));
 
 		let block = client.new_block(Default::default()).unwrap().build().unwrap().block;
-		client.import(BlockOrigin::Own, block).unwrap();
+		executor::block_on(client.import(BlockOrigin::Own, block)).unwrap();
 	}
 
 	// assert initial head sent.
@@ -259,7 +259,7 @@ fn should_notify_about_finalized_block() {
 		));
 
 		let block = client.new_block(Default::default()).unwrap().build().unwrap().block;
-		client.import(BlockOrigin::Own, block).unwrap();
+		executor::block_on(client.import(BlockOrigin::Own, block)).unwrap();
 		client.finalize_block(BlockId::number(1), None).unwrap();
 	}
 
diff --git a/client/rpc/src/state/tests.rs b/client/rpc/src/state/tests.rs
index 87b0fae1d6b3c..b5d30b3413903 100644
--- a/client/rpc/src/state/tests.rs
+++ b/client/rpc/src/state/tests.rs
@@ -180,7 +180,7 @@ fn should_notify_about_storage_changes() {
 			nonce: 0,
 		}).unwrap();
 		let block = builder.build().unwrap().block;
-		client.import(BlockOrigin::Own, block).unwrap();
+		executor::block_on(client.import(BlockOrigin::Own, block)).unwrap();
 	}
 
 	// assert notification sent to transport
@@ -222,7 +222,7 @@ fn should_send_initial_storage_changes_and_notifications() {
 			nonce: 0,
 		}).unwrap();
 		let block = builder.build().unwrap().block;
-		client.import(BlockOrigin::Own, block).unwrap();
+		executor::block_on(client.import(BlockOrigin::Own, block)).unwrap();
 	}
 
 	// assert initial values sent to transport
@@ -258,7 +258,7 @@ fn should_query_storage() {
 			builder.push_storage_change(vec![5], Some(vec![nonce as u8])).unwrap();
 			let block = builder.build().unwrap().block;
 			let hash = block.header.hash();
-			client.import(BlockOrigin::Own, block).unwrap();
+			executor::block_on(client.import(BlockOrigin::Own, block)).unwrap();
 			hash
 		};
 		let block1_hash = add_block(0);
diff --git a/client/service/Cargo.toml b/client/service/Cargo.toml
index 6ce1ed8b34e14..cff05390d7874 100644
--- a/client/service/Cargo.toml
+++ b/client/service/Cargo.toml
@@ -78,6 +78,7 @@ sp-tracing = { version = "3.0.0", path = "../../primitives/tracing" }
 tracing = "0.1.25"
 tracing-futures = { version = "0.2.4" }
 parity-util-mem = { version = "0.9.0", default-features = false, features = ["primitive-types"] }
+async-trait = "0.1.42"
 
 [target.'cfg(not(target_os = "unknown"))'.dependencies]
 tempfile = "3.1.0"
diff --git a/client/service/src/chain_ops/import_blocks.rs b/client/service/src/chain_ops/import_blocks.rs
index 3f918e05120e9..defa4128702a8 100644
--- a/client/service/src/chain_ops/import_blocks.rs
+++ b/client/service/src/chain_ops/import_blocks.rs
@@ -168,7 +168,7 @@ fn import_block_to_queue<TBl, TImpQu>(
 			hash,
 			header: Some(header),
 			body: Some(extrinsics),
-			justification: signed_block.justification,
+			justifications: signed_block.justifications,
 			origin: None,
 			allow_missing_state: false,
 			import_existing: force,
diff --git a/client/service/src/client/client.rs b/client/service/src/client/client.rs
index 07e8e005fa1a8..f975961c3b4e5 100644
--- a/client/service/src/client/client.rs
+++ b/client/service/src/client/client.rs
@@ -41,7 +41,7 @@ use sc_telemetry::{
 	SUBSTRATE_INFO,
 };
 use sp_runtime::{
-	Justification, BuildStorage,
+	Justification, Justifications, BuildStorage,
 	generic::{BlockId, SignedBlock, DigestItem},
 	traits::{
 		Block as BlockT, Header as HeaderT, Zero, NumberFor,
@@ -625,7 +625,7 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 		let BlockImportParams {
 			origin,
 			header,
-			justification,
+			justifications,
 			post_digests,
 			body,
 			storage_changes,
@@ -637,7 +637,7 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 			..
 		} = import_block;
 
-		assert!(justification.is_some() && finalized || justification.is_none());
+		assert!(justifications.is_some() && finalized || justifications.is_none());
 
 		if !intermediates.is_empty() {
 			return Err(Error::IncompletePipeline)
@@ -665,7 +665,7 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 			origin,
 			hash,
 			import_headers,
-			justification,
+			justifications,
 			body,
 			storage_changes,
 			new_cache,
@@ -704,7 +704,7 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 		origin: BlockOrigin,
 		hash: Block::Hash,
 		import_headers: PrePostHeader<Block::Header>,
-		justification: Option<Justification>,
+		justifications: Option<Justifications>,
 		body: Option<Vec<Block::Extrinsic>>,
 		storage_changes: Option<sp_api::StorageChanges<backend::StateBackendFor<B, Block>, Block>>,
 		new_cache: HashMap<CacheKeyId, Vec<u8>>,
@@ -767,6 +767,7 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 					offchain_sc,
 					tx, _,
 					changes_trie_tx,
+					tx_index,
 				) = storage_changes.into_inner();
 
 				if self.config.offchain_indexing_api {
@@ -775,6 +776,7 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 
 				operation.op.update_db_storage(tx)?;
 				operation.op.update_storage(main_sc.clone(), child_sc.clone())?;
+				operation.op.update_transaction_index(tx_index)?;
 
 				if let Some(changes_trie_transaction) = changes_trie_tx {
 					operation.op.update_changes_trie(changes_trie_transaction)?;
@@ -820,7 +822,7 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 		operation.op.set_block_data(
 			import_headers.post().clone(),
 			body,
-			justification,
+			justifications,
 			leaf_state,
 		)?;
 
@@ -1696,6 +1698,7 @@ impl<B, E, Block, RA> CallApiAt<Block> for Client<B, E, Block, RA> where
 /// NOTE: only use this implementation when you are sure there are NO consensus-level BlockImport
 /// objects. Otherwise, importing blocks directly into the client would be bypassing
 /// important verification work.
+#[async_trait::async_trait]
 impl<B, E, Block, RA> sp_consensus::BlockImport<Block> for &Client<B, E, Block, RA> where
 	B: backend::Backend<Block>,
 	E: CallExecutor<Block> + Send + Sync,
@@ -1703,6 +1706,8 @@ impl<B, E, Block, RA> sp_consensus::BlockImport<Block> for &Client<B, E, Block,
 	Client<B, E, Block, RA>: ProvideRuntimeApi<Block>,
 	<Client<B, E, Block, RA> as ProvideRuntimeApi<Block>>::Api: CoreApi<Block> +
 		ApiExt<Block, StateBackend = B::State>,
+	RA: Sync + Send,
+	backend::TransactionFor<B, Block>: Send + 'static,
 {
 	type Error = ConsensusError;
 	type Transaction = backend::TransactionFor<B, Block>;
@@ -1716,7 +1721,7 @@ impl<B, E, Block, RA> sp_consensus::BlockImport<Block> for &Client<B, E, Block,
 	///
 	/// If you are not sure that there are no BlockImport objects provided by the consensus
 	/// algorithm, don't use this function.
-	fn import_block(
+	async fn import_block(
 		&mut self,
 		mut import_block: BlockImportParams<Block, backend::TransactionFor<B, Block>>,
 		new_cache: HashMap<CacheKeyId, Vec<u8>>,
@@ -1740,7 +1745,7 @@ impl<B, E, Block, RA> sp_consensus::BlockImport<Block> for &Client<B, E, Block,
 	}
 
 	/// Check block preconditions.
-	fn check_block(
+	async fn check_block(
 		&mut self,
 		block: BlockCheckParams<Block>,
 	) -> Result<ImportResult, Self::Error> {
@@ -1796,6 +1801,7 @@ impl<B, E, Block, RA> sp_consensus::BlockImport<Block> for &Client<B, E, Block,
 	}
 }
 
+#[async_trait::async_trait]
 impl<B, E, Block, RA> sp_consensus::BlockImport<Block> for Client<B, E, Block, RA> where
 	B: backend::Backend<Block>,
 	E: CallExecutor<Block> + Send + Sync,
@@ -1803,23 +1809,25 @@ impl<B, E, Block, RA> sp_consensus::BlockImport<Block> for Client<B, E, Block, R
 	Self: ProvideRuntimeApi<Block>,
 	<Self as ProvideRuntimeApi<Block>>::Api: CoreApi<Block> +
 		ApiExt<Block, StateBackend = B::State>,
+	RA: Sync + Send,
+	backend::TransactionFor<B, Block>: Send + 'static,
 {
 	type Error = ConsensusError;
 	type Transaction = backend::TransactionFor<B, Block>;
 
-	fn import_block(
+	async fn import_block(
 		&mut self,
 		import_block: BlockImportParams<Block, Self::Transaction>,
 		new_cache: HashMap<CacheKeyId, Vec<u8>>,
 	) -> Result<ImportResult, Self::Error> {
-		(&*self).import_block(import_block, new_cache)
+		(&*self).import_block(import_block, new_cache).await
 	}
 
-	fn check_block(
+	async fn check_block(
 		&mut self,
 		block: BlockCheckParams<Block>,
 	) -> Result<ImportResult, Self::Error> {
-		(&*self).check_block(block)
+		(&*self).check_block(block).await
 	}
 }
 
@@ -1926,9 +1934,9 @@ impl<B, E, Block, RA> BlockBackend<Block> for Client<B, E, Block, RA>
 	}
 
 	fn block(&self, id: &BlockId<Block>) -> sp_blockchain::Result<Option<SignedBlock<Block>>> {
-		Ok(match (self.header(id)?, self.body(id)?, self.justification(id)?) {
-			(Some(header), Some(extrinsics), justification) =>
-				Some(SignedBlock { block: Block::new(header, extrinsics), justification }),
+		Ok(match (self.header(id)?, self.body(id)?, self.justifications(id)?) {
+			(Some(header), Some(extrinsics), justifications) =>
+				Some(SignedBlock { block: Block::new(header, extrinsics), justifications }),
 			_ => None,
 		})
 	}
@@ -1937,20 +1945,20 @@ impl<B, E, Block, RA> BlockBackend<Block> for Client<B, E, Block, RA>
 		Client::block_status(self, id)
 	}
 
-	fn justification(&self, id: &BlockId<Block>) -> sp_blockchain::Result<Option<Justification>> {
-		self.backend.blockchain().justification(*id)
+	fn justifications(&self, id: &BlockId<Block>) -> sp_blockchain::Result<Option<Justifications>> {
+		self.backend.blockchain().justifications(*id)
 	}
 
 	fn block_hash(&self, number: NumberFor<Block>) -> sp_blockchain::Result<Option<Block::Hash>> {
 		self.backend.blockchain().hash(number)
 	}
 
-	fn extrinsic(&self, hash: &Block::Hash) -> sp_blockchain::Result<Option<Block::Extrinsic>> {
-		self.backend.blockchain().extrinsic(hash)
+	fn indexed_transaction(&self, hash: &Block::Hash) -> sp_blockchain::Result<Option<Vec<u8>>> {
+		self.backend.blockchain().indexed_transaction(hash)
 	}
 
-	fn have_extrinsic(&self, hash: &Block::Hash) -> sp_blockchain::Result<bool> {
-		self.backend.blockchain().have_extrinsic(hash)
+	fn has_indexed_transaction(&self, hash: &Block::Hash) -> sp_blockchain::Result<bool> {
+		self.backend.blockchain().has_indexed_transaction(hash)
 	}
 }
 
diff --git a/client/service/test/Cargo.toml b/client/service/test/Cargo.toml
index e55320d6c5fb7..2108d7e26fa83 100644
--- a/client/service/test/Cargo.toml
+++ b/client/service/test/Cargo.toml
@@ -28,7 +28,7 @@ sp-trie = { version = "3.0.0", path = "../../../primitives/trie" }
 sp-storage = { version = "3.0.0", path = "../../../primitives/storage" }
 sc-client-db = { version = "0.9.0", default-features = false, path = "../../db" }
 futures = { version = "0.3.1", features = ["compat"] }
-sc-service = { version = "0.9.0", default-features = false, features = ["test-helpers"], path = "../../service" }
+sc-service = { version = "0.9.0", features = ["test-helpers"], path = "../../service" }
 sc-network = { version = "0.9.0", path = "../../network" }
 sp-consensus = { version = "0.9.0", path = "../../../primitives/consensus/common" }
 sp-runtime = { version = "3.0.0", path = "../../../primitives/runtime" }
diff --git a/client/service/test/src/client/light.rs b/client/service/test/src/client/light.rs
index f5b2d4aac83d3..a183cbce62bdb 100644
--- a/client/service/test/src/client/light.rs
+++ b/client/service/test/src/client/light.rs
@@ -28,8 +28,9 @@ use sc_light::{
 };
 use std::sync::Arc;
 use sp_runtime::{
-	traits::{BlakeTwo256, HashFor, NumberFor},
-	generic::BlockId, traits::{Block as _, Header as HeaderT}, Digest,
+	generic::BlockId,
+	traits::{BlakeTwo256, Block as _, HashFor, Header as HeaderT, NumberFor},
+	Digest, Justifications,
 };
 use std::collections::HashMap;
 use parking_lot::Mutex;
@@ -374,11 +375,11 @@ fn execution_proof_is_generated_and_checked() {
 	for i in 1u32..3u32 {
 		let mut digest = Digest::default();
 		digest.push(sp_runtime::generic::DigestItem::Other::<H256>(i.to_le_bytes().to_vec()));
-		remote_client.import_justified(
+		futures::executor::block_on(remote_client.import_justified(
 			BlockOrigin::Own,
 			remote_client.new_block(digest).unwrap().build().unwrap().block,
-			Default::default(),
-		).unwrap();
+			Justifications::from((*b"TEST", Default::default())),
+		)).unwrap();
 	}
 
 	// check method that doesn't requires environment
@@ -539,7 +540,7 @@ fn prepare_for_header_proof_check(insert_cht: bool) -> (TestChecker, Hash, Heade
 	let mut local_headers_hashes = Vec::new();
 	for i in 0..4 {
 		let block = remote_client.new_block(Default::default()).unwrap().build().unwrap().block;
-		remote_client.import(BlockOrigin::Own, block).unwrap();
+		futures::executor::block_on(remote_client.import(BlockOrigin::Own, block)).unwrap();
 		local_headers_hashes.push(
 			remote_client.block_hash(i + 1)
 				.map_err(|_| ClientError::Backend("TestError".into()))
diff --git a/client/service/test/src/client/mod.rs b/client/service/test/src/client/mod.rs
index 122782ee51ef5..0234f43513d56 100644
--- a/client/service/test/src/client/mod.rs
+++ b/client/service/test/src/client/mod.rs
@@ -36,8 +36,9 @@ use sc_client_db::{
 };
 use sc_block_builder::BlockBuilderProvider;
 use sc_service::client::{self, Client, LocalCallExecutor, new_in_mem};
-use sp_runtime::traits::{
-	BlakeTwo256, Block as BlockT, Header as HeaderT,
+use sp_runtime::{
+	ConsensusEngineId,
+	traits::{BlakeTwo256, Block as BlockT, Header as HeaderT},
 };
 use substrate_test_runtime::TestAPI;
 use sp_state_machine::backend::Backend as _;
@@ -51,12 +52,15 @@ use sp_consensus::{
 };
 use sp_storage::StorageKey;
 use sp_trie::{TrieConfiguration, trie_types::Layout};
-use sp_runtime::{generic::BlockId, DigestItem};
+use sp_runtime::{generic::BlockId, DigestItem, Justifications};
 use hex_literal::hex;
+use futures::executor::block_on;
 
 mod light;
 mod db;
 
+const TEST_ENGINE_ID: ConsensusEngineId = *b"TEST";
+
 native_executor_instance!(
 	Executor,
 	substrate_test_runtime_client::runtime::api::dispatch,
@@ -105,7 +109,7 @@ pub fn prepare_client_with_key_changes() -> (
 			}).unwrap();
 		}
 		let block = builder.build().unwrap().block;
-		remote_client.import(BlockOrigin::Own, block).unwrap();
+		block_on(remote_client.import(BlockOrigin::Own, block)).unwrap();
 
 		let header = remote_client.header(&BlockId::Number(i as u64 + 1)).unwrap().unwrap();
 		let trie_root = header.digest().log(DigestItem::as_changes_trie_root)
@@ -360,7 +364,7 @@ fn block_builder_works_with_no_transactions() {
 
 	let block = client.new_block(Default::default()).unwrap().build().unwrap().block;
 
-	client.import(BlockOrigin::Own, block).unwrap();
+	block_on(client.import(BlockOrigin::Own, block)).unwrap();
 
 	assert_eq!(client.chain_info().best_number, 1);
 }
@@ -379,7 +383,7 @@ fn block_builder_works_with_transactions() {
 	}).unwrap();
 
 	let block = builder.build().unwrap().block;
-	client.import(BlockOrigin::Own, block).unwrap();
+	block_on(client.import(BlockOrigin::Own, block)).unwrap();
 
 	assert_eq!(client.chain_info().best_number, 1);
 	assert_ne!(
@@ -425,7 +429,7 @@ fn block_builder_does_not_include_invalid() {
 	);
 
 	let block = builder.build().unwrap().block;
-	client.import(BlockOrigin::Own, block).unwrap();
+	block_on(client.import(BlockOrigin::Own, block)).unwrap();
 
 	assert_eq!(client.chain_info().best_number, 1);
 	assert_ne!(
@@ -473,11 +477,11 @@ fn uncles_with_only_ancestors() {
 
 	// G -> A1
 	let a1 = client.new_block(Default::default()).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a1.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a1.clone())).unwrap();
 
 	// A1 -> A2
 	let a2 = client.new_block(Default::default()).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a2.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a2.clone())).unwrap();
 	let v: Vec<H256> = Vec::new();
 	assert_eq!(v, client.uncles(a2.hash(), 3).unwrap());
 }
@@ -493,7 +497,7 @@ fn uncles_with_multiple_forks() {
 
 	// G -> A1
 	let a1 = client.new_block(Default::default()).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a1.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a1.clone())).unwrap();
 
 	// A1 -> A2
 	let a2 = client.new_block_at(
@@ -501,7 +505,7 @@ fn uncles_with_multiple_forks() {
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a2.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a2.clone())).unwrap();
 
 	// A2 -> A3
 	let a3 = client.new_block_at(
@@ -509,7 +513,7 @@ fn uncles_with_multiple_forks() {
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a3.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a3.clone())).unwrap();
 
 	// A3 -> A4
 	let a4 = client.new_block_at(
@@ -517,7 +521,7 @@ fn uncles_with_multiple_forks() {
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a4.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a4.clone())).unwrap();
 
 	// A4 -> A5
 	let a5 = client.new_block_at(
@@ -525,7 +529,7 @@ fn uncles_with_multiple_forks() {
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a5.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a5.clone())).unwrap();
 
 	// A1 -> B2
 	let mut builder = client.new_block_at(
@@ -541,7 +545,7 @@ fn uncles_with_multiple_forks() {
 		nonce: 0,
 	}).unwrap();
 	let b2 = builder.build().unwrap().block;
-	client.import(BlockOrigin::Own, b2.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, b2.clone())).unwrap();
 
 	// B2 -> B3
 	let b3 = client.new_block_at(
@@ -549,7 +553,7 @@ fn uncles_with_multiple_forks() {
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, b3.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, b3.clone())).unwrap();
 
 	// B3 -> B4
 	let b4 = client.new_block_at(
@@ -557,7 +561,7 @@ fn uncles_with_multiple_forks() {
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, b4.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, b4.clone())).unwrap();
 
 	// // B2 -> C3
 	let mut builder = client.new_block_at(
@@ -573,7 +577,7 @@ fn uncles_with_multiple_forks() {
 		nonce: 1,
 	}).unwrap();
 	let c3 = builder.build().unwrap().block;
-	client.import(BlockOrigin::Own, c3.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, c3.clone())).unwrap();
 
 	// A1 -> D2
 	let mut builder = client.new_block_at(
@@ -589,7 +593,7 @@ fn uncles_with_multiple_forks() {
 		nonce: 0,
 	}).unwrap();
 	let d2 = builder.build().unwrap().block;
-	client.import(BlockOrigin::Own, d2.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, d2.clone())).unwrap();
 
 	let genesis_hash = client.chain_info().genesis_hash;
 
@@ -621,11 +625,11 @@ fn best_containing_on_longest_chain_with_single_chain_3_blocks() {
 
 	// G -> A1
 	let a1 = client.new_block(Default::default()).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a1.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a1.clone())).unwrap();
 
 	// A1 -> A2
 	let a2 = client.new_block(Default::default()).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a2.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a2.clone())).unwrap();
 
 	let genesis_hash = client.chain_info().genesis_hash;
 
@@ -645,7 +649,7 @@ fn best_containing_on_longest_chain_with_multiple_forks() {
 
 	// G -> A1
 	let a1 = client.new_block(Default::default()).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a1.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a1.clone())).unwrap();
 
 	// A1 -> A2
 	let a2 = client.new_block_at(
@@ -653,7 +657,7 @@ fn best_containing_on_longest_chain_with_multiple_forks() {
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a2.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a2.clone())).unwrap();
 
 	// A2 -> A3
 	let a3 = client.new_block_at(
@@ -661,7 +665,7 @@ fn best_containing_on_longest_chain_with_multiple_forks() {
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a3.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a3.clone())).unwrap();
 
 	// A3 -> A4
 	let a4 = client.new_block_at(
@@ -669,7 +673,7 @@ fn best_containing_on_longest_chain_with_multiple_forks() {
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a4.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a4.clone())).unwrap();
 
 	// A4 -> A5
 	let a5 = client.new_block_at(
@@ -677,7 +681,7 @@ fn best_containing_on_longest_chain_with_multiple_forks() {
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a5.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a5.clone())).unwrap();
 
 	// A1 -> B2
 	let mut builder = client.new_block_at(
@@ -693,7 +697,7 @@ fn best_containing_on_longest_chain_with_multiple_forks() {
 		nonce: 0,
 	}).unwrap();
 	let b2 = builder.build().unwrap().block;
-	client.import(BlockOrigin::Own, b2.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, b2.clone())).unwrap();
 
 	// B2 -> B3
 	let b3 = client.new_block_at(
@@ -701,7 +705,7 @@ fn best_containing_on_longest_chain_with_multiple_forks() {
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, b3.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, b3.clone())).unwrap();
 
 	// B3 -> B4
 	let b4 = client.new_block_at(
@@ -709,7 +713,7 @@ fn best_containing_on_longest_chain_with_multiple_forks() {
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, b4.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, b4.clone())).unwrap();
 
 	// // B2 -> C3
 	let mut builder = client.new_block_at(
@@ -725,7 +729,7 @@ fn best_containing_on_longest_chain_with_multiple_forks() {
 		nonce: 1,
 	}).unwrap();
 	let c3 = builder.build().unwrap().block;
-	client.import(BlockOrigin::Own, c3.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, c3.clone())).unwrap();
 
 	// A1 -> D2
 	let mut builder = client.new_block_at(
@@ -741,7 +745,7 @@ fn best_containing_on_longest_chain_with_multiple_forks() {
 		nonce: 0,
 	}).unwrap();
 	let d2 = builder.build().unwrap().block;
-	client.import(BlockOrigin::Own, d2.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, d2.clone())).unwrap();
 
 	assert_eq!(client.chain_info().best_hash, a5.hash());
 
@@ -949,11 +953,15 @@ fn best_containing_on_longest_chain_with_multiple_forks() {
 	assert_eq!(None, longest_chain_select.finality_target(
 		b4.hash(), Some(0)).unwrap());
 
-	assert_eq!(None, longest_chain_select.finality_target(
-		c3.hash().clone(), Some(0)).unwrap());
+	assert_eq!(
+		None,
+		longest_chain_select.finality_target(c3.hash().clone(), Some(0)).unwrap(),
+	);
 
-	assert_eq!(None, longest_chain_select.finality_target(
-		d2.hash().clone(), Some(0)).unwrap());
+	assert_eq!(
+		None,
+		longest_chain_select.finality_target(d2.hash().clone(), Some(0)).unwrap(),
+	);
 }
 
 #[test]
@@ -965,15 +973,18 @@ fn best_containing_on_longest_chain_with_max_depth_higher_than_best() {
 
 	// G -> A1
 	let a1 = client.new_block(Default::default()).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a1.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a1.clone())).unwrap();
 
 	// A1 -> A2
 	let a2 = client.new_block(Default::default()).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a2.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a2.clone())).unwrap();
 
 	let genesis_hash = client.chain_info().genesis_hash;
 
-	assert_eq!(a2.hash(), longest_chain_select.finality_target(genesis_hash, Some(10)).unwrap().unwrap());
+	assert_eq!(
+		a2.hash(),
+		longest_chain_select.finality_target(genesis_hash, Some(10)).unwrap().unwrap(),
+	);
 }
 
 #[test]
@@ -1005,7 +1016,7 @@ fn import_with_justification() {
 
 	// G -> A1
 	let a1 = client.new_block(Default::default()).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a1.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a1.clone())).unwrap();
 
 	// A1 -> A2
 	let a2 = client.new_block_at(
@@ -1013,16 +1024,16 @@ fn import_with_justification() {
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a2.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a2.clone())).unwrap();
 
 	// A2 -> A3
-	let justification = vec![1, 2, 3];
+	let justification = Justifications::from((TEST_ENGINE_ID, vec![1, 2, 3]));
 	let a3 = client.new_block_at(
 		&BlockId::Hash(a2.hash()),
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import_justified(BlockOrigin::Own, a3.clone(), justification.clone()).unwrap();
+	block_on(client.import_justified(BlockOrigin::Own, a3.clone(), justification.clone())).unwrap();
 
 	assert_eq!(
 		client.chain_info().finalized_hash,
@@ -1030,17 +1041,17 @@ fn import_with_justification() {
 	);
 
 	assert_eq!(
-		client.justification(&BlockId::Hash(a3.hash())).unwrap(),
+		client.justifications(&BlockId::Hash(a3.hash())).unwrap(),
 		Some(justification),
 	);
 
 	assert_eq!(
-		client.justification(&BlockId::Hash(a1.hash())).unwrap(),
+		client.justifications(&BlockId::Hash(a1.hash())).unwrap(),
 		None,
 	);
 
 	assert_eq!(
-		client.justification(&BlockId::Hash(a2.hash())).unwrap(),
+		client.justifications(&BlockId::Hash(a2.hash())).unwrap(),
 		None,
 	);
 }
@@ -1057,14 +1068,14 @@ fn importing_diverged_finalized_block_should_trigger_reorg() {
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a1.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a1.clone())).unwrap();
 
 	let a2 = client.new_block_at(
 		&BlockId::Hash(a1.hash()),
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a2.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a2.clone())).unwrap();
 
 	let mut b1 = client.new_block_at(
 		&BlockId::Number(0),
@@ -1088,8 +1099,8 @@ fn importing_diverged_finalized_block_should_trigger_reorg() {
 	);
 
 	// importing B1 as finalized should trigger a re-org and set it as new best
-	let justification = vec![1, 2, 3];
-	client.import_justified(BlockOrigin::Own, b1.clone(), justification).unwrap();
+	let justification = Justifications::from((TEST_ENGINE_ID, vec![1, 2, 3]));
+	block_on(client.import_justified(BlockOrigin::Own, b1.clone(), justification)).unwrap();
 
 	assert_eq!(
 		client.chain_info().best_hash,
@@ -1114,14 +1125,14 @@ fn finalizing_diverged_block_should_trigger_reorg() {
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a1.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a1.clone())).unwrap();
 
 	let a2 = client.new_block_at(
 		&BlockId::Hash(a1.hash()),
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a2.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a2.clone())).unwrap();
 
 	let mut b1 = client.new_block_at(
 		&BlockId::Number(0),
@@ -1136,14 +1147,14 @@ fn finalizing_diverged_block_should_trigger_reorg() {
 		nonce: 0,
 	}).unwrap();
 	let b1 = b1.build().unwrap().block;
-	client.import(BlockOrigin::Own, b1.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, b1.clone())).unwrap();
 
 	let b2 = client.new_block_at(
 		&BlockId::Hash(b1.hash()),
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, b2.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, b2.clone())).unwrap();
 
 	// A2 is the current best since it's the longest chain
 	assert_eq!(
@@ -1181,7 +1192,7 @@ fn finalizing_diverged_block_should_trigger_reorg() {
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, b3.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, b3.clone())).unwrap();
 
 	assert_eq!(
 		client.chain_info().best_hash,
@@ -1224,7 +1235,7 @@ fn state_reverted_on_reorg() {
 		nonce: 0,
 	}).unwrap();
 	let a1 = a1.build().unwrap().block;
-	client.import(BlockOrigin::Own, a1.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a1.clone())).unwrap();
 
 	let mut b1 = client.new_block_at(
 		&BlockId::Number(0),
@@ -1239,7 +1250,7 @@ fn state_reverted_on_reorg() {
 	}).unwrap();
 	let b1 = b1.build().unwrap().block;
 	// Reorg to B1
-	client.import_as_best(BlockOrigin::Own, b1.clone()).unwrap();
+	block_on(client.import_as_best(BlockOrigin::Own, b1.clone())).unwrap();
 
 	assert_eq!(950, current_balance(&client));
 	let mut a2 = client.new_block_at(
@@ -1255,7 +1266,7 @@ fn state_reverted_on_reorg() {
 	}).unwrap();
 	let a2 = a2.build().unwrap().block;
 	// Re-org to A2
-	client.import_as_best(BlockOrigin::Own, a2).unwrap();
+	block_on(client.import_as_best(BlockOrigin::Own, a2)).unwrap();
 	assert_eq!(980, current_balance(&client));
 }
 
@@ -1294,14 +1305,14 @@ fn doesnt_import_blocks_that_revert_finality() {
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a1.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a1.clone())).unwrap();
 
 	let a2 = client.new_block_at(
 		&BlockId::Hash(a1.hash()),
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a2.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a2.clone())).unwrap();
 
 	let mut b1 = client.new_block_at(&BlockId::Number(0), Default::default(), false).unwrap();
 
@@ -1313,11 +1324,11 @@ fn doesnt_import_blocks_that_revert_finality() {
 		nonce: 0,
 	}).unwrap();
 	let b1 = b1.build().unwrap().block;
-	client.import(BlockOrigin::Own, b1.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, b1.clone())).unwrap();
 
 	let b2 = client.new_block_at(&BlockId::Hash(b1.hash()), Default::default(), false)
 		.unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, b2.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, b2.clone())).unwrap();
 
 	// prepare B3 before we finalize A2, because otherwise we won't be able to
 	// read changes trie configuration after A2 is finalized
@@ -1328,7 +1339,7 @@ fn doesnt_import_blocks_that_revert_finality() {
 	// B3 at the same height but that doesn't include it
 	ClientExt::finalize_block(&client, BlockId::Hash(a2.hash()), None).unwrap();
 
-	let import_err = client.import(BlockOrigin::Own, b3).err().unwrap();
+	let import_err = block_on(client.import(BlockOrigin::Own, b3)).err().unwrap();
 	let expected_err = ConsensusError::ClientImport(
 		sp_blockchain::Error::RuntimeApiError(
 			sp_api::ApiError::Application(Box::new(sp_blockchain::Error::NotInFinalizedChain))
@@ -1353,7 +1364,7 @@ fn doesnt_import_blocks_that_revert_finality() {
 	}).unwrap();
 	let c1 = c1.build().unwrap().block;
 
-	let import_err = client.import(BlockOrigin::Own, c1).err().unwrap();
+	let import_err = block_on(client.import(BlockOrigin::Own, c1)).err().unwrap();
 	let expected_err = ConsensusError::ClientImport(
 		sp_blockchain::Error::NotInFinalizedChain.to_string()
 	);
@@ -1364,7 +1375,6 @@ fn doesnt_import_blocks_that_revert_finality() {
 	);
 }
 
-
 #[test]
 fn respects_block_rules() {
 	fn run_test(
@@ -1393,7 +1403,7 @@ fn respects_block_rules() {
 			allow_missing_state: false,
 			import_existing: false,
 		};
-		assert_eq!(client.check_block(params).unwrap(), ImportResult::imported(false));
+		assert_eq!(block_on(client.check_block(params)).unwrap(), ImportResult::imported(false));
 
 		// this is 0x0d6d6612a10485370d9e085aeea7ec427fb3f34d961c6a816cdbe5cde2278864
 		let mut block_not_ok = client.new_block_at(&BlockId::Number(0), Default::default(), false)
@@ -1411,11 +1421,11 @@ fn respects_block_rules() {
 		if record_only {
 			known_bad.insert(block_not_ok.hash());
 		} else {
-			assert_eq!(client.check_block(params).unwrap(), ImportResult::KnownBad);
+			assert_eq!(block_on(client.check_block(params)).unwrap(), ImportResult::KnownBad);
 		}
 
 		// Now going to the fork
-		client.import_as_final(BlockOrigin::Own, block_ok).unwrap();
+		block_on(client.import_as_final(BlockOrigin::Own, block_ok)).unwrap();
 
 		// And check good fork
 		let mut block_ok = client.new_block_at(&BlockId::Number(1), Default::default(), false)
@@ -1433,7 +1443,7 @@ fn respects_block_rules() {
 		if record_only {
 			fork_rules.push((1, block_ok.hash().clone()));
 		}
-		assert_eq!(client.check_block(params).unwrap(), ImportResult::imported(false));
+		assert_eq!(block_on(client.check_block(params)).unwrap(), ImportResult::imported(false));
 
 		// And now try bad fork
 		let mut block_not_ok = client.new_block_at(&BlockId::Number(1), Default::default(), false)
@@ -1450,7 +1460,7 @@ fn respects_block_rules() {
 		};
 
 		if !record_only {
-			assert_eq!(client.check_block(params).unwrap(), ImportResult::KnownBad);
+			assert_eq!(block_on(client.check_block(params)).unwrap(), ImportResult::KnownBad);
 		}
 	}
 
@@ -1488,8 +1498,11 @@ fn returns_status_for_pruned_blocks() {
 
 	let mut client = TestClientBuilder::with_backend(backend).build();
 
-	let a1 = client.new_block_at(&BlockId::Number(0), Default::default(), false)
-		.unwrap().build().unwrap().block;
+	let a1 = client.new_block_at(
+		&BlockId::Number(0),
+		Default::default(),
+		false,
+	).unwrap().build().unwrap().block;
 
 	let mut b1 = client.new_block_at(&BlockId::Number(0), Default::default(), false).unwrap();
 
@@ -1510,17 +1523,32 @@ fn returns_status_for_pruned_blocks() {
 		import_existing: false,
 	};
 
-	assert_eq!(client.check_block(check_block_a1.clone()).unwrap(), ImportResult::imported(false));
-	assert_eq!(client.block_status(&BlockId::hash(check_block_a1.hash)).unwrap(), BlockStatus::Unknown);
+	assert_eq!(
+		block_on(client.check_block(check_block_a1.clone())).unwrap(),
+		ImportResult::imported(false),
+	);
+	assert_eq!(
+		client.block_status(&BlockId::hash(check_block_a1.hash)).unwrap(),
+		BlockStatus::Unknown,
+	);
 
-	client.import_as_final(BlockOrigin::Own, a1.clone()).unwrap();
+	block_on(client.import_as_final(BlockOrigin::Own, a1.clone())).unwrap();
 
-	assert_eq!(client.check_block(check_block_a1.clone()).unwrap(), ImportResult::AlreadyInChain);
-	assert_eq!(client.block_status(&BlockId::hash(check_block_a1.hash)).unwrap(), BlockStatus::InChainWithState);
+	assert_eq!(
+		block_on(client.check_block(check_block_a1.clone())).unwrap(),
+		ImportResult::AlreadyInChain,
+	);
+	assert_eq!(
+		client.block_status(&BlockId::hash(check_block_a1.hash)).unwrap(),
+		BlockStatus::InChainWithState,
+	);
 
-	let a2 = client.new_block_at(&BlockId::Hash(a1.hash()), Default::default(), false)
-		.unwrap().build().unwrap().block;
-	client.import_as_final(BlockOrigin::Own, a2.clone()).unwrap();
+	let a2 = client.new_block_at(
+		&BlockId::Hash(a1.hash()),
+		Default::default(),
+		false,
+	).unwrap().build().unwrap().block;
+	block_on(client.import_as_final(BlockOrigin::Own, a2.clone())).unwrap();
 
 	let check_block_a2 = BlockCheckParams {
 		hash: a2.hash().clone(),
@@ -1530,15 +1558,30 @@ fn returns_status_for_pruned_blocks() {
 		import_existing: false,
 	};
 
-	assert_eq!(client.check_block(check_block_a1.clone()).unwrap(), ImportResult::AlreadyInChain);
-	assert_eq!(client.block_status(&BlockId::hash(check_block_a1.hash)).unwrap(), BlockStatus::InChainPruned);
-	assert_eq!(client.check_block(check_block_a2.clone()).unwrap(), ImportResult::AlreadyInChain);
-	assert_eq!(client.block_status(&BlockId::hash(check_block_a2.hash)).unwrap(), BlockStatus::InChainWithState);
+	assert_eq!(
+		block_on(client.check_block(check_block_a1.clone())).unwrap(),
+		ImportResult::AlreadyInChain,
+	);
+	assert_eq!(
+		client.block_status(&BlockId::hash(check_block_a1.hash)).unwrap(),
+		BlockStatus::InChainPruned,
+	);
+	assert_eq!(
+		block_on(client.check_block(check_block_a2.clone())).unwrap(),
+		ImportResult::AlreadyInChain,
+	);
+	assert_eq!(
+		client.block_status(&BlockId::hash(check_block_a2.hash)).unwrap(),
+		BlockStatus::InChainWithState,
+	);
 
-	let a3 = client.new_block_at(&BlockId::Hash(a2.hash()), Default::default(), false)
-		.unwrap().build().unwrap().block;
+	let a3 = client.new_block_at(
+		&BlockId::Hash(a2.hash()),
+		Default::default(),
+		false,
+	).unwrap().build().unwrap().block;
 
-	client.import_as_final(BlockOrigin::Own, a3.clone()).unwrap();
+	block_on(client.import_as_final(BlockOrigin::Own, a3.clone())).unwrap();
 	let check_block_a3 = BlockCheckParams {
 		hash: a3.hash().clone(),
 		number: 2,
@@ -1548,12 +1591,30 @@ fn returns_status_for_pruned_blocks() {
 	};
 
 	// a1 and a2 are both pruned at this point
-	assert_eq!(client.check_block(check_block_a1.clone()).unwrap(), ImportResult::AlreadyInChain);
-	assert_eq!(client.block_status(&BlockId::hash(check_block_a1.hash)).unwrap(), BlockStatus::InChainPruned);
-	assert_eq!(client.check_block(check_block_a2.clone()).unwrap(), ImportResult::AlreadyInChain);
-	assert_eq!(client.block_status(&BlockId::hash(check_block_a2.hash)).unwrap(), BlockStatus::InChainPruned);
-	assert_eq!(client.check_block(check_block_a3.clone()).unwrap(), ImportResult::AlreadyInChain);
-	assert_eq!(client.block_status(&BlockId::hash(check_block_a3.hash)).unwrap(), BlockStatus::InChainWithState);
+	assert_eq!(
+		block_on(client.check_block(check_block_a1.clone())).unwrap(),
+		ImportResult::AlreadyInChain,
+	);
+	assert_eq!(
+		client.block_status(&BlockId::hash(check_block_a1.hash)).unwrap(),
+		BlockStatus::InChainPruned,
+	);
+	assert_eq!(
+		block_on(client.check_block(check_block_a2.clone())).unwrap(),
+		ImportResult::AlreadyInChain,
+	);
+	assert_eq!(
+		client.block_status(&BlockId::hash(check_block_a2.hash)).unwrap(),
+		BlockStatus::InChainPruned,
+	);
+	assert_eq!(
+		block_on(client.check_block(check_block_a3.clone())).unwrap(),
+		ImportResult::AlreadyInChain,
+	);
+	assert_eq!(
+		client.block_status(&BlockId::hash(check_block_a3.hash)).unwrap(),
+		BlockStatus::InChainWithState,
+	);
 
 	let mut check_block_b1 = BlockCheckParams {
 		hash: b1.hash().clone(),
@@ -1562,11 +1623,20 @@ fn returns_status_for_pruned_blocks() {
 		allow_missing_state: false,
 		import_existing: false,
 	};
-	assert_eq!(client.check_block(check_block_b1.clone()).unwrap(), ImportResult::MissingState);
+	assert_eq!(
+		block_on(client.check_block(check_block_b1.clone())).unwrap(),
+		ImportResult::MissingState,
+	);
 	check_block_b1.allow_missing_state = true;
-	assert_eq!(client.check_block(check_block_b1.clone()).unwrap(), ImportResult::imported(false));
+	assert_eq!(
+		block_on(client.check_block(check_block_b1.clone())).unwrap(),
+		ImportResult::imported(false),
+	);
 	check_block_b1.parent_hash = H256::random();
-	assert_eq!(client.check_block(check_block_b1.clone()).unwrap(), ImportResult::UnknownParent);
+	assert_eq!(
+		block_on(client.check_block(check_block_b1.clone())).unwrap(),
+		ImportResult::UnknownParent,
+	);
 }
 
 #[test]
@@ -1597,18 +1667,18 @@ fn imports_blocks_with_changes_tries_config_change() {
 	(1..11).for_each(|number| {
 		let block = client.new_block_at(&BlockId::Number(number - 1), Default::default(), false)
 			.unwrap().build().unwrap().block;
-		client.import(BlockOrigin::Own, block).unwrap();
+		block_on(client.import(BlockOrigin::Own, block)).unwrap();
 	});
 	(11..12).for_each(|number| {
 		let mut block = client.new_block_at(&BlockId::Number(number - 1), Default::default(), false).unwrap();
 		block.push_storage_change(vec![42], Some(number.to_le_bytes().to_vec())).unwrap();
 		let block = block.build().unwrap().block;
-		client.import(BlockOrigin::Own, block).unwrap();
+		block_on(client.import(BlockOrigin::Own, block)).unwrap();
 	});
 	(12..23).for_each(|number| {
 		let block = client.new_block_at(&BlockId::Number(number - 1), Default::default(), false)
 			.unwrap().build().unwrap().block;
-		client.import(BlockOrigin::Own, block).unwrap();
+		block_on(client.import(BlockOrigin::Own, block)).unwrap();
 	});
 	(23..24).for_each(|number| {
 		let mut block = client.new_block_at(&BlockId::Number(number - 1), Default::default(), false).unwrap();
@@ -1617,24 +1687,24 @@ fn imports_blocks_with_changes_tries_config_change() {
 			digest_levels: 1,
 		})).unwrap();
 		let block = block.build().unwrap().block;
-		client.import(BlockOrigin::Own, block).unwrap();
+		block_on(client.import(BlockOrigin::Own, block)).unwrap();
 	});
 	(24..26).for_each(|number| {
 		let mut block = client.new_block_at(&BlockId::Number(number - 1), Default::default(), false).unwrap();
 		block.push_storage_change(vec![42], Some(number.to_le_bytes().to_vec())).unwrap();
 		let block = block.build().unwrap().block;
-		client.import(BlockOrigin::Own, block).unwrap();
+		block_on(client.import(BlockOrigin::Own, block)).unwrap();
 	});
 	(26..27).for_each(|number| {
 		let block = client.new_block_at(&BlockId::Number(number - 1), Default::default(), false)
 			.unwrap().build().unwrap().block;
-		client.import(BlockOrigin::Own, block).unwrap();
+		block_on(client.import(BlockOrigin::Own, block)).unwrap();
 	});
 	(27..28).for_each(|number| {
 		let mut block = client.new_block_at(&BlockId::Number(number - 1), Default::default(), false).unwrap();
 		block.push_storage_change(vec![42], Some(number.to_le_bytes().to_vec())).unwrap();
 		let block = block.build().unwrap().block;
-		client.import(BlockOrigin::Own, block).unwrap();
+		block_on(client.import(BlockOrigin::Own, block)).unwrap();
 	});
 	(28..29).for_each(|number| {
 		let mut block = client.new_block_at(&BlockId::Number(number - 1), Default::default(), false).unwrap();
@@ -1643,23 +1713,23 @@ fn imports_blocks_with_changes_tries_config_change() {
 			digest_levels: 1,
 		})).unwrap();
 		let block = block.build().unwrap().block;
-		client.import(BlockOrigin::Own, block).unwrap();
+		block_on(client.import(BlockOrigin::Own, block)).unwrap();
 	});
 	(29..30).for_each(|number| {
 		let block = client.new_block_at(&BlockId::Number(number - 1), Default::default(), false)
 			.unwrap().build().unwrap().block;
-		client.import(BlockOrigin::Own, block).unwrap();
+		block_on(client.import(BlockOrigin::Own, block)).unwrap();
 	});
 	(30..31).for_each(|number| {
 		let mut block = client.new_block_at(&BlockId::Number(number - 1), Default::default(), false).unwrap();
 		block.push_storage_change(vec![42], Some(number.to_le_bytes().to_vec())).unwrap();
 		let block = block.build().unwrap().block;
-		client.import(BlockOrigin::Own, block).unwrap();
+		block_on(client.import(BlockOrigin::Own, block)).unwrap();
 	});
 	(31..32).for_each(|number| {
 		let block = client.new_block_at(&BlockId::Number(number - 1), Default::default(), false)
 			.unwrap().build().unwrap().block;
-		client.import(BlockOrigin::Own, block).unwrap();
+		block_on(client.import(BlockOrigin::Own, block)).unwrap();
 	});
 
 	// now check that configuration cache works
@@ -1775,7 +1845,7 @@ fn cleans_up_closed_notification_sinks_on_block_import() {
 		let mut import = BlockImportParams::new(origin, header);
 		import.body = Some(extrinsics);
 		import.fork_choice = Some(ForkChoiceStrategy::LongestChain);
-		client.import_block(import, Default::default()).unwrap();
+		block_on(client.import_block(import, Default::default())).unwrap();
 	};
 
 	// after importing a block we should still have 4 notification sinks
@@ -1818,14 +1888,14 @@ fn reorg_triggers_a_notification_even_for_sources_that_should_not_trigger_notifi
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::NetworkInitialSync, a1.clone()).unwrap();
+	block_on(client.import(BlockOrigin::NetworkInitialSync, a1.clone())).unwrap();
 
 	let a2 = client.new_block_at(
 		&BlockId::Hash(a1.hash()),
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::NetworkInitialSync, a2.clone()).unwrap();
+	block_on(client.import(BlockOrigin::NetworkInitialSync, a2.clone())).unwrap();
 
 	let mut b1 = client.new_block_at(
 		&BlockId::Number(0),
@@ -1840,7 +1910,7 @@ fn reorg_triggers_a_notification_even_for_sources_that_should_not_trigger_notifi
 		nonce: 0,
 	}).unwrap();
 	let b1 = b1.build().unwrap().block;
-	client.import(BlockOrigin::NetworkInitialSync, b1.clone()).unwrap();
+	block_on(client.import(BlockOrigin::NetworkInitialSync, b1.clone())).unwrap();
 
 	let b2 = client.new_block_at(
 		&BlockId::Hash(b1.hash()),
@@ -1849,7 +1919,7 @@ fn reorg_triggers_a_notification_even_for_sources_that_should_not_trigger_notifi
 	).unwrap().build().unwrap().block;
 
 	// Should trigger a notification because we reorg
-	client.import_as_best(BlockOrigin::NetworkInitialSync, b2.clone()).unwrap();
+	block_on(client.import_as_best(BlockOrigin::NetworkInitialSync, b2.clone())).unwrap();
 
 	// There should be one notification
 	let notification = notification_stream.next().unwrap();
diff --git a/client/sync-state-rpc/src/lib.rs b/client/sync-state-rpc/src/lib.rs
index 8466523116440..4cb4955995540 100644
--- a/client/sync-state-rpc/src/lib.rs
+++ b/client/sync-state-rpc/src/lib.rs
@@ -37,7 +37,7 @@ type SharedEpochChanges<TBl> = sc_consensus_epochs::SharedEpochChanges<TBl, sc_c
 enum Error<Block: BlockT> {
 	#[error(transparent)]
 	Blockchain(#[from] sp_blockchain::Error),
-	
+
 	#[error("Failed to load the block weight for block {0:?}")]
 	LoadingBlockWeightFailed(<Block as BlockT>::Hash),
 
@@ -94,7 +94,7 @@ impl<TBl, TCl> SyncStateRpcHandler<TBl, TCl>
 			chain_spec, client, shared_authority_set, shared_epoch_changes, deny_unsafe,
 		}
 	}
-	
+
 	fn build_sync_state(&self) -> Result<sc_chain_spec::LightSyncState<TBl>, Error<TBl>> {
 		let finalized_hash = self.client.info().finalized_hash;
 		let finalized_header = self.client.header(BlockId::Hash(finalized_hash))?
@@ -108,7 +108,7 @@ impl<TBl, TCl> SyncStateRpcHandler<TBl, TCl>
 
 		Ok(sc_chain_spec::LightSyncState {
 			finalized_block_header: finalized_header,
-			babe_epoch_changes: self.shared_epoch_changes.lock().clone(),
+			babe_epoch_changes: self.shared_epoch_changes.shared_data().clone(),
 			babe_finalized_block_weight: finalized_block_weight,
 			grandpa_authority_set: self.shared_authority_set.clone_inner(),
 		})
diff --git a/client/telemetry/Cargo.toml b/client/telemetry/Cargo.toml
index ac64d34bea9fe..ab02104c15c35 100644
--- a/client/telemetry/Cargo.toml
+++ b/client/telemetry/Cargo.toml
@@ -18,7 +18,7 @@ targets = ["x86_64-unknown-linux-gnu"]
 parking_lot = "0.11.1"
 futures = "0.3.9"
 wasm-timer = "0.2.5"
-libp2p = { version = "0.35.1", default-features = false, features = ["dns", "tcp-async-io", "wasm-ext", "websocket"] }
+libp2p = { version = "0.36.0", default-features = false, features = ["dns-async-std", "tcp-async-io", "wasm-ext", "websocket"] }
 log = "0.4.8"
 pin-project = "1.0.4"
 rand = "0.7.2"
diff --git a/client/telemetry/src/transport.rs b/client/telemetry/src/transport.rs
index e32a29d9a950d..0aed263a7275d 100644
--- a/client/telemetry/src/transport.rs
+++ b/client/telemetry/src/transport.rs
@@ -17,6 +17,7 @@
 // along with this program. If not, see <https://www.gnu.org/licenses/>.
 
 use futures::{
+	executor::block_on,
 	prelude::*,
 	ready,
 	task::{Context, Poll},
@@ -47,7 +48,7 @@ pub(crate) fn initialize_transport(
 	// an external transport on desktop and the fallback is used all the time.
 	#[cfg(not(target_os = "unknown"))]
 	let transport = transport.or_transport({
-		let inner = libp2p::dns::DnsConfig::new(libp2p::tcp::TcpConfig::new())?;
+		let inner = block_on(libp2p::dns::DnsConfig::system(libp2p::tcp::TcpConfig::new()))?;
 		libp2p::websocket::framed::WsConfig::new(inner).and_then(|connec, _| {
 			let connec = connec
 				.with(|item| {
diff --git a/client/tracing/src/logging/event_format.rs b/client/tracing/src/logging/event_format.rs
index 25fd2f3ba3d70..5e7a5246cca00 100644
--- a/client/tracing/src/logging/event_format.rs
+++ b/client/tracing/src/logging/event_format.rs
@@ -43,6 +43,8 @@ pub struct EventFormat<T = SystemTime> {
 	pub display_thread_name: bool,
 	/// Enable ANSI terminal colors for formatted output.
 	pub enable_color: bool,
+	/// Duplicate INFO, WARN and ERROR messages to stdout.
+	pub dup_to_stdout: bool,
 }
 
 impl<T> EventFormat<T>
@@ -123,7 +125,19 @@ where
 		writer: &mut dyn fmt::Write,
 		event: &Event,
 	) -> fmt::Result {
-		self.format_event_custom(CustomFmtContext::FmtContext(ctx), writer, event)
+		if self.dup_to_stdout && (
+			event.metadata().level() == &Level::INFO ||
+			event.metadata().level() == &Level::WARN ||
+			event.metadata().level() == &Level::ERROR
+		) {
+			let mut out = String::new();
+			self.format_event_custom(CustomFmtContext::FmtContext(ctx), &mut out, event)?;
+			writer.write_str(&out)?;
+			print!("{}", out);
+			Ok(())
+		} else {
+			self.format_event_custom(CustomFmtContext::FmtContext(ctx), writer, event)
+		}
 	}
 }
 
diff --git a/client/tracing/src/logging/mod.rs b/client/tracing/src/logging/mod.rs
index 187b6a387f328..1023879e3d7f0 100644
--- a/client/tracing/src/logging/mod.rs
+++ b/client/tracing/src/logging/mod.rs
@@ -167,6 +167,7 @@ where
 		display_level: !simple,
 		display_thread_name: !simple,
 		enable_color,
+		dup_to_stdout: !atty::is(atty::Stream::Stderr) && atty::is(atty::Stream::Stdout),
 	};
 	let builder = FmtSubscriber::builder().with_env_filter(env_filter);
 
diff --git a/client/transaction-pool/src/testing/pool.rs b/client/transaction-pool/src/testing/pool.rs
index a41632ed8de88..063947b383d03 100644
--- a/client/transaction-pool/src/testing/pool.rs
+++ b/client/transaction-pool/src/testing/pool.rs
@@ -985,7 +985,7 @@ fn import_notification_to_pool_maintain_works() {
 	let mut block_builder = client.new_block(Default::default()).unwrap();
 	block_builder.push(xt).unwrap();
 	let block = block_builder.build().unwrap().block;
-	client.import(BlockOrigin::Own, block).unwrap();
+	block_on(client.import(BlockOrigin::Own, block)).unwrap();
 
 	// Get the notification of the block import and maintain the pool with it,
 	// Now, the pool should not contain any transactions.
diff --git a/docs/CONTRIBUTING.adoc b/docs/CONTRIBUTING.adoc
index 6262ed9086a5e..c0f43f01f4130 100644
--- a/docs/CONTRIBUTING.adoc
+++ b/docs/CONTRIBUTING.adoc
@@ -35,12 +35,21 @@ A PR needs to be reviewed and approved by project maintainers unless:
 
 *Process:*
 
-. Please tag each PR with exactly one `A`, `B` and `C` label at the minimum.
+. Please tag each PR with exactly one `A`, `B`, `C` and `D` label at the minimum.
 . Once a PR is ready for review please add the https://github.com/paritytech/substrate/pulls?q=is%3Apr+is%3Aopen+label%3AA0-pleasereview[`A0-pleasereview`] label. Generally PRs should sit with this label for 48 hours in order to garner feedback. It may be merged before if all relevant parties had a look at it.
 . If the first review is not an approval, swap `A0-pleasereview` to any label `[A3, A7]` to indicate that the PR has received some feedback, but needs further work. For example. https://github.com/paritytech/substrate/labels/A3-inprogress[`A3-inprogress`] is a general indicator that the PR is work in progress and https://github.com/paritytech/substrate/labels/A4-gotissues[`A4-gotissues`] means that it has significant problems that need fixing. Once the work is done, change the label back to `A0-pleasereview`. You might end up swapping a few times back and forth to climb up the A label group. Once a PR is https://github.com/paritytech/substrate/labels/A8-mergeoncegreen[`A8-mergeoncegreen`], it is ready to merge.
-. PRs must be tagged with respect to _release notes_ with https://github.com/paritytech/substrate/labels/B0-silent[`B0-silent`] and `B1-..`. The former indicates that no changes should be mentioned in any release notes. The latter indicates that the changes should be reported in the corresponding release note
-. PRs that break the external API must be tagged with https://github.com/paritytech/substrate/labels/D2-breaksapi[`D2-breaksapi`], when it changes the FRAME or consensus of running system with https://github.com/paritytech/substrate/labels/B3-breaksconsensus[`B3-breaksconsensus`].
-. PRs should be labeled with their release importance via the `C1-C9`.
+. PRs must be tagged with their release notes requirements via the `B1-B9` labels.
+. PRs must be tagged with their release importance via the `C1-C9` labels.
+. PRs must be tagged with their audit requirements via the `D1-D9` labels.
+. PRs that must be backported to a stable branch must be tagged with https://github.com/paritytech/substrate/labels/E1-runtimemigration[`E0-patchthis`].
+. PRs that introduce runtime migrations must be tagged with https://github.com/paritytech/substrate/labels/E1-runtimemigration[`E1-runtimemigration`].
+. PRs that introduce irreversible database migrations must be tagged with https://github.com/paritytech/substrate/labels/E2-databasemigration[`E2-databasemigration`].
+. PRs that add host functions must be tagged with with https://github.com/paritytech/substrate/labels/E4-newhostfunctions[`E4-newhostfunctions`].
+. PRs that break the external API must be tagged with https://github.com/paritytech/substrate/labels/E5-breaksapi[`E5-breaksapi`].
+. PRs that materially change the FRAME/runtime semantics must be tagged with https://github.com/paritytech/substrate/labels/E6-transactionversion[`E6-transactionversion`].
+. PRs that change the mechanism for block authoring in a backwards-incompatible way must be tagged with https://github.com/paritytech/substrate/labels/E7-breaksauthoring[`E7-breaksauthoring`].
+. PRs that "break everything" must be tagged with https://github.com/paritytech/substrate/labels/E8-breakseverything[`E8-breakseverything`].
+. PRs that block a new release must be tagged with https://github.com/paritytech/substrate/labels/E9-blocker%20%E2%9B%94%EF%B8%8F[`E9-blocker`].
 . PRs should be categorized into projects.
 . No PR should be merged until all reviews' comments are addressed and CI is successful.
 
diff --git a/docs/node-template-release.md b/docs/node-template-release.md
new file mode 100644
index 0000000000000..25834ae99f438
--- /dev/null
+++ b/docs/node-template-release.md
@@ -0,0 +1,78 @@
+# Substrate Node Template Release Process
+
+1. This release process has to be run in a github checkout Substrate directory with your work
+committed into `https://github.com/paritytech/substrate/`, because the build script will check
+the existence of your current git commit ID in the remote repository.
+
+	Assume you are in root directory of Substrate. Run:
+
+	```bash
+	cd .maintain/
+	./node-template-release.sh <output tar.gz file>
+	```
+
+2. Expand the output tar gzipped file and replace files in current Substrate Node Template
+by running the following command.
+
+	```bash
+	# This is where the tar.gz file uncompressed
+	cd substrate-node-template
+	# rsync with force copying. Note the slash at the destination directory is important
+	rsync -avh * <destination node-template directory>/
+	# For dry-running add `-n` argument
+	# rsync -avhn * <destination node-template directory>/
+	```
+
+	The above command only copies existing files from the source to the destination, but does not
+	delete files/directories that are removed from the source. So you need to manually check and
+	remove them in the destination.
+
+3. There are actually three packages in the Node Template, `node-template` (the node),
+`node-template-runtime` (the runtime), and `pallet-template`, and each has its own `Cargo.toml`.
+Inside these three files, dependencies are listed in expanded form and linked to a certain git
+commit in Substrate remote repository, such as:
+
+	```toml
+	[dev-dependencies.sp-core]
+	default-features = false
+	git = 'https://github.com/paritytech/substrate.git'
+	rev = 'c1fe59d060600a10eebb4ace277af1fee20bad17'
+	version = '3.0.0'
+	```
+
+	We will update each of them to the shortened form and link them to the Rust
+	[crate registry](https://crates.io/). After confirming the versioned package is published in
+	the crate, the above will become:
+
+	```toml
+	[dev-dependencies]
+	sp-core = { version = '3.0.0', default-features = false }
+	```
+
+	P.S: This step can be automated if we update `node-template-release` package in
+	`.maintain/node-template-release`.
+
+4. Once the three `Cargo.toml`s are updated, compile and confirm that the Node Template builds. Then
+commit the changes to a new branch in [Substrate Node Template](https://github.com/substrate-developer-hub/substrate-node-template), and make a PR.
+
+	> Note that there is a chance the code in Substrate Node Template works with the linked Substrate git
+	commit but not with published packages due to the latest (as yet) unpublished features. In this case,
+	rollback that section of the Node Template to its previous version to ensure the Node Template builds.
+
+5. Once the PR is merged, tag the merged commit in master branch with the version number
+`vX.Y.Z+A` (e.g. `v3.0.0+1`). The `X`(major), `Y`(minor), and `Z`(patch) version number should
+follow Substrate release version. The last digit is any significant fixes made in the Substrate
+Node Template apart from Substrate. When the Substrate version is updated, this digit is reset to 0.
+
+## Troubleshooting
+
+- Running the script `./node-template-release.sh <output tar.gz file>`, after all tests passed
+	successfully, seeing the following error message:
+
+	```
+	thread 'main' panicked at 'Creates output file: Os { code: 2, kind: NotFound, message: "No such file or directory" }', src/main.rs:250:10
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
+	```
+
+	This is likely due to that your output path is not a valid `tar.gz` filename or you don't have write
+	permission to the destination. Try with a simple output path such as `~/node-tpl.tar.gz`.
diff --git a/frame/assets/src/benchmarking.rs b/frame/assets/src/benchmarking.rs
index 42f876ff7f3de..227d45623d688 100644
--- a/frame/assets/src/benchmarking.rs
+++ b/frame/assets/src/benchmarking.rs
@@ -29,7 +29,7 @@ use frame_benchmarking::{
 use frame_support::traits::Get;
 use frame_support::{traits::EnsureOrigin, dispatch::UnfilteredDispatchable};
 
-use crate::Module as Assets;
+use crate::Pallet as Assets;
 
 const SEED: u32 = 0;
 
@@ -120,13 +120,21 @@ fn add_approvals<T: Config>(minter: T::AccountId, n: u32) {
 }
 
 fn assert_last_event<T: Config>(generic_event: <T as Config>::Event) {
-	let events = frame_system::Module::<T>::events();
+	let events = frame_system::Pallet::<T>::events();
 	let system_event: <T as frame_system::Config>::Event = generic_event.into();
 	// compare to the last event record
 	let frame_system::EventRecord { event, .. } = &events[events.len() - 1];
 	assert_eq!(event, &system_event);
 }
 
+fn assert_event<T: Config>(generic_event: <T as Config>::Event) {
+	let system_event: <T as frame_system::Config>::Event = generic_event.into();
+	let events = frame_system::Pallet::<T>::events();
+	assert!(events.iter().any(|event_record| {
+		matches!(&event_record, frame_system::EventRecord { event, .. } if &system_event == event)
+	}));
+}
+
 benchmarks! {
 	create {
 		let caller: T::AccountId = whitelisted_caller();
@@ -193,7 +201,7 @@ benchmarks! {
 		let target_lookup = T::Lookup::unlookup(target.clone());
 	}: _(SystemOrigin::Signed(caller.clone()), Default::default(), target_lookup, amount)
 	verify {
-		assert!(frame_system::Module::<T>::account_exists(&caller));
+		assert!(frame_system::Pallet::<T>::account_exists(&caller));
 		assert_last_event::<T>(Event::Transferred(Default::default(), caller, target, amount).into());
 	}
 
@@ -383,7 +391,8 @@ benchmarks! {
 		let dest_lookup = T::Lookup::unlookup(dest.clone());
 	}: _(SystemOrigin::Signed(delegate.clone()), id, owner_lookup, dest_lookup, amount)
 	verify {
-		assert_last_event::<T>(Event::TransferredApproved(id, owner, delegate, dest, amount).into());
+		assert!(T::Currency::reserved_balance(&owner).is_zero());
+		assert_event::<T>(Event::Transferred(id, owner, dest, amount).into());
 	}
 
 	cancel_approval {
diff --git a/frame/assets/src/extra_mutator.rs b/frame/assets/src/extra_mutator.rs
new file mode 100644
index 0000000000000..26a9a3f357c52
--- /dev/null
+++ b/frame/assets/src/extra_mutator.rs
@@ -0,0 +1,105 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2017-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Datatype for easy mutation of the extra "sidecar" data.
+
+use super::*;
+
+/// A mutator type allowing inspection and possible modification of the extra "sidecar" data.
+///
+/// This may be used as a `Deref` for the pallet's extra data. If mutated (using `DerefMut`), then
+/// any uncommitted changes (see `commit` function) will be automatically committed to storage when
+/// dropped. Changes, even after committed, may be reverted to their original values with the
+/// `revert` function.
+pub struct ExtraMutator<T: Config> {
+	id: T::AssetId,
+	who: T::AccountId,
+	original: T::Extra,
+	pending: Option<T::Extra>,
+}
+
+impl<T: Config> Drop for ExtraMutator<T> {
+	fn drop(&mut self) {
+		debug_assert!(self.commit().is_ok(), "attempt to write to non-existent asset account");
+	}
+}
+
+impl<T: Config> sp_std::ops::Deref for ExtraMutator<T> {
+	type Target = T::Extra;
+	fn deref(&self) -> &T::Extra {
+		match self.pending {
+			Some(ref value) => value,
+			None => &self.original,
+		}
+	}
+}
+
+impl<T: Config> sp_std::ops::DerefMut for ExtraMutator<T> {
+	fn deref_mut(&mut self) -> &mut T::Extra {
+		if self.pending.is_none() {
+			self.pending = Some(self.original.clone());
+		}
+		self.pending.as_mut().unwrap()
+	}
+}
+
+impl<T: Config> ExtraMutator<T> {
+	pub(super) fn maybe_new(id: T::AssetId, who: impl sp_std::borrow::Borrow<T::AccountId>)
+		-> Option<ExtraMutator<T>>
+	{
+		if Account::<T>::contains_key(id, who.borrow()) {
+			Some(ExtraMutator::<T> {
+				id,
+				who: who.borrow().clone(),
+				original: Account::<T>::get(id, who.borrow()).extra,
+				pending: None,
+			})
+		} else {
+			None
+		}
+	}
+
+
+	/// Commit any changes to storage.
+	pub fn commit(&mut self) -> Result<(), ()> {
+		if let Some(extra) = self.pending.take() {
+			Account::<T>::try_mutate_exists(self.id, self.who.borrow(), |maybe_account|
+				if let Some(ref mut account) = maybe_account {
+					account.extra = extra;
+					Ok(())
+				} else {
+					Err(())
+				}
+			)
+		} else {
+			Ok(())
+		}
+	}
+
+	/// Revert any changes, even those already committed by `self` and drop self.
+	pub fn revert(mut self) -> Result<(), ()> {
+		self.pending = None;
+		Account::<T>::try_mutate_exists(self.id, self.who.borrow(), |maybe_account|
+			if let Some(ref mut account) = maybe_account {
+				account.extra = self.original.clone();
+				Ok(())
+			} else {
+				Err(())
+			}
+		)
+	}
+}
diff --git a/frame/assets/src/functions.rs b/frame/assets/src/functions.rs
new file mode 100644
index 0000000000000..197b010b6eb87
--- /dev/null
+++ b/frame/assets/src/functions.rs
@@ -0,0 +1,469 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2017-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Functions for the Assets pallet.
+
+use super::*;
+
+// The main implementation block for the module.
+impl<T: Config> Pallet<T> {
+	// Public immutables
+
+	/// Return the extra "sid-car" data for `id`/`who`, or `None` if the account doesn't exist.
+	pub fn adjust_extra(id: T::AssetId, who: impl sp_std::borrow::Borrow<T::AccountId>)
+		-> Option<ExtraMutator<T>>
+	{
+		ExtraMutator::maybe_new(id, who)
+	}
+
+	/// Get the asset `id` balance of `who`.
+	pub fn balance(id: T::AssetId, who: impl sp_std::borrow::Borrow<T::AccountId>) -> T::Balance {
+		Account::<T>::get(id, who.borrow()).balance
+	}
+
+	/// Get the total supply of an asset `id`.
+	pub fn total_supply(id: T::AssetId) -> T::Balance {
+		Asset::<T>::get(id).map(|x| x.supply).unwrap_or_else(Zero::zero)
+	}
+
+	pub(super) fn new_account(
+		who: &T::AccountId,
+		d: &mut AssetDetails<T::Balance, T::AccountId, DepositBalanceOf<T>>,
+	) -> Result<bool, DispatchError> {
+		let accounts = d.accounts.checked_add(1).ok_or(Error::<T>::Overflow)?;
+		let is_sufficient = if d.is_sufficient {
+			frame_system::Pallet::<T>::inc_sufficients(who);
+			d.sufficients += 1;
+			true
+		} else {
+			frame_system::Pallet::<T>::inc_consumers(who).map_err(|_| Error::<T>::NoProvider)?;
+			false
+		};
+		d.accounts = accounts;
+		Ok(is_sufficient)
+	}
+
+	pub(super) fn dead_account(
+		what: T::AssetId,
+		who: &T::AccountId,
+		d: &mut AssetDetails<T::Balance, T::AccountId, DepositBalanceOf<T>>,
+		sufficient: bool,
+	) {
+		if sufficient {
+			d.sufficients = d.sufficients.saturating_sub(1);
+			frame_system::Pallet::<T>::dec_sufficients(who);
+		} else {
+			frame_system::Pallet::<T>::dec_consumers(who);
+		}
+		d.accounts = d.accounts.saturating_sub(1);
+		T::Freezer::died(what, who)
+	}
+
+	pub(super) fn can_increase(id: T::AssetId, who: &T::AccountId, amount: T::Balance) -> DepositConsequence {
+		let details = match Asset::<T>::get(id) {
+			Some(details) => details,
+			None => return DepositConsequence::UnknownAsset,
+		};
+		if details.supply.checked_add(&amount).is_none() {
+			return DepositConsequence::Overflow
+		}
+		let account = Account::<T>::get(id, who);
+		if account.balance.checked_add(&amount).is_none() {
+			return DepositConsequence::Overflow
+		}
+		if account.balance.is_zero() {
+			if amount < details.min_balance {
+				return DepositConsequence::BelowMinimum
+			}
+			if !details.is_sufficient && frame_system::Pallet::<T>::providers(who) == 0 {
+				return DepositConsequence::CannotCreate
+			}
+			if details.is_sufficient && details.sufficients.checked_add(1).is_none() {
+				return DepositConsequence::Overflow
+			}
+		}
+
+		DepositConsequence::Success
+	}
+
+	/// Return the consequence of a withdraw.
+	pub(super) fn can_decrease(
+		id: T::AssetId,
+		who: &T::AccountId,
+		amount: T::Balance,
+		keep_alive: bool,
+	) -> WithdrawConsequence<T::Balance> {
+		use WithdrawConsequence::*;
+		let details = match Asset::<T>::get(id) {
+			Some(details) => details,
+			None => return UnknownAsset,
+		};
+		if details.supply.checked_sub(&amount).is_none() {
+			return Underflow
+		}
+		if details.is_frozen {
+			return Frozen
+		}
+		let account = Account::<T>::get(id, who);
+		if account.is_frozen {
+			return Frozen
+		}
+		if let Some(rest) = account.balance.checked_sub(&amount) {
+			if let Some(frozen) = T::Freezer::frozen_balance(id, who) {
+				match frozen.checked_add(&details.min_balance) {
+					Some(required) if rest < required => return Frozen,
+					None => return Overflow,
+					_ => {}
+				}
+			}
+
+			let is_provider = false;
+			let is_required = is_provider && !frame_system::Pallet::<T>::can_dec_provider(who);
+			let must_keep_alive = keep_alive || is_required;
+
+			if rest < details.min_balance {
+				if must_keep_alive {
+					WouldDie
+				} else {
+					ReducedToZero(rest)
+				}
+			} else {
+				Success
+			}
+		} else {
+			NoFunds
+		}
+	}
+
+	// Maximum `amount` that can be passed into `can_withdraw` to result in a `WithdrawConsequence`
+	// of `Success`.
+	pub(super) fn reducible_balance(
+		id: T::AssetId,
+		who: &T::AccountId,
+		keep_alive: bool,
+	) -> Result<T::Balance, Error<T>> {
+		let details = match Asset::<T>::get(id) {
+			Some(details) => details,
+			None => return Err(Error::<T>::Unknown),
+		};
+		ensure!(!details.is_frozen, Error::<T>::Frozen);
+
+		let account = Account::<T>::get(id, who);
+		ensure!(!account.is_frozen, Error::<T>::Frozen);
+
+		let amount = if let Some(frozen) = T::Freezer::frozen_balance(id, who) {
+			// Frozen balance: account CANNOT be deleted
+			let required = frozen.checked_add(&details.min_balance).ok_or(Error::<T>::Overflow)?;
+			account.balance.saturating_sub(required)
+		} else {
+			let is_provider = false;
+			let is_required = is_provider && !frame_system::Pallet::<T>::can_dec_provider(who);
+			if keep_alive || is_required {
+				// We want to keep the account around.
+				account.balance.saturating_sub(details.min_balance)
+			} else {
+				// Don't care if the account dies
+				account.balance
+			}
+		};
+		Ok(amount.min(details.supply))
+	}
+
+	/// Make preparatory checks for debiting some funds from an account. Flags indicate requirements
+	/// of the debit.
+	///
+	/// - `amount`: The amount desired to be debited. The actual amount returned for debit may be
+	///   less (in the case of `best_effort` being `true`) or greater by up to the minimum balance
+	///   less one.
+	/// - `keep_alive`: Require that `target` must stay alive.
+	/// - `respect_freezer`: Respect any freezes on the account or token (or not).
+	/// - `best_effort`: The debit amount may be less than `amount`.
+	///
+	/// On success, the amount which should be debited (this will always be at least `amount` unless
+	/// `best_effort` is `true`) together with an optional value indicating the argument which must
+	/// be passed into the `melted` function of the `T::Freezer` if `Some`.
+	///
+	/// If no valid debit can be made then return an `Err`.
+	pub(super) fn prep_debit(
+		id: T::AssetId,
+		target: &T::AccountId,
+		amount: T::Balance,
+		f: DebitFlags,
+	) -> Result<T::Balance, DispatchError> {
+		let actual = Self::reducible_balance(id, target, f.keep_alive)?
+			.min(amount);
+		ensure!(f.best_effort || actual >= amount, Error::<T>::BalanceLow);
+
+		let conseq = Self::can_decrease(id, target, actual, f.keep_alive);
+		let actual = match conseq.into_result() {
+			Ok(dust) => actual.saturating_add(dust), //< guaranteed by reducible_balance
+			Err(e) => {
+				debug_assert!(false, "passed from reducible_balance; qed");
+				return Err(e.into())
+			}
+		};
+
+		Ok(actual)
+	}
+
+	/// Make preparatory checks for crediting some funds from an account. Flags indicate
+	/// requirements of the credit.
+	///
+	/// - `amount`: The amount desired to be credited.
+	/// - `debit`: The amount by which some other account has been debited. If this is greater than
+	///   `amount`, then the `burn_dust` parameter takes effect.
+	/// - `burn_dust`: Indicates that in the case of debit being greater than amount, the additional
+	///   (dust) value should be burned, rather than credited.
+	///
+	/// On success, the amount which should be credited (this will always be at least `amount`)
+	/// together with an optional value indicating the value which should be burned. The latter
+	/// will always be `None` as long as `burn_dust` is `false` or `debit` is no greater than
+	/// `amount`.
+	///
+	/// If no valid credit can be made then return an `Err`.
+	pub(super) fn prep_credit(
+		id: T::AssetId,
+		dest: &T::AccountId,
+		amount: T::Balance,
+		debit: T::Balance,
+		burn_dust: bool,
+	) -> Result<(T::Balance, Option<T::Balance>), DispatchError> {
+		let (credit, maybe_burn) = match (burn_dust, debit.checked_sub(&amount)) {
+			(true, Some(dust)) => (amount, Some(dust)),
+			_ => (debit, None),
+		};
+		Self::can_increase(id, &dest, credit).into_result()?;
+		Ok((credit, maybe_burn))
+	}
+
+	/// Increases the asset `id` balance of `beneficiary` by `amount`.
+	///
+	/// This alters the registered supply of the asset and emits an event.
+	///
+	/// Will return an error or will increase the amount by exactly `amount`.
+	pub(super) fn do_mint(
+		id: T::AssetId,
+		beneficiary: &T::AccountId,
+		amount: T::Balance,
+		maybe_check_issuer: Option<T::AccountId>,
+	) -> DispatchResult {
+		Self::increase_balance(id, beneficiary, amount, |details| -> DispatchResult {
+			if let Some(check_issuer) = maybe_check_issuer {
+				ensure!(&check_issuer == &details.issuer, Error::<T>::NoPermission);
+			}
+			debug_assert!(T::Balance::max_value() - details.supply >= amount, "checked in prep; qed");
+			details.supply = details.supply.saturating_add(amount);
+			Ok(())
+		})?;
+		Self::deposit_event(Event::Issued(id, beneficiary.clone(), amount));
+		Ok(())
+	}
+
+	/// Increases the asset `id` balance of `beneficiary` by `amount`.
+	///
+	/// LOW-LEVEL: Does not alter the supply of asset or emit an event. Use `do_mint` if you need
+	/// that. This is not intended to be used alone.
+	///
+	/// Will return an error or will increase the amount by exactly `amount`.
+	pub(super) fn increase_balance(
+		id: T::AssetId,
+		beneficiary: &T::AccountId,
+		amount: T::Balance,
+		check: impl FnOnce(&mut AssetDetails<T::Balance, T::AccountId, DepositBalanceOf<T>>) -> DispatchResult,
+	) -> DispatchResult {
+		if amount.is_zero() { return Ok(()) }
+
+		Self::can_increase(id, beneficiary, amount).into_result()?;
+		Asset::<T>::try_mutate(id, |maybe_details| -> DispatchResult {
+			let details = maybe_details.as_mut().ok_or(Error::<T>::Unknown)?;
+
+			check(details)?;
+
+			Account::<T>::try_mutate(id, beneficiary, |t| -> DispatchResult {
+				let new_balance = t.balance.saturating_add(amount);
+				ensure!(new_balance >= details.min_balance, TokenError::BelowMinimum);
+				if t.balance.is_zero() {
+					t.sufficient = Self::new_account(beneficiary, details)?;
+				}
+				t.balance = new_balance;
+				Ok(())
+			})?;
+			Ok(())
+		})?;
+		Ok(())
+	}
+
+	/// Reduces asset `id` balance of `target` by `amount`. Flags `f` can be given to alter whether
+	/// it attempts a `best_effort` or makes sure to `keep_alive` the account.
+	///
+	/// This alters the registered supply of the asset and emits an event.
+	///
+	/// Will return an error and do nothing or will decrease the amount and return the amount
+	/// reduced by.
+	pub(super) fn do_burn(
+		id: T::AssetId,
+		target: &T::AccountId,
+		amount: T::Balance,
+		maybe_check_admin: Option<T::AccountId>,
+		f: DebitFlags,
+	) -> Result<T::Balance, DispatchError> {
+		let actual = Self::decrease_balance(id, target, amount, f, |actual, details| {
+			// Check admin rights.
+			if let Some(check_admin) = maybe_check_admin {
+				ensure!(&check_admin == &details.admin, Error::<T>::NoPermission);
+			}
+
+			debug_assert!(details.supply >= actual, "checked in prep; qed");
+			details.supply = details.supply.saturating_sub(actual);
+
+			Ok(())
+		})?;
+		Self::deposit_event(Event::Burned(id, target.clone(), actual));
+		Ok(actual)
+	}
+
+	/// Reduces asset `id` balance of `target` by `amount`. Flags `f` can be given to alter whether
+	/// it attempts a `best_effort` or makes sure to `keep_alive` the account.
+	///
+	/// LOW-LEVEL: Does not alter the supply of asset or emit an event. Use `do_burn` if you need
+	/// that. This is not intended to be used alone.
+	///
+	/// Will return an error and do nothing or will decrease the amount and return the amount
+	/// reduced by.
+	pub(super) fn decrease_balance(
+		id: T::AssetId,
+		target: &T::AccountId,
+		amount: T::Balance,
+		f: DebitFlags,
+		check: impl FnOnce(
+			T::Balance,
+			&mut AssetDetails<T::Balance, T::AccountId, DepositBalanceOf<T>>,
+		) -> DispatchResult,
+	) -> Result<T::Balance, DispatchError> {
+		if amount.is_zero() { return Ok(amount) }
+
+		let actual = Self::prep_debit(id, target, amount, f)?;
+
+		Asset::<T>::try_mutate(id, |maybe_details| -> DispatchResult {
+			let details = maybe_details.as_mut().ok_or(Error::<T>::Unknown)?;
+
+			check(actual, details)?;
+
+			Account::<T>::try_mutate_exists(id, target, |maybe_account| -> DispatchResult {
+				let mut account = maybe_account.take().unwrap_or_default();
+				debug_assert!(account.balance >= actual, "checked in prep; qed");
+
+				// Make the debit.
+				account.balance = account.balance.saturating_sub(actual);
+				*maybe_account = if account.balance < details.min_balance {
+					debug_assert!(account.balance.is_zero(), "checked in prep; qed");
+					Self::dead_account(id, target, details, account.sufficient);
+					None
+				} else {
+					Some(account)
+				};
+				Ok(())
+			})?;
+
+			Ok(())
+		})?;
+
+		Ok(actual)
+	}
+
+	/// Reduces the asset `id` balance of `source` by some `amount` and increases the balance of
+	/// `dest` by (similar) amount.
+	///
+	/// Returns the actual amount placed into `dest`. Exact semantics are determined by the flags
+	/// `f`.
+	///
+	/// Will fail if the amount transferred is so small that it cannot create the destination due
+	/// to minimum balance requirements.
+	pub(super) fn do_transfer(
+		id: T::AssetId,
+		source: &T::AccountId,
+		dest: &T::AccountId,
+		amount: T::Balance,
+		maybe_need_admin: Option<T::AccountId>,
+		f: TransferFlags,
+	) -> Result<T::Balance, DispatchError> {
+		// Early exist if no-op.
+		if amount.is_zero() {
+			Self::deposit_event(Event::Transferred(id, source.clone(), dest.clone(), amount));
+			return Ok(amount)
+		}
+
+		// Figure out the debit and credit, together with side-effects.
+		let debit = Self::prep_debit(id, &source, amount, f.into())?;
+		let (credit, maybe_burn) = Self::prep_credit(id, &dest, amount, debit, f.burn_dust)?;
+
+		let mut source_account = Account::<T>::get(id, &source);
+
+		Asset::<T>::try_mutate(id, |maybe_details| -> DispatchResult {
+			let details = maybe_details.as_mut().ok_or(Error::<T>::Unknown)?;
+
+			// Check admin rights.
+			if let Some(need_admin) = maybe_need_admin {
+				ensure!(&need_admin == &details.admin, Error::<T>::NoPermission);
+			}
+
+			// Skip if source == dest
+			if source == dest {
+				return Ok(())
+			}
+
+			// Burn any dust if needed.
+			if let Some(burn) = maybe_burn {
+				// Debit dust from supply; this will not saturate since it's already checked in prep.
+				debug_assert!(details.supply >= burn, "checked in prep; qed");
+				details.supply = details.supply.saturating_sub(burn);
+			}
+
+			// Debit balance from source; this will not saturate since it's already checked in prep.
+			debug_assert!(source_account.balance >= debit, "checked in prep; qed");
+			source_account.balance = source_account.balance.saturating_sub(debit);
+
+			Account::<T>::try_mutate(id, &dest, |a| -> DispatchResult {
+				// Calculate new balance; this will not saturate since it's already checked in prep.
+				debug_assert!(a.balance.checked_add(&credit).is_some(), "checked in prep; qed");
+				let new_balance = a.balance.saturating_add(credit);
+
+				// Create a new account if there wasn't one already.
+				if a.balance.is_zero() {
+					a.sufficient = Self::new_account(&dest, details)?;
+				}
+
+				a.balance = new_balance;
+				Ok(())
+			})?;
+
+			// Remove source account if it's now dead.
+			if source_account.balance < details.min_balance {
+				debug_assert!(source_account.balance.is_zero(), "checked in prep; qed");
+				Self::dead_account(id, &source, details, source_account.sufficient);
+				Account::<T>::remove(id, &source);
+			} else {
+				Account::<T>::insert(id, &source, &source_account)
+			}
+
+			Ok(())
+		})?;
+
+		Self::deposit_event(Event::Transferred(id, source.clone(), dest.clone(), credit));
+		Ok(credit)
+	}
+}
diff --git a/frame/assets/src/impl_fungibles.rs b/frame/assets/src/impl_fungibles.rs
new file mode 100644
index 0000000000000..a4cff9b7e9a62
--- /dev/null
+++ b/frame/assets/src/impl_fungibles.rs
@@ -0,0 +1,153 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2017-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Implementations for fungibles trait.
+
+use super::*;
+
+impl<T: Config> fungibles::Inspect<<T as SystemConfig>::AccountId> for Pallet<T> {
+	type AssetId = T::AssetId;
+	type Balance = T::Balance;
+
+	fn total_issuance(asset: Self::AssetId) -> Self::Balance {
+		Asset::<T>::get(asset).map(|x| x.supply).unwrap_or_else(Zero::zero)
+	}
+
+	fn minimum_balance(asset: Self::AssetId) -> Self::Balance {
+		Asset::<T>::get(asset).map(|x| x.min_balance).unwrap_or_else(Zero::zero)
+	}
+
+	fn balance(
+		asset: Self::AssetId,
+		who: &<T as SystemConfig>::AccountId,
+	) -> Self::Balance {
+		Pallet::<T>::balance(asset, who)
+	}
+
+	fn reducible_balance(
+		asset: Self::AssetId,
+		who: &<T as SystemConfig>::AccountId,
+		keep_alive: bool,
+	) -> Self::Balance {
+		Pallet::<T>::reducible_balance(asset, who, keep_alive).unwrap_or(Zero::zero())
+	}
+
+	fn can_deposit(
+		asset: Self::AssetId,
+		who: &<T as SystemConfig>::AccountId,
+		amount: Self::Balance,
+	) -> DepositConsequence {
+		Pallet::<T>::can_increase(asset, who, amount)
+	}
+
+	fn can_withdraw(
+		asset: Self::AssetId,
+		who: &<T as SystemConfig>::AccountId,
+		amount: Self::Balance,
+	) -> WithdrawConsequence<Self::Balance> {
+		Pallet::<T>::can_decrease(asset, who, amount, false)
+	}
+}
+
+impl<T: Config> fungibles::Mutate<<T as SystemConfig>::AccountId> for Pallet<T> {
+	fn mint_into(
+		asset: Self::AssetId,
+		who: &<T as SystemConfig>::AccountId,
+		amount: Self::Balance,
+	) -> DispatchResult {
+		Self::do_mint(asset, who, amount, None)
+	}
+
+	fn burn_from(
+		asset: Self::AssetId,
+		who: &<T as SystemConfig>::AccountId,
+		amount: Self::Balance,
+	) -> Result<Self::Balance, DispatchError> {
+		let f = DebitFlags {
+			keep_alive: false,
+			best_effort: false,
+		};
+		Self::do_burn(asset, who, amount, None, f)
+	}
+
+	fn slash(
+		asset: Self::AssetId,
+		who: &<T as SystemConfig>::AccountId,
+		amount: Self::Balance,
+	) -> Result<Self::Balance, DispatchError> {
+		let f = DebitFlags {
+			keep_alive: false,
+			best_effort: true,
+		};
+		Self::do_burn(asset, who, amount, None, f)
+	}
+}
+
+impl<T: Config> fungibles::Transfer<T::AccountId> for Pallet<T> {
+	fn transfer(
+		asset: Self::AssetId,
+		source: &T::AccountId,
+		dest: &T::AccountId,
+		amount: T::Balance,
+		keep_alive: bool,
+	) -> Result<T::Balance, DispatchError> {
+		let f = TransferFlags {
+			keep_alive,
+			best_effort: false,
+			burn_dust: false
+		};
+		Self::do_transfer(asset, source, dest, amount, None, f)
+	}
+}
+
+impl<T: Config> fungibles::Unbalanced<T::AccountId> for Pallet<T> {
+	fn set_balance(_: Self::AssetId, _: &T::AccountId, _: Self::Balance) -> DispatchResult {
+		unreachable!("set_balance is not used if other functions are impl'd");
+	}
+	fn set_total_issuance(id: T::AssetId, amount: Self::Balance) {
+		Asset::<T>::mutate_exists(id, |maybe_asset| if let Some(ref mut asset) = maybe_asset {
+			asset.supply = amount
+		});
+	}
+	fn decrease_balance(asset: T::AssetId, who: &T::AccountId, amount: Self::Balance)
+						-> Result<Self::Balance, DispatchError>
+	{
+		let f = DebitFlags { keep_alive: false, best_effort: false };
+		Self::decrease_balance(asset, who, amount, f, |_, _| Ok(()))
+	}
+	fn decrease_balance_at_most(asset: T::AssetId, who: &T::AccountId, amount: Self::Balance)
+								-> Self::Balance
+	{
+		let f = DebitFlags { keep_alive: false, best_effort: true };
+		Self::decrease_balance(asset, who, amount, f, |_, _| Ok(()))
+			.unwrap_or(Zero::zero())
+	}
+	fn increase_balance(asset: T::AssetId, who: &T::AccountId, amount: Self::Balance)
+						-> Result<Self::Balance, DispatchError>
+	{
+		Self::increase_balance(asset, who, amount, |_| Ok(()))?;
+		Ok(amount)
+	}
+	fn increase_balance_at_most(asset: T::AssetId, who: &T::AccountId, amount: Self::Balance)
+								-> Self::Balance
+	{
+		match Self::increase_balance(asset, who, amount, |_| Ok(())) {
+			Ok(()) => amount,
+			Err(_) => Zero::zero(),
+		}
+	}
+}
diff --git a/frame/assets/src/impl_stored_map.rs b/frame/assets/src/impl_stored_map.rs
new file mode 100644
index 0000000000000..a8a6f95557dfb
--- /dev/null
+++ b/frame/assets/src/impl_stored_map.rs
@@ -0,0 +1,58 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2017-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Assets pallet's `StoredMap` implementation.
+
+use super::*;
+
+impl<T: Config> StoredMap<(T::AssetId, T::AccountId), T::Extra> for Pallet<T> {
+	fn get(id_who: &(T::AssetId, T::AccountId)) -> T::Extra {
+		let &(id, ref who) = id_who;
+		if Account::<T>::contains_key(id, who) {
+			Account::<T>::get(id, who).extra
+		} else {
+			Default::default()
+		}
+	}
+
+	fn try_mutate_exists<R, E: From<StoredMapError>>(
+		id_who: &(T::AssetId, T::AccountId),
+		f: impl FnOnce(&mut Option<T::Extra>) -> Result<R, E>,
+	) -> Result<R, E> {
+		let &(id, ref who) = id_who;
+		let mut maybe_extra = Some(Account::<T>::get(id, who).extra);
+		let r = f(&mut maybe_extra)?;
+		// They want to write some value or delete it.
+		// If the account existed and they want to write a value, then we write.
+		// If the account didn't exist and they want to delete it, then we let it pass.
+		// Otherwise, we fail.
+		Account::<T>::try_mutate_exists(id, who, |maybe_account| {
+			if let Some(extra) = maybe_extra {
+				// They want to write a value. Let this happen only if the account actually exists.
+				if let Some(ref mut account) = maybe_account {
+					account.extra = extra;
+				} else {
+					Err(StoredMapError::NoProviders)?;
+				}
+			} else {
+				// They want to delete it. Let this pass if the item never existed anyway.
+				ensure!(maybe_account.is_none(), StoredMapError::ConsumerRemaining);
+			}
+			Ok(r)
+		})
+	}
+}
diff --git a/frame/assets/src/lib.rs b/frame/assets/src/lib.rs
index e5cb39db2b8e5..2a162c2c936b1 100644
--- a/frame/assets/src/lib.rs
+++ b/frame/assets/src/lib.rs
@@ -130,127 +130,30 @@ pub mod mock;
 #[cfg(test)]
 mod tests;
 
-use sp_std::prelude::*;
+mod extra_mutator;
+pub use extra_mutator::*;
+mod impl_stored_map;
+mod impl_fungibles;
+mod functions;
+mod types;
+pub use types::*;
+
+use sp_std::{prelude::*, borrow::Borrow};
 use sp_runtime::{
-	RuntimeDebug,
-	traits::{
-		AtLeast32BitUnsigned, Zero, StaticLookup, Saturating, CheckedSub, CheckedAdd,
+	RuntimeDebug, TokenError, traits::{
+		AtLeast32BitUnsigned, Zero, StaticLookup, Saturating, CheckedSub, CheckedAdd, Bounded,
+		StoredMapError,
 	}
 };
 use codec::{Encode, Decode, HasCompact};
-use frame_support::{
-	ensure,
-	traits::{Currency, ReservableCurrency, BalanceStatus::Reserved},
-	dispatch::{DispatchError, DispatchResult},
-};
-pub use weights::WeightInfo;
+use frame_support::{ensure, dispatch::{DispatchError, DispatchResult}};
+use frame_support::traits::{Currency, ReservableCurrency, BalanceStatus::Reserved, StoredMap};
+use frame_support::traits::tokens::{WithdrawConsequence, DepositConsequence, fungibles};
+use frame_system::Config as SystemConfig;
 
+pub use weights::WeightInfo;
 pub use pallet::*;
 
-type DepositBalanceOf<T> = <<T as Config>::Currency as Currency<<T as frame_system::Config>::AccountId>>::Balance;
-
-#[derive(Clone, Encode, Decode, Eq, PartialEq, RuntimeDebug)]
-pub struct AssetDetails<
-	Balance,
-	AccountId,
-	DepositBalance,
-> {
-	/// Can change `owner`, `issuer`, `freezer` and `admin` accounts.
-	owner: AccountId,
-	/// Can mint tokens.
-	issuer: AccountId,
-	/// Can thaw tokens, force transfers and burn tokens from any account.
-	admin: AccountId,
-	/// Can freeze tokens.
-	freezer: AccountId,
-	/// The total supply across all accounts.
-	supply: Balance,
-	/// The balance deposited for this asset. This pays for the data stored here.
-	deposit: DepositBalance,
-	/// The ED for virtual accounts.
-	min_balance: Balance,
-	/// If `true`, then any account with this asset is given a provider reference. Otherwise, it
-	/// requires a consumer reference.
-	is_sufficient: bool,
-	/// The total number of accounts.
-	accounts: u32,
-	/// The total number of accounts for which we have placed a self-sufficient reference.
-	sufficients: u32,
-	/// The total number of approvals.
-	approvals: u32,
-	/// Whether the asset is frozen for non-admin transfers.
-	is_frozen: bool,
-}
-
-impl<Balance, AccountId, DepositBalance> AssetDetails<Balance, AccountId, DepositBalance> {
-	pub fn destroy_witness(&self) -> DestroyWitness {
-		DestroyWitness {
-			accounts: self.accounts,
-			sufficients: self.sufficients,
-			approvals: self.approvals,
-		}
-	}
-}
-
-/// A pair to act as a key for the approval storage map.
-#[derive(Clone, Encode, Decode, Eq, PartialEq, RuntimeDebug)]
-pub struct ApprovalKey<AccountId> {
-	/// The owner of the funds that are being approved.
-	owner: AccountId,
-	/// The party to whom transfer of the funds is being delegated.
-	delegate: AccountId,
-}
-
-/// Data concerning an approval.
-#[derive(Clone, Encode, Decode, Eq, PartialEq, RuntimeDebug, Default)]
-pub struct Approval<Balance, DepositBalance> {
-	/// The amount of funds approved for the balance transfer from the owner to some delegated
-	/// target.
-	amount: Balance,
-	/// The amount reserved on the owner's account to hold this item in storage.
-	deposit: DepositBalance,
-}
-
-#[derive(Clone, Encode, Decode, Eq, PartialEq, RuntimeDebug, Default)]
-pub struct AssetBalance<Balance> {
-	/// The balance.
-	balance: Balance,
-	/// Whether the account is frozen.
-	is_frozen: bool,
-	/// `true` if this balance gave the account a self-sufficient reference.
-	sufficient: bool,
-}
-
-#[derive(Clone, Encode, Decode, Eq, PartialEq, RuntimeDebug, Default)]
-pub struct AssetMetadata<DepositBalance> {
-	/// The balance deposited for this metadata.
-	///
-	/// This pays for the data stored in this struct.
-	deposit: DepositBalance,
-	/// The user friendly name of this asset. Limited in length by `StringLimit`.
-	name: Vec<u8>,
-	/// The ticker symbol for this asset. Limited in length by `StringLimit`.
-	symbol: Vec<u8>,
-	/// The number of decimals this asset uses to represent one unit.
-	decimals: u8,
-	/// Whether the asset metadata may be changed by a non Force origin.
-	is_frozen: bool,
-}
-
-/// Witness data for the destroy transactions.
-#[derive(Copy, Clone, Encode, Decode, Eq, PartialEq, RuntimeDebug)]
-pub struct DestroyWitness {
-	/// The number of accounts holding the asset.
-	#[codec(compact)]
-	accounts: u32,
-	/// The number of accounts holding the asset with a self-sufficient reference.
-	#[codec(compact)]
-	sufficients: u32,
-	/// The number of transfer-approvals of the asset.
-	#[codec(compact)]
-	approvals: u32,
-}
-
 #[frame_support::pallet]
 pub mod pallet {
 	use frame_support::{
@@ -273,7 +176,7 @@ pub mod pallet {
 		/// The units in which we record balances.
 		type Balance: Member + Parameter + AtLeast32BitUnsigned + Default + Copy;
 
-		/// The arithmetic type of asset identifier.
+		/// Identifier for the class of asset.
 		type AssetId: Member + Parameter + Default + Copy + HasCompact;
 
 		/// The currency mechanism.
@@ -299,6 +202,13 @@ pub mod pallet {
 		/// The maximum length of a name or symbol stored on-chain.
 		type StringLimit: Get<u32>;
 
+		/// A hook to allow a per-asset, per-account minimum balance to be enforced. This must be
+		/// respected in all permissionless operations.
+		type Freezer: FrozenBalance<Self::AssetId, Self::AccountId, Self::Balance>;
+
+		/// Additional data to be stored with an account's asset balance.
+		type Extra: Member + Parameter + Default;
+
 		/// Weight information for extrinsics in this pallet.
 		type WeightInfo: WeightInfo;
 	}
@@ -320,7 +230,7 @@ pub mod pallet {
 		T::AssetId,
 		Blake2_128Concat,
 		T::AccountId,
-		AssetBalance<T::Balance>,
+		AssetBalance<T::Balance, T::Extra>,
 		ValueQuery,
 	>;
 
@@ -435,8 +345,7 @@ pub mod pallet {
 		///
 		/// The origin must be Signed and the sender must have sufficient funds free.
 		///
-		/// Funds of sender are reserved according to the formula:
-		/// `AssetDepositBase + AssetDepositPerZombie * max_zombies`.
+		/// Funds of sender are reserved by `AssetDeposit`.
 		///
 		/// Parameters:
 		/// - `id`: The identifier of the new asset. This must not be currently in use to identify
@@ -574,7 +483,7 @@ pub mod pallet {
 				ensure!(details.approvals == witness.approvals, Error::<T>::BadWitness);
 
 				for (who, v) in Account::<T>::drain_prefix(id) {
-					Self::dead_account(&who, &mut details, v.sufficient);
+					Self::dead_account(id, &who, &mut details, v.sufficient);
 				}
 				debug_assert_eq!(details.accounts, 0);
 				debug_assert_eq!(details.sufficients, 0);
@@ -611,25 +520,9 @@ pub mod pallet {
 		) -> DispatchResult {
 			let origin = ensure_signed(origin)?;
 			let beneficiary = T::Lookup::lookup(beneficiary)?;
-
-			Asset::<T>::try_mutate(id, |maybe_details| {
-				let details = maybe_details.as_mut().ok_or(Error::<T>::Unknown)?;
-
-				ensure!(&origin == &details.issuer, Error::<T>::NoPermission);
-				details.supply = details.supply.checked_add(&amount).ok_or(Error::<T>::Overflow)?;
-
-				Account::<T>::try_mutate(id, &beneficiary, |t| -> DispatchResult {
-					let new_balance = t.balance.saturating_add(amount);
-					ensure!(new_balance >= details.min_balance, Error::<T>::BalanceLow);
-					if t.balance.is_zero() {
-						t.sufficient = Self::new_account(&beneficiary, details)?;
-					}
-					t.balance = new_balance;
-					Ok(())
-				})?;
-				Self::deposit_event(Event::Issued(id, beneficiary, amount));
-				Ok(())
-			})
+			Self::do_mint(id, &beneficiary, amount, Some(origin))?;
+			Self::deposit_event(Event::Issued(id, beneficiary, amount));
+			Ok(())
 		}
 
 		/// Reduce the balance of `who` by as much as possible up to `amount` assets of `id`.
@@ -657,33 +550,10 @@ pub mod pallet {
 			let origin = ensure_signed(origin)?;
 			let who = T::Lookup::lookup(who)?;
 
-			Asset::<T>::try_mutate(id, |maybe_details| {
-				let d = maybe_details.as_mut().ok_or(Error::<T>::Unknown)?;
-				ensure!(&origin == &d.admin, Error::<T>::NoPermission);
-
-				let burned = Account::<T>::try_mutate_exists(
-					id,
-					&who,
-					|maybe_account| -> Result<T::Balance, DispatchError> {
-						let mut account = maybe_account.take().ok_or(Error::<T>::BalanceZero)?;
-						let mut burned = amount.min(account.balance);
-						account.balance -= burned;
-						*maybe_account = if account.balance < d.min_balance {
-							burned += account.balance;
-							Self::dead_account(&who, d, account.sufficient);
-							None
-						} else {
-							Some(account)
-						};
-						Ok(burned)
-					}
-				)?;
-
-				d.supply = d.supply.saturating_sub(burned);
-
-				Self::deposit_event(Event::Burned(id, who, burned));
-				Ok(())
-			})
+			let f = DebitFlags { keep_alive: false, best_effort: true };
+			let burned = Self::do_burn(id, &who, amount, Some(origin), f)?;
+			Self::deposit_event(Event::Burned(id, who, burned));
+			Ok(())
 		}
 
 		/// Move some assets from the sender account to another.
@@ -714,9 +584,12 @@ pub mod pallet {
 			let origin = ensure_signed(origin)?;
 			let dest = T::Lookup::lookup(target)?;
 
-			Self::do_transfer(id, &origin, &dest, amount, None, false)?;
-			Self::deposit_event(Event::Transferred(id, origin, dest, amount));
-			Ok(())
+			let f = TransferFlags {
+				keep_alive: false,
+				best_effort: false,
+				burn_dust: false
+			};
+			Self::do_transfer(id, &origin, &dest, amount, None, f).map(|_| ())
 		}
 
 		/// Move some assets from the sender account to another, keeping the sender account alive.
@@ -744,12 +617,15 @@ pub mod pallet {
 			target: <T::Lookup as StaticLookup>::Source,
 			#[pallet::compact] amount: T::Balance
 		) -> DispatchResult {
-			let origin = ensure_signed(origin)?;
+			let source = ensure_signed(origin)?;
 			let dest = T::Lookup::lookup(target)?;
 
-			Self::do_transfer(id, &origin, &dest, amount, None, true)?;
-			Self::deposit_event(Event::Transferred(id, origin, dest, amount));
-			Ok(())
+			let f = TransferFlags {
+				keep_alive: true,
+				best_effort: false,
+				burn_dust: false
+			};
+			Self::do_transfer(id, &source, &dest, amount, None, f).map(|_| ())
 		}
 
 		/// Move some assets from one account to another.
@@ -783,9 +659,12 @@ pub mod pallet {
 			let source = T::Lookup::lookup(source)?;
 			let dest = T::Lookup::lookup(dest)?;
 
-			Self::do_transfer(id, &source, &dest, amount, Some(origin), false)?;
-			Self::deposit_event(Event::Transferred(id, source, dest, amount));
-			Ok(())
+			let f = TransferFlags {
+				keep_alive: false,
+				best_effort: false,
+				burn_dust: false
+			};
+			Self::do_transfer(id, &source, &dest, amount, Some(origin), f).map(|_| ())
 		}
 
 		/// Disallow further unprivileged transfers from an account.
@@ -1338,7 +1217,12 @@ pub mod pallet {
 				let mut approved = maybe_approved.take().ok_or(Error::<T>::Unapproved)?;
 				let remaining = approved.amount.checked_sub(&amount).ok_or(Error::<T>::Unapproved)?;
 
-				Self::do_transfer(id, &key.owner, &destination, amount, None, false)?;
+				let f = TransferFlags {
+					keep_alive: false,
+					best_effort: false,
+					burn_dust: false
+				};
+				Self::do_transfer(id, &key.owner, &destination, amount, None, f)?;
 
 				if remaining.is_zero() {
 					T::Currency::unreserve(&key.owner, approved.deposit);
@@ -1348,113 +1232,7 @@ pub mod pallet {
 				}
 				Ok(())
 			})?;
-			let event = Event::TransferredApproved(id, key.owner, key.delegate, destination, amount);
-			Self::deposit_event(event);
 			Ok(())
 		}
 	}
 }
-
-// The main implementation block for the module.
-impl<T: Config> Pallet<T> {
-	// Public immutables
-
-	/// Get the asset `id` balance of `who`.
-	pub fn balance(id: T::AssetId, who: T::AccountId) -> T::Balance {
-		Account::<T>::get(id, who).balance
-	}
-
-	/// Get the total supply of an asset `id`.
-	pub fn total_supply(id: T::AssetId) -> T::Balance {
-		Asset::<T>::get(id).map(|x| x.supply).unwrap_or_else(Zero::zero)
-	}
-
-	fn new_account(
-		who: &T::AccountId,
-		d: &mut AssetDetails<T::Balance, T::AccountId, DepositBalanceOf<T>>,
-	) -> Result<bool, DispatchError> {
-		let accounts = d.accounts.checked_add(1).ok_or(Error::<T>::Overflow)?;
-		let is_sufficient = if d.is_sufficient {
-			frame_system::Module::<T>::inc_sufficients(who);
-			d.sufficients += 1;
-			true
-		} else {
-			frame_system::Module::<T>::inc_consumers(who).map_err(|_| Error::<T>::NoProvider)?;
-			false
-		};
-		d.accounts = accounts;
-		Ok(is_sufficient)
-	}
-
-	fn dead_account(
-		who: &T::AccountId,
-		d: &mut AssetDetails<T::Balance, T::AccountId, DepositBalanceOf<T>>,
-		sufficient: bool,
-	) {
-		if sufficient {
-			d.sufficients = d.sufficients.saturating_sub(1);
-			frame_system::Module::<T>::dec_sufficients(who);
-		} else {
-			frame_system::Module::<T>::dec_consumers(who);
-		}
-		d.accounts = d.accounts.saturating_sub(1);
-	}
-
-	fn do_transfer(
-		id: T::AssetId,
-		source: &T::AccountId,
-		dest: &T::AccountId,
-		amount: T::Balance,
-		maybe_need_admin: Option<T::AccountId>,
-		keep_alive: bool,
-	) -> DispatchResult {
-		let mut source_account = Account::<T>::get(id, source);
-		ensure!(!source_account.is_frozen, Error::<T>::Frozen);
-
-		source_account.balance = source_account.balance.checked_sub(&amount)
-			.ok_or(Error::<T>::BalanceLow)?;
-
-		Asset::<T>::try_mutate(id, |maybe_details| {
-			let details = maybe_details.as_mut().ok_or(Error::<T>::Unknown)?;
-			ensure!(!details.is_frozen, Error::<T>::Frozen);
-
-			if let Some(need_admin) = maybe_need_admin {
-				ensure!(&need_admin == &details.admin, Error::<T>::NoPermission);
-			}
-
-			if dest == source || amount.is_zero() {
-				return Ok(())
-			}
-
-			let mut amount = amount;
-			if source_account.balance < details.min_balance {
-				ensure!(!keep_alive, Error::<T>::WouldDie);
-				amount += source_account.balance;
-				source_account.balance = Zero::zero();
-			}
-
-			Account::<T>::try_mutate(id, dest, |a| -> DispatchResult {
-				let new_balance = a.balance.saturating_add(amount);
-
-				// This is impossible since `new_balance > amount > min_balance`, but we can
-				// handle it, so we do.
-				ensure!(new_balance >= details.min_balance, Error::<T>::BalanceLow);
-
-				if a.balance.is_zero() {
-					a.sufficient = Self::new_account(dest, details)?;
-				}
-				a.balance = new_balance;
-				Ok(())
-			})?;
-
-			if source_account.balance.is_zero() {
-				Self::dead_account(source, details, source_account.sufficient);
-				Account::<T>::remove(id, source);
-			} else {
-				Account::<T>::insert(id, source, &source_account)
-			}
-
-			Ok(())
-		})
-	}
-}
diff --git a/frame/assets/src/mock.rs b/frame/assets/src/mock.rs
index 434a7ccce0757..26ff938512a2f 100644
--- a/frame/assets/src/mock.rs
+++ b/frame/assets/src/mock.rs
@@ -33,9 +33,9 @@ construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
-		Assets: pallet_assets::{Module, Call, Storage, Event<T>},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
+		Assets: pallet_assets::{Pallet, Call, Storage, Event<T>},
 	}
 );
 
@@ -100,7 +100,42 @@ impl Config for Test {
 	type MetadataDepositPerByte = MetadataDepositPerByte;
 	type ApprovalDeposit = ApprovalDeposit;
 	type StringLimit = StringLimit;
+	type Freezer = TestFreezer;
 	type WeightInfo = ();
+	type Extra = ();
+}
+
+use std::cell::RefCell;
+use std::collections::HashMap;
+
+#[derive(Copy, Clone, Eq, PartialEq, Debug)]
+pub(crate) enum Hook {
+	Died(u32, u64),
+}
+thread_local! {
+	static FROZEN: RefCell<HashMap<(u32, u64), u64>> = RefCell::new(Default::default());
+	static HOOKS: RefCell<Vec<Hook>> = RefCell::new(Default::default());
+}
+
+pub struct TestFreezer;
+impl FrozenBalance<u32, u64, u64> for TestFreezer {
+	fn frozen_balance(asset: u32, who: &u64) -> Option<u64> {
+		FROZEN.with(|f| f.borrow().get(&(asset, who.clone())).cloned())
+	}
+
+	fn died(asset: u32, who: &u64) {
+		HOOKS.with(|h| h.borrow_mut().push(Hook::Died(asset, who.clone())));
+	}
+}
+
+pub(crate) fn set_frozen_balance(asset: u32, who: u64, amount: u64) {
+	FROZEN.with(|f| f.borrow_mut().insert((asset, who), amount));
+}
+pub(crate) fn clear_frozen_balance(asset: u32, who: u64) {
+	FROZEN.with(|f| f.borrow_mut().remove(&(asset, who)));
+}
+pub(crate) fn hooks() -> Vec<Hook> {
+	HOOKS.with(|h| h.borrow().clone())
 }
 
 pub(crate) fn new_test_ext() -> sp_io::TestExternalities {
diff --git a/frame/assets/src/tests.rs b/frame/assets/src/tests.rs
index 89173b64d5898..953164a0b9380 100644
--- a/frame/assets/src/tests.rs
+++ b/frame/assets/src/tests.rs
@@ -19,11 +19,12 @@
 
 use super::*;
 use crate::{Error, mock::*};
+use sp_runtime::TokenError;
 use frame_support::{assert_ok, assert_noop, traits::Currency};
 use pallet_balances::Error as BalancesError;
 
 fn last_event() -> mock::Event {
-	frame_system::Module::<Test>::events().pop().expect("Event expected").event
+	frame_system::Pallet::<Test>::events().pop().expect("Event expected").event
 }
 
 #[test]
@@ -198,11 +199,11 @@ fn non_providing_should_work() {
 		assert_ok!(Assets::mint(Origin::signed(1), 0, 0, 100));
 
 		// Cannot mint into account 2 since it doesn't (yet) exist...
-		assert_noop!(Assets::mint(Origin::signed(1), 0, 1, 100), Error::<Test>::NoProvider);
+		assert_noop!(Assets::mint(Origin::signed(1), 0, 1, 100), TokenError::CannotCreate);
 		// ...or transfer...
-		assert_noop!(Assets::transfer(Origin::signed(0), 0, 1, 50), Error::<Test>::NoProvider);
+		assert_noop!(Assets::transfer(Origin::signed(0), 0, 1, 50), TokenError::CannotCreate);
 		// ...or force-transfer
-		assert_noop!(Assets::force_transfer(Origin::signed(1), 0, 0, 1, 50), Error::<Test>::NoProvider);
+		assert_noop!(Assets::force_transfer(Origin::signed(1), 0, 0, 1, 50), TokenError::CannotCreate);
 
 		Balances::make_free_balance_be(&1, 100);
 		Balances::make_free_balance_be(&2, 100);
@@ -219,12 +220,11 @@ fn min_balance_should_work() {
 		assert_eq!(Asset::<Test>::get(0).unwrap().accounts, 1);
 
 		// Cannot create a new account with a balance that is below minimum...
-		assert_noop!(Assets::mint(Origin::signed(1), 0, 2, 9), Error::<Test>::BalanceLow);
-		assert_noop!(Assets::transfer(Origin::signed(1), 0, 2, 9), Error::<Test>::BalanceLow);
-		assert_noop!(Assets::force_transfer(Origin::signed(1), 0, 1, 2, 9), Error::<Test>::BalanceLow);
+		assert_noop!(Assets::mint(Origin::signed(1), 0, 2, 9), TokenError::BelowMinimum);
+		assert_noop!(Assets::transfer(Origin::signed(1), 0, 2, 9), TokenError::BelowMinimum);
+		assert_noop!(Assets::force_transfer(Origin::signed(1), 0, 1, 2, 9), TokenError::BelowMinimum);
 
 		// When deducting from an account to below minimum, it should be reaped.
-
 		assert_ok!(Assets::transfer(Origin::signed(1), 0, 2, 91));
 		assert!(Assets::balance(0, 1).is_zero());
 		assert_eq!(Assets::balance(0, 2), 100);
@@ -277,7 +277,7 @@ fn transferring_enough_to_kill_source_when_keep_alive_should_fail() {
 		assert_ok!(Assets::force_create(Origin::root(), 0, 1, true, 10));
 		assert_ok!(Assets::mint(Origin::signed(1), 0, 1, 100));
 		assert_eq!(Assets::balance(0, 1), 100);
-		assert_noop!(Assets::transfer_keep_alive(Origin::signed(1), 0, 2, 91), Error::<Test>::WouldDie);
+		assert_noop!(Assets::transfer_keep_alive(Origin::signed(1), 0, 2, 91), Error::<Test>::BalanceLow);
 		assert_ok!(Assets::transfer_keep_alive(Origin::signed(1), 0, 2, 90));
 		assert_eq!(Assets::balance(0, 1), 10);
 		assert_eq!(Assets::balance(0, 2), 90);
@@ -430,12 +430,14 @@ fn burning_asset_balance_with_positive_balance_should_work() {
 }
 
 #[test]
-fn burning_asset_balance_with_zero_balance_should_not_work() {
+fn burning_asset_balance_with_zero_balance_does_nothing() {
 	new_test_ext().execute_with(|| {
 		assert_ok!(Assets::force_create(Origin::root(), 0, 1, true, 1));
 		assert_ok!(Assets::mint(Origin::signed(1), 0, 1, 100));
 		assert_eq!(Assets::balance(0, 2), 0);
-		assert_noop!(Assets::burn(Origin::signed(1), 0, 2, u64::max_value()), Error::<Test>::BalanceZero);
+		assert_ok!(Assets::burn(Origin::signed(1), 0, 2, u64::max_value()));
+		assert_eq!(Assets::balance(0, 2), 0);
+		assert_eq!(Assets::total_supply(0), 100);
 	});
 }
 
@@ -491,3 +493,66 @@ fn set_metadata_should_work() {
 }
 
 // TODO: tests for force_set_metadata, force_clear_metadata, force_asset_status
+// https://github.com/paritytech/substrate/issues/8470
+
+#[test]
+fn freezer_should_work() {
+	new_test_ext().execute_with(|| {
+		assert_ok!(Assets::force_create(Origin::root(), 0, 1, true, 10));
+		assert_ok!(Assets::mint(Origin::signed(1), 0, 1, 100));
+		assert_eq!(Assets::balance(0, 1), 100);
+
+
+		// freeze 50 of it.
+		set_frozen_balance(0, 1, 50);
+
+		assert_ok!(Assets::transfer(Origin::signed(1), 0, 2, 20));
+		// cannot transfer another 21 away as this would take the non-frozen balance (30) to below
+		// the minimum balance (10).
+		assert_noop!(Assets::transfer(Origin::signed(1), 0, 2, 21), Error::<Test>::BalanceLow);
+
+		// create an approved transfer...
+		Balances::make_free_balance_be(&1, 100);
+		assert_ok!(Assets::approve_transfer(Origin::signed(1), 0, 2, 50));
+		let e = Error::<Test>::BalanceLow;
+		// ...but that wont work either:
+		assert_noop!(Assets::transfer_approved(Origin::signed(2), 0, 1, 2, 21), e);
+		// a force transfer won't work also.
+		let e = Error::<Test>::BalanceLow;
+		assert_noop!(Assets::force_transfer(Origin::signed(1), 0, 1, 2, 21), e);
+
+		// reduce it to only 49 frozen...
+		set_frozen_balance(0, 1, 49);
+		// ...and it's all good:
+		assert_ok!(Assets::force_transfer(Origin::signed(1), 0, 1, 2, 21));
+
+		// and if we clear it, we can remove the account completely.
+		clear_frozen_balance(0, 1);
+		assert_ok!(Assets::transfer(Origin::signed(1), 0, 2, 50));
+		assert_eq!(hooks(), vec![Hook::Died(0, 1)]);
+	});
+}
+
+#[test]
+fn imbalances_should_work() {
+	use frame_support::traits::tokens::fungibles::Balanced;
+
+	new_test_ext().execute_with(|| {
+		assert_ok!(Assets::force_create(Origin::root(), 0, 1, true, 1));
+
+		let imb = Assets::issue(0, 100);
+		assert_eq!(Assets::total_supply(0), 100);
+		assert_eq!(imb.peek(), 100);
+
+		let (imb1, imb2) = imb.split(30);
+		assert_eq!(imb1.peek(), 30);
+		assert_eq!(imb2.peek(), 70);
+
+		drop(imb2);
+		assert_eq!(Assets::total_supply(0), 30);
+
+		assert!(Assets::resolve(&1, imb1).is_ok());
+		assert_eq!(Assets::balance(0, 1), 30);
+		assert_eq!(Assets::total_supply(0), 30);
+	});
+}
diff --git a/frame/assets/src/types.rs b/frame/assets/src/types.rs
new file mode 100644
index 0000000000000..7e0e235b1b7e6
--- /dev/null
+++ b/frame/assets/src/types.rs
@@ -0,0 +1,186 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2017-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Various basic tyoes for use in the assets pallet.
+
+use super::*;
+
+pub(super) type DepositBalanceOf<T> = <<T as Config>::Currency as Currency<<T as SystemConfig>::AccountId>>::Balance;
+
+#[derive(Clone, Encode, Decode, Eq, PartialEq, RuntimeDebug)]
+pub struct AssetDetails<
+	Balance,
+	AccountId,
+	DepositBalance,
+> {
+	/// Can change `owner`, `issuer`, `freezer` and `admin` accounts.
+	pub(super) owner: AccountId,
+	/// Can mint tokens.
+	pub(super) issuer: AccountId,
+	/// Can thaw tokens, force transfers and burn tokens from any account.
+	pub(super) admin: AccountId,
+	/// Can freeze tokens.
+	pub(super) freezer: AccountId,
+	/// The total supply across all accounts.
+	pub(super) supply: Balance,
+	/// The balance deposited for this asset. This pays for the data stored here.
+	pub(super) deposit: DepositBalance,
+	/// The ED for virtual accounts.
+	pub(super) min_balance: Balance,
+	/// If `true`, then any account with this asset is given a provider reference. Otherwise, it
+	/// requires a consumer reference.
+	pub(super) is_sufficient: bool,
+	/// The total number of accounts.
+	pub(super) accounts: u32,
+	/// The total number of accounts for which we have placed a self-sufficient reference.
+	pub(super) sufficients: u32,
+	/// The total number of approvals.
+	pub(super) approvals: u32,
+	/// Whether the asset is frozen for non-admin transfers.
+	pub(super) is_frozen: bool,
+}
+
+impl<Balance, AccountId, DepositBalance> AssetDetails<Balance, AccountId, DepositBalance> {
+	pub fn destroy_witness(&self) -> DestroyWitness {
+		DestroyWitness {
+			accounts: self.accounts,
+			sufficients: self.sufficients,
+			approvals: self.approvals,
+		}
+	}
+}
+
+/// A pair to act as a key for the approval storage map.
+#[derive(Clone, Encode, Decode, Eq, PartialEq, RuntimeDebug)]
+pub struct ApprovalKey<AccountId> {
+	/// The owner of the funds that are being approved.
+	pub(super) owner: AccountId,
+	/// The party to whom transfer of the funds is being delegated.
+	pub(super) delegate: AccountId,
+}
+
+/// Data concerning an approval.
+#[derive(Clone, Encode, Decode, Eq, PartialEq, RuntimeDebug, Default)]
+pub struct Approval<Balance, DepositBalance> {
+	/// The amount of funds approved for the balance transfer from the owner to some delegated
+	/// target.
+	pub(super) amount: Balance,
+	/// The amount reserved on the owner's account to hold this item in storage.
+	pub(super) deposit: DepositBalance,
+}
+
+#[derive(Clone, Encode, Decode, Eq, PartialEq, RuntimeDebug, Default)]
+pub struct AssetBalance<Balance, Extra> {
+	/// The balance.
+	pub(super) balance: Balance,
+	/// Whether the account is frozen.
+	pub(super) is_frozen: bool,
+	/// `true` if this balance gave the account a self-sufficient reference.
+	pub(super) sufficient: bool,
+	/// Additional "sidecar" data, in case some other pallet wants to use this storage item.
+	pub(super) extra: Extra,
+}
+
+#[derive(Clone, Encode, Decode, Eq, PartialEq, RuntimeDebug, Default)]
+pub struct AssetMetadata<DepositBalance> {
+	/// The balance deposited for this metadata.
+	///
+	/// This pays for the data stored in this struct.
+	pub(super) deposit: DepositBalance,
+	/// The user friendly name of this asset. Limited in length by `StringLimit`.
+	pub(super) name: Vec<u8>,
+	/// The ticker symbol for this asset. Limited in length by `StringLimit`.
+	pub(super) symbol: Vec<u8>,
+	/// The number of decimals this asset uses to represent one unit.
+	pub(super) decimals: u8,
+	/// Whether the asset metadata may be changed by a non Force origin.
+	pub(super) is_frozen: bool,
+}
+
+/// Witness data for the destroy transactions.
+#[derive(Copy, Clone, Encode, Decode, Eq, PartialEq, RuntimeDebug)]
+pub struct DestroyWitness {
+	/// The number of accounts holding the asset.
+	#[codec(compact)]
+	pub(super) accounts: u32,
+	/// The number of accounts holding the asset with a self-sufficient reference.
+	#[codec(compact)]
+	pub(super) sufficients: u32,
+	/// The number of transfer-approvals of the asset.
+	#[codec(compact)]
+	pub(super) approvals: u32,
+}
+
+/// Trait for allowing a minimum balance on the account to be specified, beyond the
+/// `minimum_balance` of the asset. This is additive - the `minimum_balance` of the asset must be
+/// met *and then* anything here in addition.
+pub trait FrozenBalance<AssetId, AccountId, Balance> {
+	/// Return the frozen balance. Under normal behaviour, this amount should always be
+	/// withdrawable.
+	///
+	/// In reality, the balance of every account must be at least the sum of this (if `Some`) and
+	/// the asset's minimum_balance, since there may be complications to destroying an asset's
+	/// account completely.
+	///
+	/// If `None` is returned, then nothing special is enforced.
+	///
+	/// If any operation ever breaks this requirement (which will only happen through some sort of
+	/// privileged intervention), then `melted` is called to do any cleanup.
+	fn frozen_balance(asset: AssetId, who: &AccountId) -> Option<Balance>;
+
+	/// Called when an account has been removed.
+	fn died(asset: AssetId, who: &AccountId);
+}
+
+impl<AssetId, AccountId, Balance> FrozenBalance<AssetId, AccountId, Balance> for () {
+	fn frozen_balance(_: AssetId, _: &AccountId) -> Option<Balance> { None }
+	fn died(_: AssetId, _: &AccountId) {}
+}
+
+#[derive(Copy, Clone, PartialEq, Eq)]
+pub(super) struct TransferFlags {
+	/// The debited account must stay alive at the end of the operation; an error is returned if
+	/// this cannot be achieved legally.
+	pub(super) keep_alive: bool,
+	/// Less than the amount specified needs be debited by the operation for it to be considered
+	/// successful. If `false`, then the amount debited will always be at least the amount
+	/// specified.
+	pub(super) best_effort: bool,
+	/// Any additional funds debited (due to minimum balance requirements) should be burned rather
+	/// than credited to the destination account.
+	pub(super) burn_dust: bool,
+}
+
+#[derive(Copy, Clone, PartialEq, Eq)]
+pub(super) struct DebitFlags {
+	/// The debited account must stay alive at the end of the operation; an error is returned if
+	/// this cannot be achieved legally.
+	pub(super) keep_alive: bool,
+	/// Less than the amount specified needs be debited by the operation for it to be considered
+	/// successful. If `false`, then the amount debited will always be at least the amount
+	/// specified.
+	pub(super) best_effort: bool,
+}
+
+impl From<TransferFlags> for DebitFlags {
+	fn from(f: TransferFlags) -> Self {
+		Self {
+			keep_alive: f.keep_alive,
+			best_effort: f.best_effort,
+		}
+	}
+}
diff --git a/frame/atomic-swap/src/lib.rs b/frame/atomic-swap/src/lib.rs
index e6d44d73c40d2..513a9343a72e1 100644
--- a/frame/atomic-swap/src/lib.rs
+++ b/frame/atomic-swap/src/lib.rs
@@ -17,15 +17,15 @@
 
 //! # Atomic Swap
 //!
-//! A module for atomically sending funds.
+//! A pallet for atomically sending funds.
 //!
-//! - [`atomic_swap::Config`](./trait.Config.html)
-//! - [`Call`](./enum.Call.html)
-//! - [`Module`](./struct.Module.html)
+//! - [`Config`]
+//! - [`Call`]
+//! - [`Pallet`]
 //!
 //! ## Overview
 //!
-//! A module for atomically sending funds from an origin to a target. A proof
+//! A pallet for atomically sending funds from an origin to a target. A proof
 //! is used to allow the target to approve (claim) the swap. If the swap is not
 //! claimed within a specified duration of time, the sender may cancel it.
 //!
@@ -33,9 +33,9 @@
 //!
 //! ### Dispatchable Functions
 //!
-//! * `create_swap` - called by a sender to register a new atomic swap
-//! * `claim_swap` - called by the target to approve a swap
-//! * `cancel_swap` - may be called by a sender after a specified duration
+//! * [`create_swap`](Call::create_swap) - called by a sender to register a new atomic swap
+//! * [`claim_swap`](Call::claim_swap) - called by the target to approve a swap
+//! * [`cancel_swap`](Call::cancel_swap) - may be called by a sender after a specified duration
 
 // Ensure we're `no_std` when compiling for Wasm.
 #![cfg_attr(not(feature = "std"), no_std)]
@@ -45,17 +45,16 @@ mod tests;
 use sp_std::{prelude::*, marker::PhantomData, ops::{Deref, DerefMut}};
 use sp_io::hashing::blake2_256;
 use frame_support::{
-	Parameter, decl_module, decl_storage, decl_event, decl_error, ensure,
+	RuntimeDebugNoBound,
 	traits::{Get, Currency, ReservableCurrency, BalanceStatus},
 	weights::Weight,
 	dispatch::DispatchResult,
 };
-use frame_system::{self as system, ensure_signed};
 use codec::{Encode, Decode};
 use sp_runtime::RuntimeDebug;
 
 /// Pending atomic swap operation.
-#[derive(Clone, Eq, PartialEq, RuntimeDebug, Encode, Decode)]
+#[derive(Clone, Eq, PartialEq, RuntimeDebugNoBound, Encode, Decode)]
 pub struct PendingSwap<T: Config> {
 	/// Source of the swap.
 	pub source: T::AccountId,
@@ -135,35 +134,50 @@ impl<T: Config, AccountId, C> SwapAction<AccountId, T> for BalanceSwapAction<Acc
 	}
 }
 
-/// Atomic swap's pallet configuration trait.
-pub trait Config: frame_system::Config {
-	/// The overarching event type.
-	type Event: From<Event<Self>> + Into<<Self as frame_system::Config>::Event>;
-	/// Swap action.
-	type SwapAction: SwapAction<Self::AccountId, Self> + Parameter;
-	/// Limit of proof size.
-	///
-	/// Atomic swap is only atomic if once the proof is revealed, both parties can submit the proofs
-	/// on-chain. If A is the one that generates the proof, then it requires that either:
-	/// - A's blockchain has the same proof length limit as B's blockchain.
-	/// - Or A's blockchain has shorter proof length limit as B's blockchain.
-	///
-	/// If B sees A is on a blockchain with larger proof length limit, then it should kindly refuse
-	/// to accept the atomic swap request if A generates the proof, and asks that B generates the
-	/// proof instead.
-	type ProofLimit: Get<u32>;
-}
-
-decl_storage! {
-	trait Store for Module<T: Config> as AtomicSwap {
-		pub PendingSwaps: double_map
-			hasher(twox_64_concat) T::AccountId, hasher(blake2_128_concat) HashedProof
-			=> Option<PendingSwap<T>>;
+pub use pallet::*;
+
+#[frame_support::pallet]
+pub mod pallet {
+	use frame_support::pallet_prelude::*;
+	use frame_system::pallet_prelude::*;
+	use super::*;
+
+	/// Atomic swap's pallet configuration trait.
+	#[pallet::config]
+	pub trait Config: frame_system::Config {
+		/// The overarching event type.
+		type Event: From<Event<Self>> + IsType<<Self as frame_system::Config>::Event>;
+		/// Swap action.
+		type SwapAction: SwapAction<Self::AccountId, Self> + Parameter;
+		/// Limit of proof size.
+		///
+		/// Atomic swap is only atomic if once the proof is revealed, both parties can submit the proofs
+		/// on-chain. If A is the one that generates the proof, then it requires that either:
+		/// - A's blockchain has the same proof length limit as B's blockchain.
+		/// - Or A's blockchain has shorter proof length limit as B's blockchain.
+		///
+		/// If B sees A is on a blockchain with larger proof length limit, then it should kindly refuse
+		/// to accept the atomic swap request if A generates the proof, and asks that B generates the
+		/// proof instead.
+		type ProofLimit: Get<u32>;
 	}
-}
 
-decl_error! {
-	pub enum Error for Module<T: Config> {
+	#[pallet::pallet]
+	#[pallet::generate_store(pub(super) trait Store)]
+	pub struct Pallet<T>(PhantomData<T>);
+
+	#[pallet::storage]
+	pub type PendingSwaps<T: Config> = StorageDoubleMap<_,
+		Twox64Concat, T::AccountId,
+		Blake2_128Concat, HashedProof,
+		PendingSwap<T>,
+	>;
+
+	#[pallet::hooks]
+	impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {}
+
+	#[pallet::error]
+	pub enum Error<T> {
 		/// Swap already exists.
 		AlreadyExist,
 		/// Swap proof is invalid.
@@ -181,31 +195,27 @@ decl_error! {
 		/// Duration has not yet passed for the swap to be cancelled.
 		DurationNotPassed,
 	}
-}
 
-decl_event!(
 	/// Event of atomic swap pallet.
-	pub enum Event<T> where
-		AccountId = <T as system::Config>::AccountId,
-		PendingSwap = PendingSwap<T>,
-	{
+	#[pallet::event]
+	#[pallet::metadata(T::AccountId = "AccountId", PendingSwap<T> = "PendingSwap")]
+	#[pallet::generate_deposit(pub(super) fn deposit_event)]
+	pub enum Event<T: Config> {
 		/// Swap created. \[account, proof, swap\]
-		NewSwap(AccountId, HashedProof, PendingSwap),
-		/// Swap claimed. The last parameter indicates whether the execution succeeds. 
+		NewSwap(T::AccountId, HashedProof, PendingSwap<T>),
+		/// Swap claimed. The last parameter indicates whether the execution succeeds.
 		/// \[account, proof, success\]
-		SwapClaimed(AccountId, HashedProof, bool),
+		SwapClaimed(T::AccountId, HashedProof, bool),
 		/// Swap cancelled. \[account, proof\]
-		SwapCancelled(AccountId, HashedProof),
+		SwapCancelled(T::AccountId, HashedProof),
 	}
-);
-
-decl_module! {
-	/// Module definition of atomic swap pallet.
-	pub struct Module<T: Config> for enum Call where origin: T::Origin {
-		type Error = Error<T>;
 
-		fn deposit_event() = default;
+	/// Old name generated by `decl_event`.
+	#[deprecated(note="use `Event` instead")]
+	pub type RawEvent<T> = Event<T>;
 
+	#[pallet::call]
+	impl<T: Config> Pallet<T> {
 		/// Register a new atomic swap, declaring an intention to send funds from origin to target
 		/// on the current blockchain. The target can claim the fund using the revealed proof. If
 		/// the fund is not claimed after `duration` blocks, then the sender can cancel the swap.
@@ -218,14 +228,14 @@ decl_module! {
 		/// - `duration`: Locked duration of the atomic swap. For safety reasons, it is recommended
 		///   that the revealer uses a shorter duration than the counterparty, to prevent the
 		///   situation where the revealer reveals the proof too late around the end block.
-		#[weight = T::DbWeight::get().reads_writes(1, 1).saturating_add(40_000_000)]
-		fn create_swap(
-			origin,
+		#[pallet::weight(T::DbWeight::get().reads_writes(1, 1).saturating_add(40_000_000))]
+		pub(crate) fn create_swap(
+			origin: OriginFor<T>,
 			target: T::AccountId,
 			hashed_proof: HashedProof,
 			action: T::SwapAction,
 			duration: T::BlockNumber,
-		) {
+		) -> DispatchResult {
 			let source = ensure_signed(origin)?;
 			ensure!(
 				!PendingSwaps::<T>::contains_key(&target, hashed_proof),
@@ -237,13 +247,15 @@ decl_module! {
 			let swap = PendingSwap {
 				source,
 				action,
-				end_block: frame_system::Module::<T>::block_number() + duration,
+				end_block: frame_system::Pallet::<T>::block_number() + duration,
 			};
 			PendingSwaps::<T>::insert(target.clone(), hashed_proof.clone(), swap.clone());
 
 			Self::deposit_event(
-				RawEvent::NewSwap(target, hashed_proof, swap)
+				Event::NewSwap(target, hashed_proof, swap)
 			);
+
+			Ok(())
 		}
 
 		/// Claim an atomic swap.
@@ -253,13 +265,14 @@ decl_module! {
 		/// - `proof`: Revealed proof of the claim.
 		/// - `action`: Action defined in the swap, it must match the entry in blockchain. Otherwise
 		///   the operation fails. This is used for weight calculation.
-		#[weight = T::DbWeight::get().reads_writes(1, 1)
-		  .saturating_add(40_000_000)
-		  .saturating_add((proof.len() as Weight).saturating_mul(100))
-		  .saturating_add(action.weight())
-		]
-		fn claim_swap(
-			origin,
+		#[pallet::weight(
+			T::DbWeight::get().reads_writes(1, 1)
+				.saturating_add(40_000_000)
+				.saturating_add((proof.len() as Weight).saturating_mul(100))
+				.saturating_add(action.weight())
+		)]
+		pub(crate) fn claim_swap(
+			origin: OriginFor<T>,
 			proof: Vec<u8>,
 			action: T::SwapAction,
 		) -> DispatchResult {
@@ -280,7 +293,7 @@ decl_module! {
 			PendingSwaps::<T>::remove(target.clone(), hashed_proof.clone());
 
 			Self::deposit_event(
-				RawEvent::SwapClaimed(target, hashed_proof, succeeded)
+				Event::SwapClaimed(target, hashed_proof, succeeded)
 			);
 
 			Ok(())
@@ -292,12 +305,12 @@ decl_module! {
 		///
 		/// - `target`: Target of the original atomic swap.
 		/// - `hashed_proof`: Hashed proof of the original atomic swap.
-		#[weight = T::DbWeight::get().reads_writes(1, 1).saturating_add(40_000_000)]
-		fn cancel_swap(
-			origin,
+		#[pallet::weight(T::DbWeight::get().reads_writes(1, 1).saturating_add(40_000_000))]
+		pub(crate) fn cancel_swap(
+			origin: OriginFor<T>,
 			target: T::AccountId,
 			hashed_proof: HashedProof,
-		) {
+		) -> DispatchResult {
 			let source = ensure_signed(origin)?;
 
 			let swap = PendingSwaps::<T>::get(&target, hashed_proof)
@@ -307,7 +320,7 @@ decl_module! {
 				Error::<T>::SourceMismatch,
 			);
 			ensure!(
-				frame_system::Module::<T>::block_number() >= swap.end_block,
+				frame_system::Pallet::<T>::block_number() >= swap.end_block,
 				Error::<T>::DurationNotPassed,
 			);
 
@@ -315,8 +328,10 @@ decl_module! {
 			PendingSwaps::<T>::remove(&target, hashed_proof.clone());
 
 			Self::deposit_event(
-				RawEvent::SwapCancelled(target, hashed_proof)
+				Event::SwapCancelled(target, hashed_proof)
 			);
+
+			Ok(())
 		}
 	}
 }
diff --git a/frame/atomic-swap/src/tests.rs b/frame/atomic-swap/src/tests.rs
index 977b17f8710e3..baa9a08957d4a 100644
--- a/frame/atomic-swap/src/tests.rs
+++ b/frame/atomic-swap/src/tests.rs
@@ -19,9 +19,9 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
-		AtomicSwap: pallet_atomic_swap::{Module, Call, Event<T>},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
+		AtomicSwap: pallet_atomic_swap::{Pallet, Call, Event<T>},
 	}
 );
 
diff --git a/frame/aura/src/lib.rs b/frame/aura/src/lib.rs
index 17484461cdeff..a9b91737235ae 100644
--- a/frame/aura/src/lib.rs
+++ b/frame/aura/src/lib.rs
@@ -17,8 +17,8 @@
 
 //! # Aura Module
 //!
-//! - [`aura::Config`](./trait.Config.html)
-//! - [`Module`](./struct.Module.html)
+//! - [`Config`]
+//! - [`Pallet`]
 //!
 //! ## Overview
 //!
@@ -130,7 +130,7 @@ impl<T: Config> Pallet<T> {
 			AURA_ENGINE_ID,
 			ConsensusLog::AuthoritiesChange(new).encode()
 		);
-		<frame_system::Module<T>>::deposit_log(log.into());
+		<frame_system::Pallet<T>>::deposit_log(log.into());
 	}
 
 	fn initialize_authorities(authorities: &[T::AuthorityId]) {
@@ -194,7 +194,7 @@ impl<T: Config> OneSessionHandler<T::AccountId> for Pallet<T> {
 			ConsensusLog::<T::AuthorityId>::OnDisabled(i as AuthorityIndex).encode(),
 		);
 
-		<frame_system::Module<T>>::deposit_log(log.into());
+		<frame_system::Pallet<T>>::deposit_log(log.into());
 	}
 }
 
diff --git a/frame/aura/src/mock.rs b/frame/aura/src/mock.rs
index a5ef12f5935f1..481edbaff487f 100644
--- a/frame/aura/src/mock.rs
+++ b/frame/aura/src/mock.rs
@@ -34,9 +34,9 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Timestamp: pallet_timestamp::{Module, Call, Storage, Inherent},
-		Aura: pallet_aura::{Module, Call, Storage, Config<T>},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Timestamp: pallet_timestamp::{Pallet, Call, Storage, Inherent},
+		Aura: pallet_aura::{Pallet, Call, Storage, Config<T>},
 	}
 );
 
diff --git a/frame/authority-discovery/src/lib.rs b/frame/authority-discovery/src/lib.rs
index cc3f41f59ed89..ca8f3eeff3d68 100644
--- a/frame/authority-discovery/src/lib.rs
+++ b/frame/authority-discovery/src/lib.rs
@@ -136,9 +136,9 @@ mod tests {
 			NodeBlock = Block,
 			UncheckedExtrinsic = UncheckedExtrinsic,
 		{
-			System: frame_system::{Module, Call, Config, Storage, Event<T>},
-			Session: pallet_session::{Module, Call, Storage, Event, Config<T>},
-			AuthorityDiscovery: pallet_authority_discovery::{Module, Call, Config},
+			System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+			Session: pallet_session::{Pallet, Call, Storage, Event, Config<T>},
+			AuthorityDiscovery: pallet_authority_discovery::{Pallet, Call, Config},
 		}
 	);
 
diff --git a/frame/authorship/src/lib.rs b/frame/authorship/src/lib.rs
index 3d89ab24d01cf..286abc721cbba 100644
--- a/frame/authorship/src/lib.rs
+++ b/frame/authorship/src/lib.rs
@@ -234,7 +234,7 @@ impl<T: Config> Module<T> {
 			return author;
 		}
 
-		let digest = <frame_system::Module<T>>::digest();
+		let digest = <frame_system::Pallet<T>>::digest();
 		let pre_runtime_digests = digest.logs.iter().filter_map(|d| d.as_pre_runtime());
 		if let Some(author) = T::FindAuthor::find_author(pre_runtime_digests) {
 			<Self as Store>::Author::put(&author);
@@ -245,7 +245,7 @@ impl<T: Config> Module<T> {
 	}
 
 	fn verify_and_import_uncles(new_uncles: Vec<T::Header>) -> dispatch::DispatchResult {
-		let now = <frame_system::Module<T>>::block_number();
+		let now = <frame_system::Pallet<T>>::block_number();
 
 		let mut uncles = <Self as Store>::Uncles::get();
 		uncles.push(UncleEntryItem::InclusionHeight(now));
@@ -278,7 +278,7 @@ impl<T: Config> Module<T> {
 		accumulator: &mut <T::FilterUncle as FilterUncle<T::Header, T::AccountId>>::Accumulator,
 	) -> Result<Option<T::AccountId>, dispatch::DispatchError>
 	{
-		let now = <frame_system::Module<T>>::block_number();
+		let now = <frame_system::Pallet<T>>::block_number();
 
 		let (minimum_height, maximum_height) = {
 			let uncle_generations = T::UncleGenerations::get();
@@ -303,7 +303,7 @@ impl<T: Config> Module<T> {
 
 		{
 			let parent_number = uncle.number().clone() - One::one();
-			let parent_hash = <frame_system::Module<T>>::block_hash(&parent_number);
+			let parent_hash = <frame_system::Pallet<T>>::block_hash(&parent_number);
 			if &parent_hash != uncle.parent_hash() {
 				return Err(Error::<T>::InvalidUncleParent.into());
 			}
@@ -314,7 +314,7 @@ impl<T: Config> Module<T> {
 		}
 
 		let duplicate = existing_uncles.into_iter().find(|h| **h == hash).is_some();
-		let in_chain = <frame_system::Module<T>>::block_hash(uncle.number()) == hash;
+		let in_chain = <frame_system::Pallet<T>>::block_hash(uncle.number()) == hash;
 
 		if duplicate || in_chain {
 			return Err(Error::<T>::UncleAlreadyIncluded.into())
@@ -413,8 +413,8 @@ mod tests {
 			NodeBlock = Block,
 			UncheckedExtrinsic = UncheckedExtrinsic,
 		{
-			System: frame_system::{Module, Call, Config, Storage, Event<T>},
-			Authorship: pallet_authorship::{Module, Call, Storage, Inherent},
+			System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+			Authorship: pallet_authorship::{Pallet, Call, Storage, Inherent},
 		}
 	);
 
diff --git a/frame/babe/Cargo.toml b/frame/babe/Cargo.toml
index 6c7bb508b53d1..f7bebce98acf3 100644
--- a/frame/babe/Cargo.toml
+++ b/frame/babe/Cargo.toml
@@ -37,7 +37,7 @@ pallet-offences = { version = "3.0.0", path = "../offences" }
 pallet-staking = { version = "3.0.0", path = "../staking" }
 pallet-staking-reward-curve = { version = "3.0.0", path = "../staking/reward-curve" }
 sp-core = { version = "3.0.0", path = "../../primitives/core" }
-sp-election-providers = { version = "3.0.0", path = "../../primitives/election-providers" }
+frame-election-provider-support = { version = "3.0.0", path = "../election-provider-support" }
 
 [features]
 default = ["std"]
diff --git a/frame/babe/src/benchmarking.rs b/frame/babe/src/benchmarking.rs
index 087cac2ed6cc6..145a82c4f8049 100644
--- a/frame/babe/src/benchmarking.rs
+++ b/frame/babe/src/benchmarking.rs
@@ -91,7 +91,7 @@ mod tests {
 			let equivocation_proof = generate_equivocation_proof(
 				offending_authority_index,
 				offending_authority_pair,
-				CurrentSlot::get() + 1,
+				CurrentSlot::<Test>::get() + 1,
 			);
 
 			println!("equivocation_proof: {:?}", equivocation_proof);
diff --git a/frame/babe/src/equivocation.rs b/frame/babe/src/equivocation.rs
index 14ba0f16cb9e2..154faa49f0b26 100644
--- a/frame/babe/src/equivocation.rs
+++ b/frame/babe/src/equivocation.rs
@@ -48,7 +48,7 @@ use sp_staking::{
 };
 use sp_std::prelude::*;
 
-use crate::{Call, Module, Config};
+use crate::{Call, Pallet, Config};
 
 /// A trait with utility methods for handling equivocation reports in BABE.
 /// The trait provides methods for reporting an offence triggered by a valid
@@ -182,7 +182,7 @@ where
 /// A `ValidateUnsigned` implementation that restricts calls to `report_equivocation_unsigned`
 /// to local calls (i.e. extrinsics generated on this node) or that already in a block. This
 /// guarantees that only block authors can include unsigned equivocation reports.
-impl<T: Config> frame_support::unsigned::ValidateUnsigned for Module<T> {
+impl<T: Config> frame_support::unsigned::ValidateUnsigned for Pallet<T> {
 	type Call = Call<T>;
 	fn validate_unsigned(source: TransactionSource, call: &Self::Call) -> TransactionValidity {
 		if let Call::report_equivocation_unsigned(equivocation_proof, key_owner_proof) = call {
@@ -290,7 +290,7 @@ impl<FullIdentification: Clone> Offence<FullIdentification>
 
 	fn slash_fraction(offenders_count: u32, validator_set_count: u32) -> Perbill {
 		// the formula is min((3k / n)^2, 1)
-		let x = Perbill::from_rational_approximation(3 * offenders_count, validator_set_count);
+		let x = Perbill::from_rational(3 * offenders_count, validator_set_count);
 		// _ ^ 2
 		x.square()
 	}
diff --git a/frame/babe/src/lib.rs b/frame/babe/src/lib.rs
index 00bfa4f2656c9..fb1e32e5350b5 100644
--- a/frame/babe/src/lib.rs
+++ b/frame/babe/src/lib.rs
@@ -23,13 +23,10 @@
 
 use codec::{Decode, Encode};
 use frame_support::{
-	decl_error, decl_module, decl_storage,
 	dispatch::DispatchResultWithPostInfo,
 	traits::{FindAuthor, Get, KeyOwnerProofSystem, OneSessionHandler, OnTimestampSet},
 	weights::{Pays, Weight},
-	Parameter,
 };
-use frame_system::{ensure_none, ensure_root, ensure_signed};
 use sp_application_crypto::Public;
 use sp_runtime::{
 	generic::DigestItem,
@@ -64,52 +61,7 @@ pub use randomness::{
 	CurrentBlockRandomness, RandomnessFromOneEpochAgo, RandomnessFromTwoEpochsAgo,
 };
 
-pub trait Config: pallet_timestamp::Config {
-	/// The amount of time, in slots, that each epoch should last.
-	/// NOTE: Currently it is not possible to change the epoch duration after
-	/// the chain has started. Attempting to do so will brick block production.
-	type EpochDuration: Get<u64>;
-
-	/// The expected average block time at which BABE should be creating
-	/// blocks. Since BABE is probabilistic it is not trivial to figure out
-	/// what the expected average block time should be based on the slot
-	/// duration and the security parameter `c` (where `1 - c` represents
-	/// the probability of a slot being empty).
-	type ExpectedBlockTime: Get<Self::Moment>;
-
-	/// BABE requires some logic to be triggered on every block to query for whether an epoch
-	/// has ended and to perform the transition to the next epoch.
-	///
-	/// Typically, the `ExternalTrigger` type should be used. An internal trigger should only be used
-	/// when no other module is responsible for changing authority set.
-	type EpochChangeTrigger: EpochChangeTrigger;
-
-	/// The proof of key ownership, used for validating equivocation reports.
-	/// The proof must include the session index and validator count of the
-	/// session at which the equivocation occurred.
-	type KeyOwnerProof: Parameter + GetSessionNumber + GetValidatorCount;
-
-	/// The identification of a key owner, used when reporting equivocations.
-	type KeyOwnerIdentification: Parameter;
-
-	/// A system for proving ownership of keys, i.e. that a given key was part
-	/// of a validator set, needed for validating equivocation reports.
-	type KeyOwnerProofSystem: KeyOwnerProofSystem<
-		(KeyTypeId, AuthorityId),
-		Proof = Self::KeyOwnerProof,
-		IdentificationTuple = Self::KeyOwnerIdentification,
-	>;
-
-	/// The equivocation handling subsystem, defines methods to report an
-	/// offence (after the equivocation has been validated) and for submitting a
-	/// transaction to report an equivocation (from an offchain context).
-	/// NOTE: when enabling equivocation handling (i.e. this type isn't set to
-	/// `()`) you must use this pallet's `ValidateUnsigned` in the runtime
-	/// definition.
-	type HandleEquivocation: HandleEquivocation<Self>;
-
-	type WeightInfo: WeightInfo;
-}
+pub use pallet::*;
 
 pub trait WeightInfo {
 	fn plan_config_change() -> Weight;
@@ -137,11 +89,11 @@ pub struct SameAuthoritiesForever;
 
 impl EpochChangeTrigger for SameAuthoritiesForever {
 	fn trigger<T: Config>(now: T::BlockNumber) {
-		if <Module<T>>::should_epoch_change(now) {
-			let authorities = <Module<T>>::authorities();
+		if <Pallet<T>>::should_epoch_change(now) {
+			let authorities = <Pallet<T>>::authorities();
 			let next_authorities = authorities.clone();
 
-			<Module<T>>::enact_epoch_change(authorities, next_authorities);
+			<Pallet<T>>::enact_epoch_change(authorities, next_authorities);
 		}
 	}
 }
@@ -150,8 +102,70 @@ const UNDER_CONSTRUCTION_SEGMENT_LENGTH: usize = 256;
 
 type MaybeRandomness = Option<schnorrkel::Randomness>;
 
-decl_error! {
-	pub enum Error for Module<T: Config> {
+#[frame_support::pallet]
+pub mod pallet {
+	use frame_support::pallet_prelude::*;
+	use frame_system::pallet_prelude::*;
+	use super::*;
+
+	/// The BABE Pallet
+	#[pallet::pallet]
+	#[pallet::generate_store(pub(super) trait Store)]
+	pub struct Pallet<T>(_);
+
+	#[pallet::config]
+	#[pallet::disable_frame_system_supertrait_check]
+	pub trait Config: pallet_timestamp::Config {
+		/// The amount of time, in slots, that each epoch should last.
+		/// NOTE: Currently it is not possible to change the epoch duration after
+		/// the chain has started. Attempting to do so will brick block production.
+		#[pallet::constant]
+		type EpochDuration: Get<u64>;
+
+		/// The expected average block time at which BABE should be creating
+		/// blocks. Since BABE is probabilistic it is not trivial to figure out
+		/// what the expected average block time should be based on the slot
+		/// duration and the security parameter `c` (where `1 - c` represents
+		/// the probability of a slot being empty).
+		#[pallet::constant]
+		type ExpectedBlockTime: Get<Self::Moment>;
+
+		/// BABE requires some logic to be triggered on every block to query for whether an epoch
+		/// has ended and to perform the transition to the next epoch.
+		///
+		/// Typically, the `ExternalTrigger` type should be used. An internal trigger should only be used
+		/// when no other module is responsible for changing authority set.
+		type EpochChangeTrigger: EpochChangeTrigger;
+
+		/// The proof of key ownership, used for validating equivocation reports.
+		/// The proof must include the session index and validator count of the
+		/// session at which the equivocation occurred.
+		type KeyOwnerProof: Parameter + GetSessionNumber + GetValidatorCount;
+
+		/// The identification of a key owner, used when reporting equivocations.
+		type KeyOwnerIdentification: Parameter;
+
+		/// A system for proving ownership of keys, i.e. that a given key was part
+		/// of a validator set, needed for validating equivocation reports.
+		type KeyOwnerProofSystem: KeyOwnerProofSystem<
+			(KeyTypeId, AuthorityId),
+			Proof = Self::KeyOwnerProof,
+			IdentificationTuple = Self::KeyOwnerIdentification,
+		>;
+
+		/// The equivocation handling subsystem, defines methods to report an
+		/// offence (after the equivocation has been validated) and for submitting a
+		/// transaction to report an equivocation (from an offchain context).
+		/// NOTE: when enabling equivocation handling (i.e. this type isn't set to
+		/// `()`) you must use this pallet's `ValidateUnsigned` in the runtime
+		/// definition.
+		type HandleEquivocation: HandleEquivocation<Self>;
+
+		type WeightInfo: WeightInfo;
+	}
+
+	#[pallet::error]
+	pub enum Error<T> {
 		/// An equivocation proof provided as part of an equivocation report is invalid.
 		InvalidEquivocationProof,
 		/// A key ownership proof provided as part of an equivocation report is invalid.
@@ -159,150 +173,189 @@ decl_error! {
 		/// A given equivocation report is valid but already previously reported.
 		DuplicateOffenceReport,
 	}
-}
 
-decl_storage! {
-	trait Store for Module<T: Config> as Babe {
-		/// Current epoch index.
-		pub EpochIndex get(fn epoch_index): u64;
+	/// Current epoch index.
+	#[pallet::storage]
+	#[pallet::getter(fn epoch_index)]
+	pub type EpochIndex<T> = StorageValue<_, u64, ValueQuery>;
 
-		/// Current epoch authorities.
-		pub Authorities get(fn authorities): Vec<(AuthorityId, BabeAuthorityWeight)>;
+	/// Current epoch authorities.
+	#[pallet::storage]
+	#[pallet::getter(fn authorities)]
+	pub type Authorities<T> = StorageValue<_, Vec<(AuthorityId, BabeAuthorityWeight)>, ValueQuery>;
 
-		/// The slot at which the first epoch actually started. This is 0
-		/// until the first block of the chain.
-		pub GenesisSlot get(fn genesis_slot): Slot;
+	/// The slot at which the first epoch actually started. This is 0
+	/// until the first block of the chain.
+	#[pallet::storage]
+	#[pallet::getter(fn genesis_slot)]
+	pub type GenesisSlot<T> = StorageValue<_, Slot, ValueQuery>;
 
-		/// Current slot number.
-		pub CurrentSlot get(fn current_slot): Slot;
+	/// Current slot number.
+	#[pallet::storage]
+	#[pallet::getter(fn current_slot)]
+	pub type CurrentSlot<T> = StorageValue<_, Slot, ValueQuery>;
 
-		/// The epoch randomness for the *current* epoch.
-		///
-		/// # Security
-		///
-		/// This MUST NOT be used for gambling, as it can be influenced by a
-		/// malicious validator in the short term. It MAY be used in many
-		/// cryptographic protocols, however, so long as one remembers that this
-		/// (like everything else on-chain) it is public. For example, it can be
-		/// used where a number is needed that cannot have been chosen by an
-		/// adversary, for purposes such as public-coin zero-knowledge proofs.
-		// NOTE: the following fields don't use the constants to define the
-		// array size because the metadata API currently doesn't resolve the
-		// variable to its underlying value.
-		pub Randomness get(fn randomness): schnorrkel::Randomness;
-
-		/// Pending epoch configuration change that will be applied when the next epoch is enacted.
-		PendingEpochConfigChange: Option<NextConfigDescriptor>;
-
-		/// Next epoch randomness.
-		NextRandomness: schnorrkel::Randomness;
-
-		/// Next epoch authorities.
-		NextAuthorities: Vec<(AuthorityId, BabeAuthorityWeight)>;
-
-		/// Randomness under construction.
-		///
-		/// We make a tradeoff between storage accesses and list length.
-		/// We store the under-construction randomness in segments of up to
-		/// `UNDER_CONSTRUCTION_SEGMENT_LENGTH`.
-		///
-		/// Once a segment reaches this length, we begin the next one.
-		/// We reset all segments and return to `0` at the beginning of every
-		/// epoch.
-		SegmentIndex build(|_| 0): u32;
-
-		/// TWOX-NOTE: `SegmentIndex` is an increasing integer, so this is okay.
-		UnderConstruction: map hasher(twox_64_concat) u32 => Vec<schnorrkel::Randomness>;
-
-		/// Temporary value (cleared at block finalization) which is `Some`
-		/// if per-block initialization has already been called for current block.
-		Initialized get(fn initialized): Option<MaybeRandomness>;
-
-		/// Temporary value (cleared at block finalization) that includes the VRF output generated
-		/// at this block. This field should always be populated during block processing unless
-		/// secondary plain slots are enabled (which don't contain a VRF output).
-		AuthorVrfRandomness get(fn author_vrf_randomness): MaybeRandomness;
-
-		/// The block numbers when the last and current epoch have started, respectively `N-1` and
-		/// `N`.
-		/// NOTE: We track this is in order to annotate the block number when a given pool of
-		/// entropy was fixed (i.e. it was known to chain observers). Since epochs are defined in
-		/// slots, which may be skipped, the block numbers may not line up with the slot numbers.
-		EpochStart: (T::BlockNumber, T::BlockNumber);
-
-		/// How late the current block is compared to its parent.
-		///
-		/// This entry is populated as part of block execution and is cleaned up
-		/// on block finalization. Querying this storage entry outside of block
-		/// execution context should always yield zero.
-		Lateness get(fn lateness): T::BlockNumber;
-
-		/// The configuration for the current epoch. Should never be `None` as it is initialized in genesis.
-		EpochConfig: Option<BabeEpochConfiguration>;
-
-		/// The configuration for the next epoch, `None` if the config will not change
-		/// (you can fallback to `EpochConfig` instead in that case).
-		NextEpochConfig: Option<BabeEpochConfiguration>;
-	}
-	add_extra_genesis {
-		config(authorities): Vec<(AuthorityId, BabeAuthorityWeight)>;
-		config(epoch_config): Option<BabeEpochConfiguration>;
-		build(|config| {
-			Module::<T>::initialize_authorities(&config.authorities);
-			EpochConfig::put(config.epoch_config.clone().expect("epoch_config must not be None"));
-		})
-	}
-}
+	/// The epoch randomness for the *current* epoch.
+	///
+	/// # Security
+	///
+	/// This MUST NOT be used for gambling, as it can be influenced by a
+	/// malicious validator in the short term. It MAY be used in many
+	/// cryptographic protocols, however, so long as one remembers that this
+	/// (like everything else on-chain) it is public. For example, it can be
+	/// used where a number is needed that cannot have been chosen by an
+	/// adversary, for purposes such as public-coin zero-knowledge proofs.
+	// NOTE: the following fields don't use the constants to define the
+	// array size because the metadata API currently doesn't resolve the
+	// variable to its underlying value.
+	#[pallet::storage]
+	#[pallet::getter(fn randomness)]
+	pub type Randomness<T> = StorageValue<_, schnorrkel::Randomness, ValueQuery>;
+
+	/// Pending epoch configuration change that will be applied when the next epoch is enacted.
+	#[pallet::storage]
+	pub(super) type PendingEpochConfigChange<T> = StorageValue<_, NextConfigDescriptor>;
+
+	/// Next epoch randomness.
+	#[pallet::storage]
+	pub(super) type NextRandomness<T> = StorageValue<_, schnorrkel::Randomness, ValueQuery>;
+
+	/// Next epoch authorities.
+	#[pallet::storage]
+	pub(super) type NextAuthorities<T> = StorageValue<
+		_,
+		Vec<(AuthorityId, BabeAuthorityWeight)>,
+		ValueQuery,
+	>;
 
-decl_module! {
-	/// The BABE Pallet
-	pub struct Module<T: Config> for enum Call where origin: T::Origin {
-		/// The number of **slots** that an epoch takes. We couple sessions to
-		/// epochs, i.e. we start a new session once the new epoch begins.
-		/// NOTE: Currently it is not possible to change the epoch duration
-		/// after the chain has started. Attempting to do so will brick block
-		/// production.
-		const EpochDuration: u64 = T::EpochDuration::get();
+	/// Randomness under construction.
+	///
+	/// We make a tradeoff between storage accesses and list length.
+	/// We store the under-construction randomness in segments of up to
+	/// `UNDER_CONSTRUCTION_SEGMENT_LENGTH`.
+	///
+	/// Once a segment reaches this length, we begin the next one.
+	/// We reset all segments and return to `0` at the beginning of every
+	/// epoch.
+	#[pallet::storage]
+	pub(super) type SegmentIndex<T> = StorageValue<_, u32, ValueQuery>;
+
+	/// TWOX-NOTE: `SegmentIndex` is an increasing integer, so this is okay.
+	#[pallet::storage]
+	pub(super) type UnderConstruction<T> = StorageMap<
+		_,
+		Twox64Concat,
+		u32,
+		Vec<schnorrkel::Randomness>,
+		ValueQuery,
+	>;
 
-		/// The expected average block time at which BABE should be creating
-		/// blocks. Since BABE is probabilistic it is not trivial to figure out
-		/// what the expected average block time should be based on the slot
-		/// duration and the security parameter `c` (where `1 - c` represents
-		/// the probability of a slot being empty).
-		const ExpectedBlockTime: T::Moment = T::ExpectedBlockTime::get();
+	/// Temporary value (cleared at block finalization) which is `Some`
+	/// if per-block initialization has already been called for current block.
+	#[pallet::storage]
+	#[pallet::getter(fn initialized)]
+	pub(super) type Initialized<T> = StorageValue<_, MaybeRandomness>;
+
+	/// Temporary value (cleared at block finalization) that includes the VRF output generated
+	/// at this block. This field should always be populated during block processing unless
+	/// secondary plain slots are enabled (which don't contain a VRF output).
+	#[pallet::storage]
+	#[pallet::getter(fn author_vrf_randomness)]
+	pub(super) type AuthorVrfRandomness<T> = StorageValue<_, MaybeRandomness, ValueQuery>;
+
+	/// The block numbers when the last and current epoch have started, respectively `N-1` and
+	/// `N`.
+	/// NOTE: We track this is in order to annotate the block number when a given pool of
+	/// entropy was fixed (i.e. it was known to chain observers). Since epochs are defined in
+	/// slots, which may be skipped, the block numbers may not line up with the slot numbers.
+	#[pallet::storage]
+	pub(super) type EpochStart<T: Config> = StorageValue<
+		_,
+		(T::BlockNumber, T::BlockNumber),
+		ValueQuery,
+	>;
+
+	/// How late the current block is compared to its parent.
+	///
+	/// This entry is populated as part of block execution and is cleaned up
+	/// on block finalization. Querying this storage entry outside of block
+	/// execution context should always yield zero.
+	#[pallet::storage]
+	#[pallet::getter(fn lateness)]
+	pub(super) type Lateness<T: Config> = StorageValue<_, T::BlockNumber, ValueQuery>;
+
+	/// The configuration for the current epoch. Should never be `None` as it is initialized in genesis.
+	#[pallet::storage]
+	pub(super) type EpochConfig<T> = StorageValue<_, BabeEpochConfiguration>;
+
+	/// The configuration for the next epoch, `None` if the config will not change
+	/// (you can fallback to `EpochConfig` instead in that case).
+	#[pallet::storage]
+	pub(super) type NextEpochConfig<T> = StorageValue<_, BabeEpochConfiguration>;
+
+	#[pallet::genesis_config]
+	pub struct GenesisConfig {
+		pub authorities: Vec<(AuthorityId, BabeAuthorityWeight)>,
+		pub epoch_config: Option<BabeEpochConfiguration>,
+	}
+
+	#[cfg(feature = "std")]
+	impl Default for GenesisConfig {
+		fn default() -> Self {
+			GenesisConfig {
+				authorities: Default::default(),
+				epoch_config: Default::default(),
+			}
+		}
+	}
 
+	#[pallet::genesis_build]
+	impl<T: Config> GenesisBuild<T> for GenesisConfig {
+		fn build(&self) {
+			SegmentIndex::<T>::put(0);
+			Pallet::<T>::initialize_authorities(&self.authorities);
+			EpochConfig::<T>::put(self.epoch_config.clone().expect("epoch_config must not be None"));
+		}
+	}
+
+	#[pallet::hooks]
+	impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {
 		/// Initialization
-		fn on_initialize(now: T::BlockNumber) -> Weight {
+		fn on_initialize(now: BlockNumberFor<T>) -> Weight {
 			Self::do_initialize(now);
-
 			0
 		}
 
 		/// Block finalization
-		fn on_finalize() {
+		fn on_finalize(_n: BlockNumberFor<T>) {
 			// at the end of the block, we can safely include the new VRF output
 			// from this block into the under-construction randomness. If we've determined
 			// that this block was the first in a new epoch, the changeover logic has
 			// already occurred at this point, so the under-construction randomness
 			// will only contain outputs from the right epoch.
-			if let Some(Some(randomness)) = Initialized::take() {
+			if let Some(Some(randomness)) = Initialized::<T>::take() {
 				Self::deposit_randomness(&randomness);
 			}
 
 			// The stored author generated VRF output is ephemeral.
-			AuthorVrfRandomness::kill();
+			AuthorVrfRandomness::<T>::kill();
 
 			// remove temporary "environment" entry from storage
 			Lateness::<T>::kill();
 		}
+	}
 
+	#[pallet::call]
+	impl<T: Config> Pallet<T> {
 		/// Report authority equivocation/misbehavior. This method will verify
 		/// the equivocation proof and validate the given key ownership proof
 		/// against the extracted offender. If both are valid, the offence will
 		/// be reported.
-		#[weight = <T as Config>::WeightInfo::report_equivocation(key_owner_proof.validator_count())]
-		fn report_equivocation(
-			origin,
+		#[pallet::weight(<T as Config>::WeightInfo::report_equivocation(
+			key_owner_proof.validator_count(),
+		))]
+		pub fn report_equivocation(
+			origin: OriginFor<T>,
 			equivocation_proof: EquivocationProof<T::Header>,
 			key_owner_proof: T::KeyOwnerProof,
 		) -> DispatchResultWithPostInfo {
@@ -323,9 +376,11 @@ decl_module! {
 		/// block authors will call it (validated in `ValidateUnsigned`), as such
 		/// if the block author is defined it will be defined as the equivocation
 		/// reporter.
-		#[weight = <T as Config>::WeightInfo::report_equivocation(key_owner_proof.validator_count())]
-		fn report_equivocation_unsigned(
-			origin,
+		#[pallet::weight(<T as Config>::WeightInfo::report_equivocation(
+			key_owner_proof.validator_count(),
+		))]
+		pub fn report_equivocation_unsigned(
+			origin: OriginFor<T>,
 			equivocation_proof: EquivocationProof<T::Header>,
 			key_owner_proof: T::KeyOwnerProof,
 		) -> DispatchResultWithPostInfo {
@@ -342,13 +397,14 @@ decl_module! {
 		/// the next call to `enact_epoch_change`. The config will be activated one epoch after.
 		/// Multiple calls to this method will replace any existing planned config change that had
 		/// not been enacted yet.
-		#[weight = <T as Config>::WeightInfo::plan_config_change()]
-		fn plan_config_change(
-			origin,
+		#[pallet::weight(<T as Config>::WeightInfo::plan_config_change())]
+		pub fn plan_config_change(
+			origin: OriginFor<T>,
 			config: NextConfigDescriptor,
-		) {
+		) -> DispatchResultWithPostInfo {
 			ensure_root(origin)?;
-			PendingEpochConfigChange::put(config);
+			PendingEpochConfigChange::<T>::put(config);
+			Ok(().into())
 		}
 	}
 }
@@ -356,7 +412,7 @@ decl_module! {
 /// A BABE public key
 pub type BabeKey = [u8; PUBLIC_KEY_LENGTH];
 
-impl<T: Config> FindAuthor<u32> for Module<T> {
+impl<T: Config> FindAuthor<u32> for Pallet<T> {
 	fn find_author<'a, I>(digests: I) -> Option<u32> where
 		I: 'a + IntoIterator<Item=(ConsensusEngineId, &'a [u8])>
 	{
@@ -371,15 +427,15 @@ impl<T: Config> FindAuthor<u32> for Module<T> {
 	}
 }
 
-impl<T: Config> IsMember<AuthorityId> for Module<T> {
+impl<T: Config> IsMember<AuthorityId> for Pallet<T> {
 	fn is_member(authority_id: &AuthorityId) -> bool {
-		<Module<T>>::authorities()
+		<Pallet<T>>::authorities()
 			.iter()
 			.any(|id| &id.0 == authority_id)
 	}
 }
 
-impl<T: Config> pallet_session::ShouldEndSession<T::BlockNumber> for Module<T> {
+impl<T: Config> pallet_session::ShouldEndSession<T::BlockNumber> for Pallet<T> {
 	fn should_end_session(now: T::BlockNumber) -> bool {
 		// it might be (and it is in current implementation) that session module is calling
 		// should_end_session() from it's own on_initialize() handler
@@ -391,7 +447,7 @@ impl<T: Config> pallet_session::ShouldEndSession<T::BlockNumber> for Module<T> {
 	}
 }
 
-impl<T: Config> Module<T> {
+impl<T: Config> Pallet<T> {
 	/// Determine the BABE slot duration based on the Timestamp module configuration.
 	pub fn slot_duration() -> T::Moment {
 		// we double the minimum block-period so each author can always propose within
@@ -411,7 +467,7 @@ impl<T: Config> Module<T> {
 		// the same randomness and validator set as signalled in the genesis,
 		// so we don't rotate the epoch.
 		now != One::one() && {
-			let diff = CurrentSlot::get().saturating_sub(Self::current_epoch_start());
+			let diff = CurrentSlot::<T>::get().saturating_sub(Self::current_epoch_start());
 			*diff >= T::EpochDuration::get()
 		}
 	}
@@ -435,7 +491,7 @@ impl<T: Config> Module<T> {
 	pub fn next_expected_epoch_change(now: T::BlockNumber) -> Option<T::BlockNumber> {
 		let next_slot = Self::current_epoch_start().saturating_add(T::EpochDuration::get());
 		next_slot
-			.checked_sub(*CurrentSlot::get())
+			.checked_sub(*CurrentSlot::<T>::get())
 			.map(|slots_remaining| {
 				// This is a best effort guess. Drifts in the slot/block ratio will cause errors here.
 				let blocks_remaining: T::BlockNumber = slots_remaining.saturated_into();
@@ -457,12 +513,12 @@ impl<T: Config> Module<T> {
 		debug_assert!(Self::initialized().is_some());
 
 		// Update epoch index
-		let epoch_index = EpochIndex::get()
+		let epoch_index = EpochIndex::<T>::get()
 			.checked_add(1)
 			.expect("epoch indices will never reach 2^64 before the death of the universe; qed");
 
-		EpochIndex::put(epoch_index);
-		Authorities::put(authorities);
+		EpochIndex::<T>::put(epoch_index);
+		Authorities::<T>::put(authorities);
 
 		// Update epoch randomness.
 		let next_epoch_index = epoch_index
@@ -472,20 +528,20 @@ impl<T: Config> Module<T> {
 		// Returns randomness for the current epoch and computes the *next*
 		// epoch randomness.
 		let randomness = Self::randomness_change_epoch(next_epoch_index);
-		Randomness::put(randomness);
+		Randomness::<T>::put(randomness);
 
 		// Update the next epoch authorities.
-		NextAuthorities::put(&next_authorities);
+		NextAuthorities::<T>::put(&next_authorities);
 
 		// Update the start blocks of the previous and new current epoch.
 		<EpochStart<T>>::mutate(|(previous_epoch_start_block, current_epoch_start_block)| {
 			*previous_epoch_start_block = sp_std::mem::take(current_epoch_start_block);
-			*current_epoch_start_block = <frame_system::Module<T>>::block_number();
+			*current_epoch_start_block = <frame_system::Pallet<T>>::block_number();
 		});
 
 		// After we update the current epoch, we signal the *next* epoch change
 		// so that nodes can track changes.
-		let next_randomness = NextRandomness::get();
+		let next_randomness = NextRandomness::<T>::get();
 
 		let next_epoch = NextEpochDescriptor {
 			authorities: next_authorities,
@@ -493,14 +549,14 @@ impl<T: Config> Module<T> {
 		};
 		Self::deposit_consensus(ConsensusLog::NextEpochData(next_epoch));
 
-		if let Some(next_config) = NextEpochConfig::get() {
-			EpochConfig::put(next_config);
+		if let Some(next_config) = NextEpochConfig::<T>::get() {
+			EpochConfig::<T>::put(next_config);
 		}
 
-		if let Some(pending_epoch_config_change) = PendingEpochConfigChange::take() {
+		if let Some(pending_epoch_config_change) = PendingEpochConfigChange::<T>::take() {
 			let next_epoch_config: BabeEpochConfiguration =
 				pending_epoch_config_change.clone().into();
-			NextEpochConfig::put(next_epoch_config);
+			NextEpochConfig::<T>::put(next_epoch_config);
 
 			Self::deposit_consensus(ConsensusLog::NextConfigData(pending_epoch_config_change));
 		}
@@ -510,25 +566,25 @@ impl<T: Config> Module<T> {
 	/// give correct results after `do_initialize` of the first block
 	/// in the chain (as its result is based off of `GenesisSlot`).
 	pub fn current_epoch_start() -> Slot {
-		Self::epoch_start(EpochIndex::get())
+		Self::epoch_start(EpochIndex::<T>::get())
 	}
 
 	/// Produces information about the current epoch.
 	pub fn current_epoch() -> Epoch {
 		Epoch {
-			epoch_index: EpochIndex::get(),
+			epoch_index: EpochIndex::<T>::get(),
 			start_slot: Self::current_epoch_start(),
 			duration: T::EpochDuration::get(),
 			authorities: Self::authorities(),
 			randomness: Self::randomness(),
-			config: EpochConfig::get().expect("EpochConfig is initialized in genesis; we never `take` or `kill` it; qed"),
+			config: EpochConfig::<T>::get().expect("EpochConfig is initialized in genesis; we never `take` or `kill` it; qed"),
 		}
 	}
 
 	/// Produces information about the next epoch (which was already previously
 	/// announced).
 	pub fn next_epoch() -> Epoch {
-		let next_epoch_index = EpochIndex::get().checked_add(1).expect(
+		let next_epoch_index = EpochIndex::<T>::get().checked_add(1).expect(
 			"epoch index is u64; it is always only incremented by one; \
 			 if u64 is not enough we should crash for safety; qed.",
 		);
@@ -537,10 +593,10 @@ impl<T: Config> Module<T> {
 			epoch_index: next_epoch_index,
 			start_slot: Self::epoch_start(next_epoch_index),
 			duration: T::EpochDuration::get(),
-			authorities: NextAuthorities::get(),
-			randomness: NextRandomness::get(),
-			config: NextEpochConfig::get().unwrap_or_else(|| {
-				EpochConfig::get().expect("EpochConfig is initialized in genesis; we never `take` or `kill` it; qed")
+			authorities: NextAuthorities::<T>::get(),
+			randomness: NextRandomness::<T>::get(),
+			config: NextEpochConfig::<T>::get().unwrap_or_else(|| {
+				EpochConfig::<T>::get().expect("EpochConfig is initialized in genesis; we never `take` or `kill` it; qed")
 			}),
 		}
 	}
@@ -555,26 +611,26 @@ impl<T: Config> Module<T> {
 			.checked_mul(T::EpochDuration::get())
 			.expect(PROOF);
 
-		epoch_start.checked_add(*GenesisSlot::get()).expect(PROOF).into()
+		epoch_start.checked_add(*GenesisSlot::<T>::get()).expect(PROOF).into()
 	}
 
 	fn deposit_consensus<U: Encode>(new: U) {
 		let log: DigestItem<T::Hash> = DigestItem::Consensus(BABE_ENGINE_ID, new.encode());
-		<frame_system::Module<T>>::deposit_log(log.into())
+		<frame_system::Pallet<T>>::deposit_log(log.into())
 	}
 
 	fn deposit_randomness(randomness: &schnorrkel::Randomness) {
-		let segment_idx = <SegmentIndex>::get();
-		let mut segment = <UnderConstruction>::get(&segment_idx);
+		let segment_idx = SegmentIndex::<T>::get();
+		let mut segment = UnderConstruction::<T>::get(&segment_idx);
 		if segment.len() < UNDER_CONSTRUCTION_SEGMENT_LENGTH {
 			// push onto current segment: not full.
 			segment.push(*randomness);
-			<UnderConstruction>::insert(&segment_idx, &segment);
+			UnderConstruction::<T>::insert(&segment_idx, &segment);
 		} else {
 			// move onto the next segment and update the index.
 			let segment_idx = segment_idx + 1;
-			<UnderConstruction>::insert(&segment_idx, &vec![randomness.clone()]);
-			<SegmentIndex>::put(&segment_idx);
+			UnderConstruction::<T>::insert(&segment_idx, &vec![randomness.clone()]);
+			SegmentIndex::<T>::put(&segment_idx);
 		}
 	}
 
@@ -586,7 +642,7 @@ impl<T: Config> Module<T> {
 			return;
 		}
 
-		let maybe_pre_digest: Option<PreDigest> = <frame_system::Module<T>>::digest()
+		let maybe_pre_digest: Option<PreDigest> = <frame_system::Pallet<T>>::digest()
 			.logs
 			.iter()
 			.filter_map(|s| s.as_pre_runtime())
@@ -603,9 +659,9 @@ impl<T: Config> Module<T> {
 			// on the first non-zero block (i.e. block #1)
 			// this is where the first epoch (epoch #0) actually starts.
 			// we need to adjust internal storage accordingly.
-			if *GenesisSlot::get() == 0 {
-				GenesisSlot::put(digest.slot());
-				debug_assert_ne!(*GenesisSlot::get(), 0);
+			if *GenesisSlot::<T>::get() == 0 {
+				GenesisSlot::<T>::put(digest.slot());
+				debug_assert_ne!(*GenesisSlot::<T>::get(), 0);
 
 				// deposit a log because this is the first block in epoch #0
 				// we use the same values as genesis because we haven't collected any
@@ -622,11 +678,11 @@ impl<T: Config> Module<T> {
 			let current_slot = digest.slot();
 
 			// how many slots were skipped between current and last block
-			let lateness = current_slot.saturating_sub(CurrentSlot::get() + 1);
+			let lateness = current_slot.saturating_sub(CurrentSlot::<T>::get() + 1);
 			let lateness = T::BlockNumber::from(*lateness as u32);
 
 			Lateness::<T>::put(lateness);
-			CurrentSlot::put(current_slot);
+			CurrentSlot::<T>::put(current_slot);
 
 			let authority_index = digest.authority_index();
 
@@ -635,7 +691,7 @@ impl<T: Config> Module<T> {
 				.vrf_output()
 				.and_then(|vrf_output| {
 					// Reconstruct the bytes of VRFInOut using the authority id.
-					Authorities::get()
+					Authorities::<T>::get()
 						.get(authority_index as usize)
 						.and_then(|author| {
 							schnorrkel::PublicKey::from_bytes(author.0.as_slice()).ok()
@@ -644,7 +700,7 @@ impl<T: Config> Module<T> {
 							let transcript = sp_consensus_babe::make_transcript(
 								&Self::randomness(),
 								current_slot,
-								EpochIndex::get(),
+								EpochIndex::<T>::get(),
 							);
 
 							vrf_output.0.attach_input_hash(
@@ -661,11 +717,11 @@ impl<T: Config> Module<T> {
 		// For primary VRF output we place it in the `Initialized` storage
 		// item and it'll be put onto the under-construction randomness later,
 		// once we've decided which epoch this block is in.
-		Initialized::put(if is_primary { maybe_randomness } else { None });
+		Initialized::<T>::put(if is_primary { maybe_randomness } else { None });
 
 		// Place either the primary or secondary VRF output into the
 		// `AuthorVrfRandomness` storage item.
-		AuthorVrfRandomness::put(maybe_randomness);
+		AuthorVrfRandomness::<T>::put(maybe_randomness);
 
 		// enact epoch change, if necessary.
 		T::EpochChangeTrigger::trigger::<T>(now)
@@ -674,8 +730,8 @@ impl<T: Config> Module<T> {
 	/// Call this function exactly once when an epoch changes, to update the
 	/// randomness. Returns the new randomness.
 	fn randomness_change_epoch(next_epoch_index: u64) -> schnorrkel::Randomness {
-		let this_randomness = NextRandomness::get();
-		let segment_idx: u32 = <SegmentIndex>::mutate(|s| sp_std::mem::replace(s, 0));
+		let this_randomness = NextRandomness::<T>::get();
+		let segment_idx: u32 = SegmentIndex::<T>::mutate(|s| sp_std::mem::replace(s, 0));
 
 		// overestimate to the segment being full.
 		let rho_size = segment_idx.saturating_add(1) as usize * UNDER_CONSTRUCTION_SEGMENT_LENGTH;
@@ -683,18 +739,18 @@ impl<T: Config> Module<T> {
 		let next_randomness = compute_randomness(
 			this_randomness,
 			next_epoch_index,
-			(0..segment_idx).flat_map(|i| <UnderConstruction>::take(&i)),
+			(0..segment_idx).flat_map(|i| UnderConstruction::<T>::take(&i)),
 			Some(rho_size),
 		);
-		NextRandomness::put(&next_randomness);
+		NextRandomness::<T>::put(&next_randomness);
 		this_randomness
 	}
 
 	fn initialize_authorities(authorities: &[(AuthorityId, BabeAuthorityWeight)]) {
 		if !authorities.is_empty() {
-			assert!(Authorities::get().is_empty(), "Authorities are already initialized!");
-			Authorities::put(authorities);
-			NextAuthorities::put(authorities);
+			assert!(Authorities::<T>::get().is_empty(), "Authorities are already initialized!");
+			Authorities::<T>::put(authorities);
+			NextAuthorities::<T>::put(authorities);
 		}
 	}
 
@@ -714,7 +770,7 @@ impl<T: Config> Module<T> {
 		let validator_set_count = key_owner_proof.validator_count();
 		let session_index = key_owner_proof.session();
 
-		let epoch_index = (*slot.saturating_sub(GenesisSlot::get()) / T::EpochDuration::get())
+		let epoch_index = (*slot.saturating_sub(GenesisSlot::<T>::get()) / T::EpochDuration::get())
 			.saturated_into::<u32>();
 
 		// check that the slot number is consistent with the session index
@@ -763,7 +819,7 @@ impl<T: Config> Module<T> {
 	}
 }
 
-impl<T: Config> OnTimestampSet<T::Moment> for Module<T> {
+impl<T: Config> OnTimestampSet<T::Moment> for Pallet<T> {
 	fn on_timestamp_set(moment: T::Moment) {
 		let slot_duration = Self::slot_duration();
 		assert!(!slot_duration.is_zero(), "Babe slot duration cannot be zero.");
@@ -771,20 +827,20 @@ impl<T: Config> OnTimestampSet<T::Moment> for Module<T> {
 		let timestamp_slot = moment / slot_duration;
 		let timestamp_slot = Slot::from(timestamp_slot.saturated_into::<u64>());
 
-		assert!(CurrentSlot::get() == timestamp_slot, "Timestamp slot must match `CurrentSlot`");
+		assert!(CurrentSlot::<T>::get() == timestamp_slot, "Timestamp slot must match `CurrentSlot`");
 	}
 }
 
-impl<T: Config> frame_support::traits::EstimateNextSessionRotation<T::BlockNumber> for Module<T> {
+impl<T: Config> frame_support::traits::EstimateNextSessionRotation<T::BlockNumber> for Pallet<T> {
 	fn average_session_length() -> T::BlockNumber {
 		T::EpochDuration::get().saturated_into()
 	}
 
 	fn estimate_current_session_progress(_now: T::BlockNumber) -> (Option<Percent>, Weight) {
-		let elapsed = CurrentSlot::get().saturating_sub(Self::current_epoch_start()) + 1;
+		let elapsed = CurrentSlot::<T>::get().saturating_sub(Self::current_epoch_start()) + 1;
 
 		(
-			Some(Percent::from_rational_approximation(
+			Some(Percent::from_rational(
 				*elapsed,
 				T::EpochDuration::get(),
 			)),
@@ -802,17 +858,17 @@ impl<T: Config> frame_support::traits::EstimateNextSessionRotation<T::BlockNumbe
 	}
 }
 
-impl<T: Config> frame_support::traits::Lateness<T::BlockNumber> for Module<T> {
+impl<T: Config> frame_support::traits::Lateness<T::BlockNumber> for Pallet<T> {
 	fn lateness(&self) -> T::BlockNumber {
 		Self::lateness()
 	}
 }
 
-impl<T: Config> sp_runtime::BoundToRuntimeAppPublic for Module<T> {
+impl<T: Config> sp_runtime::BoundToRuntimeAppPublic for Pallet<T> {
 	type Public = AuthorityId;
 }
 
-impl<T: Config> OneSessionHandler<T::AccountId> for Module<T> {
+impl<T: Config> OneSessionHandler<T::AccountId> for Pallet<T> {
 	type Key = AuthorityId;
 
 	fn on_genesis_session<'a, I: 'a>(validators: I)
@@ -890,7 +946,7 @@ pub mod migrations {
 		let mut reads = 0;
 
 		if let Some(pending_change) = OldNextEpochConfig::<T>::get() {
-			PendingEpochConfigChange::put(pending_change);
+			PendingEpochConfigChange::<T>::put(pending_change);
 
 			writes += 1;
 		}
@@ -899,8 +955,8 @@ pub mod migrations {
 
 		OldNextEpochConfig::<T>::kill();
 
-		EpochConfig::put(epoch_config.clone());
-		NextEpochConfig::put(epoch_config);
+		EpochConfig::<T>::put(epoch_config.clone());
+		NextEpochConfig::<T>::put(epoch_config);
 
 		writes += 3;
 
diff --git a/frame/babe/src/mock.rs b/frame/babe/src/mock.rs
index c46b55c2c4ace..137f32b5e502c 100644
--- a/frame/babe/src/mock.rs
+++ b/frame/babe/src/mock.rs
@@ -27,7 +27,7 @@ use sp_runtime::{
 };
 use frame_system::InitKind;
 use frame_support::{
-	parameter_types, StorageValue,
+	parameter_types,
 	traits::{KeyOwnerProofSystem, OnInitialize},
 	weights::Weight,
 };
@@ -37,7 +37,7 @@ use sp_consensus_babe::{AuthorityId, AuthorityPair, Slot};
 use sp_consensus_vrf::schnorrkel::{VRFOutput, VRFProof};
 use sp_staking::SessionIndex;
 use pallet_staking::EraIndex;
-use sp_election_providers::onchain;
+use frame_election_provider_support::onchain;
 use pallet_session::historical as pallet_session_historical;
 
 type DummyValidatorId = u64;
@@ -51,14 +51,14 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
-		Historical: pallet_session_historical::{Module},
-		Offences: pallet_offences::{Module, Call, Storage, Event},
-		Babe: pallet_babe::{Module, Call, Storage, Config, ValidateUnsigned},
-		Staking: pallet_staking::{Module, Call, Storage, Config<T>, Event<T>},
-		Session: pallet_session::{Module, Call, Storage, Event, Config<T>},
-		Timestamp: pallet_timestamp::{Module, Call, Storage, Inherent},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
+		Historical: pallet_session_historical::{Pallet},
+		Offences: pallet_offences::{Pallet, Call, Storage, Event},
+		Babe: pallet_babe::{Pallet, Call, Storage, Config, ValidateUnsigned},
+		Staking: pallet_staking::{Pallet, Call, Storage, Config<T>, Event<T>},
+		Session: pallet_session::{Pallet, Call, Storage, Event, Config<T>},
+		Timestamp: pallet_timestamp::{Pallet, Call, Storage, Inherent},
 	}
 );
 
@@ -104,7 +104,7 @@ where
 
 impl_opaque_keys! {
 	pub struct MockSessionKeys {
-		pub babe_authority: super::Module<Test>,
+		pub babe_authority: super::Pallet<Test>,
 	}
 }
 
@@ -187,11 +187,13 @@ parameter_types! {
 impl onchain::Config for Test {
 	type AccountId = <Self as frame_system::Config>::AccountId;
 	type BlockNumber = <Self as frame_system::Config>::BlockNumber;
+	type BlockWeights = ();
 	type Accuracy = Perbill;
 	type DataProvider = Staking;
 }
 
 impl pallet_staking::Config for Test {
+	const MAX_NOMINATIONS: u32 = 16;
 	type RewardRemainder = ();
 	type CurrencyToVote = frame_support::traits::SaturatingCurrencyToVote;
 	type Event = Event;
@@ -203,16 +205,10 @@ impl pallet_staking::Config for Test {
 	type SlashDeferDuration = SlashDeferDuration;
 	type SlashCancelOrigin = frame_system::EnsureRoot<Self::AccountId>;
 	type SessionInterface = Self;
-	type UnixTime = pallet_timestamp::Module<Test>;
-	type RewardCurve = RewardCurve;
+	type UnixTime = pallet_timestamp::Pallet<Test>;
+	type EraPayout = pallet_staking::ConvertCurve<RewardCurve>;
 	type MaxNominatorRewardedPerValidator = MaxNominatorRewardedPerValidator;
 	type NextNewSession = Session;
-	type ElectionLookahead = ElectionLookahead;
-	type Call = Call;
-	type UnsignedPriority = StakingUnsignedPriority;
-	type MaxIterations = ();
-	type MinSolutionScoreBump = ();
-	type OffchainSolutionWeightLimit = ();
 	type ElectionProvider = onchain::OnChainSequentialPhragmen<Self>;
 	type WeightInfo = ();
 }
@@ -450,7 +446,7 @@ pub fn generate_equivocation_proof(
 	use sp_consensus_babe::digests::CompatibleDigestItem;
 
 	let current_block = System::block_number();
-	let current_slot = CurrentSlot::get();
+	let current_slot = CurrentSlot::<Test>::get();
 
 	let make_header = || {
 		let parent_hash = System::parent_hash();
diff --git a/frame/babe/src/randomness.rs b/frame/babe/src/randomness.rs
index 71412a962becf..a7e8b31577681 100644
--- a/frame/babe/src/randomness.rs
+++ b/frame/babe/src/randomness.rs
@@ -21,7 +21,7 @@
 use super::{
 	AuthorVrfRandomness, Config, EpochStart, NextRandomness, Randomness, VRF_OUTPUT_LENGTH,
 };
-use frame_support::{traits::Randomness as RandomnessT, StorageValue};
+use frame_support::{traits::Randomness as RandomnessT};
 use sp_runtime::traits::Hash;
 
 /// Randomness usable by consensus protocols that **depend** upon finality and take action
@@ -117,7 +117,7 @@ impl<T: Config> RandomnessT<T::Hash, T::BlockNumber> for RandomnessFromTwoEpochs
 	fn random(subject: &[u8]) -> (T::Hash, T::BlockNumber) {
 		let mut subject = subject.to_vec();
 		subject.reserve(VRF_OUTPUT_LENGTH);
-		subject.extend_from_slice(&Randomness::get()[..]);
+		subject.extend_from_slice(&Randomness::<T>::get()[..]);
 
 		(T::Hashing::hash(&subject[..]), EpochStart::<T>::get().0)
 	}
@@ -127,7 +127,7 @@ impl<T: Config> RandomnessT<T::Hash, T::BlockNumber> for RandomnessFromOneEpochA
 	fn random(subject: &[u8]) -> (T::Hash, T::BlockNumber) {
 		let mut subject = subject.to_vec();
 		subject.reserve(VRF_OUTPUT_LENGTH);
-		subject.extend_from_slice(&NextRandomness::get()[..]);
+		subject.extend_from_slice(&NextRandomness::<T>::get()[..]);
 
 		(T::Hashing::hash(&subject[..]), EpochStart::<T>::get().1)
 	}
@@ -135,7 +135,7 @@ impl<T: Config> RandomnessT<T::Hash, T::BlockNumber> for RandomnessFromOneEpochA
 
 impl<T: Config> RandomnessT<Option<T::Hash>, T::BlockNumber> for CurrentBlockRandomness<T> {
 	fn random(subject: &[u8]) -> (Option<T::Hash>, T::BlockNumber) {
-		let random = AuthorVrfRandomness::get().map(|random| {
+		let random = AuthorVrfRandomness::<T>::get().map(|random| {
 			let mut subject = subject.to_vec();
 			subject.reserve(VRF_OUTPUT_LENGTH);
 			subject.extend_from_slice(&random);
@@ -143,6 +143,6 @@ impl<T: Config> RandomnessT<Option<T::Hash>, T::BlockNumber> for CurrentBlockRan
 			T::Hashing::hash(&subject[..])
 		});
 
-		(random, <frame_system::Module<T>>::block_number())
+		(random, <frame_system::Pallet<T>>::block_number())
 	}
 }
diff --git a/frame/babe/src/tests.rs b/frame/babe/src/tests.rs
index 0ccc3db4df0b0..6aa80e9697339 100644
--- a/frame/babe/src/tests.rs
+++ b/frame/babe/src/tests.rs
@@ -19,7 +19,7 @@
 
 use super::{Call, *};
 use frame_support::{
-	assert_err, assert_ok,
+	assert_err, assert_ok, assert_noop,
 	traits::{Currency, EstimateNextSessionRotation, OnFinalize},
 	weights::{GetDispatchInfo, Pays},
 };
@@ -92,11 +92,11 @@ fn first_block_epoch_zero_start() {
 		Babe::on_finalize(1);
 		let header = System::finalize();
 
-		assert_eq!(SegmentIndex::get(), 0);
-		assert_eq!(UnderConstruction::get(0), vec![vrf_randomness]);
+		assert_eq!(SegmentIndex::<Test>::get(), 0);
+		assert_eq!(UnderConstruction::<Test>::get(0), vec![vrf_randomness]);
 		assert_eq!(Babe::randomness(), [0; 32]);
 		assert_eq!(Babe::author_vrf_randomness(), None);
-		assert_eq!(NextRandomness::get(), [0; 32]);
+		assert_eq!(NextRandomness::<Test>::get(), [0; 32]);
 
 		assert_eq!(header.digest.logs.len(), 2);
 		assert_eq!(pre_digest.logs.len(), 1);
@@ -278,10 +278,10 @@ fn can_enact_next_config() {
 			allowed_slots: sp_consensus_babe::AllowedSlots::PrimarySlots,
 		};
 
-		EpochConfig::put(current_config);
-		NextEpochConfig::put(next_config.clone());
+		EpochConfig::<Test>::put(current_config);
+		NextEpochConfig::<Test>::put(next_config.clone());
 
-		assert_eq!(NextEpochConfig::get(), Some(next_config.clone()));
+		assert_eq!(NextEpochConfig::<Test>::get(), Some(next_config.clone()));
 
 		Babe::plan_config_change(
 			Origin::root(),
@@ -295,8 +295,8 @@ fn can_enact_next_config() {
 		Babe::on_finalize(9);
 		let header = System::finalize();
 
-		assert_eq!(EpochConfig::get(), Some(next_config));
-		assert_eq!(NextEpochConfig::get(), Some(next_next_config.clone()));
+		assert_eq!(EpochConfig::<Test>::get(), Some(next_config));
+		assert_eq!(NextEpochConfig::<Test>::get(), Some(next_next_config.clone()));
 
 		let consensus_log = sp_consensus_babe::ConsensusLog::NextConfigData(
 			NextConfigDescriptor::V1 {
@@ -325,14 +325,14 @@ fn only_root_can_enact_config_change() {
 			next_config.clone(),
 		);
 
-		assert_eq!(res, Err(DispatchError::BadOrigin));
+		assert_noop!(res, DispatchError::BadOrigin);
 
 		let res = Babe::plan_config_change(
 			Origin::signed(1),
 			next_config.clone(),
 		);
 
-		assert_eq!(res, Err(DispatchError::BadOrigin));
+		assert_noop!(res, DispatchError::BadOrigin);
 
 		let res = Babe::plan_config_change(
 			Origin::root(),
@@ -346,7 +346,7 @@ fn only_root_can_enact_config_change() {
 #[test]
 fn can_fetch_current_and_next_epoch_data() {
 	new_test_ext(5).execute_with(|| {
-		EpochConfig::put(BabeEpochConfiguration {
+		EpochConfig::<Test>::put(BabeEpochConfiguration {
 			c: (1, 4),
 			allowed_slots: sp_consensus_babe::AllowedSlots::PrimarySlots,
 		});
@@ -356,7 +356,6 @@ fn can_fetch_current_and_next_epoch_data() {
 			Babe::current_epoch().authorities,
 			Babe::next_epoch().authorities,
 		);
-
 		// 1 era = 3 epochs
 		// 1 epoch = 3 slots
 		// Eras start from 0.
@@ -444,7 +443,7 @@ fn report_equivocation_current_session_works() {
 		let equivocation_proof = generate_equivocation_proof(
 			offending_validator_index as u32,
 			&offending_authority_pair,
-			CurrentSlot::get(),
+			CurrentSlot::<Test>::get(),
 		);
 
 		// create the key ownership proof
@@ -518,7 +517,7 @@ fn report_equivocation_old_session_works() {
 		let equivocation_proof = generate_equivocation_proof(
 			offending_validator_index as u32,
 			&offending_authority_pair,
-			CurrentSlot::get(),
+			CurrentSlot::<Test>::get(),
 		);
 
 		// create the key ownership proof
@@ -584,7 +583,7 @@ fn report_equivocation_invalid_key_owner_proof() {
 		let equivocation_proof = generate_equivocation_proof(
 			offending_validator_index as u32,
 			&offending_authority_pair,
-			CurrentSlot::get(),
+			CurrentSlot::<Test>::get(),
 		);
 
 		// create the key ownership proof
@@ -664,7 +663,7 @@ fn report_equivocation_invalid_equivocation_proof() {
 		let mut equivocation_proof = generate_equivocation_proof(
 			offending_validator_index as u32,
 			&offending_authority_pair,
-			CurrentSlot::get(),
+			CurrentSlot::<Test>::get(),
 		);
 		equivocation_proof.second_header = equivocation_proof.first_header.clone();
 		assert_invalid_equivocation(equivocation_proof);
@@ -673,7 +672,7 @@ fn report_equivocation_invalid_equivocation_proof() {
 		let mut equivocation_proof = generate_equivocation_proof(
 			offending_validator_index as u32,
 			&offending_authority_pair,
-			CurrentSlot::get(),
+			CurrentSlot::<Test>::get(),
 		);
 		equivocation_proof.first_header.digest_mut().logs.remove(0);
 		assert_invalid_equivocation(equivocation_proof);
@@ -682,7 +681,7 @@ fn report_equivocation_invalid_equivocation_proof() {
 		let mut equivocation_proof = generate_equivocation_proof(
 			offending_validator_index as u32,
 			&offending_authority_pair,
-			CurrentSlot::get(),
+			CurrentSlot::<Test>::get(),
 		);
 		equivocation_proof.first_header.digest_mut().logs.remove(1);
 		assert_invalid_equivocation(equivocation_proof);
@@ -691,7 +690,7 @@ fn report_equivocation_invalid_equivocation_proof() {
 		let mut equivocation_proof = generate_equivocation_proof(
 			offending_validator_index as u32,
 			&offending_authority_pair,
-			CurrentSlot::get(),
+			CurrentSlot::<Test>::get(),
 		);
 		equivocation_proof.slot = Slot::from(0);
 		assert_invalid_equivocation(equivocation_proof.clone());
@@ -701,7 +700,7 @@ fn report_equivocation_invalid_equivocation_proof() {
 		let mut equivocation_proof = generate_equivocation_proof(
 			offending_validator_index as u32,
 			&offending_authority_pair,
-			CurrentSlot::get() + 1,
+			CurrentSlot::<Test>::get() + 1,
 		);
 
 		// use the header from the previous equivocation generated
@@ -714,7 +713,7 @@ fn report_equivocation_invalid_equivocation_proof() {
 		let mut equivocation_proof = generate_equivocation_proof(
 			offending_validator_index as u32,
 			&offending_authority_pair,
-			CurrentSlot::get() + 1,
+			CurrentSlot::<Test>::get() + 1,
 		);
 
 		// replace the seal digest with the digest from the
@@ -753,7 +752,7 @@ fn report_equivocation_validate_unsigned_prevents_duplicates() {
 		let equivocation_proof = generate_equivocation_proof(
 			offending_validator_index as u32,
 			&offending_authority_pair,
-			CurrentSlot::get(),
+			CurrentSlot::<Test>::get(),
 		);
 
 		let key = (
@@ -775,7 +774,7 @@ fn report_equivocation_validate_unsigned_prevents_duplicates() {
 		);
 
 		// the transaction is valid when passed as local
-		let tx_tag = (offending_authority_pair.public(), CurrentSlot::get());
+		let tx_tag = (offending_authority_pair.public(), CurrentSlot::<Test>::get());
 		assert_eq!(
 			<Babe as sp_runtime::traits::ValidateUnsigned>::validate_unsigned(
 				TransactionSource::Local,
@@ -848,7 +847,7 @@ fn valid_equivocation_reports_dont_pay_fees() {
 
 		// generate an equivocation proof.
 		let equivocation_proof =
-			generate_equivocation_proof(0, &offending_authority_pair, CurrentSlot::get());
+			generate_equivocation_proof(0, &offending_authority_pair, CurrentSlot::<Test>::get());
 
 		// create the key ownership proof.
 		let key_owner_proof = Historical::prove((
@@ -941,7 +940,7 @@ fn add_epoch_configurations_migration_works() {
 			&[],
 		).is_none());
 
-		assert_eq!(EpochConfig::get(), Some(current_epoch));
-		assert_eq!(PendingEpochConfigChange::get(), Some(next_config_descriptor));
+		assert_eq!(EpochConfig::<Test>::get(), Some(current_epoch));
+		assert_eq!(PendingEpochConfigChange::<Test>::get(), Some(next_config_descriptor));
 	});
 }
diff --git a/frame/balances/src/benchmarking.rs b/frame/balances/src/benchmarking.rs
index c7cb67403d749..62959c4f1dc4a 100644
--- a/frame/balances/src/benchmarking.rs
+++ b/frame/balances/src/benchmarking.rs
@@ -25,7 +25,7 @@ use frame_system::RawOrigin;
 use frame_benchmarking::{benchmarks_instance_pallet, account, whitelisted_caller, impl_benchmark_test_suite};
 use sp_runtime::traits::Bounded;
 
-use crate::Module as Balances;
+use crate::Pallet as Balances;
 
 const SEED: u32 = 0;
 // existential deposit multiplier
diff --git a/frame/balances/src/lib.rs b/frame/balances/src/lib.rs
index cc7b6351c2584..35841c504adf9 100644
--- a/frame/balances/src/lib.rs
+++ b/frame/balances/src/lib.rs
@@ -39,7 +39,7 @@
 //! ### Terminology
 //!
 //! - **Existential Deposit:** The minimum balance required to create or keep an account open. This prevents
-//! "dust accounts" from filling storage. When the free plus the reserved balance (i.e. the total balance)
+//!   "dust accounts" from filling storage. When the free plus the reserved balance (i.e. the total balance)
 //!   fall below this, then the account is said to be dead; and it loses its functionality as well as any
 //!   prior history and all information on it is removed from the chain's state.
 //!   No account should ever have a total balance that is strictly between 0 and the existential
@@ -164,7 +164,8 @@ use frame_support::{
 		Currency, OnUnbalanced, TryDrop, StoredMap,
 		WithdrawReasons, LockIdentifier, LockableCurrency, ExistenceRequirement,
 		Imbalance, SignedImbalance, ReservableCurrency, Get, ExistenceRequirement::KeepAlive,
-		ExistenceRequirement::AllowDeath, BalanceStatus as Status,
+		ExistenceRequirement::AllowDeath,
+		tokens::{fungible, DepositConsequence, WithdrawConsequence, BalanceStatus as Status}
 	}
 };
 #[cfg(feature = "std")]
@@ -624,7 +625,7 @@ pub struct DustCleaner<T: Config<I>, I: 'static = ()>(Option<(T::AccountId, Nega
 impl<T: Config<I>, I: 'static> Drop for DustCleaner<T, I> {
 	fn drop(&mut self) {
 		if let Some((who, dust)) = self.0.take() {
-			Module::<T, I>::deposit_event(Event::DustLost(who, dust.peek()));
+			Pallet::<T, I>::deposit_event(Event::DustLost(who, dust.peek()));
 			T::DustRemoval::on_unbalanced(dust);
 		}
 	}
@@ -682,6 +683,78 @@ impl<T: Config<I>, I: 'static> Pallet<T, I> {
 		}
 	}
 
+	fn deposit_consequence(
+		_who: &T::AccountId,
+		amount: T::Balance,
+		account: &AccountData<T::Balance>,
+	) -> DepositConsequence {
+		if amount.is_zero() { return DepositConsequence::Success }
+
+		if TotalIssuance::<T, I>::get().checked_add(&amount).is_none() {
+			return DepositConsequence::Overflow
+		}
+
+		let new_total_balance = match account.total().checked_add(&amount) {
+			Some(x) => x,
+			None => return DepositConsequence::Overflow,
+		};
+
+		if new_total_balance < T::ExistentialDeposit::get() {
+			return DepositConsequence::BelowMinimum
+		}
+
+		// NOTE: We assume that we are a provider, so don't need to do any checks in the
+		// case of account creation.
+
+		DepositConsequence::Success
+	}
+
+	fn withdraw_consequence(
+		who: &T::AccountId,
+		amount: T::Balance,
+		account: &AccountData<T::Balance>,
+	) -> WithdrawConsequence<T::Balance> {
+		if amount.is_zero() { return WithdrawConsequence::Success }
+
+		if TotalIssuance::<T, I>::get().checked_sub(&amount).is_none() {
+			return WithdrawConsequence::Underflow
+		}
+
+		let new_total_balance = match account.total().checked_sub(&amount) {
+			Some(x) => x,
+			None => return WithdrawConsequence::NoFunds,
+		};
+
+		// Provider restriction - total account balance cannot be reduced to zero if it cannot
+		// sustain the loss of a provider reference.
+		// NOTE: This assumes that the pallet is a provider (which is true). Is this ever changes,
+		// then this will need to adapt accordingly.
+		let ed = T::ExistentialDeposit::get();
+		let success = if new_total_balance < ed {
+			if frame_system::Pallet::<T>::can_dec_provider(who) {
+				WithdrawConsequence::ReducedToZero(new_total_balance)
+			} else {
+				return WithdrawConsequence::WouldDie
+			}
+		} else {
+			WithdrawConsequence::Success
+		};
+
+		// Enough free funds to have them be reduced.
+		let new_free_balance = match account.free.checked_sub(&amount) {
+			Some(b) => b,
+			None => return WithdrawConsequence::NoFunds,
+		};
+
+		// Eventual free funds must be no less than the frozen balance.
+		let min_balance = account.frozen(Reasons::All);
+		if new_free_balance < min_balance {
+			return WithdrawConsequence::Frozen
+		}
+
+		success
+	}
+
 	/// Mutate an account to some new value, or delete it entirely with `None`. Will enforce
 	/// `ExistentialDeposit` law, annulling the account as needed.
 	///
@@ -692,7 +765,7 @@ impl<T: Config<I>, I: 'static> Pallet<T, I> {
 	/// the caller will do this.
 	pub fn mutate_account<R>(
 		who: &T::AccountId,
-		f: impl FnOnce(&mut AccountData<T::Balance>) -> R
+		f: impl FnOnce(&mut AccountData<T::Balance>) -> R,
 	) -> Result<R, StoredMapError> {
 		Self::try_mutate_account(who, |a, _| -> Result<R, StoredMapError> { Ok(f(a)) })
 	}
@@ -708,7 +781,7 @@ impl<T: Config<I>, I: 'static> Pallet<T, I> {
 	/// the caller will do this.
 	fn try_mutate_account<R, E: From<StoredMapError>>(
 		who: &T::AccountId,
-		f: impl FnOnce(&mut AccountData<T::Balance>, bool) -> Result<R, E>
+		f: impl FnOnce(&mut AccountData<T::Balance>, bool) -> Result<R, E>,
 	) -> Result<R, E> {
 		Self::try_mutate_account_with_dust(who, f)
 			.map(|(result, dust_cleaner)| {
@@ -732,7 +805,7 @@ impl<T: Config<I>, I: 'static> Pallet<T, I> {
 	/// the caller will do this.
 	fn try_mutate_account_with_dust<R, E: From<StoredMapError>>(
 		who: &T::AccountId,
-		f: impl FnOnce(&mut AccountData<T::Balance>, bool) -> Result<R, E>
+		f: impl FnOnce(&mut AccountData<T::Balance>, bool) -> Result<R, E>,
 	) -> Result<(R, DustCleaner<T, I>), E> {
 		let result = T::AccountStore::try_mutate_exists(who, |maybe_account| {
 			let is_new = maybe_account.is_none();
@@ -763,7 +836,7 @@ impl<T: Config<I>, I: 'static> Pallet<T, I> {
 			);
 		}
 		// No way this can fail since we do not alter the existential balances.
-		let _ = Self::mutate_account(who, |b| {
+		let res = Self::mutate_account(who, |b| {
 			b.misc_frozen = Zero::zero();
 			b.fee_frozen = Zero::zero();
 			for l in locks.iter() {
@@ -775,6 +848,7 @@ impl<T: Config<I>, I: 'static> Pallet<T, I> {
 				}
 			}
 		});
+		debug_assert!(res.is_ok());
 
 		let existed = Locks::<T, I>::contains_key(who);
 		if locks.is_empty() {
@@ -800,6 +874,192 @@ impl<T: Config<I>, I: 'static> Pallet<T, I> {
 			}
 		}
 	}
+
+
+	/// Move the reserved balance of one account into the balance of another, according to `status`.
+	///
+	/// Is a no-op if:
+	/// - the value to be moved is zero; or
+	/// - the `slashed` id equal to `beneficiary` and the `status` is `Reserved`.
+	fn do_transfer_reserved(
+		slashed: &T::AccountId,
+		beneficiary: &T::AccountId,
+		value: T::Balance,
+		best_effort: bool,
+		status: Status,
+	) -> Result<T::Balance, DispatchError> {
+		if value.is_zero() { return Ok(Zero::zero()) }
+
+		if slashed == beneficiary {
+			return match status {
+				Status::Free => Ok(Self::unreserve(slashed, value)),
+				Status::Reserved => Ok(value.saturating_sub(Self::reserved_balance(slashed))),
+			};
+		}
+
+		let ((actual, _maybe_one_dust), _maybe_other_dust) = Self::try_mutate_account_with_dust(
+			beneficiary,
+			|to_account, is_new| -> Result<(T::Balance, DustCleaner<T, I>), DispatchError> {
+				ensure!(!is_new, Error::<T, I>::DeadAccount);
+				Self::try_mutate_account_with_dust(
+					slashed,
+					|from_account, _| -> Result<T::Balance, DispatchError> {
+						let actual = cmp::min(from_account.reserved, value);
+						ensure!(best_effort || actual == value, Error::<T, I>::InsufficientBalance);
+						match status {
+							Status::Free => to_account.free = to_account.free
+								.checked_add(&actual)
+								.ok_or(Error::<T, I>::Overflow)?,
+							Status::Reserved => to_account.reserved = to_account.reserved
+								.checked_add(&actual)
+								.ok_or(Error::<T, I>::Overflow)?,
+						}
+						from_account.reserved -= actual;
+						Ok(actual)
+					}
+				)
+			}
+		)?;
+
+		Self::deposit_event(Event::ReserveRepatriated(slashed.clone(), beneficiary.clone(), actual, status));
+		Ok(actual)
+	}
+}
+
+impl<T: Config<I>, I: 'static> fungible::Inspect<T::AccountId> for Pallet<T, I> {
+	type Balance = T::Balance;
+
+	fn total_issuance() -> Self::Balance {
+		TotalIssuance::<T, I>::get()
+	}
+	fn minimum_balance() -> Self::Balance {
+		T::ExistentialDeposit::get()
+	}
+	fn balance(who: &T::AccountId) -> Self::Balance {
+		Self::account(who).total()
+	}
+	fn reducible_balance(who: &T::AccountId, keep_alive: bool) -> Self::Balance {
+		let a = Self::account(who);
+		// Liquid balance is what is neither reserved nor locked/frozen.
+		let liquid = a.free.saturating_sub(a.fee_frozen.max(a.misc_frozen));
+		if frame_system::Pallet::<T>::can_dec_provider(who) && !keep_alive {
+			liquid
+		} else {
+			// `must_remain_to_exist` is the part of liquid balance which must remain to keep total over
+			// ED.
+			let must_remain_to_exist = T::ExistentialDeposit::get().saturating_sub(a.total() - liquid);
+			liquid.saturating_sub(must_remain_to_exist)
+		}
+	}
+	fn can_deposit(who: &T::AccountId, amount: Self::Balance) -> DepositConsequence {
+		Self::deposit_consequence(who, amount, &Self::account(who))
+	}
+	fn can_withdraw(who: &T::AccountId, amount: Self::Balance) -> WithdrawConsequence<Self::Balance> {
+		Self::withdraw_consequence(who, amount, &Self::account(who))
+	}
+}
+
+impl<T: Config<I>, I: 'static> fungible::Mutate<T::AccountId> for Pallet<T, I> {
+	fn mint_into(who: &T::AccountId, amount: Self::Balance) -> DispatchResult {
+		if amount.is_zero() { return Ok(()) }
+		Self::try_mutate_account(who, |account, _is_new| -> DispatchResult {
+			Self::deposit_consequence(who, amount, &account).into_result()?;
+			account.free += amount;
+			Ok(())
+		})?;
+		TotalIssuance::<T, I>::mutate(|t| *t += amount);
+		Ok(())
+	}
+
+	fn burn_from(who: &T::AccountId, amount: Self::Balance) -> Result<Self::Balance, DispatchError> {
+		if amount.is_zero() { return Ok(Self::Balance::zero()); }
+		let actual = Self::try_mutate_account(who, |account, _is_new| -> Result<T::Balance, DispatchError> {
+			let extra = Self::withdraw_consequence(who, amount, &account).into_result()?;
+			let actual = amount + extra;
+			account.free -= actual;
+			Ok(actual)
+		})?;
+		TotalIssuance::<T, I>::mutate(|t| *t -= actual);
+		Ok(actual)
+	}
+}
+
+impl<T: Config<I>, I: 'static> fungible::Transfer<T::AccountId> for Pallet<T, I> {
+	fn transfer(
+		source: &T::AccountId,
+		dest: &T::AccountId,
+		amount: T::Balance,
+		keep_alive: bool,
+	) -> Result<T::Balance, DispatchError> {
+		let er = if keep_alive { KeepAlive } else { AllowDeath };
+		<Self as Currency::<T::AccountId>>::transfer(source, dest, amount, er)
+			.map(|_| amount)
+	}
+}
+
+impl<T: Config<I>, I: 'static> fungible::Unbalanced<T::AccountId> for Pallet<T, I> {
+	fn set_balance(who: &T::AccountId, amount: Self::Balance) -> DispatchResult {
+		Self::mutate_account(who, |account| account.free = amount)?;
+		Ok(())
+	}
+
+	fn set_total_issuance(amount: Self::Balance) {
+		TotalIssuance::<T, I>::mutate(|t| *t = amount);
+	}
+}
+
+impl<T: Config<I>, I: 'static> fungible::InspectHold<T::AccountId> for Pallet<T, I> {
+	fn balance_on_hold(who: &T::AccountId) -> T::Balance {
+		Self::account(who).reserved
+	}
+	fn can_hold(who: &T::AccountId, amount: T::Balance) -> bool {
+		let a = Self::account(who);
+		let min_balance = T::ExistentialDeposit::get().max(a.frozen(Reasons::All));
+		if a.reserved.checked_add(&amount).is_none() { return false }
+		// We require it to be min_balance + amount to ensure that the full reserved funds may be
+		// slashed without compromising locked funds or destroying the account.
+		let required_free = match min_balance.checked_add(&amount) {
+			Some(x) => x,
+			None => return false,
+		};
+		a.free >= required_free
+	}
+}
+impl<T: Config<I>, I: 'static> fungible::MutateHold<T::AccountId> for Pallet<T, I> {
+	fn hold(who: &T::AccountId, amount: Self::Balance) -> DispatchResult {
+		if amount.is_zero() { return Ok(()) }
+		ensure!(Self::can_reserve(who, amount), Error::<T, I>::InsufficientBalance);
+		Self::mutate_account(who, |a| {
+			a.free -= amount;
+			a.reserved += amount;
+		})?;
+		Ok(())
+	}
+	fn release(who: &T::AccountId, amount: Self::Balance, best_effort: bool)
+		-> Result<T::Balance, DispatchError>
+	{
+		if amount.is_zero() { return Ok(amount) }
+		// Done on a best-effort basis.
+		Self::try_mutate_account(who, |a, _| {
+			let new_free = a.free.saturating_add(amount.min(a.reserved));
+			let actual = new_free - a.free;
+			ensure!(best_effort || actual == amount, Error::<T, I>::InsufficientBalance);
+			// ^^^ Guaranteed to be <= amount and <= a.reserved
+			a.free = new_free;
+			a.reserved = a.reserved.saturating_sub(actual.clone());
+			Ok(actual)
+		})
+	}
+	fn transfer_held(
+		source: &T::AccountId,
+		dest: &T::AccountId,
+		amount: Self::Balance,
+		best_effort: bool,
+		on_hold: bool,
+	) -> Result<Self::Balance, DispatchError> {
+		let status = if on_hold { Status::Reserved } else { Status::Free };
+		Self::do_transfer_reserved(source, dest, amount, best_effort, status)
+	}
 }
 
 // wrapping these imbalances in a private module is necessary to ensure absolute privacy
@@ -810,6 +1070,7 @@ mod imbalances {
 		TryDrop, RuntimeDebug,
 	};
 	use sp_std::mem;
+	use frame_support::traits::SameOrOther;
 
 	/// Opaque, move-only struct with private fields that serves as a token denoting that
 	/// funds have been created without any equal and opposite accounting.
@@ -843,6 +1104,12 @@ mod imbalances {
 		}
 	}
 
+	impl<T: Config<I>, I: 'static> Default for PositiveImbalance<T, I> {
+		fn default() -> Self {
+			Self::zero()
+		}
+	}
+
 	impl<T: Config<I>, I: 'static> Imbalance<T::Balance> for PositiveImbalance<T, I> {
 		type Opposite = NegativeImbalance<T, I>;
 
@@ -873,14 +1140,16 @@ mod imbalances {
 			self.0 = self.0.saturating_add(other.0);
 			mem::forget(other);
 		}
-		fn offset(self, other: Self::Opposite) -> result::Result<Self, Self::Opposite> {
+		fn offset(self, other: Self::Opposite) -> SameOrOther<Self, Self::Opposite> {
 			let (a, b) = (self.0, other.0);
 			mem::forget((self, other));
 
-			if a >= b {
-				Ok(Self(a - b))
+			if a > b {
+				SameOrOther::Same(Self(a - b))
+			} else if b > a {
+				SameOrOther::Other(NegativeImbalance::new(b - a))
 			} else {
-				Err(NegativeImbalance::new(b - a))
+				SameOrOther::None
 			}
 		}
 		fn peek(&self) -> T::Balance {
@@ -894,6 +1163,12 @@ mod imbalances {
 		}
 	}
 
+	impl<T: Config<I>, I: 'static> Default for NegativeImbalance<T, I> {
+		fn default() -> Self {
+			Self::zero()
+		}
+	}
+
 	impl<T: Config<I>, I: 'static> Imbalance<T::Balance> for NegativeImbalance<T, I> {
 		type Opposite = PositiveImbalance<T, I>;
 
@@ -924,14 +1199,16 @@ mod imbalances {
 			self.0 = self.0.saturating_add(other.0);
 			mem::forget(other);
 		}
-		fn offset(self, other: Self::Opposite) -> result::Result<Self, Self::Opposite> {
+		fn offset(self, other: Self::Opposite) -> SameOrOther<Self, Self::Opposite> {
 			let (a, b) = (self.0, other.0);
 			mem::forget((self, other));
 
-			if a >= b {
-				Ok(Self(a - b))
+			if a > b {
+				SameOrOther::Same(Self(a - b))
+			} else if b > a {
+				SameOrOther::Other(PositiveImbalance::new(b - a))
 			} else {
-				Err(PositiveImbalance::new(b - a))
+				SameOrOther::None
 			}
 		}
 		fn peek(&self) -> T::Balance {
@@ -1362,40 +1639,8 @@ impl<T: Config<I>, I: 'static> ReservableCurrency<T::AccountId> for Pallet<T, I>
 		value: Self::Balance,
 		status: Status,
 	) -> Result<Self::Balance, DispatchError> {
-		if value.is_zero() { return Ok(Zero::zero()) }
-
-		if slashed == beneficiary {
-			return match status {
-				Status::Free => Ok(Self::unreserve(slashed, value)),
-				Status::Reserved => Ok(value.saturating_sub(Self::reserved_balance(slashed))),
-			};
-		}
-
-		let ((actual, _maybe_one_dust), _maybe_other_dust) = Self::try_mutate_account_with_dust(
-			beneficiary,
-			|to_account, is_new| -> Result<(Self::Balance, DustCleaner<T, I>), DispatchError> {
-				ensure!(!is_new, Error::<T, I>::DeadAccount);
-				Self::try_mutate_account_with_dust(
-					slashed,
-					|from_account, _| -> Result<Self::Balance, DispatchError> {
-						let actual = cmp::min(from_account.reserved, value);
-						match status {
-							Status::Free => to_account.free = to_account.free
-								.checked_add(&actual)
-								.ok_or(Error::<T, I>::Overflow)?,
-							Status::Reserved => to_account.reserved = to_account.reserved
-								.checked_add(&actual)
-								.ok_or(Error::<T, I>::Overflow)?,
-						}
-						from_account.reserved -= actual;
-						Ok(actual)
-					}
-				)
-			}
-		)?;
-
-		Self::deposit_event(Event::ReserveRepatriated(slashed.clone(), beneficiary.clone(), actual, status));
-		Ok(value - actual)
+		let actual = Self::do_transfer_reserved(slashed, beneficiary, value, true, status)?;
+		Ok(value.saturating_sub(actual))
 	}
 }
 
diff --git a/frame/balances/src/tests.rs b/frame/balances/src/tests.rs
index 776cda140efb8..3eb70e401e7f8 100644
--- a/frame/balances/src/tests.rs
+++ b/frame/balances/src/tests.rs
@@ -55,7 +55,7 @@ macro_rules! decl_tests {
 		}
 
 		fn last_event() -> Event {
-			system::Module::<Test>::events().pop().expect("Event expected").event
+			system::Pallet::<Test>::events().pop().expect("Event expected").event
 		}
 
 		#[test]
@@ -684,7 +684,7 @@ macro_rules! decl_tests {
 					let _ = Balances::deposit_creating(&1, 100);
 
 					System::set_block_number(2);
-					let _ = Balances::reserve(&1, 10);
+					assert_ok!(Balances::reserve(&1, 10));
 
 					assert_eq!(
 						last_event(),
@@ -692,7 +692,7 @@ macro_rules! decl_tests {
 					);
 
 					System::set_block_number(3);
-					let _ = Balances::unreserve(&1, 5);
+					assert!(Balances::unreserve(&1, 5).is_zero());
 
 					assert_eq!(
 						last_event(),
@@ -700,7 +700,7 @@ macro_rules! decl_tests {
 					);
 
 					System::set_block_number(4);
-					let _ = Balances::unreserve(&1, 6);
+					assert_eq!(Balances::unreserve(&1, 6), 1);
 
 					// should only unreserve 5
 					assert_eq!(
diff --git a/frame/balances/src/tests_composite.rs b/frame/balances/src/tests_composite.rs
index 14dfd0c4b33d6..90bcaf1a480ad 100644
--- a/frame/balances/src/tests_composite.rs
+++ b/frame/balances/src/tests_composite.rs
@@ -30,7 +30,7 @@ use frame_support::weights::{Weight, DispatchInfo, IdentityFee};
 use pallet_transaction_payment::CurrencyAdapter;
 use crate::{
 	self as pallet_balances,
-	Module, Config, decl_tests,
+	Pallet, Config, decl_tests,
 };
 type UncheckedExtrinsic = frame_system::mocking::MockUncheckedExtrinsic<Test>;
 type Block = frame_system::mocking::MockBlock<Test>;
@@ -41,8 +41,8 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
 	}
 );
 
@@ -80,7 +80,7 @@ parameter_types! {
 	pub const TransactionByteFee: u64 = 1;
 }
 impl pallet_transaction_payment::Config for Test {
-	type OnChargeTransaction = CurrencyAdapter<Module<Test>, ()>;
+	type OnChargeTransaction = CurrencyAdapter<Pallet<Test>, ()>;
 	type TransactionByteFee = TransactionByteFee;
 	type WeightToFee = IdentityFee<u64>;
 	type FeeMultiplierUpdate = ();
diff --git a/frame/balances/src/tests_local.rs b/frame/balances/src/tests_local.rs
index 02088e88b98ec..10ea74d8887bc 100644
--- a/frame/balances/src/tests_local.rs
+++ b/frame/balances/src/tests_local.rs
@@ -30,7 +30,7 @@ use frame_support::traits::StorageMapShim;
 use frame_support::weights::{Weight, DispatchInfo, IdentityFee};
 use crate::{
 	self as pallet_balances,
-	Module, Config, decl_tests,
+	Pallet, Config, decl_tests,
 };
 use pallet_transaction_payment::CurrencyAdapter;
 
@@ -43,8 +43,8 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
 	}
 );
 
@@ -82,7 +82,7 @@ parameter_types! {
 	pub const TransactionByteFee: u64 = 1;
 }
 impl pallet_transaction_payment::Config for Test {
-	type OnChargeTransaction = CurrencyAdapter<Module<Test>, ()>;
+	type OnChargeTransaction = CurrencyAdapter<Pallet<Test>, ()>;
 	type TransactionByteFee = TransactionByteFee;
 	type WeightToFee = IdentityFee<u64>;
 	type FeeMultiplierUpdate = ();
diff --git a/frame/balances/src/tests_reentrancy.rs b/frame/balances/src/tests_reentrancy.rs
index 020c514b6317c..547c7dd7cfb72 100644
--- a/frame/balances/src/tests_reentrancy.rs
+++ b/frame/balances/src/tests_reentrancy.rs
@@ -30,7 +30,7 @@ use frame_support::traits::StorageMapShim;
 use frame_support::weights::{IdentityFee};
 use crate::{
 	self as pallet_balances,
-	Module, Config,
+	Pallet, Config,
 };
 use pallet_transaction_payment::CurrencyAdapter;
 
@@ -47,7 +47,7 @@ type UncheckedExtrinsic = frame_system::mocking::MockUncheckedExtrinsic<Test>;
 type Block = frame_system::mocking::MockBlock<Test>;
 
 fn last_event() -> Event {
-	system::Module::<Test>::events().pop().expect("Event expected").event
+	system::Pallet::<Test>::events().pop().expect("Event expected").event
 }
 
 frame_support::construct_runtime!(
@@ -56,8 +56,8 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
 	}
 );
 
@@ -95,7 +95,7 @@ parameter_types! {
 	pub const TransactionByteFee: u64 = 1;
 }
 impl pallet_transaction_payment::Config for Test {
-	type OnChargeTransaction = CurrencyAdapter<Module<Test>, ()>;
+	type OnChargeTransaction = CurrencyAdapter<Pallet<Test>, ()>;
 	type TransactionByteFee = TransactionByteFee;
 	type WeightToFee = IdentityFee<u64>;
 	type FeeMultiplierUpdate = ();
diff --git a/frame/benchmarking/src/lib.rs b/frame/benchmarking/src/lib.rs
index c2f60a5e13c41..b134e79ca2450 100644
--- a/frame/benchmarking/src/lib.rs
+++ b/frame/benchmarking/src/lib.rs
@@ -676,7 +676,7 @@ macro_rules! impl_benchmark {
 		( $( $name_extra:ident ),* )
 	) => {
 		impl<T: Config $(<$instance>, $instance: $instance_bound )? >
-			$crate::Benchmarking<$crate::BenchmarkResults> for Module<T $(, $instance)? >
+			$crate::Benchmarking<$crate::BenchmarkResults> for Pallet<T $(, $instance)? >
 			where T: frame_system::Config, $( $where_clause )*
 		{
 			fn benchmarks(extra: bool) -> $crate::Vec<&'static [u8]> {
@@ -744,8 +744,8 @@ macro_rules! impl_benchmark {
 						>::instance(&selected_benchmark, c, verify)?;
 
 						// Set the block number to at least 1 so events are deposited.
-						if $crate::Zero::is_zero(&frame_system::Module::<T>::block_number()) {
-							frame_system::Module::<T>::set_block_number(1u32.into());
+						if $crate::Zero::is_zero(&frame_system::Pallet::<T>::block_number()) {
+							frame_system::Pallet::<T>::set_block_number(1u32.into());
 						}
 
 						// Commit the externalities to the database, flushing the DB cache.
@@ -915,8 +915,8 @@ macro_rules! impl_benchmark_test {
 					>::instance(&selected_benchmark, &c, true)?;
 
 					// Set the block number to at least 1 so events are deposited.
-					if $crate::Zero::is_zero(&frame_system::Module::<T>::block_number()) {
-						frame_system::Module::<T>::set_block_number(1u32.into());
+					if $crate::Zero::is_zero(&frame_system::Pallet::<T>::block_number()) {
+						frame_system::Pallet::<T>::set_block_number(1u32.into());
 					}
 
 					// Run execution + verification
@@ -961,7 +961,7 @@ macro_rules! impl_benchmark_test {
 /// When called in `pallet_example` as
 ///
 /// ```rust,ignore
-/// impl_benchmark_test_suite!(Module, crate::tests::new_test_ext(), crate::tests::Test);
+/// impl_benchmark_test_suite!(Pallet, crate::tests::new_test_ext(), crate::tests::Test);
 /// ```
 ///
 /// It expands to the equivalent of:
@@ -1019,11 +1019,11 @@ macro_rules! impl_benchmark_test {
 /// }
 ///
 /// mod tests {
-/// 	// because of macro syntax limitations, neither Module nor benches can be paths, but both have
+/// 	// because of macro syntax limitations, neither Pallet nor benches can be paths, but both have
 /// 	// to be idents in the scope of `impl_benchmark_test_suite`.
-/// 	use crate::{benches, Module};
+/// 	use crate::{benches, Pallet};
 ///
-/// 	impl_benchmark_test_suite!(Module, new_test_ext(), Test, benchmarks_path = benches);
+/// 	impl_benchmark_test_suite!(Pallet, new_test_ext(), Test, benchmarks_path = benches);
 ///
 /// 	// new_test_ext and the Test item are defined later in this module
 /// }
diff --git a/frame/benchmarking/src/tests.rs b/frame/benchmarking/src/tests.rs
index 8431f3e46c277..ac0a208543058 100644
--- a/frame/benchmarking/src/tests.rs
+++ b/frame/benchmarking/src/tests.rs
@@ -76,8 +76,8 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		TestPallet: pallet_test::{Module, Call, Storage},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		TestPallet: pallet_test::{Pallet, Call, Storage},
 	}
 );
 
@@ -133,7 +133,7 @@ mod benchmarks {
 	use crate::{BenchmarkingSetup, BenchmarkParameter, account};
 
 	// Additional used internally by the benchmark macro.
-	use super::pallet_test::{Call, Config, Module};
+	use super::pallet_test::{Call, Config, Pallet};
 
 	crate::benchmarks!{
 		where_clause {
diff --git a/frame/bounties/src/benchmarking.rs b/frame/bounties/src/benchmarking.rs
index 632f951f05e19..cb7933079763a 100644
--- a/frame/bounties/src/benchmarking.rs
+++ b/frame/bounties/src/benchmarking.rs
@@ -84,7 +84,7 @@ fn setup_pot_account<T: Config>() {
 }
 
 fn assert_last_event<T: Config>(generic_event: <T as Config>::Event) {
-	let events = frame_system::Module::<T>::events();
+	let events = frame_system::Pallet::<T>::events();
 	let system_event: <T as frame_system::Config>::Event = generic_event.into();
 	// compare to the last event record
 	let EventRecord { event, .. } = &events[events.len() - 1];
@@ -122,7 +122,7 @@ benchmarks! {
 		let (curator_lookup, bounty_id) = create_bounty::<T>()?;
 		Bounties::<T>::on_initialize(T::BlockNumber::zero());
 		let bounty_id = BountyCount::get() - 1;
-		frame_system::Module::<T>::set_block_number(T::BountyUpdatePeriod::get() + 1u32.into());
+		frame_system::Pallet::<T>::set_block_number(T::BountyUpdatePeriod::get() + 1u32.into());
 		let caller = whitelisted_caller();
 	}: _(RawOrigin::Signed(caller), bounty_id)
 
@@ -159,7 +159,7 @@ benchmarks! {
 		let beneficiary = T::Lookup::unlookup(beneficiary_account.clone());
 		Bounties::<T>::award_bounty(RawOrigin::Signed(curator.clone()).into(), bounty_id, beneficiary)?;
 
-		frame_system::Module::<T>::set_block_number(T::BountyDepositPayoutDelay::get());
+		frame_system::Pallet::<T>::set_block_number(T::BountyDepositPayoutDelay::get());
 		ensure!(T::Currency::free_balance(&beneficiary_account).is_zero(), "Beneficiary already has balance");
 
 	}: _(RawOrigin::Signed(curator), bounty_id)
diff --git a/frame/bounties/src/lib.rs b/frame/bounties/src/lib.rs
index ba0d4a5b16cb4..dafa7cd61d054 100644
--- a/frame/bounties/src/lib.rs
+++ b/frame/bounties/src/lib.rs
@@ -424,7 +424,7 @@ decl_module! {
 								// If the sender is not the curator, and the curator is inactive,
 								// slash the curator.
 								if sender != *curator {
-									let block_number = system::Module::<T>::block_number();
+									let block_number = system::Pallet::<T>::block_number();
 									if *update_due < block_number {
 										slash_curator(curator, &mut bounty.curator_deposit);
 										// Continue to change bounty status below...
@@ -435,7 +435,8 @@ decl_module! {
 								} else {
 									// Else this is the curator, willingly giving up their role.
 									// Give back their deposit.
-									let _ = T::Currency::unreserve(&curator, bounty.curator_deposit);
+									let err_amount = T::Currency::unreserve(&curator, bounty.curator_deposit);
+									debug_assert!(err_amount.is_zero());
 									// Continue to change bounty status below...
 								}
 							},
@@ -479,7 +480,7 @@ decl_module! {
 						T::Currency::reserve(curator, deposit)?;
 						bounty.curator_deposit = deposit;
 
-						let update_due = system::Module::<T>::block_number() + T::BountyUpdatePeriod::get();
+						let update_due = system::Pallet::<T>::block_number() + T::BountyUpdatePeriod::get();
 						bounty.status = BountyStatus::Active { curator: curator.clone(), update_due };
 
 						Ok(())
@@ -518,7 +519,7 @@ decl_module! {
 				bounty.status = BountyStatus::PendingPayout {
 					curator: signer,
 					beneficiary: beneficiary.clone(),
-					unlock_at: system::Module::<T>::block_number() + T::BountyDepositPayoutDelay::get(),
+					unlock_at: system::Pallet::<T>::block_number() + T::BountyDepositPayoutDelay::get(),
 				};
 
 				Ok(())
@@ -543,14 +544,18 @@ decl_module! {
 			Bounties::<T>::try_mutate_exists(bounty_id, |maybe_bounty| -> DispatchResult {
 				let bounty = maybe_bounty.take().ok_or(Error::<T>::InvalidIndex)?;
 				if let BountyStatus::PendingPayout { curator, beneficiary, unlock_at } = bounty.status {
-					ensure!(system::Module::<T>::block_number() >= unlock_at, Error::<T>::Premature);
+					ensure!(system::Pallet::<T>::block_number() >= unlock_at, Error::<T>::Premature);
 					let bounty_account = Self::bounty_account_id(bounty_id);
 					let balance = T::Currency::free_balance(&bounty_account);
 					let fee = bounty.fee.min(balance); // just to be safe
 					let payout = balance.saturating_sub(fee);
-					let _ = T::Currency::unreserve(&curator, bounty.curator_deposit);
-					let _ = T::Currency::transfer(&bounty_account, &curator, fee, AllowDeath); // should not fail
-					let _ = T::Currency::transfer(&bounty_account, &beneficiary, payout, AllowDeath); // should not fail
+					let err_amount = T::Currency::unreserve(&curator, bounty.curator_deposit);
+					debug_assert!(err_amount.is_zero());
+					let res = T::Currency::transfer(&bounty_account, &curator, fee, AllowDeath); // should not fail
+					debug_assert!(res.is_ok());
+					let res = T::Currency::transfer(&bounty_account, &beneficiary, payout, AllowDeath); // should not fail
+					debug_assert!(res.is_ok());
+
 					*maybe_bounty = None;
 
 					BountyDescriptions::remove(bounty_id);
@@ -604,7 +609,8 @@ decl_module! {
 					},
 					BountyStatus::Active { curator, .. } => {
 						// Cancelled by council, refund deposit of the working curator.
-						let _ = T::Currency::unreserve(&curator, bounty.curator_deposit);
+						let err_amount = T::Currency::unreserve(&curator, bounty.curator_deposit);
+						debug_assert!(err_amount.is_zero());
 						// Then execute removal of the bounty below.
 					},
 					BountyStatus::PendingPayout { .. } => {
@@ -621,7 +627,8 @@ decl_module! {
 				BountyDescriptions::remove(bounty_id);
 
 				let balance = T::Currency::free_balance(&bounty_account);
-				let _ = T::Currency::transfer(&bounty_account, &Self::account_id(), balance, AllowDeath); // should not fail
+				let res = T::Currency::transfer(&bounty_account, &Self::account_id(), balance, AllowDeath); // should not fail
+				debug_assert!(res.is_ok());
 				*maybe_bounty = None;
 
 				Self::deposit_event(Event::<T>::BountyCanceled(bounty_id));
@@ -649,7 +656,7 @@ decl_module! {
 				match bounty.status {
 					BountyStatus::Active { ref curator, ref mut update_due } => {
 						ensure!(*curator == signer, Error::<T>::RequireCurator);
-						*update_due = (system::Module::<T>::block_number() + T::BountyUpdatePeriod::get()).max(*update_due);
+						*update_due = (system::Pallet::<T>::block_number() + T::BountyUpdatePeriod::get()).max(*update_due);
 					},
 					_ => return Err(Error::<T>::UnexpectedStatus.into()),
 				}
@@ -736,7 +743,8 @@ impl<T: Config> pallet_treasury::SpendFunds<T> for Module<T> {
 							bounty.status = BountyStatus::Funded;
 
 							// return their deposit.
-							let _ = T::Currency::unreserve(&bounty.proposer, bounty.bond);
+							let err_amount = T::Currency::unreserve(&bounty.proposer, bounty.bond);
+							debug_assert!(err_amount.is_zero());
 
 							// fund the bounty account
 							imbalance.subsume(T::Currency::deposit_creating(&Self::bounty_account_id(index), bounty.value));
diff --git a/frame/bounties/src/tests.rs b/frame/bounties/src/tests.rs
index cbff502daa65e..617f186975269 100644
--- a/frame/bounties/src/tests.rs
+++ b/frame/bounties/src/tests.rs
@@ -43,10 +43,10 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
-		Bounties: pallet_bounties::{Module, Call, Storage, Event<T>},
-		Treasury: pallet_treasury::{Module, Call, Storage, Config, Event<T>},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
+		Bounties: pallet_bounties::{Pallet, Call, Storage, Event<T>},
+		Treasury: pallet_treasury::{Pallet, Call, Storage, Config, Event<T>},
 	}
 );
 
@@ -107,7 +107,7 @@ parameter_types! {
 // impl pallet_treasury::Config for Test {
 impl pallet_treasury::Config for Test {
 	type ModuleId = TreasuryModuleId;
-	type Currency = pallet_balances::Module<Test>;
+	type Currency = pallet_balances::Pallet<Test>;
 	type ApproveOrigin = frame_system::EnsureRoot<u128>;
 	type RejectOrigin = frame_system::EnsureRoot<u128>;
 	type Event = Event;
diff --git a/frame/collective/README.md b/frame/collective/README.md
index f62df65f728cd..444927e51da22 100644
--- a/frame/collective/README.md
+++ b/frame/collective/README.md
@@ -7,19 +7,19 @@ The pallet assumes that the amount of members stays at or below `MaxMembers` for
 calculations, but enforces this neither in `set_members` nor in `change_members_sorted`.
 
 A "prime" member may be set to help determine the default vote behavior based on chain
-config. If `PreimDefaultVote` is used, the prime vote acts as the default vote in case of any
+config. If `PrimeDefaultVote` is used, the prime vote acts as the default vote in case of any
 abstentions after the voting period. If `MoreThanMajorityThenPrimeDefaultVote` is used, then
 abstentations will first follow the majority of the collective voting, and then the prime
 member.
 
-Voting happens through motions comprising a proposal (i.e. a curried dispatchable) plus a
+Voting happens through motions comprising a proposal (i.e. a dispatchable) plus a
 number of approvals required for it to pass and be called. Motions are open for members to
-vote on for a minimum period given by `MotionDuration`. As soon as the needed number of
+vote on for a minimum period given by `MotionDuration`. As soon as the required number of
 approvals is given, the motion is closed and executed. If the number of approvals is not reached
 during the voting period, then `close` may be called by any account in order to force the end
-the motion explicitly. If a prime member is defined then their vote is used in place of any
+the motion explicitly. If a prime member is defined, then their vote is used instead of any
 abstentions and the proposal is executed if there are enough approvals counting the new votes.
 
-If there are not, or if no prime is set, then the motion is dropped without being executed.
+If there are not, or if no prime member is set, then the motion is dropped without being executed.
 
-License: Apache-2.0
\ No newline at end of file
+License: Apache-2.0
diff --git a/frame/collective/src/benchmarking.rs b/frame/collective/src/benchmarking.rs
index 1afdd14b1ad38..cd4fcfba5fe1e 100644
--- a/frame/collective/src/benchmarking.rs
+++ b/frame/collective/src/benchmarking.rs
@@ -31,7 +31,7 @@ use sp_runtime::traits::Bounded;
 use sp_std::mem::size_of;
 
 use frame_system::Call as SystemCall;
-use frame_system::Module as System;
+use frame_system::Pallet as System;
 use crate::Module as Collective;
 
 const SEED: u32 = 0;
diff --git a/frame/collective/src/lib.rs b/frame/collective/src/lib.rs
index 6d9066bca241c..28c2ff77b81fe 100644
--- a/frame/collective/src/lib.rs
+++ b/frame/collective/src/lib.rs
@@ -472,7 +472,7 @@ decl_module! {
 				let index = Self::proposal_count();
 				<ProposalCount<I>>::mutate(|i| *i += 1);
 				<ProposalOf<T, I>>::insert(proposal_hash, *proposal);
-				let end = system::Module::<T>::block_number() + T::MotionDuration::get();
+				let end = system::Pallet::<T>::block_number() + T::MotionDuration::get();
 				let votes = Votes { index, threshold, ayes: vec![who.clone()], nays: vec![], end };
 				<Voting<T, I>>::insert(proposal_hash, votes);
 
@@ -647,7 +647,7 @@ decl_module! {
 			}
 
 			// Only allow actual closing of the proposal after the voting period has ended.
-			ensure!(system::Module::<T>::block_number() >= voting.end, Error::<T, I>::TooEarly);
+			ensure!(system::Pallet::<T>::block_number() >= voting.end, Error::<T, I>::TooEarly);
 
 			let prime_vote = Self::prime().map(|who| voting.ayes.iter().any(|a| a == &who));
 
@@ -1045,10 +1045,10 @@ mod tests {
 			NodeBlock = Block,
 			UncheckedExtrinsic = UncheckedExtrinsic
 		{
-			System: system::{Module, Call, Event<T>},
-			Collective: collective::<Instance1>::{Module, Call, Event<T>, Origin<T>, Config<T>},
-			CollectiveMajority: collective::<Instance2>::{Module, Call, Event<T>, Origin<T>, Config<T>},
-			DefaultCollective: collective::{Module, Call, Event<T>, Origin<T>, Config<T>},
+			System: system::{Pallet, Call, Event<T>},
+			Collective: collective::<Instance1>::{Pallet, Call, Event<T>, Origin<T>, Config<T>},
+			CollectiveMajority: collective::<Instance2>::{Pallet, Call, Event<T>, Origin<T>, Config<T>},
+			DefaultCollective: collective::{Pallet, Call, Event<T>, Origin<T>, Config<T>},
 		}
 	);
 
diff --git a/frame/contracts/CHANGELOG.md b/frame/contracts/CHANGELOG.md
index ef69e050a2c5f..efc3eb93c5701 100644
--- a/frame/contracts/CHANGELOG.md
+++ b/frame/contracts/CHANGELOG.md
@@ -20,7 +20,14 @@ In other words: Upgrading this pallet will not break pre-existing contracts.
 
 ### Added
 
+- Make storage and fields of `Schedule` private to the crate.
+[1](https://github.com/paritytech/substrate/pull/8359)
+
+- Add new version of `seal_random` which exposes additional information.
+[1](https://github.com/paritytech/substrate/pull/8329)
+
 - Add `seal_rent_params` contract callable function.
+[1](https://github.com/paritytech/substrate/pull/8231)
 
 ## [v3.0.0] 2021-02-25
 
diff --git a/frame/contracts/COMPLEXITY.md b/frame/contracts/COMPLEXITY.md
index 32f6f84b89b6a..f0e5a035586bc 100644
--- a/frame/contracts/COMPLEXITY.md
+++ b/frame/contracts/COMPLEXITY.md
@@ -176,7 +176,7 @@ Before a call or instantiate can be performed the execution context must be init
 For the first call or instantiation in the handling of an extrinsic, this involves two calls:
 
 1. `<timestamp::Module<T>>::now()`
-2. `<system::Module<T>>::block_number()`
+2. `<system::Pallet<T>>::block_number()`
 
 The complexity of initialization depends on the complexity of these functions. In the current
 implementation they just involve a DB read.
diff --git a/frame/contracts/README.md b/frame/contracts/README.md
index 1cb384e14c5a4..6c987165990b8 100644
--- a/frame/contracts/README.md
+++ b/frame/contracts/README.md
@@ -57,4 +57,19 @@ will make things a lot easier. One such language is [`ink`](https://github.com/p
 which is an [`eDSL`](https://wiki.haskell.org/Embedded_domain_specific_language) that enables
 writing WebAssembly based smart contracts in the Rust programming language.
 
+## Debugging
+
+Contracts can emit messages to the node console when run on a development chain through the
+`seal_println` API. This is exposed in ink! via
+[`ink_env::debug_println()`](https://docs.rs/ink_env/latest/ink_env/fn.debug_println.html).
+
+In order to see these messages the log level for the `runtime::contracts` target needs to be raised
+to at least the `info` level which is the default. However, those messages are easy to overlook
+because of the noise generated by block production. A good starting point for contract debugging
+could be:
+
+```bash
+cargo run --release -- --dev --tmp -lerror,runtime::contracts
+```
+
 License: Apache-2.0
diff --git a/frame/contracts/src/benchmarking/code.rs b/frame/contracts/src/benchmarking/code.rs
index 64d2a0cf011d9..118ce038fc229 100644
--- a/frame/contracts/src/benchmarking/code.rs
+++ b/frame/contracts/src/benchmarking/code.rs
@@ -24,9 +24,7 @@
 //! we define this simple definition of a contract that can be passed to `create_code` that
 //! compiles it down into a `WasmModule` that can be used as a contract's code.
 
-use crate::Config;
-use crate::Module as Contracts;
-
+use crate::{Config, CurrentSchedule};
 use parity_wasm::elements::{
 	Instruction, Instructions, FuncBody, ValueType, BlockType, Section, CustomSection,
 };
@@ -225,7 +223,7 @@ where
 		if def.inject_stack_metering {
 			code = inject_limiter(
 				code,
-				Contracts::<T>::current_schedule().limits.stack_height
+				<CurrentSchedule<T>>::get().limits.stack_height
 			)
 			.unwrap();
 		}
@@ -505,5 +503,5 @@ where
 	T: Config,
 	T::AccountId: UncheckedFrom<T::Hash> + AsRef<[u8]>,
 {
-	Contracts::<T>::current_schedule().limits.memory_pages
+	<CurrentSchedule<T>>::get().limits.memory_pages
 }
diff --git a/frame/contracts/src/benchmarking/mod.rs b/frame/contracts/src/benchmarking/mod.rs
index d41154e995a67..3db04d3caf3dd 100644
--- a/frame/contracts/src/benchmarking/mod.rs
+++ b/frame/contracts/src/benchmarking/mod.rs
@@ -23,7 +23,7 @@ mod code;
 mod sandbox;
 
 use crate::{
-	*, Module as Contracts,
+	*, Pallet as Contracts,
 	exec::StorageKey,
 	rent::Rent,
 	schedule::{API_BENCHMARK_BATCH_SIZE, INSTR_BENCHMARK_BATCH_SIZE},
@@ -36,8 +36,9 @@ use self::{
 	},
 	sandbox::Sandbox,
 };
+use codec::Encode;
 use frame_benchmarking::{benchmarks, account, whitelisted_caller, impl_benchmark_test_suite};
-use frame_system::{Module as System, RawOrigin};
+use frame_system::{Pallet as System, RawOrigin};
 use parity_wasm::elements::{Instruction, ValueType, BlockType};
 use sp_runtime::traits::{Hash, Bounded, Zero};
 use sp_std::{default::Default, convert::{TryInto}, vec::Vec, vec};
@@ -313,7 +314,7 @@ benchmarks! {
 		let WasmModule { code, hash, .. } = WasmModule::<T>::sized(c * 1024);
 		Contracts::<T>::store_code_raw(code)?;
 		let mut module = PrefabWasmModule::from_storage_noinstr(hash)?;
-		let schedule = Contracts::<T>::current_schedule();
+		let schedule = <CurrentSchedule<T>>::get();
 	}: {
 		Contracts::<T>::reinstrument_module(&mut module, &schedule)?;
 	}
@@ -936,7 +937,7 @@ benchmarks! {
 	seal_random {
 		let r in 0 .. API_BENCHMARK_BATCHES;
 		let pages = code::max_pages::<T>();
-		let subject_len = Contracts::<T>::current_schedule().limits.subject_len;
+		let subject_len = <CurrentSchedule<T>>::get().limits.subject_len;
 		assert!(subject_len < 1024);
 		let code = WasmModule::<T>::from(ModuleDefinition {
 			memory: Some(ImportedMemory::max::<T>()),
@@ -992,7 +993,7 @@ benchmarks! {
 	// `t`: Number of topics
 	// `n`: Size of event payload in kb
 	seal_deposit_event_per_topic_and_kb {
-		let t in 0 .. Contracts::<T>::current_schedule().limits.event_topics;
+		let t in 0 .. <CurrentSchedule<T>>::get().limits.event_topics;
 		let n in 0 .. T::MaxValueSize::get() / 1024;
 		let mut topics = (0..API_BENCHMARK_BATCH_SIZE)
 			.map(|n| (n * t..n * t + t).map(|i| T::Hashing::hash_of(&i)).collect::<Vec<_>>().encode())
@@ -1922,7 +1923,7 @@ benchmarks! {
 
 	// w_br_table_per_entry = w_bench
 	instr_br_table_per_entry {
-		let e in 1 .. Contracts::<T>::current_schedule().limits.br_table_size;
+		let e in 1 .. <CurrentSchedule<T>>::get().limits.br_table_size;
 		let entry: Vec<u32> = [0, 1].iter()
 			.cloned()
 			.cycle()
@@ -1978,7 +1979,7 @@ benchmarks! {
 	// w_call_indrect = w_bench - 3 * w_param
 	instr_call_indirect {
 		let r in 0 .. INSTR_BENCHMARK_BATCHES;
-		let num_elements = Contracts::<T>::current_schedule().limits.table_size;
+		let num_elements = <CurrentSchedule<T>>::get().limits.table_size;
 		use self::code::TableSegment;
 		let mut sbox = Sandbox::from(&WasmModule::<T>::from(ModuleDefinition {
 			// We need to make use of the stack here in order to trigger stack height
@@ -2008,8 +2009,8 @@ benchmarks! {
 	// linearly depend on the amount of parameters to this function.
 	// Please note that this is not necessary with a direct call.
 	instr_call_indirect_per_param {
-		let p in 0 .. Contracts::<T>::current_schedule().limits.parameters;
-		let num_elements = Contracts::<T>::current_schedule().limits.table_size;
+		let p in 0 .. <CurrentSchedule<T>>::get().limits.parameters;
+		let num_elements = <CurrentSchedule<T>>::get().limits.table_size;
 		use self::code::TableSegment;
 		let mut sbox = Sandbox::from(&WasmModule::<T>::from(ModuleDefinition {
 			// We need to make use of the stack here in order to trigger stack height
@@ -2039,7 +2040,7 @@ benchmarks! {
 	// w_local_get = w_bench - 1 * w_param
 	instr_local_get {
 		let r in 0 .. INSTR_BENCHMARK_BATCHES;
-		let max_locals = Contracts::<T>::current_schedule().limits.stack_height;
+		let max_locals = <CurrentSchedule<T>>::get().limits.stack_height;
 		let mut call_body = body::repeated_dyn(r * INSTR_BENCHMARK_BATCH_SIZE, vec![
 			RandomGetLocal(0, max_locals),
 			Regular(Instruction::Drop),
@@ -2056,7 +2057,7 @@ benchmarks! {
 	// w_local_set = w_bench - 1 * w_param
 	instr_local_set {
 		let r in 0 .. INSTR_BENCHMARK_BATCHES;
-		let max_locals = Contracts::<T>::current_schedule().limits.stack_height;
+		let max_locals = <CurrentSchedule<T>>::get().limits.stack_height;
 		let mut call_body = body::repeated_dyn(r * INSTR_BENCHMARK_BATCH_SIZE, vec![
 			RandomI64Repeated(1),
 			RandomSetLocal(0, max_locals),
@@ -2073,7 +2074,7 @@ benchmarks! {
 	// w_local_tee = w_bench - 2 * w_param
 	instr_local_tee {
 		let r in 0 .. INSTR_BENCHMARK_BATCHES;
-		let max_locals = Contracts::<T>::current_schedule().limits.stack_height;
+		let max_locals = <CurrentSchedule<T>>::get().limits.stack_height;
 		let mut call_body = body::repeated_dyn(r * INSTR_BENCHMARK_BATCH_SIZE, vec![
 			RandomI64Repeated(1),
 			RandomTeeLocal(0, max_locals),
@@ -2091,7 +2092,7 @@ benchmarks! {
 	// w_global_get = w_bench - 1 * w_param
 	instr_global_get {
 		let r in 0 .. INSTR_BENCHMARK_BATCHES;
-		let max_globals = Contracts::<T>::current_schedule().limits.globals;
+		let max_globals = <CurrentSchedule<T>>::get().limits.globals;
 		let mut sbox = Sandbox::from(&WasmModule::<T>::from(ModuleDefinition {
 			call_body: Some(body::repeated_dyn(r * INSTR_BENCHMARK_BATCH_SIZE, vec![
 				RandomGetGlobal(0, max_globals),
@@ -2107,7 +2108,7 @@ benchmarks! {
 	// w_global_set = w_bench - 1 * w_param
 	instr_global_set {
 		let r in 0 .. INSTR_BENCHMARK_BATCHES;
-		let max_globals = Contracts::<T>::current_schedule().limits.globals;
+		let max_globals = <CurrentSchedule<T>>::get().limits.globals;
 		let mut sbox = Sandbox::from(&WasmModule::<T>::from(ModuleDefinition {
 			call_body: Some(body::repeated_dyn(r * INSTR_BENCHMARK_BATCH_SIZE, vec![
 				RandomI64Repeated(1),
diff --git a/frame/contracts/src/chain_extension.rs b/frame/contracts/src/chain_extension.rs
index dc6e9771775ca..4ac5300d57d7f 100644
--- a/frame/contracts/src/chain_extension.rs
+++ b/frame/contracts/src/chain_extension.rs
@@ -47,6 +47,12 @@
 //! induces. In order to be able to charge the correct weight for the functions defined
 //! by a chain extension benchmarks must be written, too. In the near future this crate
 //! will provide the means for easier creation of those specialized benchmarks.
+//!
+//! # Example
+//!
+//! The ink! repository maintains an
+//! [end-to-end example](https://github.com/paritytech/ink/tree/master/examples/rand-extension)
+//! on how to use a chain extension in order to provide new features to ink! contracts.
 
 use crate::{
 	Error,
@@ -141,8 +147,8 @@ pub enum RetVal {
 
 /// Grants the chain extension access to its parameters and execution environment.
 ///
-/// It uses the typestate pattern to enforce the correct usage of the parameters passed
-/// to the chain extension.
+/// It uses [typestate programming](https://docs.rust-embedded.org/book/static-guarantees/typestate-programming.html)
+/// to enforce the correct usage of the parameters passed to the chain extension.
 pub struct Environment<'a, 'b, E: Ext, S: state::State> {
 	/// The actual data of this type.
 	inner: Inner<'a, 'b, E>,
@@ -376,6 +382,8 @@ mod state {
 	pub trait BufIn: State {}
 	pub trait BufOut: State {}
 
+	/// The initial state of an [`Environment`](`super::Environment`).
+	/// See [typestate programming](https://docs.rust-embedded.org/book/static-guarantees/typestate-programming.html).
 	pub enum Init {}
 	pub enum OnlyIn {}
 	pub enum PrimInBufOut {}
diff --git a/frame/contracts/src/exec.rs b/frame/contracts/src/exec.rs
index 427cf1ada5ad5..27f70dea8c598 100644
--- a/frame/contracts/src/exec.rs
+++ b/frame/contracts/src/exec.rs
@@ -16,7 +16,7 @@
 // limitations under the License.
 
 use crate::{
-	CodeHash, Event, Config, Module as Contracts,
+	CodeHash, Event, Config, Pallet as Contracts,
 	TrieId, BalanceOf, ContractInfo, gas::GasMeter, rent::Rent, storage::{self, Storage},
 	Error, ContractInfoOf, Schedule, AliveContractInfo,
 };
@@ -243,7 +243,7 @@ pub trait Ext: sealing::Sealed {
 	fn tombstone_deposit(&self) -> BalanceOf<Self::T>;
 
 	/// Returns a random number for the current block with the given subject.
-	fn random(&self, subject: &[u8]) -> SeedOf<Self::T>;
+	fn random(&self, subject: &[u8]) -> (SeedOf<Self::T>, BlockNumberOf<Self::T>);
 
 	/// Deposit an event with the given topics.
 	///
@@ -384,7 +384,7 @@ where
 			depth: 0,
 			schedule,
 			timestamp: T::Time::now(),
-			block_number: <frame_system::Module<T>>::block_number(),
+			block_number: <frame_system::Pallet<T>>::block_number(),
 			_phantom: Default::default(),
 		}
 	}
@@ -845,10 +845,8 @@ where
 		self.value_transferred
 	}
 
-	fn random(&self, subject: &[u8]) -> SeedOf<T> {
-		// TODO: change API to expose randomness freshness
-		// https://github.com/paritytech/substrate/issues/8297
-		T::Randomness::random(subject).0
+	fn random(&self, subject: &[u8]) -> (SeedOf<T>, BlockNumberOf<T>) {
+		T::Randomness::random(subject)
 	}
 
 	fn now(&self) -> &MomentOf<T> {
@@ -909,7 +907,7 @@ fn deposit_event<T: Config>(
 	topics: Vec<T::Hash>,
 	event: Event<T>,
 ) {
-	<frame_system::Module<T>>::deposit_event_indexed(
+	<frame_system::Pallet<T>>::deposit_event_indexed(
 		&*topics,
 		<T as Config>::Event::from(event).into(),
 	)
@@ -945,7 +943,7 @@ mod tests {
 			test_utils::{place_contract, set_balance, get_balance},
 		},
 		exec::ExportedFunction::*,
-		Error, Weight,
+		Error, Weight, CurrentSchedule,
 	};
 	use sp_runtime::DispatchError;
 	use assert_matches::assert_matches;
@@ -961,7 +959,7 @@ mod tests {
 	}
 
 	fn events() -> Vec<Event<Test>> {
-		<frame_system::Module<Test>>::events()
+		<frame_system::Pallet<Test>>::events()
 			.into_iter()
 			.filter_map(|meta| match meta.event {
 				MetaEvent::pallet_contracts(contract_event) => Some(contract_event),
@@ -1141,7 +1139,7 @@ mod tests {
 		});
 
 		ExtBuilder::default().build().execute_with(|| {
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(ALICE, &schedule);
 			place_contract(&BOB, exec_ch);
 
@@ -1191,7 +1189,7 @@ mod tests {
 		);
 
 		ExtBuilder::default().build().execute_with(|| {
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(origin.clone(), &schedule);
 			place_contract(&BOB, return_ch);
 			set_balance(&origin, 100);
@@ -1251,7 +1249,7 @@ mod tests {
 		);
 
 		ExtBuilder::default().build().execute_with(|| {
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(origin, &schedule);
 			place_contract(&BOB, return_ch);
 
@@ -1280,7 +1278,7 @@ mod tests {
 		);
 
 		ExtBuilder::default().build().execute_with(|| {
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(origin, &schedule);
 			place_contract(&BOB, return_ch);
 
@@ -1306,7 +1304,7 @@ mod tests {
 
 		// This one tests passing the input data into a contract via call.
 		ExtBuilder::default().build().execute_with(|| {
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(ALICE, &schedule);
 			place_contract(&BOB, input_data_ch);
 
@@ -1329,7 +1327,7 @@ mod tests {
 
 		// This one tests passing the input data into a contract via instantiate.
 		ExtBuilder::default().build().execute_with(|| {
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let subsistence = Contracts::<Test>::subsistence_threshold();
 			let mut ctx = MockContext::top_level(ALICE, &schedule);
 			let mut gas_meter = GasMeter::<Test>::new(GAS_LIMIT);
@@ -1382,7 +1380,7 @@ mod tests {
 		});
 
 		ExtBuilder::default().build().execute_with(|| {
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(ALICE, &schedule);
 			set_balance(&BOB, 1);
 			place_contract(&BOB, recurse_ch);
@@ -1430,7 +1428,7 @@ mod tests {
 		});
 
 		ExtBuilder::default().build().execute_with(|| {
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(origin.clone(), &schedule);
 			place_contract(&dest, bob_ch);
 			place_contract(&CHARLIE, charlie_ch);
@@ -1468,7 +1466,7 @@ mod tests {
 		});
 
 		ExtBuilder::default().build().execute_with(|| {
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(ALICE, &schedule);
 			place_contract(&BOB, bob_ch);
 			place_contract(&CHARLIE, charlie_ch);
@@ -1489,7 +1487,7 @@ mod tests {
 		let dummy_ch = MockLoader::insert(Constructor, |_, _| exec_success());
 
 		ExtBuilder::default().existential_deposit(15).build().execute_with(|| {
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(ALICE, &schedule);
 			let mut gas_meter = GasMeter::<Test>::new(GAS_LIMIT);
 			let executable = MockExecutable::from_storage(
@@ -1517,7 +1515,7 @@ mod tests {
 		);
 
 		ExtBuilder::default().existential_deposit(15).build().execute_with(|| {
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(ALICE, &schedule);
 			let mut gas_meter = GasMeter::<Test>::new(GAS_LIMIT);
 			let executable = MockExecutable::from_storage(
@@ -1553,7 +1551,7 @@ mod tests {
 		);
 
 		ExtBuilder::default().existential_deposit(15).build().execute_with(|| {
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(ALICE, &schedule);
 			let mut gas_meter = GasMeter::<Test>::new(GAS_LIMIT);
 			let executable = MockExecutable::from_storage(
@@ -1601,7 +1599,7 @@ mod tests {
 		});
 
 		ExtBuilder::default().existential_deposit(15).build().execute_with(|| {
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(ALICE, &schedule);
 			set_balance(&ALICE, Contracts::<Test>::subsistence_threshold() * 100);
 			place_contract(&BOB, instantiator_ch);
@@ -1650,7 +1648,7 @@ mod tests {
 		});
 
 		ExtBuilder::default().existential_deposit(15).build().execute_with(|| {
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(ALICE, &schedule);
 			set_balance(&ALICE, 1000);
 			set_balance(&BOB, 100);
@@ -1678,7 +1676,7 @@ mod tests {
 			.existential_deposit(15)
 			.build()
 			.execute_with(|| {
-				let schedule = Contracts::current_schedule();
+				let schedule = <CurrentSchedule<Test>>::get();
 				let mut ctx = MockContext::top_level(ALICE, &schedule);
 				let mut gas_meter = GasMeter::<Test>::new(GAS_LIMIT);
 				let executable = MockExecutable::from_storage(
@@ -1717,7 +1715,7 @@ mod tests {
 
 		ExtBuilder::default().build().execute_with(|| {
 			let subsistence = Contracts::<Test>::subsistence_threshold();
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(ALICE, &schedule);
 			let mut gas_meter = GasMeter::<Test>::new(GAS_LIMIT);
 			let executable = MockExecutable::from_storage(
@@ -1749,7 +1747,7 @@ mod tests {
 
 		ExtBuilder::default().build().execute_with(|| {
 			let subsistence = Contracts::<Test>::subsistence_threshold();
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(ALICE, &schedule);
 			let mut gas_meter = GasMeter::<Test>::new(GAS_LIMIT);
 			set_balance(&ALICE, subsistence * 10);
@@ -1797,7 +1795,7 @@ mod tests {
 
 		ExtBuilder::default().build().execute_with(|| {
 			let subsistence = Contracts::<Test>::subsistence_threshold();
-			let schedule = Contracts::current_schedule();
+			let schedule = <CurrentSchedule<Test>>::get();
 			let mut ctx = MockContext::top_level(ALICE, &schedule);
 			let mut gas_meter = GasMeter::<Test>::new(GAS_LIMIT);
 			set_balance(&ALICE, subsistence * 100);
diff --git a/frame/contracts/src/lib.rs b/frame/contracts/src/lib.rs
index 5453e079e3ae4..46947ea9e1aef 100644
--- a/frame/contracts/src/lib.rs
+++ b/frame/contracts/src/lib.rs
@@ -15,21 +15,21 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//! # Contract Module
+//! # Contract Pallet
 //!
 //! The Contract module provides functionality for the runtime to deploy and execute WebAssembly smart-contracts.
 //!
-//! - [`contract::Config`](./trait.Config.html)
-//! - [`Call`](./enum.Call.html)
+//! - [`Config`]
+//! - [`Call`]
 //!
 //! ## Overview
 //!
-//! This module extends accounts based on the `Currency` trait to have smart-contract functionality. It can
-//! be used with other modules that implement accounts based on `Currency`. These "smart-contract accounts"
+//! This module extends accounts based on the [`Currency`] trait to have smart-contract functionality. It can
+//! be used with other modules that implement accounts based on [`Currency`]. These "smart-contract accounts"
 //! have the ability to instantiate smart-contracts and make calls to other contract and non-contract accounts.
 //!
-//! The smart-contract code is stored once in a `code_cache`, and later retrievable via its `code_hash`.
-//! This means that multiple smart-contracts can be instantiated from the same `code_cache`, without replicating
+//! The smart-contract code is stored once in a code cache, and later retrievable via its hash.
+//! This means that multiple smart-contracts can be instantiated from the same hash, without replicating
 //! the code each time.
 //!
 //! When a smart-contract is called, its associated code is retrieved via the code hash and gets executed.
@@ -59,12 +59,17 @@
 //!
 //! ### Dispatchable functions
 //!
-//! * `instantiate_with_code` - Deploys a new contract from the supplied wasm binary, optionally transferring
-//! some balance. This instantiates a new smart contract account and calls its contract deploy
-//! handler to initialize the contract.
-//! * `instantiate` - The same as `instantiate_with_code` but instead of uploading new code an
-//! existing `code_hash` is supplied.
-//! * `call` - Makes a call to an account, optionally transferring some balance.
+//! * [`Pallet::update_schedule`] -
+//! ([Root Origin](https://substrate.dev/docs/en/knowledgebase/runtime/origin) Only) -
+//! Set a new [`Schedule`].
+//! * [`Pallet::instantiate_with_code`] - Deploys a new contract from the supplied wasm binary,
+//! optionally transferring
+//! some balance. This instantiates a new smart contract account with the supplied code and
+//! calls its constructor to initialize the contract.
+//! * [`Pallet::instantiate`] - The same as `instantiate_with_code` but instead of uploading new
+//! code an existing `code_hash` is supplied.
+//! * [`Pallet::call`] - Makes a call to an account, optionally transferring some balance.
+//! * [`Pallet::claim_surcharge`] - Evict a contract that cannot pay rent anymore.
 //!
 //! ## Usage
 //!
@@ -98,47 +103,38 @@ pub mod weights;
 #[cfg(test)]
 mod tests;
 
-pub use crate::{
-	wasm::PrefabWasmModule,
-	schedule::{Schedule, HostFnWeights, InstructionWeights, Limits},
-	pallet::*,
-};
+pub use crate::{pallet::*, schedule::Schedule};
 use crate::{
 	gas::GasMeter,
 	exec::{ExecutionContext, Executable},
 	rent::Rent,
-	storage::{Storage, DeletedContract},
+	storage::{Storage, DeletedContract, ContractInfo, AliveContractInfo, TombstoneContractInfo},
 	weights::WeightInfo,
+	wasm::PrefabWasmModule,
 };
 use sp_core::crypto::UncheckedFrom;
-use sp_std::{prelude::*, marker::PhantomData, fmt::Debug};
-use codec::{Codec, Encode, Decode};
+use sp_std::prelude::*;
 use sp_runtime::{
 	traits::{
-		Hash, StaticLookup, MaybeSerializeDeserialize, Member, Convert, Saturating, Zero,
+		Hash, StaticLookup, Convert, Saturating, Zero,
 	},
-	RuntimeDebug, Perbill,
+	Perbill,
 };
 use frame_support::{
-	storage::child::ChildInfo,
 	traits::{OnUnbalanced, Currency, Get, Time, Randomness},
 	weights::{Weight, PostDispatchInfo, WithPostDispatchInfo},
 };
-use frame_system::Module as System;
+use frame_system::Pallet as System;
 use pallet_contracts_primitives::{
 	RentProjectionResult, GetStorageResult, ContractAccessError, ContractExecResult,
 };
 
-pub type CodeHash<T> = <T as frame_system::Config>::Hash;
-pub type TrieId = Vec<u8>;
-pub type BalanceOf<T> =
+type CodeHash<T> = <T as frame_system::Config>::Hash;
+type TrieId = Vec<u8>;
+type BalanceOf<T> =
 	<<T as Config>::Currency as Currency<<T as frame_system::Config>::AccountId>>::Balance;
-pub type NegativeImbalanceOf<T> =
+type NegativeImbalanceOf<T> =
 	<<T as Config>::Currency as Currency<<T as frame_system::Config>::AccountId>>::NegativeImbalance;
-pub type AliveContractInfo<T> =
-	RawAliveContractInfo<CodeHash<T>, BalanceOf<T>, <T as frame_system::Config>::BlockNumber>;
-pub type TombstoneContractInfo<T> =
-	RawTombstoneContractInfo<<T as frame_system::Config>::Hash, <T as frame_system::Config>::Hashing>;
 
 #[frame_support::pallet]
 pub mod pallet {
@@ -221,7 +217,7 @@ pub mod pallet {
 		#[pallet::constant]
 		type MaxValueSize: Get<u32>;
 
-		/// Used to answer contracts's queries regarding the current weight price. This is **not**
+		/// Used to answer contracts' queries regarding the current weight price. This is **not**
 		/// used to calculate the actual fee and is only for informational purposes.
 		type WeightPrice: Convert<Weight, BalanceOf<Self>>;
 
@@ -248,7 +244,6 @@ pub mod pallet {
 	}
 
 	#[pallet::pallet]
-	#[pallet::generate_store(pub(super) trait Store)]
 	pub struct Pallet<T>(PhantomData<T>);
 
 	#[pallet::hooks]
@@ -290,7 +285,7 @@ pub mod pallet {
 			schedule: Schedule<T>
 		) -> DispatchResultWithPostInfo {
 			ensure_root(origin)?;
-			if <Module<T>>::current_schedule().version > schedule.version {
+			if <CurrentSchedule<T>>::get().version > schedule.version {
 				Err(Error::<T>::InvalidScheduleVersion)?
 			}
 			Self::deposit_event(Event::ScheduleUpdated(schedule.version));
@@ -316,7 +311,7 @@ pub mod pallet {
 			let origin = ensure_signed(origin)?;
 			let dest = T::Lookup::lookup(dest)?;
 			let mut gas_meter = GasMeter::new(gas_limit);
-			let schedule = <Module<T>>::current_schedule();
+			let schedule = <CurrentSchedule<T>>::get();
 			let mut ctx = ExecutionContext::<T, PrefabWasmModule<T>>::top_level(origin, &schedule);
 			let (result, code_len) = match ctx.call(dest, value, &mut gas_meter, data) {
 				Ok((output, len)) => (Ok(output), len),
@@ -336,7 +331,7 @@ pub mod pallet {
 		/// * `gas_limit`: The gas limit enforced when executing the constructor.
 		/// * `code`: The contract code to deploy in raw bytes.
 		/// * `data`: The input data to pass to the contract constructor.
-		/// * `salt`: Used for the address derivation. See [`Self::contract_address`].
+		/// * `salt`: Used for the address derivation. See [`Pallet::contract_address`].
 		///
 		/// Instantiation is executed as follows:
 		///
@@ -365,7 +360,7 @@ pub mod pallet {
 			let code_len = code.len() as u32;
 			ensure!(code_len <= T::MaxCodeSize::get(), Error::<T>::CodeTooLarge);
 			let mut gas_meter = GasMeter::new(gas_limit);
-			let schedule = <Module<T>>::current_schedule();
+			let schedule = <CurrentSchedule<T>>::get();
 			let executable = PrefabWasmModule::from_code(code, &schedule)?;
 			let code_len = executable.code_len();
 			ensure!(code_len <= T::MaxCodeSize::get(), Error::<T>::CodeTooLarge);
@@ -397,7 +392,7 @@ pub mod pallet {
 		) -> DispatchResultWithPostInfo {
 			let origin = ensure_signed(origin)?;
 			let mut gas_meter = GasMeter::new(gas_limit);
-			let schedule = <Module<T>>::current_schedule();
+			let schedule = <CurrentSchedule<T>>::get();
 			let executable = PrefabWasmModule::from_storage(code_hash, &schedule, &mut gas_meter)?;
 			let mut ctx = ExecutionContext::<T, PrefabWasmModule<T>>::top_level(origin, &schedule);
 			let code_len = executable.code_len();
@@ -614,33 +609,33 @@ pub mod pallet {
 
 	/// Current cost schedule for contracts.
 	#[pallet::storage]
-	#[pallet::getter(fn current_schedule)]
-	pub(super) type CurrentSchedule<T: Config> = StorageValue<_, Schedule<T>, ValueQuery>;
+	pub(crate) type CurrentSchedule<T: Config> = StorageValue<_, Schedule<T>, ValueQuery>;
 
 	/// A mapping from an original code hash to the original code, untouched by instrumentation.
 	#[pallet::storage]
-	pub type PristineCode<T: Config> = StorageMap<_, Identity, CodeHash<T>, Vec<u8>>;
+	pub(crate) type PristineCode<T: Config> = StorageMap<_, Identity, CodeHash<T>, Vec<u8>>;
 
 	/// A mapping between an original code hash and instrumented wasm code, ready for execution.
 	#[pallet::storage]
-	pub type CodeStorage<T: Config> = StorageMap<_, Identity, CodeHash<T>, PrefabWasmModule<T>>;
+	pub(crate) type CodeStorage<T: Config> = StorageMap<_, Identity, CodeHash<T>, PrefabWasmModule<T>>;
 
 	/// The subtrie counter.
 	#[pallet::storage]
-	pub type AccountCounter<T: Config> = StorageValue<_, u64, ValueQuery>;
+	pub(crate) type AccountCounter<T: Config> = StorageValue<_, u64, ValueQuery>;
 
 	/// The code associated with a given account.
 	///
 	/// TWOX-NOTE: SAFE since `AccountId` is a secure hash.
 	#[pallet::storage]
-	pub type ContractInfoOf<T: Config> = StorageMap<_, Twox64Concat, T::AccountId, ContractInfo<T>>;
+	pub(crate) type ContractInfoOf<T: Config> = StorageMap<_, Twox64Concat, T::AccountId, ContractInfo<T>>;
 
 	/// Evicted contracts that await child trie deletion.
 	///
 	/// Child trie deletion is a heavy operation depending on the amount of storage items
 	/// stored in said trie. Therefore this operation is performed lazily in `on_initialize`.
 	#[pallet::storage]
-	pub type DeletionQueue<T: Config> = StorageValue<_, Vec<DeletedContract>, ValueQuery>;
+	pub(crate) type DeletionQueue<T: Config> = StorageValue<_, Vec<DeletedContract>, ValueQuery>;
+
 
 	#[pallet::genesis_config]
 	pub struct GenesisConfig<T: Config> {
@@ -665,7 +660,7 @@ pub mod pallet {
 	}
 }
 
-impl<T: Config> Module<T>
+impl<T: Config> Pallet<T>
 where
 	T::AccountId: UncheckedFrom<T::Hash> + AsRef<[u8]>,
 {
@@ -683,7 +678,7 @@ where
 		input_data: Vec<u8>,
 	) -> ContractExecResult {
 		let mut gas_meter = GasMeter::new(gas_limit);
-		let schedule = <Module<T>>::current_schedule();
+		let schedule = <CurrentSchedule<T>>::get();
 		let mut ctx = ExecutionContext::<T, PrefabWasmModule<T>>::top_level(origin, &schedule);
 		let result = ctx.call(dest, value, &mut gas_meter, input_data);
 		let gas_consumed = gas_meter.gas_spent();
@@ -743,10 +738,24 @@ where
 		T::Currency::minimum_balance().saturating_add(T::TombstoneDeposit::get())
 	}
 
+	/// The in-memory size in bytes of the data structure associated with each contract.
+	///
+	/// The data structure is also put into storage for each contract. The in-storage size
+	/// is never larger than the in-memory representation and usually smaller due to compact
+	/// encoding and lack of padding.
+	///
+	/// # Note
+	///
+	/// This returns the in-memory size because the in-storage size (SCALE encoded) cannot
+	/// be efficiently determined. Treat this as an upper bound of the in-storage size.
+	pub fn contract_info_size() -> u32 {
+		sp_std::mem::size_of::<ContractInfo<T>>() as u32
+	}
+
 	/// Store code for benchmarks which does not check nor instrument the code.
 	#[cfg(feature = "runtime-benchmarks")]
 	fn store_code_raw(code: Vec<u8>) -> frame_support::dispatch::DispatchResult {
-		let schedule = <Module<T>>::current_schedule();
+		let schedule = <CurrentSchedule<T>>::get();
 		PrefabWasmModule::store_code_unchecked(code, &schedule)?;
 		Ok(())
 	}
@@ -760,127 +769,3 @@ where
 		self::wasm::reinstrument(module, schedule)
 	}
 }
-
-/// Information for managing an account and its sub trie abstraction.
-/// This is the required info to cache for an account
-#[derive(Encode, Decode, RuntimeDebug)]
-pub enum ContractInfo<T: Config> {
-	Alive(AliveContractInfo<T>),
-	Tombstone(TombstoneContractInfo<T>),
-}
-
-impl<T: Config> ContractInfo<T> {
-	/// If contract is alive then return some alive info
-	pub fn get_alive(self) -> Option<AliveContractInfo<T>> {
-		if let ContractInfo::Alive(alive) = self {
-			Some(alive)
-		} else {
-			None
-		}
-	}
-	/// If contract is alive then return some reference to alive info
-	pub fn as_alive(&self) -> Option<&AliveContractInfo<T>> {
-		if let ContractInfo::Alive(ref alive) = self {
-			Some(alive)
-		} else {
-			None
-		}
-	}
-	/// If contract is alive then return some mutable reference to alive info
-	pub fn as_alive_mut(&mut self) -> Option<&mut AliveContractInfo<T>> {
-		if let ContractInfo::Alive(ref mut alive) = self {
-			Some(alive)
-		} else {
-			None
-		}
-	}
-
-	/// If contract is tombstone then return some tombstone info
-	pub fn get_tombstone(self) -> Option<TombstoneContractInfo<T>> {
-		if let ContractInfo::Tombstone(tombstone) = self {
-			Some(tombstone)
-		} else {
-			None
-		}
-	}
-	/// If contract is tombstone then return some reference to tombstone info
-	pub fn as_tombstone(&self) -> Option<&TombstoneContractInfo<T>> {
-		if let ContractInfo::Tombstone(ref tombstone) = self {
-			Some(tombstone)
-		} else {
-			None
-		}
-	}
-	/// If contract is tombstone then return some mutable reference to tombstone info
-	pub fn as_tombstone_mut(&mut self) -> Option<&mut TombstoneContractInfo<T>> {
-		if let ContractInfo::Tombstone(ref mut tombstone) = self {
-			Some(tombstone)
-		} else {
-			None
-		}
-	}
-}
-
-/// Information for managing an account and its sub trie abstraction.
-/// This is the required info to cache for an account.
-#[derive(Encode, Decode, Clone, PartialEq, Eq, RuntimeDebug)]
-pub struct RawAliveContractInfo<CodeHash, Balance, BlockNumber> {
-	/// Unique ID for the subtree encoded as a bytes vector.
-	pub trie_id: TrieId,
-	/// The total number of bytes used by this contract.
-	///
-	/// It is a sum of each key-value pair stored by this contract.
-	pub storage_size: u32,
-	/// The total number of key-value pairs in storage of this contract.
-	pub pair_count: u32,
-	/// The code associated with a given account.
-	pub code_hash: CodeHash,
-	/// Pay rent at most up to this value.
-	pub rent_allowance: Balance,
-	/// The amount of rent that was payed by the contract over its whole lifetime.
-	///
-	/// A restored contract starts with a value of zero just like a new contract.
-	pub rent_payed: Balance,
-	/// Last block rent has been payed.
-	pub deduct_block: BlockNumber,
-	/// Last block child storage has been written.
-	pub last_write: Option<BlockNumber>,
-	/// This field is reserved for future evolution of format.
-	pub _reserved: Option<()>,
-}
-
-impl<CodeHash, Balance, BlockNumber> RawAliveContractInfo<CodeHash, Balance, BlockNumber> {
-	/// Associated child trie unique id is built from the hash part of the trie id.
-	pub fn child_trie_info(&self) -> ChildInfo {
-		child_trie_info(&self.trie_id[..])
-	}
-}
-
-/// Associated child trie unique id is built from the hash part of the trie id.
-pub(crate) fn child_trie_info(trie_id: &[u8]) -> ChildInfo {
-	ChildInfo::new_default(trie_id)
-}
-
-#[derive(Encode, Decode, PartialEq, Eq, RuntimeDebug)]
-pub struct RawTombstoneContractInfo<H, Hasher>(H, PhantomData<Hasher>);
-
-impl<H, Hasher> RawTombstoneContractInfo<H, Hasher>
-where
-	H: Member + MaybeSerializeDeserialize+ Debug
-		+ AsRef<[u8]> + AsMut<[u8]> + Copy + Default
-		+ sp_std::hash::Hash + Codec,
-	Hasher: Hash<Output=H>,
-{
-	fn new(storage_root: &[u8], code_hash: H) -> Self {
-		let mut buf = Vec::new();
-		storage_root.using_encoded(|encoded| buf.extend_from_slice(encoded));
-		buf.extend_from_slice(code_hash.as_ref());
-		RawTombstoneContractInfo(<Hasher as Hash>::hash(&buf[..]), PhantomData)
-	}
-}
-
-impl<T: Config> From<AliveContractInfo<T>> for ContractInfo<T> {
-	fn from(alive_info: AliveContractInfo<T>) -> Self {
-		Self::Alive(alive_info)
-	}
-}
diff --git a/frame/contracts/src/rent.rs b/frame/contracts/src/rent.rs
index e9befeee2d370..8605451ad1ee7 100644
--- a/frame/contracts/src/rent.rs
+++ b/frame/contracts/src/rent.rs
@@ -18,7 +18,7 @@
 //! A module responsible for computing the right amount of weight and charging it.
 
 use crate::{
-	AliveContractInfo, BalanceOf, ContractInfo, ContractInfoOf, Module, Event,
+	AliveContractInfo, BalanceOf, ContractInfo, ContractInfoOf, Pallet, Event,
 	TombstoneContractInfo, Config, CodeHash, Error,
 	storage::Storage, wasm::PrefabWasmModule, exec::Executable,
 };
@@ -124,7 +124,7 @@ where
 		free_balance: &BalanceOf<T>,
 		contract: &AliveContractInfo<T>,
 	) -> Option<BalanceOf<T>> {
-		let subsistence_threshold = Module::<T>::subsistence_threshold();
+		let subsistence_threshold = Pallet::<T>::subsistence_threshold();
 		// Reserved balance contributes towards the subsistence threshold to stay consistent
 		// with the existential deposit where the reserved balance is also counted.
 		if *total_balance < subsistence_threshold {
@@ -245,7 +245,6 @@ where
 		evictable_code: Option<PrefabWasmModule<T>>,
 	) -> Result<Option<AliveContractInfo<T>>, DispatchError> {
 		match (verdict, evictable_code) {
-			(Verdict::Exempt, _) => return Ok(Some(alive_contract_info)),
 			(Verdict::Evict { amount }, Some(code)) => {
 				// We need to remove the trie first because it is the only operation
 				// that can fail and this function is called without a storage
@@ -268,12 +267,20 @@ where
 				let tombstone_info = ContractInfo::Tombstone(tombstone);
 				<ContractInfoOf<T>>::insert(account, &tombstone_info);
 				code.drop_from_storage();
-				<Module<T>>::deposit_event(Event::Evicted(account.clone()));
+				<Pallet<T>>::deposit_event(Event::Evicted(account.clone()));
 				Ok(None)
 			}
 			(Verdict::Evict { amount: _ }, None) => {
 				Ok(None)
 			}
+			(Verdict::Exempt, _) =>  {
+				let contract = ContractInfo::Alive(AliveContractInfo::<T> {
+					deduct_block: current_block_number,
+					..alive_contract_info
+				});
+				<ContractInfoOf<T>>::insert(account, &contract);
+				Ok(Some(contract.get_alive().expect("We just constructed it as alive. qed")))
+			},
 			(Verdict::Charge { amount }, _) => {
 				let contract = ContractInfo::Alive(AliveContractInfo::<T> {
 					rent_allowance: alive_contract_info.rent_allowance - amount.peek(),
@@ -298,7 +305,7 @@ where
 		contract: AliveContractInfo<T>,
 		code_size: u32,
 	) -> Result<Option<AliveContractInfo<T>>, DispatchError> {
-		let current_block_number = <frame_system::Module<T>>::block_number();
+		let current_block_number = <frame_system::Pallet<T>>::block_number();
 		let verdict = Self::consider_case(
 			account,
 			current_block_number,
@@ -333,7 +340,7 @@ where
 		};
 		let module = PrefabWasmModule::<T>::from_storage_noinstr(contract.code_hash)?;
 		let code_len = module.code_len();
-		let current_block_number = <frame_system::Module<T>>::block_number();
+		let current_block_number = <frame_system::Pallet<T>>::block_number();
 		let verdict = Self::consider_case(
 			account,
 			current_block_number,
@@ -384,7 +391,7 @@ where
 		let module = PrefabWasmModule::from_storage_noinstr(alive_contract_info.code_hash)
 			.map_err(|_| IsTombstone)?;
 		let code_size = module.occupied_storage();
-		let current_block_number = <frame_system::Module<T>>::block_number();
+		let current_block_number = <frame_system::Pallet<T>>::block_number();
 		let verdict = Self::consider_case(
 			account,
 			current_block_number,
@@ -465,7 +472,7 @@ where
 
 		let child_trie_info = origin_contract.child_trie_info();
 
-		let current_block = <frame_system::Module<T>>::block_number();
+		let current_block = <frame_system::Pallet<T>>::block_number();
 
 		if origin_contract.last_write == Some(current_block) {
 			return Err((Error::<T>::InvalidContractOrigin.into(), 0, 0));
diff --git a/frame/contracts/src/schedule.rs b/frame/contracts/src/schedule.rs
index 24ba83cc1b799..90c396c627775 100644
--- a/frame/contracts/src/schedule.rs
+++ b/frame/contracts/src/schedule.rs
@@ -39,7 +39,11 @@ pub const API_BENCHMARK_BATCH_SIZE: u32 = 100;
 /// as for `API_BENCHMARK_BATCH_SIZE`.
 pub const INSTR_BENCHMARK_BATCH_SIZE: u32 = 1_000;
 
-/// Definition of the cost schedule and other parameterizations for wasm vm.
+/// Definition of the cost schedule and other parameterizations for the wasm vm.
+///
+/// Its fields are private to the crate in order to allow addition of new contract
+/// callable functions without bumping to a new major version. A genesis config should
+/// rely on public functions of this type.
 #[cfg_attr(feature = "std", derive(Serialize, Deserialize))]
 #[cfg_attr(feature = "std", serde(bound(serialize = "", deserialize = "")))]
 #[derive(Clone, Encode, Decode, PartialEq, Eq, ScheduleDebug)]
@@ -53,20 +57,20 @@ pub struct Schedule<T: Config> {
 	/// of all contracts which are triggered by a version comparison on call.
 	/// Changes to other parts of the schedule should not increment the version in
 	/// order to avoid unnecessary re-instrumentations.
-	pub version: u32,
+	pub(crate) version: u32,
 
 	/// Whether the `seal_println` function is allowed to be used contracts.
 	/// MUST only be enabled for `dev` chains, NOT for production chains
-	pub enable_println: bool,
+	pub(crate) enable_println: bool,
 
 	/// Describes the upper limits on various metrics.
-	pub limits: Limits,
+	pub(crate) limits: Limits,
 
 	/// The weights for individual wasm instructions.
-	pub instruction_weights: InstructionWeights<T>,
+	pub(crate) instruction_weights: InstructionWeights<T>,
 
 	/// The weights for each imported function a contract is allowed to call.
-	pub host_fn_weights: HostFnWeights<T>,
+	pub(crate) host_fn_weights: HostFnWeights<T>,
 }
 
 /// Describes the upper limits on various metrics.
@@ -602,7 +606,21 @@ struct ScheduleRules<'a, T: Config> {
 }
 
 impl<T: Config> Schedule<T> {
-	pub fn rules(&self, module: &elements::Module) -> impl rules::Rules + '_ {
+	/// Allow contracts to call `seal_println` in order to print messages to the console.
+	///
+	/// This should only ever be activated in development chains. The printed messages
+	/// can be observed on the console by setting the environment variable
+	/// `RUST_LOG=runtime=debug` when running the node.
+	///
+	/// # Note
+	///
+	/// Is set to `false` by default.
+	pub fn enable_println(mut self, enable: bool) -> Self {
+		self.enable_println = enable;
+		self
+	}
+
+	pub(crate) fn rules(&self, module: &elements::Module) -> impl rules::Rules + '_ {
 		ScheduleRules {
 			schedule: &self,
 			params: module
diff --git a/frame/contracts/src/storage.rs b/frame/contracts/src/storage.rs
index 970eec2003668..d78551f8f170e 100644
--- a/frame/contracts/src/storage.rs
+++ b/frame/contracts/src/storage.rs
@@ -19,23 +19,131 @@
 
 use crate::{
 	exec::{AccountIdOf, StorageKey},
-	AliveContractInfo, BalanceOf, CodeHash, ContractInfo, ContractInfoOf, Config, TrieId,
+	BalanceOf, CodeHash, ContractInfoOf, Config, TrieId,
 	AccountCounter, DeletionQueue, Error,
 	weights::WeightInfo,
 };
-use codec::{Encode, Decode};
+use codec::{Codec, Encode, Decode};
 use sp_std::prelude::*;
-use sp_std::marker::PhantomData;
+use sp_std::{marker::PhantomData, fmt::Debug};
 use sp_io::hashing::blake2_256;
-use sp_runtime::traits::{Bounded, Saturating, Zero};
+use sp_runtime::{
+	RuntimeDebug,
+	traits::{Bounded, Saturating, Zero, Hash, Member, MaybeSerializeDeserialize},
+};
 use sp_core::crypto::UncheckedFrom;
 use frame_support::{
 	dispatch::{DispatchError, DispatchResult},
-	storage::child::{self, KillChildStorageResult},
+	storage::child::{self, KillChildStorageResult, ChildInfo},
 	traits::Get,
 	weights::Weight,
 };
 
+pub type AliveContractInfo<T> =
+	RawAliveContractInfo<CodeHash<T>, BalanceOf<T>, <T as frame_system::Config>::BlockNumber>;
+pub type TombstoneContractInfo<T> =
+	RawTombstoneContractInfo<<T as frame_system::Config>::Hash, <T as frame_system::Config>::Hashing>;
+
+/// Information for managing an account and its sub trie abstraction.
+/// This is the required info to cache for an account
+#[derive(Encode, Decode, RuntimeDebug)]
+pub enum ContractInfo<T: Config> {
+	Alive(AliveContractInfo<T>),
+	Tombstone(TombstoneContractInfo<T>),
+}
+
+impl<T: Config> ContractInfo<T> {
+	/// If contract is alive then return some alive info
+	pub fn get_alive(self) -> Option<AliveContractInfo<T>> {
+		if let ContractInfo::Alive(alive) = self {
+			Some(alive)
+		} else {
+			None
+		}
+	}
+	/// If contract is alive then return some reference to alive info
+	pub fn as_alive(&self) -> Option<&AliveContractInfo<T>> {
+		if let ContractInfo::Alive(ref alive) = self {
+			Some(alive)
+		} else {
+			None
+		}
+	}
+
+	/// If contract is tombstone then return some tombstone info
+	pub fn get_tombstone(self) -> Option<TombstoneContractInfo<T>> {
+		if let ContractInfo::Tombstone(tombstone) = self {
+			Some(tombstone)
+		} else {
+			None
+		}
+	}
+}
+
+/// Information for managing an account and its sub trie abstraction.
+/// This is the required info to cache for an account.
+#[derive(Encode, Decode, Clone, PartialEq, Eq, RuntimeDebug)]
+pub struct RawAliveContractInfo<CodeHash, Balance, BlockNumber> {
+	/// Unique ID for the subtree encoded as a bytes vector.
+	pub trie_id: TrieId,
+	/// The total number of bytes used by this contract.
+	///
+	/// It is a sum of each key-value pair stored by this contract.
+	pub storage_size: u32,
+	/// The total number of key-value pairs in storage of this contract.
+	pub pair_count: u32,
+	/// The code associated with a given account.
+	pub code_hash: CodeHash,
+	/// Pay rent at most up to this value.
+	pub rent_allowance: Balance,
+	/// The amount of rent that was payed by the contract over its whole lifetime.
+	///
+	/// A restored contract starts with a value of zero just like a new contract.
+	pub rent_payed: Balance,
+	/// Last block rent has been payed.
+	pub deduct_block: BlockNumber,
+	/// Last block child storage has been written.
+	pub last_write: Option<BlockNumber>,
+	/// This field is reserved for future evolution of format.
+	pub _reserved: Option<()>,
+}
+
+impl<CodeHash, Balance, BlockNumber> RawAliveContractInfo<CodeHash, Balance, BlockNumber> {
+	/// Associated child trie unique id is built from the hash part of the trie id.
+	pub fn child_trie_info(&self) -> ChildInfo {
+		child_trie_info(&self.trie_id[..])
+	}
+}
+
+/// Associated child trie unique id is built from the hash part of the trie id.
+fn child_trie_info(trie_id: &[u8]) -> ChildInfo {
+	ChildInfo::new_default(trie_id)
+}
+
+#[derive(Encode, Decode, PartialEq, Eq, RuntimeDebug)]
+pub struct RawTombstoneContractInfo<H, Hasher>(H, PhantomData<Hasher>);
+
+impl<H, Hasher> RawTombstoneContractInfo<H, Hasher>
+where
+	H: Member + MaybeSerializeDeserialize+ Debug
+		+ AsRef<[u8]> + AsMut<[u8]> + Copy + Default
+		+ sp_std::hash::Hash + Codec,
+	Hasher: Hash<Output=H>,
+{
+	pub fn new(storage_root: &[u8], code_hash: H) -> Self {
+		let mut buf = Vec::new();
+		storage_root.using_encoded(|encoded| buf.extend_from_slice(encoded));
+		buf.extend_from_slice(code_hash.as_ref());
+		RawTombstoneContractInfo(<Hasher as Hash>::hash(&buf[..]), PhantomData)
+	}
+}
+
+impl<T: Config> From<AliveContractInfo<T>> for ContractInfo<T> {
+	fn from(alive_info: AliveContractInfo<T>) -> Self {
+		Self::Alive(alive_info)
+	}
+}
+
 /// An error that means that the account requested either doesn't exist or represents a tombstone
 /// account.
 #[cfg_attr(test, derive(PartialEq, Eq, Debug))]
@@ -59,7 +167,7 @@ where
 	/// The read is performed from the `trie_id` only. The `address` is not necessary. If the contract
 	/// doesn't store under the given `key` `None` is returned.
 	pub fn read(trie_id: &TrieId, key: &StorageKey) -> Option<Vec<u8>> {
-		child::get_raw(&crate::child_trie_info(&trie_id), &blake2_256(key))
+		child::get_raw(&child_trie_info(&trie_id), &blake2_256(key))
 	}
 
 	/// Update a storage entry into a contract's kv storage.
@@ -87,7 +195,7 @@ where
 		};
 
 		let hashed_key = blake2_256(key);
-		let child_trie_info = &crate::child_trie_info(&trie_id);
+		let child_trie_info = &child_trie_info(&trie_id);
 
 		let opt_prev_len = child::len(&child_trie_info, &hashed_key);
 
@@ -117,7 +225,7 @@ where
 			.and_then(|val| val.checked_add(new_value_len))
 			.ok_or_else(|| Error::<T>::StorageExhausted)?;
 
-		new_info.last_write = Some(<frame_system::Module<T>>::block_number());
+		new_info.last_write = Some(<frame_system::Pallet<T>>::block_number());
 		<ContractInfoOf<T>>::insert(&account, ContractInfo::Alive(new_info));
 
 		// Finally, perform the change on the storage.
@@ -176,7 +284,7 @@ where
 					// We want to charge rent for the first block in advance. Therefore we
 					// treat the contract as if it was created in the last block and then
 					// charge rent for it during instantiation.
-					<frame_system::Module<T>>::block_number().saturating_sub(1u32.into()),
+					<frame_system::Pallet<T>>::block_number().saturating_sub(1u32.into()),
 				rent_allowance: <BalanceOf<T>>::max_value(),
 				rent_payed: <BalanceOf<T>>::zero(),
 				pair_count: 0,
@@ -257,7 +365,7 @@ where
 			let trie = &mut queue[0];
 			let pair_count = trie.pair_count;
 			let outcome = child::kill_storage(
-				&crate::child_trie_info(&trie.trie_id),
+				&child_trie_info(&trie.trie_id),
 				Some(remaining_key_budget),
 			);
 			if pair_count > remaining_key_budget {
@@ -290,7 +398,6 @@ where
 	/// This generator uses inner counter for account id and applies the hash over `AccountId +
 	/// accountid_counter`.
 	pub fn generate_trie_id(account_id: &AccountIdOf<T>) -> TrieId {
-		use sp_runtime::traits::Hash;
 		// Note that skipping a value due to error is not an issue here.
 		// We only need uniqueness, not sequence.
 		let new_seed = <AccountCounter<T>>::mutate(|v| {
diff --git a/frame/contracts/src/tests.rs b/frame/contracts/src/tests.rs
index 2fa09e3405c1c..5fb637f3e9f18 100644
--- a/frame/contracts/src/tests.rs
+++ b/frame/contracts/src/tests.rs
@@ -16,8 +16,8 @@
 // limitations under the License.
 
 use crate::{
-	BalanceOf, ContractInfo, ContractInfoOf, Module,
-	RawAliveContractInfo, Config, Schedule,
+	BalanceOf, ContractInfo, ContractInfoOf, Pallet,
+	Config, Schedule,
 	Error, storage::Storage,
 	chain_extension::{
 		Result as ExtensionResult, Environment, ChainExtension, Ext, SysConfig, RetVal,
@@ -26,6 +26,7 @@ use crate::{
 	exec::{AccountIdOf, Executable}, wasm::PrefabWasmModule,
 	weights::WeightInfo,
 	wasm::ReturnCode as RuntimeReturnCode,
+	storage::RawAliveContractInfo,
 };
 use assert_matches::assert_matches;
 use codec::Encode;
@@ -57,11 +58,11 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
-		Timestamp: pallet_timestamp::{Module, Call, Storage, Inherent},
-		Randomness: pallet_randomness_collective_flip::{Module, Call, Storage},
-		Contracts: pallet_contracts::{Module, Call, Config<T>, Storage, Event<T>},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
+		Timestamp: pallet_timestamp::{Pallet, Call, Storage, Inherent},
+		Randomness: pallet_randomness_collective_flip::{Pallet, Call, Storage},
+		Contracts: pallet_contracts::{Pallet, Call, Config<T>, Storage, Event<T>},
 	}
 );
 
@@ -72,7 +73,7 @@ pub mod test_utils {
 		ContractInfoOf, CodeHash,
 		storage::Storage,
 		exec::{StorageKey, AccountIdOf},
-		Module as Contracts,
+		Pallet as Contracts,
 	};
 	use frame_support::traits::Currency;
 
@@ -246,7 +247,7 @@ parameter_types! {
 	pub const DepositPerContract: u64 = 8 * DepositPerStorageByte::get();
 	pub const DepositPerStorageByte: u64 = 10_000;
 	pub const DepositPerStorageItem: u64 = 10_000;
-	pub RentFraction: Perbill = Perbill::from_rational_approximation(4u32, 10_000u32);
+	pub RentFraction: Perbill = Perbill::from_rational(4u32, 10_000u32);
 	pub const SurchargeReward: u64 = 500_000;
 	pub const MaxDepth: u32 = 100;
 	pub const MaxValueSize: u32 = 16_384;
@@ -457,7 +458,7 @@ fn instantiate_and_call_and_deposit_event() {
 		.build()
 		.execute_with(|| {
 			let _ = Balances::deposit_creating(&ALICE, 1_000_000);
-			let subsistence = Module::<Test>::subsistence_threshold();
+			let subsistence = Pallet::<Test>::subsistence_threshold();
 
 			// Check at the end to get hash on error easily
 			let creation = Contracts::instantiate_with_code(
@@ -572,7 +573,7 @@ fn deposit_event_max_value_limit() {
 #[test]
 fn run_out_of_gas() {
 	let (wasm, code_hash) = compile_module::<Test>("run_out_of_gas").unwrap();
-	let subsistence = Module::<Test>::subsistence_threshold();
+	let subsistence = Pallet::<Test>::subsistence_threshold();
 
 	ExtBuilder::default()
 		.existential_deposit(50)
@@ -908,7 +909,7 @@ fn removals(trigger_call: impl Fn(AccountIdOf<Test>) -> bool) {
 				.unwrap().get_alive().unwrap().rent_allowance;
 			let balance = Balances::free_balance(&addr);
 
-			let subsistence_threshold = Module::<Test>::subsistence_threshold();
+			let subsistence_threshold = Pallet::<Test>::subsistence_threshold();
 
 			// Trigger rent must have no effect
 			assert!(!trigger_call(addr.clone()));
@@ -997,7 +998,7 @@ fn removals(trigger_call: impl Fn(AccountIdOf<Test>) -> bool) {
 		.build()
 		.execute_with(|| {
 			// Create
-			let subsistence_threshold = Module::<Test>::subsistence_threshold();
+			let subsistence_threshold = Pallet::<Test>::subsistence_threshold();
 			let _ = Balances::deposit_creating(&ALICE, subsistence_threshold * 1000);
 			assert_ok!(Contracts::instantiate_with_code(
 				Origin::signed(ALICE),
@@ -1878,7 +1879,7 @@ fn crypto_hashes() {
 				// We offset data in the contract tables by 1.
 				let mut params = vec![(n + 1) as u8];
 				params.extend_from_slice(input);
-				let result = <Module<Test>>::bare_call(
+				let result = <Pallet<Test>>::bare_call(
 					ALICE,
 					addr.clone(),
 					0,
@@ -1896,7 +1897,7 @@ fn crypto_hashes() {
 fn transfer_return_code() {
 	let (wasm, code_hash) = compile_module::<Test>("transfer_return_code").unwrap();
 	ExtBuilder::default().existential_deposit(50).build().execute_with(|| {
-		let subsistence = Module::<Test>::subsistence_threshold();
+		let subsistence = Pallet::<Test>::subsistence_threshold();
 		let _ = Balances::deposit_creating(&ALICE, 1000 * subsistence);
 
 		assert_ok!(
@@ -1943,7 +1944,7 @@ fn call_return_code() {
 	let (caller_code, caller_hash) = compile_module::<Test>("call_return_code").unwrap();
 	let (callee_code, callee_hash) = compile_module::<Test>("ok_trap_revert").unwrap();
 	ExtBuilder::default().existential_deposit(50).build().execute_with(|| {
-		let subsistence = Module::<Test>::subsistence_threshold();
+		let subsistence = Pallet::<Test>::subsistence_threshold();
 		let _ = Balances::deposit_creating(&ALICE, 1000 * subsistence);
 		let _ = Balances::deposit_creating(&CHARLIE, 1000 * subsistence);
 
@@ -2036,7 +2037,7 @@ fn instantiate_return_code() {
 	let (caller_code, caller_hash) = compile_module::<Test>("instantiate_return_code").unwrap();
 	let (callee_code, callee_hash) = compile_module::<Test>("ok_trap_revert").unwrap();
 	ExtBuilder::default().existential_deposit(50).build().execute_with(|| {
-		let subsistence = Module::<Test>::subsistence_threshold();
+		let subsistence = Pallet::<Test>::subsistence_threshold();
 		let _ = Balances::deposit_creating(&ALICE, 1000 * subsistence);
 		let _ = Balances::deposit_creating(&CHARLIE, 1000 * subsistence);
 		let callee_hash = callee_hash.as_ref().to_vec();
@@ -2127,7 +2128,7 @@ fn instantiate_return_code() {
 fn disabled_chain_extension_wont_deploy() {
 	let (code, _hash) = compile_module::<Test>("chain_extension").unwrap();
 	ExtBuilder::default().existential_deposit(50).build().execute_with(|| {
-		let subsistence = Module::<Test>::subsistence_threshold();
+		let subsistence = Pallet::<Test>::subsistence_threshold();
 		let _ = Balances::deposit_creating(&ALICE, 1000 * subsistence);
 		TestExtension::disable();
 		assert_err_ignore_postinfo!(
@@ -2148,7 +2149,7 @@ fn disabled_chain_extension_wont_deploy() {
 fn disabled_chain_extension_errors_on_call() {
 	let (code, hash) = compile_module::<Test>("chain_extension").unwrap();
 	ExtBuilder::default().existential_deposit(50).build().execute_with(|| {
-		let subsistence = Module::<Test>::subsistence_threshold();
+		let subsistence = Pallet::<Test>::subsistence_threshold();
 		let _ = Balances::deposit_creating(&ALICE, 1000 * subsistence);
 		assert_ok!(
 			Contracts::instantiate_with_code(
@@ -2179,7 +2180,7 @@ fn disabled_chain_extension_errors_on_call() {
 fn chain_extension_works() {
 	let (code, hash) = compile_module::<Test>("chain_extension").unwrap();
 	ExtBuilder::default().existential_deposit(50).build().execute_with(|| {
-		let subsistence = Module::<Test>::subsistence_threshold();
+		let subsistence = Pallet::<Test>::subsistence_threshold();
 		let _ = Balances::deposit_creating(&ALICE, 1000 * subsistence);
 		assert_ok!(
 			Contracts::instantiate_with_code(
@@ -2248,7 +2249,7 @@ fn chain_extension_works() {
 fn lazy_removal_works() {
 	let (code, hash) = compile_module::<Test>("self_destruct").unwrap();
 	ExtBuilder::default().existential_deposit(50).build().execute_with(|| {
-		let subsistence = Module::<Test>::subsistence_threshold();
+		let subsistence = Pallet::<Test>::subsistence_threshold();
 		let _ = Balances::deposit_creating(&ALICE, 1000 * subsistence);
 
 		assert_ok!(
@@ -2308,7 +2309,7 @@ fn lazy_removal_partial_remove_works() {
 	let mut ext = ExtBuilder::default().existential_deposit(50).build();
 
 	let trie = ext.execute_with(|| {
-		let subsistence = Module::<Test>::subsistence_threshold();
+		let subsistence = Pallet::<Test>::subsistence_threshold();
 		let _ = Balances::deposit_creating(&ALICE, 1000 * subsistence);
 
 		assert_ok!(
@@ -2389,7 +2390,7 @@ fn lazy_removal_partial_remove_works() {
 fn lazy_removal_does_no_run_on_full_block() {
 	let (code, hash) = compile_module::<Test>("self_destruct").unwrap();
 	ExtBuilder::default().existential_deposit(50).build().execute_with(|| {
-		let subsistence = Module::<Test>::subsistence_threshold();
+		let subsistence = Pallet::<Test>::subsistence_threshold();
 		let _ = Balances::deposit_creating(&ALICE, 1000 * subsistence);
 
 		assert_ok!(
@@ -2473,7 +2474,7 @@ fn lazy_removal_does_no_run_on_full_block() {
 fn lazy_removal_does_not_use_all_weight() {
 	let (code, hash) = compile_module::<Test>("self_destruct").unwrap();
 	ExtBuilder::default().existential_deposit(50).build().execute_with(|| {
-		let subsistence = Module::<Test>::subsistence_threshold();
+		let subsistence = Pallet::<Test>::subsistence_threshold();
 		let _ = Balances::deposit_creating(&ALICE, 1000 * subsistence);
 
 		assert_ok!(
@@ -2543,7 +2544,7 @@ fn lazy_removal_does_not_use_all_weight() {
 fn deletion_queue_full() {
 	let (code, hash) = compile_module::<Test>("self_destruct").unwrap();
 	ExtBuilder::default().existential_deposit(50).build().execute_with(|| {
-		let subsistence = Module::<Test>::subsistence_threshold();
+		let subsistence = Pallet::<Test>::subsistence_threshold();
 		let _ = Balances::deposit_creating(&ALICE, 1000 * subsistence);
 
 		assert_ok!(
@@ -2669,7 +2670,7 @@ fn refcounter() {
 	let (wasm, code_hash) = compile_module::<Test>("self_destruct").unwrap();
 	ExtBuilder::default().existential_deposit(50).build().execute_with(|| {
 		let _ = Balances::deposit_creating(&ALICE, 1_000_000);
-		let subsistence = Module::<Test>::subsistence_threshold();
+		let subsistence = Pallet::<Test>::subsistence_threshold();
 
 		// Create two contracts with the same code and check that they do in fact share it.
 		assert_ok!(Contracts::instantiate_with_code(
@@ -2741,7 +2742,7 @@ fn reinstrument_does_charge() {
 	let (wasm, code_hash) = compile_module::<Test>("return_with_data").unwrap();
 	ExtBuilder::default().existential_deposit(50).build().execute_with(|| {
 		let _ = Balances::deposit_creating(&ALICE, 1_000_000);
-		let subsistence = Module::<Test>::subsistence_threshold();
+		let subsistence = Pallet::<Test>::subsistence_threshold();
 		let zero = 0u32.to_le_bytes().encode();
 		let code_len = wasm.len() as u32;
 
diff --git a/frame/contracts/src/wasm/code_cache.rs b/frame/contracts/src/wasm/code_cache.rs
index 0b2512f17f594..f9513afe51f4f 100644
--- a/frame/contracts/src/wasm/code_cache.rs
+++ b/frame/contracts/src/wasm/code_cache.rs
@@ -29,7 +29,7 @@
 
 use crate::{
 	CodeHash, CodeStorage, PristineCode, Schedule, Config, Error, Weight,
-	wasm::{prepare, PrefabWasmModule}, Module as Contracts, Event,
+	wasm::{prepare, PrefabWasmModule}, Pallet as Contracts, Event,
 	gas::{GasMeter, Token},
 	weights::WeightInfo,
 };
diff --git a/frame/contracts/src/wasm/env_def/macros.rs b/frame/contracts/src/wasm/env_def/macros.rs
index 3c10d3225e430..cfb529d2932b6 100644
--- a/frame/contracts/src/wasm/env_def/macros.rs
+++ b/frame/contracts/src/wasm/env_def/macros.rs
@@ -43,21 +43,23 @@ macro_rules! gen_signature {
 
 macro_rules! gen_signature_dispatch {
 	(
+		$needle_module:ident,
 		$needle_name:ident,
 		$needle_sig:ident ;
+		$module:ident,
 		$name:ident
-		( $ctx:ident $( , $names:ident : $params:ty )* ) $( -> $returns:ty )* , $($rest:tt)* ) => {
-		if stringify!($name).as_bytes() == $needle_name {
+		( $ctx:ident $( , $names:ident : $params:ty )* ) $( -> $returns:ty )* , $($rest:tt)*
+	) => {
+		if stringify!($module).as_bytes() == $needle_module && stringify!($name).as_bytes() == $needle_name {
 			let signature = gen_signature!( ( $( $params ),* ) $( -> $returns )* );
 			if $needle_sig == &signature {
 				return true;
 			}
 		} else {
-			gen_signature_dispatch!($needle_name, $needle_sig ; $($rest)*);
+			gen_signature_dispatch!($needle_module, $needle_name, $needle_sig ; $($rest)*);
 		}
 	};
-	( $needle_name:ident, $needle_sig:ident ; ) => {
-	};
+	( $needle_module:ident, $needle_name:ident, $needle_sig:ident ; ) => {};
 }
 
 /// Unmarshall arguments and then execute `body` expression and return its result.
@@ -151,10 +153,11 @@ macro_rules! register_func {
 	( $reg_cb:ident, < E: $seal_ty:tt > ; ) => {};
 
 	( $reg_cb:ident, < E: $seal_ty:tt > ;
-		$name:ident ( $ctx:ident $( , $names:ident : $params:ty )* )
+		$module:ident $name:ident ( $ctx:ident $( , $names:ident : $params:ty )* )
 		$( -> $returns:ty )* => $body:tt $($rest:tt)*
 	) => {
 		$reg_cb(
+			stringify!($module).as_bytes(),
 			stringify!($name).as_bytes(),
 			{
 				define_func!(
@@ -176,14 +179,17 @@ macro_rules! register_func {
 /// and reject the code if any imported function has a mismatched signature.
 macro_rules! define_env {
 	( $init_name:ident , < E: $seal_ty:tt > ,
-		$( $name:ident ( $ctx:ident $( , $names:ident : $params:ty )* )
+		$( [$module:ident] $name:ident ( $ctx:ident $( , $names:ident : $params:ty )* )
 			$( -> $returns:ty )* => $body:tt , )*
 	) => {
 		pub struct $init_name;
 
 		impl $crate::wasm::env_def::ImportSatisfyCheck for $init_name {
-			fn can_satisfy(name: &[u8], func_type: &parity_wasm::elements::FunctionType) -> bool {
-				gen_signature_dispatch!( name, func_type ; $( $name ( $ctx $(, $names : $params )* ) $( -> $returns )* , )* );
+			fn can_satisfy(module: &[u8], name: &[u8], func_type: &parity_wasm::elements::FunctionType) -> bool {
+				gen_signature_dispatch!(
+					module, name, func_type ;
+					$( $module, $name ( $ctx $(, $names : $params )* ) $( -> $returns )* , )*
+				);
 
 				return false;
 			}
@@ -195,8 +201,12 @@ macro_rules! define_env {
 				sp_core::crypto::UncheckedFrom<<E::T as frame_system::Config>::Hash> +
 					AsRef<[u8]>
 		{
-			fn impls<F: FnMut(&[u8], $crate::wasm::env_def::HostFunc<E>)>(f: &mut F) {
-				register_func!(f, < E: $seal_ty > ; $( $name ( $ctx $( , $names : $params )* ) $( -> $returns)* => $body )* );
+			fn impls<F: FnMut(&[u8], &[u8], $crate::wasm::env_def::HostFunc<E>)>(f: &mut F) {
+				register_func!(
+					f,
+					< E: $seal_ty > ;
+					$( $module $name ( $ctx $( , $names : $params )* ) $( -> $returns)* => $body )*
+				);
 			}
 		}
 	};
@@ -327,7 +337,7 @@ mod tests {
 		use crate::wasm::env_def::ImportSatisfyCheck;
 
 		define_env!(Env, <E: Ext>,
-			seal_gas( _ctx, amount: u32 ) => {
+			[seal0] seal_gas( _ctx, amount: u32 ) => {
 				let amount = Weight::from(amount);
 				if !amount.is_zero() {
 					Ok(())
@@ -337,7 +347,11 @@ mod tests {
 			},
 		);
 
-		assert!(Env::can_satisfy(b"seal_gas", &FunctionType::new(vec![ValueType::I32], None)));
-		assert!(!Env::can_satisfy(b"not_exists", &FunctionType::new(vec![], None)));
+		assert!(
+			Env::can_satisfy(b"seal0", b"seal_gas",&FunctionType::new(vec![ValueType::I32], None))
+		);
+		assert!(
+			!Env::can_satisfy(b"seal0", b"not_exists", &FunctionType::new(vec![], None))
+		);
 	}
 }
diff --git a/frame/contracts/src/wasm/env_def/mod.rs b/frame/contracts/src/wasm/env_def/mod.rs
index 997ec29e028d5..6d33444b04dfe 100644
--- a/frame/contracts/src/wasm/env_def/mod.rs
+++ b/frame/contracts/src/wasm/env_def/mod.rs
@@ -74,7 +74,7 @@ pub type HostFunc<E> =
 	) -> Result<sp_sandbox::ReturnValue, sp_sandbox::HostError>;
 
 pub trait FunctionImplProvider<E: Ext> {
-	fn impls<F: FnMut(&[u8], HostFunc<E>)>(f: &mut F);
+	fn impls<F: FnMut(&[u8], &[u8], HostFunc<E>)>(f: &mut F);
 }
 
 /// This trait can be used to check whether the host environment can satisfy
@@ -83,5 +83,5 @@ pub trait ImportSatisfyCheck {
 	/// Returns `true` if the host environment contains a function with
 	/// the specified name and its type matches to the given type, or `false`
 	/// otherwise.
-	fn can_satisfy(name: &[u8], func_type: &FunctionType) -> bool;
+	fn can_satisfy(module: &[u8], name: &[u8], func_type: &FunctionType) -> bool;
 }
diff --git a/frame/contracts/src/wasm/mod.rs b/frame/contracts/src/wasm/mod.rs
index 6fc6bc1764e4a..f7fde5ba17861 100644
--- a/frame/contracts/src/wasm/mod.rs
+++ b/frame/contracts/src/wasm/mod.rs
@@ -192,8 +192,8 @@ where
 
 		let mut imports = sp_sandbox::EnvironmentDefinitionBuilder::new();
 		imports.add_memory(self::prepare::IMPORT_MODULE_MEMORY, "memory", memory.clone());
-		runtime::Env::impls(&mut |name, func_ptr| {
-			imports.add_host_func(self::prepare::IMPORT_MODULE_FN, name, func_ptr);
+		runtime::Env::impls(&mut |module, name, func_ptr| {
+			imports.add_host_func(module, name, func_ptr);
 		});
 
 		let mut runtime = Runtime::new(
@@ -245,8 +245,8 @@ where
 mod tests {
 	use super::*;
 	use crate::{
-		CodeHash, BalanceOf, Error, Module as Contracts,
-		exec::{Ext, StorageKey, AccountIdOf, Executable, RentParams},
+		CodeHash, BalanceOf, Error, Pallet as Contracts,
+		exec::{Ext, StorageKey, AccountIdOf, Executable, SeedOf, BlockNumberOf, RentParams},
 		gas::GasMeter,
 		tests::{Test, Call, ALICE, BOB},
 	};
@@ -414,8 +414,8 @@ mod tests {
 		fn tombstone_deposit(&self) -> u64 {
 			16
 		}
-		fn random(&self, subject: &[u8]) -> H256 {
-			H256::from_slice(subject)
+		fn random(&self, subject: &[u8]) -> (SeedOf<Self::T>, BlockNumberOf<Self::T>) {
+			(H256::from_slice(subject), 42)
 		}
 		fn deposit_event(&mut self, topics: Vec<H256>, data: Vec<u8>) {
 			self.events.push((topics, data))
@@ -515,7 +515,7 @@ mod tests {
 		fn tombstone_deposit(&self) -> u64 {
 			(**self).tombstone_deposit()
 		}
-		fn random(&self, subject: &[u8]) -> H256 {
+		fn random(&self, subject: &[u8]) -> (SeedOf<Self::T>, BlockNumberOf<Self::T>) {
 			(**self).random(subject)
 		}
 		fn deposit_event(&mut self, topics: Vec<H256>, data: Vec<u8>) {
@@ -1531,6 +1531,85 @@ mod tests {
 		);
 	}
 
+	const CODE_RANDOM_V1: &str = r#"
+(module
+	(import "seal1" "seal_random" (func $seal_random (param i32 i32 i32 i32)))
+	(import "seal0" "seal_return" (func $seal_return (param i32 i32 i32)))
+	(import "env" "memory" (memory 1 1))
+
+	;; [0,128) is reserved for the result of PRNG.
+
+	;; the subject used for the PRNG. [128,160)
+	(data (i32.const 128)
+		"\00\01\02\03\04\05\06\07\08\09\0A\0B\0C\0D\0E\0F"
+		"\00\01\02\03\04\05\06\07\08\09\0A\0B\0C\0D\0E\0F"
+	)
+
+	;; size of our buffer is 128 bytes
+	(data (i32.const 160) "\80")
+
+	(func $assert (param i32)
+		(block $ok
+			(br_if $ok
+				(get_local 0)
+			)
+			(unreachable)
+		)
+	)
+
+	(func (export "call")
+		;; This stores the block random seed in the buffer
+		(call $seal_random
+			(i32.const 128) ;; Pointer in memory to the start of the subject buffer
+			(i32.const 32) ;; The subject buffer's length
+			(i32.const 0) ;; Pointer to the output buffer
+			(i32.const 160) ;; Pointer to the output buffer length
+		)
+
+		;; assert len == 32
+		(call $assert
+			(i32.eq
+				(i32.load (i32.const 160))
+				(i32.const 40)
+			)
+		)
+
+		;; return the random data
+		(call $seal_return
+			(i32.const 0)
+			(i32.const 0)
+			(i32.const 40)
+		)
+	)
+	(func (export "deploy"))
+)
+"#;
+
+	#[test]
+	fn random_v1() {
+		let mut gas_meter = GasMeter::new(GAS_LIMIT);
+
+		let output = execute(
+			CODE_RANDOM_V1,
+			vec![],
+			MockExt::default(),
+			&mut gas_meter,
+		).unwrap();
+
+		// The mock ext just returns the same data that was passed as the subject.
+		assert_eq!(
+			output,
+			ExecReturnValue {
+				flags: ReturnFlags::empty(),
+				data: (
+						hex!("000102030405060708090A0B0C0D0E0F000102030405060708090A0B0C0D0E0F"),
+						42u64,
+					).encode(),
+			},
+		);
+	}
+
+
 	const CODE_DEPOSIT_EVENT: &str = r#"
 (module
 	(import "seal0" "seal_deposit_event" (func $seal_deposit_event (param i32 i32 i32 i32)))
diff --git a/frame/contracts/src/wasm/prepare.rs b/frame/contracts/src/wasm/prepare.rs
index caf6ef88c1ba0..15556b0c5cd06 100644
--- a/frame/contracts/src/wasm/prepare.rs
+++ b/frame/contracts/src/wasm/prepare.rs
@@ -28,11 +28,7 @@ use parity_wasm::elements::{self, Internal, External, MemoryType, Type, ValueTyp
 use sp_runtime::traits::Hash;
 use sp_std::prelude::*;
 
-/// Currently, all imported functions must be located inside this module. We might support
-/// additional modules for versioning later.
-pub const IMPORT_MODULE_FN: &str = "seal0";
-
-/// Imported memory must be located inside this module. The reason for that is that current
+/// Imported memory must be located inside this module. The reason for hardcoding is that current
 /// compiler toolchains might not support specifying other modules than "env" for memory imports.
 pub const IMPORT_MODULE_MEMORY: &str = "env";
 
@@ -194,7 +190,7 @@ impl<'a, T: Config> ContractModule<'a, T> {
 		let contract_module = pwasm_utils::inject_gas_counter(
 			self.module,
 			&gas_rules,
-			IMPORT_MODULE_FN
+			"seal0",
 		).map_err(|_| "gas instrumentation failed")?;
 		Ok(ContractModule {
 			module: contract_module,
@@ -325,12 +321,7 @@ impl<'a, T: Config> ContractModule<'a, T> {
 			let type_idx = match import.external() {
 				&External::Table(_) => return Err("Cannot import tables"),
 				&External::Global(_) => return Err("Cannot import globals"),
-				&External::Function(ref type_idx) => {
-					if import.module() != IMPORT_MODULE_FN {
-						return Err("Invalid module for imported function");
-					}
-					type_idx
-				},
+				&External::Function(ref type_idx) => type_idx,
 				&External::Memory(ref memory_type) => {
 					if import.module() != IMPORT_MODULE_MEMORY {
 						return Err("Invalid module for imported memory");
@@ -363,7 +354,9 @@ impl<'a, T: Config> ContractModule<'a, T> {
 			}
 
 			if import_fn_banlist.iter().any(|f| import.field().as_bytes() == *f)
-				|| !C::can_satisfy(import.field().as_bytes(), func_ty)
+				|| !C::can_satisfy(
+					import.module().as_bytes(), import.field().as_bytes(), func_ty,
+				)
 			{
 				return Err("module imports a non-existent function");
 			}
@@ -498,7 +491,7 @@ pub mod benchmarking {
 	use parity_wasm::elements::FunctionType;
 
 	impl ImportSatisfyCheck for () {
-		fn can_satisfy(_name: &[u8], _func_type: &FunctionType) -> bool {
+		fn can_satisfy(_module: &[u8], _name: &[u8], _func_type: &FunctionType) -> bool {
 			true
 		}
 	}
@@ -526,9 +519,8 @@ pub mod benchmarking {
 #[cfg(test)]
 mod tests {
 	use super::*;
-	use crate::{exec::Ext, Limits};
+	use crate::{exec::Ext, schedule::Limits};
 	use std::fmt;
-	use assert_matches::assert_matches;
 
 	impl fmt::Debug for PrefabWasmModule<crate::tests::Test> {
 		fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -544,14 +536,17 @@ mod tests {
 		// Define test environment for tests. We need ImportSatisfyCheck
 		// implementation from it. So actual implementations doesn't matter.
 		define_env!(Test, <E: Ext>,
-			panic(_ctx) => { unreachable!(); },
+			[seal0] panic(_ctx) => { unreachable!(); },
 
 			// gas is an implementation defined function and a contract can't import it.
-			gas(_ctx, _amount: u32) => { unreachable!(); },
+			[seal0] gas(_ctx, _amount: u32) => { unreachable!(); },
+
+			[seal0] nop(_ctx, _unused: u64) => { unreachable!(); },
 
-			nop(_ctx, _unused: u64) => { unreachable!(); },
+			// new version of nop with other data type for argumebt
+			[seal1] nop(_ctx, _unused: i32) => { unreachable!(); },
 
-			seal_println(_ctx, _ptr: u32, _len: u32) => { unreachable!(); },
+			[seal0] seal_println(_ctx, _ptr: u32, _len: u32) => { unreachable!(); },
 		);
 	}
 
@@ -572,7 +567,7 @@ mod tests {
 					.. Default::default()
 				};
 				let r = do_preparation::<env::Test, crate::tests::Test>(wasm, &schedule);
-				assert_matches!(r, $($expected)*);
+				assert_matches::assert_matches!(r, $($expected)*);
 			}
 		};
 	}
@@ -905,30 +900,16 @@ mod tests {
 			Err("Invalid module for imported memory")
 		);
 
-		// functions are in "env" and not in "seal0"
-		prepare_test!(function_not_in_env,
-			r#"
-			(module
-				(import "env" "nop" (func (param i64)))
-
-				(func (export "call"))
-				(func (export "deploy"))
-			)
-			"#,
-			Err("Invalid module for imported function")
-		);
-
-		// functions are in "seal0" and not in in some arbitrary module
-		prepare_test!(function_not_arbitrary_module,
+		prepare_test!(function_in_other_module_works,
 			r#"
 			(module
-				(import "any_module" "nop" (func (param i64)))
+				(import "seal1" "nop" (func (param i32)))
 
 				(func (export "call"))
 				(func (export "deploy"))
 			)
 			"#,
-			Err("Invalid module for imported function")
+			Ok(_)
 		);
 
 		// wrong signature
@@ -983,7 +964,7 @@ mod tests {
 			let mut schedule = Schedule::default();
 			schedule.enable_println = true;
 			let r = do_preparation::<env::Test, crate::tests::Test>(wasm, &schedule);
-			assert_matches!(r, Ok(_));
+			assert_matches::assert_matches!(r, Ok(_));
 		}
 	}
 
diff --git a/frame/contracts/src/wasm/runtime.rs b/frame/contracts/src/wasm/runtime.rs
index 2ceac1c51604e..f3757e4c2b10d 100644
--- a/frame/contracts/src/wasm/runtime.rs
+++ b/frame/contracts/src/wasm/runtime.rs
@@ -18,10 +18,11 @@
 //! Environment definition of the wasm smart-contract runtime.
 
 use crate::{
-	HostFnWeights, Config, CodeHash, BalanceOf, Error,
+	Config, CodeHash, BalanceOf, Error,
 	exec::{Ext, StorageKey, TopicOf},
 	gas::{GasMeter, Token, ChargedAmount},
 	wasm::env_def::ConvertibleToWasm,
+	schedule::HostFnWeights,
 };
 use parity_wasm::elements::ValueType;
 use frame_support::{dispatch::DispatchError, ensure, traits::Get, weights::Weight};
@@ -629,7 +630,7 @@ define_env!(Env, <E: Ext>,
 	// This call is supposed to be called only by instrumentation injected code.
 	//
 	// - amount: How much gas is used.
-	gas(ctx, amount: u32) => {
+	[seal0] gas(ctx, amount: u32) => {
 		ctx.charge_gas(RuntimeToken::MeteringBlock(amount))?;
 		Ok(())
 	},
@@ -649,7 +650,7 @@ define_env!(Env, <E: Ext>,
 	//
 	// - If value length exceeds the configured maximum value length of a storage entry.
 	// - Upon trying to set an empty storage entry (value length is 0).
-	seal_set_storage(ctx, key_ptr: u32, value_ptr: u32, value_len: u32) => {
+	[seal0] seal_set_storage(ctx, key_ptr: u32, value_ptr: u32, value_len: u32) => {
 		ctx.charge_gas(RuntimeToken::SetStorage(value_len))?;
 		if value_len > ctx.ext.max_value_size() {
 			Err(Error::<E::T>::ValueTooLarge)?;
@@ -665,7 +666,7 @@ define_env!(Env, <E: Ext>,
 	// # Parameters
 	//
 	// - `key_ptr`: pointer into the linear memory where the location to clear the value is placed.
-	seal_clear_storage(ctx, key_ptr: u32) => {
+	[seal0] seal_clear_storage(ctx, key_ptr: u32) => {
 		ctx.charge_gas(RuntimeToken::ClearStorage)?;
 		let mut key: StorageKey = [0; 32];
 		ctx.read_sandbox_memory_into_buf(key_ptr, &mut key)?;
@@ -684,7 +685,7 @@ define_env!(Env, <E: Ext>,
 	// # Errors
 	//
 	// `ReturnCode::KeyNotFound`
-	seal_get_storage(ctx, key_ptr: u32, out_ptr: u32, out_len_ptr: u32) -> ReturnCode => {
+	[seal0] seal_get_storage(ctx, key_ptr: u32, out_ptr: u32, out_len_ptr: u32) -> ReturnCode => {
 		ctx.charge_gas(RuntimeToken::GetStorageBase)?;
 		let mut key: StorageKey = [0; 32];
 		ctx.read_sandbox_memory_into_buf(key_ptr, &mut key)?;
@@ -713,7 +714,7 @@ define_env!(Env, <E: Ext>,
 	//
 	// `ReturnCode::BelowSubsistenceThreshold`
 	// `ReturnCode::TransferFailed`
-	seal_transfer(
+	[seal0] seal_transfer(
 		ctx,
 		account_ptr: u32,
 		account_len: u32,
@@ -767,7 +768,7 @@ define_env!(Env, <E: Ext>,
 	// `ReturnCode::BelowSubsistenceThreshold`
 	// `ReturnCode::TransferFailed`
 	// `ReturnCode::NotCallable`
-	seal_call(
+	[seal0] seal_call(
 		ctx,
 		callee_ptr: u32,
 		callee_len: u32,
@@ -868,7 +869,7 @@ define_env!(Env, <E: Ext>,
 	// `ReturnCode::TransferFailed`
 	// `ReturnCode::NewContractNotFunded`
 	// `ReturnCode::CodeNotFound`
-	seal_instantiate(
+	[seal0] seal_instantiate(
 		ctx,
 		code_hash_ptr: u32,
 		code_hash_len: u32,
@@ -950,7 +951,7 @@ define_env!(Env, <E: Ext>,
 	// - The contract is live i.e is already on the call stack.
 	// - Failed to send the balance to the beneficiary.
 	// - The deletion queue is full.
-	seal_terminate(
+	[seal0] seal_terminate(
 		ctx,
 		beneficiary_ptr: u32,
 		beneficiary_len: u32
@@ -981,7 +982,7 @@ define_env!(Env, <E: Ext>,
 	// # Note
 	//
 	// This function can only be called once. Calling it multiple times will trigger a trap.
-	seal_input(ctx, out_ptr: u32, out_len_ptr: u32) => {
+	[seal0] seal_input(ctx, out_ptr: u32, out_len_ptr: u32) => {
 		ctx.charge_gas(RuntimeToken::InputBase)?;
 		if let Some(input) = ctx.input_data.take() {
 			ctx.write_sandbox_output(out_ptr, out_len_ptr, &input, false, |len| {
@@ -1010,7 +1011,7 @@ define_env!(Env, <E: Ext>,
 	// --- msb ---
 	//
 	// Using a reserved bit triggers a trap.
-	seal_return(ctx, flags: u32, data_ptr: u32, data_len: u32) => {
+	[seal0] seal_return(ctx, flags: u32, data_ptr: u32, data_len: u32) => {
 		ctx.charge_gas(RuntimeToken::Return(data_len))?;
 		Err(TrapReason::Return(ReturnData {
 			flags,
@@ -1028,7 +1029,7 @@ define_env!(Env, <E: Ext>,
 	// If this is a top-level call (i.e. initiated by an extrinsic) the origin address of the
 	// extrinsic will be returned. Otherwise, if this call is initiated by another contract then the
 	// address of the contract will be returned. The value is encoded as T::AccountId.
-	seal_caller(ctx, out_ptr: u32, out_len_ptr: u32) => {
+	[seal0] seal_caller(ctx, out_ptr: u32, out_len_ptr: u32) => {
 		ctx.charge_gas(RuntimeToken::Caller)?;
 		Ok(ctx.write_sandbox_output(
 			out_ptr, out_len_ptr, &ctx.ext.caller().encode(), false, already_charged
@@ -1041,7 +1042,7 @@ define_env!(Env, <E: Ext>,
 	// `out_len_ptr` must point to a u32 value that describes the available space at
 	// `out_ptr`. This call overwrites it with the size of the value. If the available
 	// space at `out_ptr` is less than the size of the value a trap is triggered.
-	seal_address(ctx, out_ptr: u32, out_len_ptr: u32) => {
+	[seal0] seal_address(ctx, out_ptr: u32, out_len_ptr: u32) => {
 		ctx.charge_gas(RuntimeToken::Address)?;
 		Ok(ctx.write_sandbox_output(
 			out_ptr, out_len_ptr, &ctx.ext.address().encode(), false, already_charged
@@ -1061,7 +1062,7 @@ define_env!(Env, <E: Ext>,
 	//
 	// It is recommended to avoid specifying very small values for `gas` as the prices for a single
 	// gas can be smaller than one.
-	seal_weight_to_fee(ctx, gas: u64, out_ptr: u32, out_len_ptr: u32) => {
+	[seal0] seal_weight_to_fee(ctx, gas: u64, out_ptr: u32, out_len_ptr: u32) => {
 		ctx.charge_gas(RuntimeToken::WeightToFee)?;
 		Ok(ctx.write_sandbox_output(
 			out_ptr, out_len_ptr, &ctx.ext.get_weight_price(gas).encode(), false, already_charged
@@ -1076,7 +1077,7 @@ define_env!(Env, <E: Ext>,
 	// space at `out_ptr` is less than the size of the value a trap is triggered.
 	//
 	// The data is encoded as Gas.
-	seal_gas_left(ctx, out_ptr: u32, out_len_ptr: u32) => {
+	[seal0] seal_gas_left(ctx, out_ptr: u32, out_len_ptr: u32) => {
 		ctx.charge_gas(RuntimeToken::GasLeft)?;
 		Ok(ctx.write_sandbox_output(
 			out_ptr, out_len_ptr, &ctx.gas_meter.gas_left().encode(), false, already_charged
@@ -1091,7 +1092,7 @@ define_env!(Env, <E: Ext>,
 	// space at `out_ptr` is less than the size of the value a trap is triggered.
 	//
 	// The data is encoded as T::Balance.
-	seal_balance(ctx, out_ptr: u32, out_len_ptr: u32) => {
+	[seal0] seal_balance(ctx, out_ptr: u32, out_len_ptr: u32) => {
 		ctx.charge_gas(RuntimeToken::Balance)?;
 		Ok(ctx.write_sandbox_output(
 			out_ptr, out_len_ptr, &ctx.ext.balance().encode(), false, already_charged
@@ -1106,7 +1107,7 @@ define_env!(Env, <E: Ext>,
 	// space at `out_ptr` is less than the size of the value a trap is triggered.
 	//
 	// The data is encoded as T::Balance.
-	seal_value_transferred(ctx, out_ptr: u32, out_len_ptr: u32) => {
+	[seal0] seal_value_transferred(ctx, out_ptr: u32, out_len_ptr: u32) => {
 		ctx.charge_gas(RuntimeToken::ValueTransferred)?;
 		Ok(ctx.write_sandbox_output(
 			out_ptr, out_len_ptr, &ctx.ext.value_transferred().encode(), false, already_charged
@@ -1121,7 +1122,43 @@ define_env!(Env, <E: Ext>,
 	// space at `out_ptr` is less than the size of the value a trap is triggered.
 	//
 	// The data is encoded as T::Hash.
-	seal_random(ctx, subject_ptr: u32, subject_len: u32, out_ptr: u32, out_len_ptr: u32) => {
+	//
+	// # Deprecation
+	//
+	// This function is deprecated. Users should migrate to the version in the "seal1" module.
+	[seal0] seal_random(ctx, subject_ptr: u32, subject_len: u32, out_ptr: u32, out_len_ptr: u32) => {
+		ctx.charge_gas(RuntimeToken::Random)?;
+		if subject_len > ctx.ext.schedule().limits.subject_len {
+			Err(Error::<E::T>::RandomSubjectTooLong)?;
+		}
+		let subject_buf = ctx.read_sandbox_memory(subject_ptr, subject_len)?;
+		Ok(ctx.write_sandbox_output(
+			out_ptr, out_len_ptr, &ctx.ext.random(&subject_buf).0.encode(), false, already_charged
+		)?)
+	},
+
+	// Stores a random number for the current block and the given subject into the supplied buffer.
+	//
+	// The value is stored to linear memory at the address pointed to by `out_ptr`.
+	// `out_len_ptr` must point to a u32 value that describes the available space at
+	// `out_ptr`. This call overwrites it with the size of the value. If the available
+	// space at `out_ptr` is less than the size of the value a trap is triggered.
+	//
+	// The data is encoded as (T::Hash, T::BlockNumber).
+	//
+	// # Changes from v0
+	//
+	// In addition to the seed it returns the block number since which it was determinable
+	// by chain observers.
+	//
+	// # Note
+	//
+	// The returned seed should only be used to distinguish commitments made before
+	// the returned block number. If the block number is too early (i.e. commitments were
+	// made afterwards), then ensure no further commitments may be made and repeatedly
+	// call this on later blocks until the block number returned is later than the latest
+	// commitment.
+	[seal1] seal_random(ctx, subject_ptr: u32, subject_len: u32, out_ptr: u32, out_len_ptr: u32) => {
 		ctx.charge_gas(RuntimeToken::Random)?;
 		if subject_len > ctx.ext.schedule().limits.subject_len {
 			Err(Error::<E::T>::RandomSubjectTooLong)?;
@@ -1138,7 +1175,7 @@ define_env!(Env, <E: Ext>,
 	// `out_len_ptr` must point to a u32 value that describes the available space at
 	// `out_ptr`. This call overwrites it with the size of the value. If the available
 	// space at `out_ptr` is less than the size of the value a trap is triggered.
-	seal_now(ctx, out_ptr: u32, out_len_ptr: u32) => {
+	[seal0] seal_now(ctx, out_ptr: u32, out_len_ptr: u32) => {
 		ctx.charge_gas(RuntimeToken::Now)?;
 		Ok(ctx.write_sandbox_output(
 			out_ptr, out_len_ptr, &ctx.ext.now().encode(), false, already_charged
@@ -1148,7 +1185,7 @@ define_env!(Env, <E: Ext>,
 	// Stores the minimum balance (a.k.a. existential deposit) into the supplied buffer.
 	//
 	// The data is encoded as T::Balance.
-	seal_minimum_balance(ctx, out_ptr: u32, out_len_ptr: u32) => {
+	[seal0] seal_minimum_balance(ctx, out_ptr: u32, out_len_ptr: u32) => {
 		ctx.charge_gas(RuntimeToken::MinimumBalance)?;
 		Ok(ctx.write_sandbox_output(
 			out_ptr, out_len_ptr, &ctx.ext.minimum_balance().encode(), false, already_charged
@@ -1170,7 +1207,7 @@ define_env!(Env, <E: Ext>,
 	// a contract to leave a tombstone the balance of the contract must not go
 	// below the sum of existential deposit and the tombstone deposit. The sum
 	// is commonly referred as subsistence threshold in code.
-	seal_tombstone_deposit(ctx, out_ptr: u32, out_len_ptr: u32) => {
+	[seal0] seal_tombstone_deposit(ctx, out_ptr: u32, out_len_ptr: u32) => {
 		ctx.charge_gas(RuntimeToken::TombstoneDeposit)?;
 		Ok(ctx.write_sandbox_output(
 			out_ptr, out_len_ptr, &ctx.ext.tombstone_deposit().encode(), false, already_charged
@@ -1208,7 +1245,7 @@ define_env!(Env, <E: Ext>,
 	// - Tombstone hashes do not match.
 	// - The calling contract is already present on the call stack.
 	// - The supplied code_hash does not exist on-chain.
-	seal_restore_to(
+	[seal0] seal_restore_to(
 		ctx,
 		dest_ptr: u32,
 		dest_len: u32,
@@ -1279,8 +1316,13 @@ define_env!(Env, <E: Ext>,
 	// - topics_len - the length of the topics buffer. Pass 0 if you want to pass an empty vector.
 	// - data_ptr - a pointer to a raw data buffer which will saved along the event.
 	// - data_len - the length of the data buffer.
-	seal_deposit_event(ctx, topics_ptr: u32, topics_len: u32, data_ptr: u32, data_len: u32) => {
-
+	[seal0] seal_deposit_event(
+		ctx,
+		topics_ptr: u32,
+		topics_len: u32,
+		data_ptr: u32,
+		data_len: u32
+	) => {
 		fn has_duplicates<T: Ord>(items: &mut Vec<T>) -> bool {
 			// # Warning
 			//
@@ -1336,7 +1378,7 @@ define_env!(Env, <E: Ext>,
 	// - value_ptr: a pointer to the buffer with value, how much to allow for rent
 	//   Should be decodable as a `T::Balance`. Traps otherwise.
 	// - value_len: length of the value buffer.
-	seal_set_rent_allowance(ctx, value_ptr: u32, value_len: u32) => {
+	[seal0] seal_set_rent_allowance(ctx, value_ptr: u32, value_len: u32) => {
 		ctx.charge_gas(RuntimeToken::SetRentAllowance)?;
 		let value: BalanceOf<<E as Ext>::T> =
 			ctx.read_sandbox_memory_as(value_ptr, value_len)?;
@@ -1353,7 +1395,7 @@ define_env!(Env, <E: Ext>,
 	// space at `out_ptr` is less than the size of the value a trap is triggered.
 	//
 	// The data is encoded as T::Balance.
-	seal_rent_allowance(ctx, out_ptr: u32, out_len_ptr: u32) => {
+	[seal0] seal_rent_allowance(ctx, out_ptr: u32, out_len_ptr: u32) => {
 		ctx.charge_gas(RuntimeToken::RentAllowance)?;
 		Ok(ctx.write_sandbox_output(
 			out_ptr, out_len_ptr, &ctx.ext.rent_allowance().encode(), false, already_charged
@@ -1363,10 +1405,10 @@ define_env!(Env, <E: Ext>,
 	// Prints utf8 encoded string from the data buffer.
 	// Only available on `--dev` chains.
 	// This function may be removed at any time, superseded by a more general contract debugging feature.
-	seal_println(ctx, str_ptr: u32, str_len: u32) => {
+	[seal0] seal_println(ctx, str_ptr: u32, str_len: u32) => {
 		let data = ctx.read_sandbox_memory(str_ptr, str_len)?;
 		if let Ok(utf8) = core::str::from_utf8(&data) {
-			sp_runtime::print(utf8);
+			log::info!(target: "runtime::contracts", "seal_println: {}", utf8);
 		}
 		Ok(())
 	},
@@ -1377,7 +1419,7 @@ define_env!(Env, <E: Ext>,
 	// `out_len_ptr` must point to a u32 value that describes the available space at
 	// `out_ptr`. This call overwrites it with the size of the value. If the available
 	// space at `out_ptr` is less than the size of the value a trap is triggered.
-	seal_block_number(ctx, out_ptr: u32, out_len_ptr: u32) => {
+	[seal0] seal_block_number(ctx, out_ptr: u32, out_len_ptr: u32) => {
 		ctx.charge_gas(RuntimeToken::BlockNumber)?;
 		Ok(ctx.write_sandbox_output(
 			out_ptr, out_len_ptr, &ctx.ext.block_number().encode(), false, already_charged
@@ -1404,7 +1446,7 @@ define_env!(Env, <E: Ext>,
 	// - `output_ptr`: the pointer into the linear memory where the output
 	//                 data is placed. The function will write the result
 	//                 directly into this buffer.
-	seal_hash_sha2_256(ctx, input_ptr: u32, input_len: u32, output_ptr: u32) => {
+	[seal0] seal_hash_sha2_256(ctx, input_ptr: u32, input_len: u32, output_ptr: u32) => {
 		ctx.charge_gas(RuntimeToken::HashSha256(input_len))?;
 		Ok(ctx.compute_hash_on_intermediate_buffer(sha2_256, input_ptr, input_len, output_ptr)?)
 	},
@@ -1429,7 +1471,7 @@ define_env!(Env, <E: Ext>,
 	// - `output_ptr`: the pointer into the linear memory where the output
 	//                 data is placed. The function will write the result
 	//                 directly into this buffer.
-	seal_hash_keccak_256(ctx, input_ptr: u32, input_len: u32, output_ptr: u32) => {
+	[seal0] seal_hash_keccak_256(ctx, input_ptr: u32, input_len: u32, output_ptr: u32) => {
 		ctx.charge_gas(RuntimeToken::HashKeccak256(input_len))?;
 		Ok(ctx.compute_hash_on_intermediate_buffer(keccak_256, input_ptr, input_len, output_ptr)?)
 	},
@@ -1454,7 +1496,7 @@ define_env!(Env, <E: Ext>,
 	// - `output_ptr`: the pointer into the linear memory where the output
 	//                 data is placed. The function will write the result
 	//                 directly into this buffer.
-	seal_hash_blake2_256(ctx, input_ptr: u32, input_len: u32, output_ptr: u32) => {
+	[seal0] seal_hash_blake2_256(ctx, input_ptr: u32, input_len: u32, output_ptr: u32) => {
 		ctx.charge_gas(RuntimeToken::HashBlake256(input_len))?;
 		Ok(ctx.compute_hash_on_intermediate_buffer(blake2_256, input_ptr, input_len, output_ptr)?)
 	},
@@ -1479,7 +1521,7 @@ define_env!(Env, <E: Ext>,
 	// - `output_ptr`: the pointer into the linear memory where the output
 	//                 data is placed. The function will write the result
 	//                 directly into this buffer.
-	seal_hash_blake2_128(ctx, input_ptr: u32, input_len: u32, output_ptr: u32) => {
+	[seal0] seal_hash_blake2_128(ctx, input_ptr: u32, input_len: u32, output_ptr: u32) => {
 		ctx.charge_gas(RuntimeToken::HashBlake128(input_len))?;
 		Ok(ctx.compute_hash_on_intermediate_buffer(blake2_128, input_ptr, input_len, output_ptr)?)
 	},
@@ -1495,7 +1537,7 @@ define_env!(Env, <E: Ext>,
 	//
 	// If no chain extension exists the contract will trap with the `NoChainExtension`
 	// module error.
-	seal_call_chain_extension(
+	[seal0] seal_call_chain_extension(
 		ctx,
 		func_id: u32,
 		input_ptr: u32,
@@ -1531,7 +1573,7 @@ define_env!(Env, <E: Ext>,
 	// The returned information was collected and cached when the current contract call
 	// started execution. Any change to those values that happens due to actions of the
 	// current call or contracts that are called by this contract are not considered.
-	seal_rent_params(ctx, out_ptr: u32, out_len_ptr: u32) => {
+	[seal0] seal_rent_params(ctx, out_ptr: u32, out_len_ptr: u32) => {
 		ctx.charge_gas(RuntimeToken::RentParams)?;
 		Ok(ctx.write_sandbox_output(
 			out_ptr, out_len_ptr, &ctx.ext.rent_params().encode(), false, already_charged
diff --git a/frame/democracy/src/benchmarking.rs b/frame/democracy/src/benchmarking.rs
index 57447944d22a7..40bc99ec12e01 100644
--- a/frame/democracy/src/benchmarking.rs
+++ b/frame/democracy/src/benchmarking.rs
@@ -24,10 +24,10 @@ use frame_support::{
 	IterableStorageMap,
 	traits::{Currency, Get, EnsureOrigin, OnInitialize, UnfilteredDispatchable, schedule::DispatchTime},
 };
-use frame_system::{RawOrigin, Module as System, self, EventRecord};
+use frame_system::{RawOrigin, Pallet as System, self, EventRecord};
 use sp_runtime::traits::{Bounded, One};
 
-use crate::Module as Democracy;
+use crate::Pallet as Democracy;
 
 const SEED: u32 = 0;
 const MAX_REFERENDUMS: u32 = 99;
diff --git a/frame/democracy/src/lib.rs b/frame/democracy/src/lib.rs
index a7dd2d5bd9297..b3b37b0b34b68 100644
--- a/frame/democracy/src/lib.rs
+++ b/frame/democracy/src/lib.rs
@@ -17,8 +17,8 @@
 
 //! # Democracy Pallet
 //!
-//! - [`democracy::Config`](./trait.Config.html)
-//! - [`Call`](./enum.Call.html)
+//! - [`Config`]
+//! - [`Call`]
 //!
 //! ## Overview
 //!
@@ -596,7 +596,7 @@ decl_module! {
 
 			if let Some((until, _)) = <Blacklist<T>>::get(proposal_hash) {
 				ensure!(
-					<frame_system::Module<T>>::block_number() >= until,
+					<frame_system::Pallet<T>>::block_number() >= until,
 					Error::<T>::ProposalBlacklisted,
 				);
 			}
@@ -688,7 +688,7 @@ decl_module! {
 			ensure!(!<NextExternal<T>>::exists(), Error::<T>::DuplicateProposal);
 			if let Some((until, _)) = <Blacklist<T>>::get(proposal_hash) {
 				ensure!(
-					<frame_system::Module<T>>::block_number() >= until,
+					<frame_system::Pallet<T>>::block_number() >= until,
 					Error::<T>::ProposalBlacklisted,
 				);
 			}
@@ -776,7 +776,7 @@ decl_module! {
 			ensure!(proposal_hash == e_proposal_hash, Error::<T>::InvalidHash);
 
 			<NextExternal<T>>::kill();
-			let now = <frame_system::Module<T>>::block_number();
+			let now = <frame_system::Pallet<T>>::block_number();
 			Self::inject_referendum(now + voting_period, proposal_hash, threshold, delay);
 		}
 
@@ -806,7 +806,7 @@ decl_module! {
 				.err().ok_or(Error::<T>::AlreadyVetoed)?;
 
 			existing_vetoers.insert(insert_position, who.clone());
-			let until = <frame_system::Module<T>>::block_number() + T::CooloffPeriod::get();
+			let until = <frame_system::Pallet<T>>::block_number() + T::CooloffPeriod::get();
 			<Blacklist<T>>::insert(&proposal_hash, (until, existing_vetoers));
 
 			Self::deposit_event(RawEvent::Vetoed(who, proposal_hash, until));
@@ -1004,13 +1004,14 @@ decl_module! {
 					_ => None,
 				}).ok_or(Error::<T>::PreimageMissing)?;
 
-			let now = <frame_system::Module<T>>::block_number();
+			let now = <frame_system::Pallet<T>>::block_number();
 			let (voting, enactment) = (T::VotingPeriod::get(), T::EnactmentPeriod::get());
 			let additional = if who == provider { Zero::zero() } else { enactment };
 			ensure!(now >= since + voting + additional, Error::<T>::TooEarly);
 			ensure!(expiry.map_or(true, |e| now > e), Error::<T>::Imminent);
 
-			let _ = T::Currency::repatriate_reserved(&provider, &who, deposit, BalanceStatus::Free);
+			let res = T::Currency::repatriate_reserved(&provider, &who, deposit, BalanceStatus::Free);
+			debug_assert!(res.is_ok());
 			<Preimages<T>>::remove(&proposal_hash);
 			Self::deposit_event(RawEvent::PreimageReaped(proposal_hash, provider, deposit, who));
 		}
@@ -1209,7 +1210,7 @@ impl<T: Config> Module<T> {
 		delay: T::BlockNumber
 	) -> ReferendumIndex {
 		<Module<T>>::inject_referendum(
-			<frame_system::Module<T>>::block_number() + T::VotingPeriod::get(),
+			<frame_system::Pallet<T>>::block_number() + T::VotingPeriod::get(),
 			proposal_hash,
 			threshold,
 			delay
@@ -1308,7 +1309,7 @@ impl<T: Config> Module<T> {
 					Some(ReferendumInfo::Finished{end, approved}) =>
 						if let Some((lock_periods, balance)) = votes[i].1.locked_if(approved) {
 							let unlock_at = end + T::EnactmentPeriod::get() * lock_periods.into();
-							let now = system::Module::<T>::block_number();
+							let now = system::Pallet::<T>::block_number();
 							if now < unlock_at {
 								ensure!(matches!(scope, UnvoteScope::Any), Error::<T>::NoPermission);
 								prior.accumulate(unlock_at, balance)
@@ -1435,7 +1436,7 @@ impl<T: Config> Module<T> {
 				} => {
 					// remove any delegation votes to our current target.
 					let votes = Self::reduce_upstream_delegation(&target, conviction.votes(balance));
-					let now = system::Module::<T>::block_number();
+					let now = system::Pallet::<T>::block_number();
 					let lock_periods = conviction.lock_periods().into();
 					prior.accumulate(now + T::EnactmentPeriod::get() * lock_periods, balance);
 					voting.set_common(delegations, prior);
@@ -1455,7 +1456,7 @@ impl<T: Config> Module<T> {
 	/// a security hole) but may be reduced from what they are currently.
 	fn update_lock(who: &T::AccountId) {
 		let lock_needed = VotingOf::<T>::mutate(who, |voting| {
-			voting.rejig(system::Module::<T>::block_number());
+			voting.rejig(system::Pallet::<T>::block_number());
 			voting.locked_balance()
 		});
 		if lock_needed.is_zero() {
@@ -1541,7 +1542,8 @@ impl<T: Config> Module<T> {
 		let preimage = <Preimages<T>>::take(&proposal_hash);
 		if let Some(PreimageStatus::Available { data, provider, deposit, .. }) = preimage {
 			if let Ok(proposal) = T::Proposal::decode(&mut &data[..]) {
-				let _ = T::Currency::unreserve(&provider, deposit);
+				let err_amount = T::Currency::unreserve(&provider, deposit);
+				debug_assert!(err_amount.is_zero());
 				Self::deposit_event(RawEvent::PreimageUsed(proposal_hash, provider, deposit));
 
 				let ok = proposal.dispatch(frame_system::RawOrigin::Root.into()).is_ok();
@@ -1716,7 +1718,7 @@ impl<T: Config> Module<T> {
 			.saturating_mul(T::PreimageByteDeposit::get());
 		T::Currency::reserve(&who, deposit)?;
 
-		let now = <frame_system::Module<T>>::block_number();
+		let now = <frame_system::Pallet<T>>::block_number();
 		let a = PreimageStatus::Available {
 			data: encoded_proposal,
 			provider: who.clone(),
@@ -1738,7 +1740,7 @@ impl<T: Config> Module<T> {
 		let status = Preimages::<T>::get(&proposal_hash).ok_or(Error::<T>::NotImminent)?;
 		let expiry = status.to_missing_expiry().ok_or(Error::<T>::DuplicatePreimage)?;
 
-		let now = <frame_system::Module<T>>::block_number();
+		let now = <frame_system::Pallet<T>>::block_number();
 		let free = <BalanceOf<T>>::zero();
 		let a = PreimageStatus::Available {
 			data: encoded_proposal,
diff --git a/frame/democracy/src/tests.rs b/frame/democracy/src/tests.rs
index 291cfa33b5224..57e845ace9f24 100644
--- a/frame/democracy/src/tests.rs
+++ b/frame/democracy/src/tests.rs
@@ -60,10 +60,10 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
-		Scheduler: pallet_scheduler::{Module, Call, Storage, Config, Event<T>},
-		Democracy: pallet_democracy::{Module, Call, Storage, Config, Event<T>},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
+		Scheduler: pallet_scheduler::{Pallet, Call, Storage, Config, Event<T>},
+		Democracy: pallet_democracy::{Pallet, Call, Storage, Config, Event<T>},
 	}
 );
 
@@ -161,7 +161,7 @@ impl Contains<u64> for OneToFive {
 impl Config for Test {
 	type Proposal = Call;
 	type Event = Event;
-	type Currency = pallet_balances::Module<Self>;
+	type Currency = pallet_balances::Pallet<Self>;
 	type EnactmentPeriod = EnactmentPeriod;
 	type LaunchPeriod = LaunchPeriod;
 	type VotingPeriod = VotingPeriod;
diff --git a/frame/election-provider-multi-phase/Cargo.toml b/frame/election-provider-multi-phase/Cargo.toml
index 1d63f9df40a25..4b5178faa8e86 100644
--- a/frame/election-provider-multi-phase/Cargo.toml
+++ b/frame/election-provider-multi-phase/Cargo.toml
@@ -26,7 +26,7 @@ sp-std = { version = "3.0.0", default-features = false, path = "../../primitives
 sp-runtime = { version = "3.0.0", default-features = false, path = "../../primitives/runtime" }
 sp-npos-elections = { version = "3.0.0", default-features = false, path = "../../primitives/npos-elections" }
 sp-arithmetic = { version = "3.0.0", default-features = false, path = "../../primitives/arithmetic" }
-sp-election-providers = { version = "3.0.0", default-features = false, path = "../../primitives/election-providers" }
+frame-election-provider-support = { version = "3.0.0", default-features = false, path = "../election-provider-support" }
 
 # Optional imports for benchmarking
 frame-benchmarking = { version = "3.1.0", default-features = false, path = "../benchmarking", optional = true }
@@ -41,9 +41,9 @@ substrate-test-utils = { version = "3.0.0", path = "../../test-utils" }
 sp-io = { version = "3.0.0", path = "../../primitives/io" }
 sp-core = { version = "3.0.0", path = "../../primitives/core" }
 sp-tracing = { version = "3.0.0", path = "../../primitives/tracing" }
-sp-election-providers = { version = "3.0.0", features = ["runtime-benchmarks"], path = "../../primitives/election-providers" }
+frame-election-provider-support = { version = "3.0.0", features = ["runtime-benchmarks"], path = "../election-provider-support" }
 pallet-balances = { version = "3.0.0", path = "../balances" }
-frame-benchmarking = { path = "../benchmarking" , version = "3.1.0"}
+frame-benchmarking = { version = "3.1.0", path = "../benchmarking" }
 
 [features]
 default = ["std"]
@@ -60,7 +60,7 @@ std = [
 	"sp-runtime/std",
 	"sp-npos-elections/std",
 	"sp-arithmetic/std",
-	"sp-election-providers/std",
+	"frame-election-provider-support/std",
 	"log/std",
 ]
 runtime-benchmarks = [
diff --git a/frame/election-provider-multi-phase/src/benchmarking.rs b/frame/election-provider-multi-phase/src/benchmarking.rs
index 74db28c6e3929..40c7e801ae78d 100644
--- a/frame/election-provider-multi-phase/src/benchmarking.rs
+++ b/frame/election-provider-multi-phase/src/benchmarking.rs
@@ -1,6 +1,6 @@
 // This file is part of Substrate.
 
-// Copyright (C) 2020 Parity Technologies (UK) Ltd.
+// Copyright (C) 2021 Parity Technologies (UK) Ltd.
 // SPDX-License-Identifier: Apache-2.0
 
 // Licensed under the Apache License, Version 2.0 (the "License");
@@ -18,18 +18,17 @@
 //! Two phase election pallet benchmarking.
 
 use super::*;
-use crate::Module as MultiPhase;
-
-pub use frame_benchmarking::{account, benchmarks, whitelist_account, whitelisted_caller};
+use crate::Pallet as MultiPhase;
+use frame_benchmarking::impl_benchmark_test_suite;
 use frame_support::{assert_ok, traits::OnInitialize};
 use frame_system::RawOrigin;
 use rand::{prelude::SliceRandom, rngs::SmallRng, SeedableRng};
-use sp_election_providers::Assignment;
+use frame_election_provider_support::Assignment;
 use sp_arithmetic::traits::One;
 use sp_runtime::InnerOf;
 use sp_std::convert::TryInto;
 
-const SEED: u32 = 0;
+const SEED: u32 = 999;
 
 /// Creates a **valid** solution with exactly the given size.
 ///
@@ -55,9 +54,9 @@ fn solution_with_size<T: Config>(
 
 	// first generates random targets.
 	let targets: Vec<T::AccountId> =
-		(0..size.targets).map(|i| account("Targets", i, SEED)).collect();
+		(0..size.targets).map(|i| frame_benchmarking::account("Targets", i, SEED)).collect();
 
-	let mut rng = SmallRng::seed_from_u64(999u64);
+	let mut rng = SmallRng::seed_from_u64(SEED as u64);
 
 	// decide who are the winners.
 	let winners = targets
@@ -75,7 +74,7 @@ fn solution_with_size<T: Config>(
 				.choose_multiple(&mut rng, <CompactOf<T>>::LIMIT)
 				.cloned()
 				.collect::<Vec<_>>();
-			let voter = account::<T::AccountId>("Voter", i, SEED);
+			let voter = frame_benchmarking::account::<T::AccountId>("Voter", i, SEED);
 			(voter, stake, winner_votes)
 		})
 		.collect::<Vec<_>>();
@@ -89,7 +88,7 @@ fn solution_with_size<T: Config>(
 				.choose_multiple(&mut rng, <CompactOf<T>>::LIMIT)
 				.cloned()
 				.collect::<Vec<T::AccountId>>();
-			let voter = account::<T::AccountId>("Voter", i, SEED);
+			let voter = frame_benchmarking::account::<T::AccountId>("Voter", i, SEED);
 			(voter, stake, votes)
 		})
 		.collect::<Vec<_>>();
@@ -109,13 +108,14 @@ fn solution_with_size<T: Config>(
 	<DesiredTargets<T>>::put(desired_targets);
 	<Snapshot<T>>::put(RoundSnapshot { voters: all_voters.clone(), targets: targets.clone() });
 
-	// write the snapshot to staking or whoever is the data provider.
-	T::DataProvider::put_snapshot(all_voters.clone(), targets.clone());
+	// write the snapshot to staking or whoever is the data provider, in case it is needed further
+	// down the road.
+	T::DataProvider::put_snapshot(all_voters.clone(), targets.clone(), Some(stake));
 
 	let cache = helpers::generate_voter_cache::<T>(&all_voters);
 	let stake_of = helpers::stake_of_fn::<T>(&all_voters, &cache);
 	let voter_index = helpers::voter_index_fn::<T>(&cache);
-	let target_index = helpers::target_index_fn_linear::<T>(&targets);
+	let target_index = helpers::target_index_fn::<T>(&targets);
 	let voter_at = helpers::voter_at_fn::<T>(&all_voters);
 	let target_at = helpers::target_at_fn::<T>(&targets);
 
@@ -138,10 +138,12 @@ fn solution_with_size<T: Config>(
 		<CompactOf<T>>::from_assignment(assignments, &voter_index, &target_index).unwrap();
 	let score = compact.clone().score(&winners, stake_of, voter_at, target_at).unwrap();
 	let round = <MultiPhase<T>>::round();
+
+	assert!(score[0] > 0, "score is zero, this probably means that the stakes are not set.");
 	RawSolution { compact, score, round }
 }
 
-benchmarks! {
+frame_benchmarking::benchmarks! {
 	on_initialize_nothing {
 		assert!(<MultiPhase<T>>::current_phase().is_off());
 	}: {
@@ -157,7 +159,7 @@ benchmarks! {
 		assert!(<MultiPhase<T>>::snapshot().is_none());
 		assert!(<MultiPhase<T>>::current_phase().is_off());
 	}: {
-		<MultiPhase<T>>::on_initialize_open_signed();
+		<MultiPhase<T>>::on_initialize_open_signed().unwrap();
 	} verify {
 		assert!(<MultiPhase<T>>::snapshot().is_some());
 		assert!(<MultiPhase<T>>::current_phase().is_signed());
@@ -167,7 +169,7 @@ benchmarks! {
 		assert!(<MultiPhase<T>>::snapshot().is_none());
 		assert!(<MultiPhase<T>>::current_phase().is_off());
 	}: {
-		<MultiPhase<T>>::on_initialize_open_unsigned(true, true, 1u32.into());
+		<MultiPhase<T>>::on_initialize_open_unsigned(true, true, 1u32.into()).unwrap();
 	} verify {
 		assert!(<MultiPhase<T>>::snapshot().is_some());
 		assert!(<MultiPhase<T>>::current_phase().is_unsigned());
@@ -175,21 +177,51 @@ benchmarks! {
 
 	on_initialize_open_unsigned_without_snapshot {
 		// need to assume signed phase was open before
-		<MultiPhase<T>>::on_initialize_open_signed();
+		<MultiPhase<T>>::on_initialize_open_signed().unwrap();
 		assert!(<MultiPhase<T>>::snapshot().is_some());
 		assert!(<MultiPhase<T>>::current_phase().is_signed());
 	}: {
-		<MultiPhase<T>>::on_initialize_open_unsigned(false, true, 1u32.into());
+		<MultiPhase<T>>::on_initialize_open_unsigned(false, true, 1u32.into()).unwrap();
 	} verify {
 		assert!(<MultiPhase<T>>::snapshot().is_some());
 		assert!(<MultiPhase<T>>::current_phase().is_unsigned());
 	}
 
+	// a call to `<Pallet as ElectionProvider>::elect` where we only return the queued solution.
+	elect_queued {
+		// assume largest values for the election status. These will merely affect the decoding.
+		let v = T::BenchmarkingConfig::VOTERS[1];
+		let t = T::BenchmarkingConfig::TARGETS[1];
+		let a = T::BenchmarkingConfig::ACTIVE_VOTERS[1];
+		let d = T::BenchmarkingConfig::DESIRED_TARGETS[1];
+
+		let witness = SolutionOrSnapshotSize { voters: v, targets: t };
+		let raw_solution = solution_with_size::<T>(witness, a, d);
+		let ready_solution =
+			<MultiPhase<T>>::feasibility_check(raw_solution, ElectionCompute::Signed).unwrap();
+
+		// these are set by the `solution_with_size` function.
+		assert!(<DesiredTargets<T>>::get().is_some());
+		assert!(<Snapshot<T>>::get().is_some());
+		assert!(<SnapshotMetadata<T>>::get().is_some());
+		<CurrentPhase<T>>::put(Phase::Signed);
+		// assume a queued solution is stored, regardless of where it comes from.
+		<QueuedSolution<T>>::put(ready_solution);
+	}: {
+		let _ = <MultiPhase<T> as ElectionProvider<T::AccountId, T::BlockNumber>>::elect();
+	} verify {
+		assert!(<MultiPhase<T>>::queued_solution().is_none());
+		assert!(<DesiredTargets<T>>::get().is_none());
+		assert!(<Snapshot<T>>::get().is_none());
+		assert!(<SnapshotMetadata<T>>::get().is_none());
+		assert_eq!(<CurrentPhase<T>>::get(), <Phase<T::BlockNumber>>::Off);
+	}
+
 	#[extra]
 	create_snapshot {
 		assert!(<MultiPhase<T>>::snapshot().is_none());
 	}: {
-		<MultiPhase::<T>>::create_snapshot()
+		<MultiPhase::<T>>::create_snapshot().unwrap()
 	} verify {
 		assert!(<MultiPhase<T>>::snapshot().is_some());
 	}
@@ -248,35 +280,8 @@ benchmarks! {
 	}
 }
 
-#[cfg(test)]
-mod test {
-	use super::*;
-	use crate::mock::*;
-
-	#[test]
-	fn test_benchmarks() {
-		ExtBuilder::default().build_and_execute(|| {
-			assert_ok!(test_benchmark_feasibility_check::<Runtime>());
-		});
-
-		ExtBuilder::default().build_and_execute(|| {
-			assert_ok!(test_benchmark_submit_unsigned::<Runtime>());
-		});
-
-		ExtBuilder::default().build_and_execute(|| {
-			assert_ok!(test_benchmark_on_initialize_open_unsigned_with_snapshot::<Runtime>());
-		});
-
-		ExtBuilder::default().build_and_execute(|| {
-			assert_ok!(test_benchmark_on_initialize_open_unsigned_without_snapshot::<Runtime>());
-		});
-
-		ExtBuilder::default().build_and_execute(|| {
-			assert_ok!(test_benchmark_on_initialize_nothing::<Runtime>());
-		});
-
-		ExtBuilder::default().build_and_execute(|| {
-			assert_ok!(test_benchmark_create_snapshot::<Runtime>());
-		});
-	}
-}
+impl_benchmark_test_suite!(
+	MultiPhase,
+	crate::mock::ExtBuilder::default().build(),
+	crate::mock::Runtime,
+);
diff --git a/frame/election-provider-multi-phase/src/helpers.rs b/frame/election-provider-multi-phase/src/helpers.rs
index dd97163d2859c..7894f71800fdb 100644
--- a/frame/election-provider-multi-phase/src/helpers.rs
+++ b/frame/election-provider-multi-phase/src/helpers.rs
@@ -18,14 +18,14 @@
 //! Some helper functions/macros for this crate.
 
 use super::{Config, VoteWeight, CompactVoterIndexOf, CompactTargetIndexOf};
-use sp_std::{collections::btree_map::BTreeMap, convert::TryInto, boxed::Box, prelude::*};
+use sp_std::{collections::btree_map::BTreeMap, convert::TryInto, prelude::*};
 
 #[macro_export]
 macro_rules! log {
 	($level:tt, $pattern:expr $(, $values:expr)* $(,)?) => {
 		log::$level!(
 			target: $crate::LOG_TARGET,
-			concat!("🗳 ", $pattern) $(, $values)*
+			concat!("[#{:?}] 🗳  ", $pattern), <frame_system::Pallet<T>>::block_number() $(, $values)*
 		)
 	};
 }
@@ -56,10 +56,10 @@ pub fn generate_voter_cache<T: Config>(
 /// The snapshot must be the same is the one used to create `cache`.
 pub fn voter_index_fn<T: Config>(
 	cache: &BTreeMap<T::AccountId, usize>,
-) -> Box<dyn Fn(&T::AccountId) -> Option<CompactVoterIndexOf<T>> + '_> {
-	Box::new(move |who| {
+) -> impl Fn(&T::AccountId) -> Option<CompactVoterIndexOf<T>> + '_ {
+	move |who| {
 		cache.get(who).and_then(|i| <usize as TryInto<CompactVoterIndexOf<T>>>::try_into(*i).ok())
-	})
+	}
 }
 
 /// Same as [`voter_index_fn`], but the returning index is converted into usize, if possible.
@@ -69,8 +69,8 @@ pub fn voter_index_fn<T: Config>(
 /// The snapshot must be the same is the one used to create `cache`.
 pub fn voter_index_fn_usize<T: Config>(
 	cache: &BTreeMap<T::AccountId, usize>,
-) -> Box<dyn Fn(&T::AccountId) -> Option<usize> + '_> {
-	Box::new(move |who| cache.get(who).cloned())
+) -> impl Fn(&T::AccountId) -> Option<usize> + '_ {
+	move |who| cache.get(who).cloned()
 }
 
 /// A non-optimized, linear version of [`voter_index_fn`] that does not need a cache and does a
@@ -79,64 +79,90 @@ pub fn voter_index_fn_usize<T: Config>(
 /// ## Warning
 ///
 /// Not meant to be used in production.
+#[cfg(test)]
 pub fn voter_index_fn_linear<T: Config>(
 	snapshot: &Vec<(T::AccountId, VoteWeight, Vec<T::AccountId>)>,
-) -> Box<dyn Fn(&T::AccountId) -> Option<CompactVoterIndexOf<T>> + '_> {
-	Box::new(move |who| {
+) -> impl Fn(&T::AccountId) -> Option<CompactVoterIndexOf<T>> + '_ {
+	move |who| {
 		snapshot
 			.iter()
 			.position(|(x, _, _)| x == who)
 			.and_then(|i| <usize as TryInto<CompactVoterIndexOf<T>>>::try_into(i).ok())
-	})
+	}
 }
 
-/// Create a function the returns the index a targets in the snapshot.
+/// Create a function the returns the index to a target in the snapshot.
 ///
-/// The returning index type is the same as the one defined in `T::CompactSolution::Target`.
+/// The returned index type is the same as the one defined in `T::CompactSolution::Target`.
+///
+/// Note: to the extent possible, the returned function should be cached and reused. Producing that
+/// function requires a `O(n log n)` data transform. Each invocation of that function completes
+/// in `O(log n)`.
+pub fn target_index_fn<T: Config>(
+	snapshot: &Vec<T::AccountId>,
+) -> impl Fn(&T::AccountId) -> Option<CompactTargetIndexOf<T>> + '_ {
+	let cache: BTreeMap<_, _> =
+		snapshot.iter().enumerate().map(|(idx, account_id)| (account_id, idx)).collect();
+	move |who| {
+		cache
+			.get(who)
+			.and_then(|i| <usize as TryInto<CompactTargetIndexOf<T>>>::try_into(*i).ok())
+	}
+}
+
+/// Create a function the returns the index to a target in the snapshot.
+///
+/// The returned index type is the same as the one defined in `T::CompactSolution::Target`.
+///
+/// ## Warning
+///
+/// Not meant to be used in production.
+#[cfg(test)]
 pub fn target_index_fn_linear<T: Config>(
 	snapshot: &Vec<T::AccountId>,
-) -> Box<dyn Fn(&T::AccountId) -> Option<CompactTargetIndexOf<T>> + '_> {
-	Box::new(move |who| {
+) -> impl Fn(&T::AccountId) -> Option<CompactTargetIndexOf<T>> + '_ {
+	move |who| {
 		snapshot
 			.iter()
 			.position(|x| x == who)
 			.and_then(|i| <usize as TryInto<CompactTargetIndexOf<T>>>::try_into(i).ok())
-	})
+	}
 }
 
 /// Create a function that can map a voter index ([`CompactVoterIndexOf`]) to the actual voter
 /// account using a linearly indexible snapshot.
 pub fn voter_at_fn<T: Config>(
 	snapshot: &Vec<(T::AccountId, VoteWeight, Vec<T::AccountId>)>,
-) -> Box<dyn Fn(CompactVoterIndexOf<T>) -> Option<T::AccountId> + '_> {
-	Box::new(move |i| {
+) -> impl Fn(CompactVoterIndexOf<T>) -> Option<T::AccountId> + '_ {
+	move |i| {
 		<CompactVoterIndexOf<T> as TryInto<usize>>::try_into(i)
 			.ok()
 			.and_then(|i| snapshot.get(i).map(|(x, _, _)| x).cloned())
-	})
+	}
 }
 
 /// Create a function that can map a target index ([`CompactTargetIndexOf`]) to the actual target
 /// account using a linearly indexible snapshot.
 pub fn target_at_fn<T: Config>(
 	snapshot: &Vec<T::AccountId>,
-) -> Box<dyn Fn(CompactTargetIndexOf<T>) -> Option<T::AccountId> + '_> {
-	Box::new(move |i| {
+) -> impl Fn(CompactTargetIndexOf<T>) -> Option<T::AccountId> + '_ {
+	move |i| {
 		<CompactTargetIndexOf<T> as TryInto<usize>>::try_into(i)
 			.ok()
 			.and_then(|i| snapshot.get(i).cloned())
-	})
+	}
 }
 
 /// Create a function to get the stake of a voter.
 ///
 /// This is not optimized and uses a linear search.
+#[cfg(test)]
 pub fn stake_of_fn_linear<T: Config>(
 	snapshot: &Vec<(T::AccountId, VoteWeight, Vec<T::AccountId>)>,
-) -> Box<dyn Fn(&T::AccountId) -> VoteWeight + '_> {
-	Box::new(move |who| {
+) -> impl Fn(&T::AccountId) -> VoteWeight + '_ {
+	move |who| {
 		snapshot.iter().find(|(x, _, _)| x == who).map(|(_, x, _)| *x).unwrap_or_default()
-	})
+	}
 }
 
 /// Create a function to get the stake of a voter.
@@ -148,12 +174,12 @@ pub fn stake_of_fn_linear<T: Config>(
 pub fn stake_of_fn<'a, T: Config>(
 	snapshot: &'a Vec<(T::AccountId, VoteWeight, Vec<T::AccountId>)>,
 	cache: &'a BTreeMap<T::AccountId, usize>,
-) -> Box<dyn Fn(&T::AccountId) -> VoteWeight + 'a> {
-	Box::new(move |who| {
+) -> impl Fn(&T::AccountId) -> VoteWeight + 'a {
+	move |who| {
 		if let Some(index) = cache.get(who) {
 			snapshot.get(*index).map(|(_, x, _)| x).cloned().unwrap_or_default()
 		} else {
 			0
 		}
-	})
+	}
 }
diff --git a/frame/election-provider-multi-phase/src/lib.rs b/frame/election-provider-multi-phase/src/lib.rs
index 4ee6caae0a641..5545b3961124a 100644
--- a/frame/election-provider-multi-phase/src/lib.rs
+++ b/frame/election-provider-multi-phase/src/lib.rs
@@ -23,9 +23,10 @@
 //! ## Phases
 //!
 //! The timeline of pallet is as follows. At each block,
-//! [`sp_election_providers::ElectionDataProvider::next_election_prediction`] is used to estimate
-//! the time remaining to the next call to [`sp_election_providers::ElectionProvider::elect`]. Based
-//! on this, a phase is chosen. The timeline is as follows.
+//! [`frame_election_provider_support::ElectionDataProvider::next_election_prediction`] is used to
+//! estimate the time remaining to the next call to
+//! [`frame_election_provider_support::ElectionProvider::elect`]. Based on this, a phase is chosen.
+//! The timeline is as follows.
 //!
 //! ```ignore
 //!                                                                    elect()
@@ -149,7 +150,8 @@
 //!    are helpful for logging and are thus nested as:
 //!    - [`ElectionError::Miner`]: wraps a [`unsigned::MinerError`].
 //!    - [`ElectionError::Feasibility`]: wraps a [`FeasibilityError`].
-//!    - [`ElectionError::OnChainFallback`]: wraps a [`sp_election_providers::onchain::Error`].
+//!    - [`ElectionError::OnChainFallback`]: wraps a
+//!      [`frame_election_provider_support::onchain::Error`].
 //!
 //! Note that there could be an overlap between these sub-errors. For example, A
 //! `SnapshotUnavailable` can happen in both miner and feasibility check phase.
@@ -184,10 +186,10 @@
 //!
 //! **Recursive Fallback**: Currently, the fallback is a separate enum. A different and fancier way
 //! of doing this would be to have the fallback be another
-//! [`sp_election_providers::ElectionProvider`]. In this case, this pallet can even have the
-//! on-chain election provider as fallback, or special _noop_ fallback that simply returns an error,
-//! thus replicating [`FallbackStrategy::Nothing`]. In this case, we won't need the additional
-//! config OnChainAccuracy either.
+//! [`frame_election_provider_support::ElectionProvider`]. In this case, this pallet can even have
+//! the on-chain election provider as fallback, or special _noop_ fallback that simply returns an
+//! error, thus replicating [`FallbackStrategy::Nothing`]. In this case, we won't need the
+//! additional config OnChainAccuracy either.
 //!
 //! **Score based on (byte) size**: We should always prioritize small solutions over bigger ones, if
 //! there is a tie. Even more harsh should be to enforce the bound of the `reduce` algorithm.
@@ -200,6 +202,15 @@
 //! dependency from staking and the compact solution type. It should be generated at runtime, there
 //! it should be encoded how many votes each nominators have. Essentially translate
 //! <https://github.com/paritytech/substrate/pull/7929> to this pallet.
+//!
+//! **More accurate weight for error cases**: Both `ElectionDataProvider` and `ElectionProvider`
+//! assume no weight is consumed in their functions, when operations fail with `Err`. This can
+//! clearly be improved, but not a priority as we generally expect snapshot creation to fail only
+//! due to extreme circumstances.
+//!
+//! **Take into account the encode/decode weight in benchmarks.** Currently, we only take into
+//! account the weight of encode/decode in the `submit_unsigned` given its priority. Nonetheless,
+//! all operations on the solution and the snapshot are worthy of taking this into account.
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
@@ -211,7 +222,7 @@ use frame_support::{
 	weights::Weight,
 };
 use frame_system::{ensure_none, offchain::SendTransactionTypes};
-use sp_election_providers::{ElectionDataProvider, ElectionProvider, onchain};
+use frame_election_provider_support::{ElectionDataProvider, ElectionProvider, onchain};
 use sp_npos_elections::{
 	assignment_ratio_to_staked_normalized, is_score_better, CompactSolution, ElectionScore,
 	EvaluateSupport, PerThing128, Supports, VoteWeight,
@@ -222,6 +233,7 @@ use sp_runtime::{
 		TransactionValidityError, ValidTransaction,
 	},
 	DispatchError, PerThing, Perbill, RuntimeDebug, SaturatedConversion,
+	traits::Bounded,
 };
 use sp_std::prelude::*;
 use sp_arithmetic::{
@@ -261,6 +273,7 @@ struct OnChainConfig<T: Config>(sp_std::marker::PhantomData<T>);
 impl<T: Config> onchain::Config for OnChainConfig<T> {
 	type AccountId = T::AccountId;
 	type BlockNumber = T::BlockNumber;
+	type BlockWeights = T::BlockWeights;
 	type Accuracy = T::OnChainAccuracy;
 	type DataProvider = T::DataProvider;
 }
@@ -368,11 +381,11 @@ impl Default for ElectionCompute {
 #[derive(PartialEq, Eq, Clone, Encode, Decode, RuntimeDebug)]
 pub struct RawSolution<C> {
 	/// Compact election edges.
-	compact: C,
+	pub compact: C,
 	/// The _claimed_ score of the solution.
-	score: ElectionScore,
+	pub score: ElectionScore,
 	/// The round at which this solution should be submitted.
-	round: u32,
+	pub round: u32,
 }
 
 impl<C: Default> Default for RawSolution<C> {
@@ -389,13 +402,13 @@ pub struct ReadySolution<A> {
 	///
 	/// This is target-major vector, storing each winners, total backing, and each individual
 	/// backer.
-	supports: Supports<A>,
+	pub supports: Supports<A>,
 	/// The score of the solution.
 	///
 	/// This is needed to potentially challenge the solution.
-	score: ElectionScore,
+	pub score: ElectionScore,
 	/// How this election was computed.
-	compute: ElectionCompute,
+	pub compute: ElectionCompute,
 }
 
 /// A snapshot of all the data that is needed for en entire round. They are provided by
@@ -419,10 +432,10 @@ pub struct RoundSnapshot<A> {
 pub struct SolutionOrSnapshotSize {
 	/// The length of voters.
 	#[codec(compact)]
-	voters: u32,
+	pub voters: u32,
 	/// The length of targets.
 	#[codec(compact)]
-	targets: u32,
+	pub targets: u32,
 }
 
 /// Internal errors of the pallet.
@@ -436,6 +449,8 @@ pub enum ElectionError {
 	Miner(unsigned::MinerError),
 	/// An error in the on-chain fallback.
 	OnChainFallback(onchain::Error),
+	/// An error happened in the data provider.
+	DataProvider(&'static str),
 	/// No fallback is configured. This is a special case.
 	NoFallbackConfigured,
 }
@@ -563,17 +578,28 @@ pub mod pallet {
 
 			match current_phase {
 				Phase::Off if remaining <= signed_deadline && remaining > unsigned_deadline => {
-					Self::on_initialize_open_signed();
-					log!(info, "Starting signed phase at #{:?} , round {}.", now, Self::round());
-					T::WeightInfo::on_initialize_open_signed()
+					// NOTE: if signed-phase length is zero, second part of the if-condition fails.
+					match Self::on_initialize_open_signed() {
+						Ok(snap_weight) => {
+							log!(info, "Starting signed phase round {}.", Self::round());
+							T::WeightInfo::on_initialize_open_signed().saturating_add(snap_weight)
+						}
+						Err(why) => {
+							// not much we can do about this at this point.
+							log!(warn, "failed to open signed phase due to {:?}", why);
+							T::WeightInfo::on_initialize_nothing()
+							// NOTE: ^^ The trait specifies that this is a noop in terms of weight
+							// in case of error.
+						}
+					}
 				}
 				Phase::Signed | Phase::Off
-					if remaining <= unsigned_deadline && remaining > 0u32.into() =>
+					if remaining <= unsigned_deadline && remaining > Zero::zero() =>
 				{
-					let (need_snapshot, enabled, additional) = if current_phase == Phase::Signed {
+					// determine if followed by signed or not.
+					let (need_snapshot, enabled, signed_weight) = if current_phase == Phase::Signed {
 						// followed by a signed phase: close the signed phase, no need for snapshot.
-						// TWO_PHASE_NOTE: later on once we have signed phase, this should return
-						// something else.
+						// TODO: proper weight https://github.com/paritytech/substrate/pull/7910.
 						(false, true, Weight::zero())
 					} else {
 						// no signed phase: create a new snapshot, definitely `enable` the unsigned
@@ -581,15 +607,25 @@ pub mod pallet {
 						(true, true, Weight::zero())
 					};
 
-					Self::on_initialize_open_unsigned(need_snapshot, enabled, now);
-					log!(info, "Starting unsigned phase({}) at #{:?}.", enabled, now);
-
-					let base_weight = if need_snapshot {
-						T::WeightInfo::on_initialize_open_unsigned_with_snapshot()
-					} else {
-						T::WeightInfo::on_initialize_open_unsigned_without_snapshot()
-					};
-					base_weight.saturating_add(additional)
+					match Self::on_initialize_open_unsigned(need_snapshot, enabled, now) {
+						Ok(snap_weight) => {
+							log!(info, "Starting unsigned phase({}).", enabled);
+							let base_weight = if need_snapshot {
+								T::WeightInfo::on_initialize_open_unsigned_with_snapshot()
+							} else {
+								T::WeightInfo::on_initialize_open_unsigned_without_snapshot()
+							};
+
+							base_weight.saturating_add(snap_weight).saturating_add(signed_weight)
+						}
+						Err(why) => {
+							// not much we can do about this at this point.
+							log!(warn, "failed to open unsigned phase due to {:?}", why);
+							T::WeightInfo::on_initialize_nothing()
+							// NOTE: ^^ The trait specifies that this is a noop in terms of weight
+							// in case of error.
+						}
+					}
 				}
 				_ => T::WeightInfo::on_initialize_nothing(),
 			}
@@ -601,7 +637,7 @@ pub mod pallet {
 				match Self::try_acquire_offchain_lock(n) {
 					Ok(_) => {
 						let outcome = Self::mine_check_and_submit().map_err(ElectionError::from);
-						log!(info, "miner exeuction done: {:?}", outcome);
+						log!(info, "mine_check_and_submit execution done: {:?}", outcome);
 					}
 					Err(why) => log!(warn, "denied offchain worker: {:?}", why),
 				}
@@ -642,6 +678,16 @@ pub mod pallet {
 			let _: UpperOf<CompactAccuracyOf<T>> = maximum_chain_accuracy
 				.iter()
 				.fold(Zero::zero(), |acc, x| acc.checked_add(x).unwrap());
+
+			// We only accept data provider who's maximum votes per voter matches our
+			// `T::CompactSolution`'s `LIMIT`.
+			//
+			// NOTE that this pallet does not really need to enforce this in runtime. The compact
+			// solution cannot represent any voters more than `LIMIT` anyhow.
+			assert_eq!(
+				<T::DataProvider as ElectionDataProvider<T::AccountId, T::BlockNumber>>::MAXIMUM_VOTES_PER_VOTER,
+				<CompactOf<T> as CompactSolution>::LIMIT as u32,
+			);
 		}
 	}
 
@@ -838,32 +884,41 @@ pub mod pallet {
 }
 
 impl<T: Config> Pallet<T> {
-	/// Logic for `<Pallet as Hooks>::on_initialize` when signed phase is being opened.
+	/// Logic for [`<Pallet as Hooks>::on_initialize`] when signed phase is being opened.
 	///
 	/// This is decoupled for easy weight calculation.
-	pub(crate) fn on_initialize_open_signed() {
+	///
+	/// Returns `Ok(snapshot_weight)` if success, where `snapshot_weight` is the weight that
+	/// needs to recorded for the creation of snapshot.
+	pub(crate) fn on_initialize_open_signed() -> Result<Weight, ElectionError> {
+		let weight = Self::create_snapshot()?;
 		<CurrentPhase<T>>::put(Phase::Signed);
-		Self::create_snapshot();
 		Self::deposit_event(Event::SignedPhaseStarted(Self::round()));
+		Ok(weight.saturating_add(T::DbWeight::get().writes(1)))
 	}
 
-	/// Logic for `<Pallet as Hooks<T>>::on_initialize` when unsigned phase is being opened.
+	/// Logic for [`<Pallet as Hooks<T>>::on_initialize`] when unsigned phase is being opened.
+	///
+	/// This is decoupled for easy weight calculation.
 	///
-	/// This is decoupled for easy weight calculation. Note that the default weight benchmark of
-	/// this function will assume an empty signed queue for `finalize_signed_phase`.
+	/// Returns `Ok(snapshot_weight)` if success, where `snapshot_weight` is the weight that
+	/// needs to recorded for the creation of snapshot.
 	pub(crate) fn on_initialize_open_unsigned(
 		need_snapshot: bool,
 		enabled: bool,
 		now: T::BlockNumber,
-	) {
-		if need_snapshot {
+	) -> Result<Weight, ElectionError> {
+		let weight = if need_snapshot {
 			// if not being followed by a signed phase, then create the snapshots.
 			debug_assert!(Self::snapshot().is_none());
-			Self::create_snapshot();
-		}
+			Self::create_snapshot()?
+		} else {
+			0
+		};
 
 		<CurrentPhase<T>>::put(Phase::Unsigned((enabled, now)));
 		Self::deposit_event(Event::UnsignedPhaseStarted(Self::round()));
+		Ok(weight.saturating_add(T::DbWeight::get().writes(1)))
 	}
 
 	/// Creates the snapshot. Writes new data to:
@@ -871,18 +926,33 @@ impl<T: Config> Pallet<T> {
 	/// 1. [`SnapshotMetadata`]
 	/// 2. [`RoundSnapshot`]
 	/// 3. [`DesiredTargets`]
-	pub(crate) fn create_snapshot() {
-		// if any of them don't exist, create all of them. This is a bit conservative.
-		let targets = T::DataProvider::targets();
-		let voters = T::DataProvider::voters();
-		let desired_targets = T::DataProvider::desired_targets();
+	///
+	/// Returns `Ok(consumed_weight)` if operation is okay.
+	pub(crate) fn create_snapshot() -> Result<Weight, ElectionError> {
+		let target_limit = <CompactTargetIndexOf<T>>::max_value().saturated_into::<usize>();
+		let voter_limit = <CompactVoterIndexOf<T>>::max_value().saturated_into::<usize>();
+
+		let (targets, w1) =
+			T::DataProvider::targets(Some(target_limit)).map_err(ElectionError::DataProvider)?;
+		let (voters, w2) =
+			T::DataProvider::voters(Some(voter_limit)).map_err(ElectionError::DataProvider)?;
+		let (desired_targets, w3) =
+			T::DataProvider::desired_targets().map_err(ElectionError::DataProvider)?;
+
+		// defensive-only
+		if targets.len() > target_limit || voters.len() > voter_limit {
+			debug_assert!(false, "Snapshot limit has not been respected.");
+			return Err(ElectionError::DataProvider("Snapshot too big for submission."));
+		}
 
+		// only write snapshot if all existed.
 		<SnapshotMetadata<T>>::put(SolutionOrSnapshotSize {
 			voters: voters.len() as u32,
 			targets: targets.len() as u32,
 		});
 		<DesiredTargets<T>>::put(desired_targets);
 		<Snapshot<T>>::put(RoundSnapshot { voters, targets });
+		Ok(w1.saturating_add(w2).saturating_add(w3).saturating_add(T::DbWeight::get().writes(3)))
 	}
 
 	/// Kill everything created by [`Pallet::create_snapshot`].
@@ -998,7 +1068,7 @@ impl<T: Config> Pallet<T> {
 	}
 
 	/// On-chain fallback of election.
-	fn onchain_fallback() -> Result<Supports<T::AccountId>, ElectionError> {
+	fn onchain_fallback() -> Result<(Supports<T::AccountId>, Weight), ElectionError> {
 		<onchain::OnChainSequentialPhragmen<OnChainConfig<T>> as ElectionProvider<
 			T::AccountId,
 			T::BlockNumber,
@@ -1006,25 +1076,33 @@ impl<T: Config> Pallet<T> {
 		.map_err(Into::into)
 	}
 
-	fn do_elect() -> Result<Supports<T::AccountId>, ElectionError> {
+	fn do_elect() -> Result<(Supports<T::AccountId>, Weight), ElectionError> {
 		<QueuedSolution<T>>::take()
 			.map_or_else(
 				|| match T::Fallback::get() {
 					FallbackStrategy::OnChain => Self::onchain_fallback()
-						.map(|r| (r, ElectionCompute::OnChain))
+						.map(|(s, w)| (s, w, ElectionCompute::OnChain))
 						.map_err(Into::into),
 					FallbackStrategy::Nothing => Err(ElectionError::NoFallbackConfigured),
 				},
-				|ReadySolution { supports, compute, .. }| Ok((supports, compute)),
+				|ReadySolution { supports, compute, .. }| Ok((
+					supports,
+					T::WeightInfo::elect_queued(),
+					compute
+				)),
 			)
-			.map(|(supports, compute)| {
+			.map(|(supports, weight, compute)| {
 				Self::deposit_event(Event::ElectionFinalized(Some(compute)));
-				log!(info, "Finalized election round with compute {:?}.", compute);
-				supports
+				if Self::round() != 1 {
+					log!(info, "Finalized election round with compute {:?}.", compute);
+				}
+				(supports, weight)
 			})
 			.map_err(|err| {
 				Self::deposit_event(Event::ElectionFinalized(None));
-				log!(warn, "Failed to finalize election round. reason {:?}", err);
+				if Self::round() != 1 {
+					log!(warn, "Failed to finalize election round. reason {:?}", err);
+				}
 				err
 			})
 	}
@@ -1034,10 +1112,11 @@ impl<T: Config> ElectionProvider<T::AccountId, T::BlockNumber> for Pallet<T> {
 	type Error = ElectionError;
 	type DataProvider = T::DataProvider;
 
-	fn elect() -> Result<Supports<T::AccountId>, Self::Error> {
-		let outcome = Self::do_elect();
+	fn elect() -> Result<(Supports<T::AccountId>, Weight), Self::Error> {
+		let outcome_and_weight = Self::do_elect();
+		// IMPORTANT: regardless of if election was `Ok` or `Err`, we shall do some cleanup.
 		Self::post_elect();
-		outcome
+		outcome_and_weight
 	}
 }
 
@@ -1128,13 +1207,13 @@ mod feasibility_check {
 				.compact
 				.votes1
 				.iter_mut()
-				.filter(|(_, t)| *t == 3u16)
+				.filter(|(_, t)| *t == TargetIndex::from(3u16))
 				.for_each(|(_, t)| *t += 1);
 			solution.compact.votes2.iter_mut().for_each(|(_, (t0, _), t1)| {
-				if *t0 == 3u16 {
+				if *t0 == TargetIndex::from(3u16) {
 					*t0 += 1
 				};
-				if *t1 == 3u16 {
+				if *t1 == TargetIndex::from(3u16) {
 					*t1 += 1
 				};
 			});
@@ -1162,7 +1241,7 @@ mod feasibility_check {
 					.compact
 					.votes1
 					.iter_mut()
-					.filter(|(v, _)| *v == 7u32)
+					.filter(|(v, _)| *v == VoterIndex::from(7u32))
 					.map(|(v, _)| *v = 8)
 					.count() > 0
 			);
@@ -1225,7 +1304,7 @@ mod feasibility_check {
 #[cfg(test)]
 mod tests {
 	use super::{mock::*, Event, *};
-	use sp_election_providers::ElectionProvider;
+	use frame_election_provider_support::ElectionProvider;
 	use sp_npos_elections::Support;
 
 	#[test]
@@ -1397,7 +1476,7 @@ mod tests {
 
 	#[test]
 	fn fallback_strategy_works() {
-		ExtBuilder::default().fallabck(FallbackStrategy::OnChain).build_and_execute(|| {
+		ExtBuilder::default().fallback(FallbackStrategy::OnChain).build_and_execute(|| {
 			roll_to(15);
 			assert_eq!(MultiPhase::current_phase(), Phase::Signed);
 
@@ -1405,7 +1484,7 @@ mod tests {
 			assert_eq!(MultiPhase::current_phase(), Phase::Unsigned((true, 25)));
 
 			// zilch solutions thus far.
-			let supports = MultiPhase::elect().unwrap();
+			let (supports, _) = MultiPhase::elect().unwrap();
 
 			assert_eq!(
 				supports,
@@ -1416,7 +1495,7 @@ mod tests {
 			)
 		});
 
-		ExtBuilder::default().fallabck(FallbackStrategy::Nothing).build_and_execute(|| {
+		ExtBuilder::default().fallback(FallbackStrategy::Nothing).build_and_execute(|| {
 			roll_to(15);
 			assert_eq!(MultiPhase::current_phase(), Phase::Signed);
 
@@ -1428,6 +1507,26 @@ mod tests {
 		})
 	}
 
+	#[test]
+	fn snapshot_creation_fails_if_too_big() {
+		ExtBuilder::default().build_and_execute(|| {
+			Targets::set((0..(TargetIndex::max_value() as AccountId) + 1).collect::<Vec<_>>());
+
+			// signed phase failed to open.
+			roll_to(15);
+			assert_eq!(MultiPhase::current_phase(), Phase::Off);
+
+			// unsigned phase failed to open.
+			roll_to(25);
+			assert_eq!(MultiPhase::current_phase(), Phase::Off);
+
+			// on-chain backup works though.
+			roll_to(29);
+			let (supports, _) = MultiPhase::elect().unwrap();
+			assert!(supports.len() > 0);
+		})
+	}
+
 	#[test]
 	fn number_of_voters_allowed_2sec_block() {
 		// Just a rough estimate with the substrate weights.
diff --git a/frame/election-provider-multi-phase/src/mock.rs b/frame/election-provider-multi-phase/src/mock.rs
index e7a2924fd2aa6..cebd5cf06e692 100644
--- a/frame/election-provider-multi-phase/src/mock.rs
+++ b/frame/election-provider-multi-phase/src/mock.rs
@@ -31,7 +31,7 @@ use sp_core::{
 	},
 	H256,
 };
-use sp_election_providers::ElectionDataProvider;
+use frame_election_provider_support::{ElectionDataProvider, data_provider};
 use sp_npos_elections::{
 	assignment_ratio_to_staked_normalized, seq_phragmen, to_supports, to_without_backing,
 	CompactSolution, ElectionResult, EvaluateSupport,
@@ -52,18 +52,20 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic
 	{
-		System: frame_system::{Module, Call, Event<T>, Config},
-		Balances: pallet_balances::{Module, Call, Event<T>, Config<T>},
-		MultiPhase: multi_phase::{Module, Call, Event<T>},
+		System: frame_system::{Pallet, Call, Event<T>, Config},
+		Balances: pallet_balances::{Pallet, Call, Event<T>, Config<T>},
+		MultiPhase: multi_phase::{Pallet, Call, Event<T>},
 	}
 );
 
 pub(crate) type Balance = u64;
 pub(crate) type AccountId = u64;
+pub(crate) type VoterIndex = u32;
+pub(crate) type TargetIndex = u16;
 
 sp_npos_elections::generate_solution_type!(
 	#[compact]
-	pub struct TestCompact::<u32, u16, PerU16>(16)
+	pub struct TestCompact::<VoterIndex = VoterIndex, TargetIndex = TargetIndex, Accuracy = PerU16>(16)
 );
 
 /// All events of this pallet.
@@ -239,6 +241,13 @@ impl multi_phase::weights::WeightInfo for DualMockWeightInfo {
 			<() as multi_phase::weights::WeightInfo>::on_initialize_open_unsigned_without_snapshot()
 		}
 	}
+	fn elect_queued() -> Weight {
+		if MockWeightInfo::get() {
+			Zero::zero()
+		} else {
+			<() as multi_phase::weights::WeightInfo>::elect_queued()
+		}
+	}
 	fn submit_unsigned(v: u32, t: u32, a: u32, d: u32) -> Weight {
 		if MockWeightInfo::get() {
 			// 10 base
@@ -291,18 +300,44 @@ pub struct ExtBuilder {}
 
 pub struct StakingMock;
 impl ElectionDataProvider<AccountId, u64> for StakingMock {
-	fn targets() -> Vec<AccountId> {
-		Targets::get()
+	const MAXIMUM_VOTES_PER_VOTER: u32 = <TestCompact as CompactSolution>::LIMIT as u32;
+	fn targets(maybe_max_len: Option<usize>) -> data_provider::Result<(Vec<AccountId>, Weight)> {
+		let targets = Targets::get();
+
+		if maybe_max_len.map_or(false, |max_len| targets.len() > max_len) {
+			return Err("Targets too big");
+		}
+
+		Ok((targets, 0))
 	}
-	fn voters() -> Vec<(AccountId, VoteWeight, Vec<AccountId>)> {
-		Voters::get()
+
+	fn voters(
+		maybe_max_len: Option<usize>,
+	) -> data_provider::Result<(Vec<(AccountId, VoteWeight, Vec<AccountId>)>, Weight)> {
+		let voters = Voters::get();
+		if maybe_max_len.map_or(false, |max_len| voters.len() > max_len) {
+			return Err("Voters too big");
+		}
+
+		Ok((voters, 0))
 	}
-	fn desired_targets() -> u32 {
-		DesiredTargets::get()
+	fn desired_targets() -> data_provider::Result<(u32, Weight)> {
+		Ok((DesiredTargets::get(), 0))
 	}
+
 	fn next_election_prediction(now: u64) -> u64 {
 		now + EpochLength::get() - now % EpochLength::get()
 	}
+
+	#[cfg(any(feature = "runtime-benchmarks", test))]
+	fn put_snapshot(
+		voters: Vec<(AccountId, VoteWeight, Vec<AccountId>)>,
+		targets: Vec<AccountId>,
+		_target_stake: Option<VoteWeight>,
+	) {
+		Targets::set(targets);
+		Voters::set(voters);
+	}
 }
 
 impl ExtBuilder {
@@ -319,7 +354,7 @@ impl ExtBuilder {
 		<UnsignedPhase>::set(unsigned);
 		self
 	}
-	pub fn fallabck(self, fallback: FallbackStrategy) -> Self {
+	pub fn fallback(self, fallback: FallbackStrategy) -> Self {
 		<Fallback>::set(fallback);
 		self
 	}
diff --git a/frame/election-provider-multi-phase/src/unsigned.rs b/frame/election-provider-multi-phase/src/unsigned.rs
index 2039e5d9f0754..280907ac5439a 100644
--- a/frame/election-provider-multi-phase/src/unsigned.rs
+++ b/frame/election-provider-multi-phase/src/unsigned.rs
@@ -66,8 +66,17 @@ impl<T: Config> Pallet<T> {
 		let iters = Self::get_balancing_iters();
 		// get the solution, with a load of checks to ensure if submitted, IT IS ABSOLUTELY VALID.
 		let (raw_solution, witness) = Self::mine_and_check(iters)?;
+		let score = raw_solution.score.clone();
+
+		let call: <T as frame_system::offchain::SendTransactionTypes<Call<T>>>::OverarchingCall =
+			Call::submit_unsigned(raw_solution, witness).into();
+		log!(
+			info,
+			"mined a solution with score {:?} and size {}",
+			score,
+			call.using_encoded(|b| b.len())
+		);
 
-		let call = Call::submit_unsigned(raw_solution, witness).into();
 		SubmitTransaction::<T, Call<T>>::submit_unsigned_transaction(call)
 			.map_err(|_| MinerError::PoolSubmissionFailed)
 	}
@@ -136,7 +145,7 @@ impl<T: Config> Pallet<T> {
 		// closures.
 		let cache = helpers::generate_voter_cache::<T>(&voters);
 		let voter_index = helpers::voter_index_fn::<T>(&cache);
-		let target_index = helpers::target_index_fn_linear::<T>(&targets);
+		let target_index = helpers::target_index_fn::<T>(&targets);
 		let voter_at = helpers::voter_at_fn::<T>(&voters);
 		let target_at = helpers::target_at_fn::<T>(&targets);
 		let stake_of = helpers::stake_of_fn::<T>(&voters, &cache);
@@ -159,12 +168,16 @@ impl<T: Config> Pallet<T> {
 			size,
 			T::MinerMaxWeight::get(),
 		);
+
 		log!(
 			debug,
-			"miner: current compact solution voters = {}, maximum_allowed = {}",
+			"initial solution voters = {}, snapshot = {:?}, maximum_allowed(capped) = {}",
 			compact.voter_count(),
+			size,
 			maximum_allowed_voters,
 		);
+
+		// trim weight.
 		let compact = Self::trim_compact(maximum_allowed_voters, compact, &voter_index)?;
 
 		// re-calc score.
@@ -243,10 +256,12 @@ impl<T: Config> Pallet<T> {
 					}
 				}
 
+				log!(debug, "removed {} voter to meet the max weight limit.", to_remove);
 				Ok(compact)
 			}
 			_ => {
 				// nada, return as-is
+				log!(debug, "didn't remove any voter for weight limits.");
 				Ok(compact)
 			}
 		}
@@ -289,6 +304,7 @@ impl<T: Config> Pallet<T> {
 		// First binary-search the right amount of voters
 		let mut step = voters / 2;
 		let mut current_weight = weight_with(voters);
+
 		while step > 0 {
 			match next_voters(current_weight, voters, step) {
 				// proceed with the binary search
@@ -315,13 +331,14 @@ impl<T: Config> Pallet<T> {
 			voters -= 1;
 		}
 
+		let final_decision = voters.min(size.voters);
 		debug_assert!(
-			weight_with(voters.min(size.voters)) <= max_weight,
+			weight_with(final_decision) <= max_weight,
 			"weight_with({}) <= {}",
-			voters.min(size.voters),
+			final_decision,
 			max_weight,
 		);
-		voters.min(size.voters)
+		final_decision
 	}
 
 	/// Checks if an execution of the offchain worker is permitted at the given block number, or
@@ -413,6 +430,9 @@ mod max_weight {
 		fn on_initialize_open_unsigned_with_snapshot() -> Weight {
 			unreachable!()
 		}
+		fn elect_queued() -> Weight {
+			0
+		}
 		fn on_initialize_open_unsigned_without_snapshot() -> Weight {
 			unreachable!()
 		}
@@ -487,7 +507,7 @@ mod tests {
 	};
 	use frame_support::{dispatch::Dispatchable, traits::OffchainWorker};
 	use mock::Call as OuterCall;
-	use sp_election_providers::Assignment;
+	use frame_election_provider_support::Assignment;
 	use sp_runtime::{traits::ValidateUnsigned, PerU16};
 
 	#[test]
@@ -725,7 +745,6 @@ mod tests {
 			roll_to(25);
 			assert!(MultiPhase::current_phase().is_unsigned());
 
-			// mine seq_phragmen solution with 2 iters.
 			assert_eq!(
 				MultiPhase::mine_check_and_submit().unwrap_err(),
 				MinerError::PreDispatchChecksFailed,
@@ -832,7 +851,7 @@ mod tests {
 	}
 
 	#[test]
-	fn ocw_only_runs_when_signed_open_now() {
+	fn ocw_only_runs_when_unsigned_open_now() {
 		let (mut ext, pool) = ExtBuilder::default().build_offchainify(0);
 		ext.execute_with(|| {
 			roll_to(25);
diff --git a/frame/election-provider-multi-phase/src/weights.rs b/frame/election-provider-multi-phase/src/weights.rs
index 276bba330d24c..3d3a5cede3293 100644
--- a/frame/election-provider-multi-phase/src/weights.rs
+++ b/frame/election-provider-multi-phase/src/weights.rs
@@ -18,7 +18,7 @@
 //! Autogenerated weights for pallet_election_provider_multi_phase
 //!
 //! THIS FILE WAS AUTO-GENERATED USING THE SUBSTRATE BENCHMARK CLI VERSION 3.0.0
-//! DATE: 2021-02-12, STEPS: `[50, ]`, REPEAT: 20, LOW RANGE: [], HIGH RANGE: []
+//! DATE: 2021-03-19, STEPS: `[50, ]`, REPEAT: 20, LOW RANGE: `[]`, HIGH RANGE: `[]`
 //! EXECUTION: Some(Wasm), WASM-EXECUTION: Compiled, CHAIN: Some("dev"), DB CACHE: 128
 
 // Executed Command:
@@ -48,6 +48,7 @@ pub trait WeightInfo {
 	fn on_initialize_open_signed() -> Weight;
 	fn on_initialize_open_unsigned_with_snapshot() -> Weight;
 	fn on_initialize_open_unsigned_without_snapshot() -> Weight;
+	fn elect_queued() -> Weight;
 	fn submit_unsigned(v: u32, t: u32, a: u32, d: u32, ) -> Weight;
 	fn feasibility_check(v: u32, t: u32, a: u32, d: u32, ) -> Weight;
 }
@@ -56,47 +57,50 @@ pub trait WeightInfo {
 pub struct SubstrateWeight<T>(PhantomData<T>);
 impl<T: frame_system::Config> WeightInfo for SubstrateWeight<T> {
 	fn on_initialize_nothing() -> Weight {
-		(23_401_000 as Weight)
+		(22_730_000 as Weight)
 			.saturating_add(T::DbWeight::get().reads(7 as Weight))
 	}
 	fn on_initialize_open_signed() -> Weight {
-		(79_260_000 as Weight)
-			.saturating_add(T::DbWeight::get().reads(7 as Weight))
+		(112_051_000 as Weight)
+			.saturating_add(T::DbWeight::get().reads(8 as Weight))
 			.saturating_add(T::DbWeight::get().writes(4 as Weight))
 	}
 	fn on_initialize_open_unsigned_with_snapshot() -> Weight {
-		(77_745_000 as Weight)
-			.saturating_add(T::DbWeight::get().reads(7 as Weight))
+		(112_165_000 as Weight)
+			.saturating_add(T::DbWeight::get().reads(8 as Weight))
 			.saturating_add(T::DbWeight::get().writes(4 as Weight))
 	}
 	fn on_initialize_open_unsigned_without_snapshot() -> Weight {
-		(21_764_000 as Weight)
+		(21_039_000 as Weight)
 			.saturating_add(T::DbWeight::get().reads(1 as Weight))
 			.saturating_add(T::DbWeight::get().writes(1 as Weight))
 	}
-	fn submit_unsigned(v: u32, t: u32, a: u32, d: u32, ) -> Weight {
+	fn elect_queued() -> Weight {
+		(7_362_949_000 as Weight)
+			.saturating_add(T::DbWeight::get().reads(2 as Weight))
+			.saturating_add(T::DbWeight::get().writes(6 as Weight))
+	}
+	fn submit_unsigned(v: u32, _t: u32, a: u32, d: u32, ) -> Weight {
 		(0 as Weight)
-			// Standard Error: 23_000
-			.saturating_add((4_171_000 as Weight).saturating_mul(v as Weight))
-			// Standard Error: 78_000
-			.saturating_add((229_000 as Weight).saturating_mul(t as Weight))
-			// Standard Error: 23_000
-			.saturating_add((13_661_000 as Weight).saturating_mul(a as Weight))
-			// Standard Error: 117_000
-			.saturating_add((4_499_000 as Weight).saturating_mul(d as Weight))
+			// Standard Error: 21_000
+			.saturating_add((3_933_000 as Weight).saturating_mul(v as Weight))
+			// Standard Error: 21_000
+			.saturating_add((13_520_000 as Weight).saturating_mul(a as Weight))
+			// Standard Error: 107_000
+			.saturating_add((2_880_000 as Weight).saturating_mul(d as Weight))
 			.saturating_add(T::DbWeight::get().reads(6 as Weight))
 			.saturating_add(T::DbWeight::get().writes(1 as Weight))
 	}
 	fn feasibility_check(v: u32, t: u32, a: u32, d: u32, ) -> Weight {
 		(0 as Weight)
-			// Standard Error: 12_000
-			.saturating_add((4_232_000 as Weight).saturating_mul(v as Weight))
-			// Standard Error: 42_000
-			.saturating_add((636_000 as Weight).saturating_mul(t as Weight))
-			// Standard Error: 12_000
-			.saturating_add((10_294_000 as Weight).saturating_mul(a as Weight))
-			// Standard Error: 64_000
-			.saturating_add((4_428_000 as Weight).saturating_mul(d as Weight))
+			// Standard Error: 10_000
+			.saturating_add((4_069_000 as Weight).saturating_mul(v as Weight))
+			// Standard Error: 36_000
+			.saturating_add((503_000 as Weight).saturating_mul(t as Weight))
+			// Standard Error: 10_000
+			.saturating_add((10_000_000 as Weight).saturating_mul(a as Weight))
+			// Standard Error: 54_000
+			.saturating_add((3_734_000 as Weight).saturating_mul(d as Weight))
 			.saturating_add(T::DbWeight::get().reads(3 as Weight))
 	}
 }
@@ -104,47 +108,50 @@ impl<T: frame_system::Config> WeightInfo for SubstrateWeight<T> {
 // For backwards compatibility and tests
 impl WeightInfo for () {
 	fn on_initialize_nothing() -> Weight {
-		(23_401_000 as Weight)
+		(22_730_000 as Weight)
 			.saturating_add(RocksDbWeight::get().reads(7 as Weight))
 	}
 	fn on_initialize_open_signed() -> Weight {
-		(79_260_000 as Weight)
-			.saturating_add(RocksDbWeight::get().reads(7 as Weight))
+		(112_051_000 as Weight)
+			.saturating_add(RocksDbWeight::get().reads(8 as Weight))
 			.saturating_add(RocksDbWeight::get().writes(4 as Weight))
 	}
 	fn on_initialize_open_unsigned_with_snapshot() -> Weight {
-		(77_745_000 as Weight)
-			.saturating_add(RocksDbWeight::get().reads(7 as Weight))
+		(112_165_000 as Weight)
+			.saturating_add(RocksDbWeight::get().reads(8 as Weight))
 			.saturating_add(RocksDbWeight::get().writes(4 as Weight))
 	}
 	fn on_initialize_open_unsigned_without_snapshot() -> Weight {
-		(21_764_000 as Weight)
+		(21_039_000 as Weight)
 			.saturating_add(RocksDbWeight::get().reads(1 as Weight))
 			.saturating_add(RocksDbWeight::get().writes(1 as Weight))
 	}
-	fn submit_unsigned(v: u32, t: u32, a: u32, d: u32, ) -> Weight {
+	fn elect_queued() -> Weight {
+		(7_362_949_000 as Weight)
+			.saturating_add(RocksDbWeight::get().reads(2 as Weight))
+			.saturating_add(RocksDbWeight::get().writes(6 as Weight))
+	}
+	fn submit_unsigned(v: u32, _t: u32, a: u32, d: u32, ) -> Weight {
 		(0 as Weight)
-			// Standard Error: 23_000
-			.saturating_add((4_171_000 as Weight).saturating_mul(v as Weight))
-			// Standard Error: 78_000
-			.saturating_add((229_000 as Weight).saturating_mul(t as Weight))
-			// Standard Error: 23_000
-			.saturating_add((13_661_000 as Weight).saturating_mul(a as Weight))
-			// Standard Error: 117_000
-			.saturating_add((4_499_000 as Weight).saturating_mul(d as Weight))
+			// Standard Error: 21_000
+			.saturating_add((3_933_000 as Weight).saturating_mul(v as Weight))
+			// Standard Error: 21_000
+			.saturating_add((13_520_000 as Weight).saturating_mul(a as Weight))
+			// Standard Error: 107_000
+			.saturating_add((2_880_000 as Weight).saturating_mul(d as Weight))
 			.saturating_add(RocksDbWeight::get().reads(6 as Weight))
 			.saturating_add(RocksDbWeight::get().writes(1 as Weight))
 	}
 	fn feasibility_check(v: u32, t: u32, a: u32, d: u32, ) -> Weight {
 		(0 as Weight)
-			// Standard Error: 12_000
-			.saturating_add((4_232_000 as Weight).saturating_mul(v as Weight))
-			// Standard Error: 42_000
-			.saturating_add((636_000 as Weight).saturating_mul(t as Weight))
-			// Standard Error: 12_000
-			.saturating_add((10_294_000 as Weight).saturating_mul(a as Weight))
-			// Standard Error: 64_000
-			.saturating_add((4_428_000 as Weight).saturating_mul(d as Weight))
+			// Standard Error: 10_000
+			.saturating_add((4_069_000 as Weight).saturating_mul(v as Weight))
+			// Standard Error: 36_000
+			.saturating_add((503_000 as Weight).saturating_mul(t as Weight))
+			// Standard Error: 10_000
+			.saturating_add((10_000_000 as Weight).saturating_mul(a as Weight))
+			// Standard Error: 54_000
+			.saturating_add((3_734_000 as Weight).saturating_mul(d as Weight))
 			.saturating_add(RocksDbWeight::get().reads(3 as Weight))
 	}
 }
diff --git a/primitives/election-providers/Cargo.toml b/frame/election-provider-support/Cargo.toml
similarity index 57%
rename from primitives/election-providers/Cargo.toml
rename to frame/election-provider-support/Cargo.toml
index cf12dce8098d7..b360cd89eb57b 100644
--- a/primitives/election-providers/Cargo.toml
+++ b/frame/election-provider-support/Cargo.toml
@@ -1,12 +1,12 @@
 [package]
-name = "sp-election-providers"
+name = "frame-election-provider-support"
 version = "3.0.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
 license = "Apache-2.0"
 homepage = "https://substrate.dev"
 repository = "https://github.com/paritytech/substrate/"
-description = "Primitive election providers"
+description = "election provider supporting traits"
 readme = "README.md"
 
 [package.metadata.docs.rs]
@@ -14,20 +14,24 @@ targets = ["x86_64-unknown-linux-gnu"]
 
 [dependencies]
 codec = { package = "parity-scale-codec", version = "2.0.0", default-features = false, features = ["derive"] }
-sp-std = { version = "3.0.0", default-features = false, path = "../std" }
-sp-arithmetic = { version = "3.0.0", default-features = false, path = "../arithmetic" }
-sp-npos-elections = { version = "3.0.0", default-features = false, path = "../npos-elections" }
+sp-std = { version = "3.0.0", default-features = false, path = "../../primitives/std" }
+sp-arithmetic = { version = "3.0.0", default-features = false, path = "../../primitives/arithmetic" }
+sp-npos-elections = { version = "3.0.0", default-features = false, path = "../../primitives/npos-elections" }
+frame-support = { version = "3.0.0", default-features = false, path = "../support" }
+frame-system = { version = "3.0.0", default-features = false, path = "../system" }
 
 [dev-dependencies]
-sp-npos-elections = { version = "3.0.0", path = "../npos-elections" }
-sp-runtime = { version = "3.0.0", path = "../runtime" }
+sp-npos-elections = { version = "3.0.0", path = "../../primitives/npos-elections" }
+sp-runtime = { version = "3.0.0", path = "../../primitives/runtime" }
 
 [features]
 default = ["std"]
-runtime-benchmarks = []
 std = [
 	"codec/std",
 	"sp-std/std",
 	"sp-npos-elections/std",
 	"sp-arithmetic/std",
+	"frame-support/std",
+	"frame-system/std",
 ]
+runtime-benchmarks = []
diff --git a/primitives/election-providers/src/lib.rs b/frame/election-provider-support/src/lib.rs
similarity index 72%
rename from primitives/election-providers/src/lib.rs
rename to frame/election-provider-support/src/lib.rs
index 73ea58c176b26..b846460e71f8a 100644
--- a/primitives/election-providers/src/lib.rs
+++ b/frame/election-provider-support/src/lib.rs
@@ -78,14 +78,15 @@
 //! ## Example
 //!
 //! ```rust
-//! # use sp_election_providers::*;
+//! # use frame_election_provider_support::{*, data_provider};
 //! # use sp_npos_elections::{Support, Assignment};
+//! # use frame_support::weights::Weight;
 //!
 //! type AccountId = u64;
 //! type Balance = u64;
 //! type BlockNumber = u32;
 //!
-//! mod data_provider {
+//! mod data_provider_mod {
 //!     use super::*;
 //!
 //!     pub trait Config: Sized {
@@ -99,14 +100,17 @@
 //!     pub struct Module<T: Config>(std::marker::PhantomData<T>);
 //!
 //!     impl<T: Config> ElectionDataProvider<AccountId, BlockNumber> for Module<T> {
-//!         fn desired_targets() -> u32 {
-//!             1
+//!         const MAXIMUM_VOTES_PER_VOTER: u32 = 1;
+//!         fn desired_targets() -> data_provider::Result<(u32, Weight)> {
+//!             Ok((1, 0))
 //!         }
-//!         fn voters() -> Vec<(AccountId, VoteWeight, Vec<AccountId>)> {
-//!             Default::default()
+//!         fn voters(maybe_max_len: Option<usize>)
+//!         -> data_provider::Result<(Vec<(AccountId, VoteWeight, Vec<AccountId>)>, Weight)>
+//!         {
+//!             Ok((Default::default(), 0))
 //!         }
-//!         fn targets() -> Vec<AccountId> {
-//!             vec![10, 20, 30]
+//!         fn targets(maybe_max_len: Option<usize>) -> data_provider::Result<(Vec<AccountId>, Weight)> {
+//!             Ok((vec![10, 20, 30], 0))
 //!         }
 //!         fn next_election_prediction(now: BlockNumber) -> BlockNumber {
 //!             0
@@ -125,29 +129,30 @@
 //!     }
 //!
 //!     impl<T: Config> ElectionProvider<AccountId, BlockNumber> for GenericElectionProvider<T> {
-//!         type Error = ();
+//!         type Error = &'static str;
 //!         type DataProvider = T::DataProvider;
 //!
-//!         fn elect() -> Result<Supports<AccountId>, Self::Error> {
-//!             Self::DataProvider::targets()
-//!                 .first()
-//!                 .map(|winner| vec![(*winner, Support::default())])
-//!                 .ok_or(())
+//!         fn elect() -> Result<(Supports<AccountId>, Weight), Self::Error> {
+//!             Self::DataProvider::targets(None)
+//!                 .map_err(|_| "failed to elect")
+//!                 .map(|(t, weight)| {
+//! 						(vec![(t[0], Support::default())], weight)
+//! 				})
 //!         }
 //!     }
 //! }
 //!
 //! mod runtime {
 //!     use super::generic_election_provider;
-//!     use super::data_provider;
+//!     use super::data_provider_mod;
 //!     use super::AccountId;
 //!
 //!     struct Runtime;
 //!     impl generic_election_provider::Config for Runtime {
-//!         type DataProvider = data_provider::Module<Runtime>;
+//!         type DataProvider = data_provider_mod::Module<Runtime>;
 //!     }
 //!
-//!     impl data_provider::Config for Runtime {
+//!     impl data_provider_mod::Config for Runtime {
 //!         type ElectionProvider = generic_election_provider::GenericElectionProvider<Runtime>;
 //!     }
 //!
@@ -160,23 +165,49 @@
 
 pub mod onchain;
 use sp_std::{prelude::*, fmt::Debug};
+use frame_support::weights::Weight;
 
 /// Re-export some type as they are used in the interface.
 pub use sp_arithmetic::PerThing;
-pub use sp_npos_elections::{Assignment, ExtendedBalance, PerThing128, Supports, VoteWeight};
+pub use sp_npos_elections::{
+	Assignment, ExtendedBalance, PerThing128, Supports, Support, VoteWeight
+};
+
+/// Types that are used by the data provider trait.
+pub mod data_provider {
+	/// Alias for the result type of the election data provider.
+	pub type Result<T> = sp_std::result::Result<T, &'static str>;
+}
 
 /// Something that can provide the data to an [`ElectionProvider`].
 pub trait ElectionDataProvider<AccountId, BlockNumber> {
+	/// Maximum number of votes per voter that this data provider is providing.
+	const MAXIMUM_VOTES_PER_VOTER: u32;
+
 	/// All possible targets for the election, i.e. the candidates.
-	fn targets() -> Vec<AccountId>;
+	///
+	/// If `maybe_max_len` is `Some(v)` then the resulting vector MUST NOT be longer than `v` items
+	/// long.
+	///
+	/// It is assumed that this function will only consume a notable amount of weight, when it
+	/// returns `Ok(_)`.
+	fn targets(maybe_max_len: Option<usize>) -> data_provider::Result<(Vec<AccountId>, Weight)>;
 
 	/// All possible voters for the election.
 	///
 	/// Note that if a notion of self-vote exists, it should be represented here.
-	fn voters() -> Vec<(AccountId, VoteWeight, Vec<AccountId>)>;
+	///
+	/// If `maybe_max_len` is `Some(v)` then the resulting vector MUST NOT be longer than `v` items
+	/// long.
+	///
+	/// It is assumed that this function will only consume a notable amount of weight, when it
+	/// returns `Ok(_)`.
+	fn voters(
+		maybe_max_len: Option<usize>,
+	) -> data_provider::Result<(Vec<(AccountId, VoteWeight, Vec<AccountId>)>, Weight)>;
 
 	/// The number of targets to elect.
-	fn desired_targets() -> u32;
+	fn desired_targets() -> data_provider::Result<(u32, Weight)>;
 
 	/// Provide a best effort prediction about when the next election is about to happen.
 	///
@@ -192,20 +223,24 @@ pub trait ElectionDataProvider<AccountId, BlockNumber> {
 	fn put_snapshot(
 		_voters: Vec<(AccountId, VoteWeight, Vec<AccountId>)>,
 		_targets: Vec<AccountId>,
+		_target_stake: Option<VoteWeight>,
 	) {
 	}
 }
 
 #[cfg(feature = "std")]
 impl<AccountId, BlockNumber> ElectionDataProvider<AccountId, BlockNumber> for () {
-	fn targets() -> Vec<AccountId> {
-		Default::default()
+	const MAXIMUM_VOTES_PER_VOTER: u32 = 0;
+	fn targets(_maybe_max_len: Option<usize>) -> data_provider::Result<(Vec<AccountId>, Weight)> {
+		Ok(Default::default())
 	}
-	fn voters() -> Vec<(AccountId, VoteWeight, Vec<AccountId>)> {
-		Default::default()
+	fn voters(
+		_maybe_max_len: Option<usize>,
+	) -> data_provider::Result<(Vec<(AccountId, VoteWeight, Vec<AccountId>)>, Weight)> {
+		Ok(Default::default())
 	}
-	fn desired_targets() -> u32 {
-		Default::default()
+	fn desired_targets() -> data_provider::Result<(u32, Weight)> {
+		Ok(Default::default())
 	}
 	fn next_election_prediction(now: BlockNumber) -> BlockNumber {
 		now
@@ -226,8 +261,8 @@ pub trait ElectionProvider<AccountId, BlockNumber> {
 
 	/// Elect a new set of winners.
 	///
-	/// The result is returned in a target major format, namely as vector of  supports.
-	fn elect() -> Result<Supports<AccountId>, Self::Error>;
+	/// The result is returned in a target major format, namely as vector of supports.
+	fn elect() -> Result<(Supports<AccountId>, Weight), Self::Error>;
 }
 
 #[cfg(feature = "std")]
@@ -235,7 +270,7 @@ impl<AccountId, BlockNumber> ElectionProvider<AccountId, BlockNumber> for () {
 	type Error = &'static str;
 	type DataProvider = ();
 
-	fn elect() -> Result<Supports<AccountId>, Self::Error> {
+	fn elect() -> Result<(Supports<AccountId>, Weight), Self::Error> {
 		Err("<() as ElectionProvider> cannot do anything.")
 	}
 }
diff --git a/primitives/election-providers/src/onchain.rs b/frame/election-provider-support/src/onchain.rs
similarity index 69%
rename from primitives/election-providers/src/onchain.rs
rename to frame/election-provider-support/src/onchain.rs
index b50dff2ff17d9..e034a9c36a8ac 100644
--- a/primitives/election-providers/src/onchain.rs
+++ b/frame/election-provider-support/src/onchain.rs
@@ -20,12 +20,15 @@
 use crate::{ElectionDataProvider, ElectionProvider};
 use sp_npos_elections::*;
 use sp_std::{collections::btree_map::BTreeMap, marker::PhantomData, prelude::*};
+use frame_support::{traits::Get, weights::Weight};
 
 /// Errors of the on-chain election.
 #[derive(Eq, PartialEq, Debug)]
 pub enum Error {
 	/// An internal error in the NPoS elections crate.
 	NposElections(sp_npos_elections::Error),
+	/// Errors from the data provider.
+	DataProvider(&'static str),
 }
 
 impl From<sp_npos_elections::Error> for Error {
@@ -40,13 +43,20 @@ impl From<sp_npos_elections::Error> for Error {
 ///
 /// ### Warning
 ///
-/// This can be very expensive to run frequently on-chain. Use with care.
+/// This can be very expensive to run frequently on-chain. Use with care. Moreover, this
+/// implementation ignores the additional data of the election data provider and gives no insight on
+/// how much weight was consumed.
+///
+/// Finally, this implementation does not impose any limits on the number of voters and targets that
+/// are provided.
 pub struct OnChainSequentialPhragmen<T: Config>(PhantomData<T>);
 
 /// Configuration trait of [`OnChainSequentialPhragmen`].
 ///
 /// Note that this is similar to a pallet traits, but [`OnChainSequentialPhragmen`] is not a pallet.
 pub trait Config {
+	/// The block limits.
+	type BlockWeights: Get<frame_system::limits::BlockWeights>;
 	/// The account identifier type.
 	type AccountId: IdentifierT;
 	/// The block number type.
@@ -61,10 +71,11 @@ impl<T: Config> ElectionProvider<T::AccountId, T::BlockNumber> for OnChainSequen
 	type Error = Error;
 	type DataProvider = T::DataProvider;
 
-	fn elect() -> Result<Supports<T::AccountId>, Self::Error> {
-		let voters = Self::DataProvider::voters();
-		let targets = Self::DataProvider::targets();
-		let desired_targets = Self::DataProvider::desired_targets() as usize;
+	fn elect() -> Result<(Supports<T::AccountId>, Weight), Self::Error> {
+		let (voters, _) = Self::DataProvider::voters(None).map_err(Error::DataProvider)?;
+		let (targets, _) = Self::DataProvider::targets(None).map_err(Error::DataProvider)?;
+		let (desired_targets, _) =
+			Self::DataProvider::desired_targets().map_err(Error::DataProvider)?;
 
 		let mut stake_map: BTreeMap<T::AccountId, VoteWeight> = BTreeMap::new();
 
@@ -77,13 +88,13 @@ impl<T: Config> ElectionProvider<T::AccountId, T::BlockNumber> for OnChainSequen
 		};
 
 		let ElectionResult { winners, assignments } =
-			seq_phragmen::<_, T::Accuracy>(desired_targets, targets, voters, None)
+			seq_phragmen::<_, T::Accuracy>(desired_targets as usize, targets, voters, None)
 				.map_err(Error::from)?;
 
 		let staked = assignment_ratio_to_staked_normalized(assignments, &stake_of)?;
 		let winners = to_without_backing(winners);
 
-		to_supports(&winners, &staked).map_err(Error::from)
+		to_supports(&winners, &staked).map_err(Error::from).map(|s| (s, T::BlockWeights::get().max_block))
 	}
 }
 
@@ -92,12 +103,13 @@ mod tests {
 	use super::*;
 	use sp_npos_elections::Support;
 	use sp_runtime::Perbill;
+	use frame_support::weights::Weight;
 
 	type AccountId = u64;
 	type BlockNumber = u32;
-
 	struct Runtime;
 	impl Config for Runtime {
+		type BlockWeights = ();
 		type AccountId = AccountId;
 		type BlockNumber = BlockNumber;
 		type Accuracy = Perbill;
@@ -108,24 +120,24 @@ mod tests {
 
 	mod mock_data_provider {
 		use super::*;
+		use crate::data_provider;
 
 		pub struct DataProvider;
 
 		impl ElectionDataProvider<AccountId, BlockNumber> for DataProvider {
-			fn voters() -> Vec<(AccountId, VoteWeight, Vec<AccountId>)> {
-				vec![
-					(1, 10, vec![10, 20]),
-					(2, 20, vec![30, 20]),
-					(3, 30, vec![10, 30]),
-				]
+			const MAXIMUM_VOTES_PER_VOTER: u32 = 2;
+			fn voters(
+				_: Option<usize>,
+			) -> data_provider::Result<(Vec<(AccountId, VoteWeight, Vec<AccountId>)>, Weight)> {
+				Ok((vec![(1, 10, vec![10, 20]), (2, 20, vec![30, 20]), (3, 30, vec![10, 30])], 0))
 			}
 
-			fn targets() -> Vec<AccountId> {
-				vec![10, 20, 30]
+			fn targets(_: Option<usize>) -> data_provider::Result<(Vec<AccountId>, Weight)> {
+				Ok((vec![10, 20, 30], 0))
 			}
 
-			fn desired_targets() -> u32 {
-				2
+			fn desired_targets() -> data_provider::Result<(u32, Weight)> {
+				Ok((2, 0))
 			}
 
 			fn next_election_prediction(_: BlockNumber) -> BlockNumber {
@@ -137,7 +149,7 @@ mod tests {
 	#[test]
 	fn onchain_seq_phragmen_works() {
 		assert_eq!(
-			OnChainPhragmen::elect().unwrap(),
+			OnChainPhragmen::elect().unwrap().0,
 			vec![
 				(
 					10,
diff --git a/frame/elections-phragmen/src/lib.rs b/frame/elections-phragmen/src/lib.rs
index 779570ca633ee..7f0a6afb2b106 100644
--- a/frame/elections-phragmen/src/lib.rs
+++ b/frame/elections-phragmen/src/lib.rs
@@ -92,9 +92,9 @@
 //!
 //! ### Module Information
 //!
-//! - [`election_sp_phragmen::Config`](./trait.Config.html)
-//! - [`Call`](./enum.Call.html)
-//! - [`Module`](./struct.Module.html)
+//! - [`Config`]
+//! - [`Call`]
+//! - [`Module`]
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
@@ -1084,7 +1084,7 @@ mod tests {
 		type OnNewAccount = ();
 		type OnKilledAccount = ();
 		type SystemWeightInfo = ();
-	type SS58Prefix = ();
+		type SS58Prefix = ();
 	}
 
 	parameter_types! {
@@ -1096,7 +1096,7 @@ mod tests {
 		type Event = Event;
 		type DustRemoval = ();
 		type ExistentialDeposit = ExistentialDeposit;
-		type AccountStore = frame_system::Module<Test>;
+		type AccountStore = frame_system::Pallet<Test>;
 		type MaxLocks = ();
 		type WeightInfo = ();
 	}
@@ -1187,9 +1187,9 @@ mod tests {
 			NodeBlock = Block,
 			UncheckedExtrinsic = UncheckedExtrinsic
 		{
-			System: frame_system::{Module, Call, Event<T>},
-			Balances: pallet_balances::{Module, Call, Event<T>, Config<T>},
-			Elections: elections_phragmen::{Module, Call, Event<T>, Config<T>},
+			System: frame_system::{Pallet, Call, Event<T>},
+			Balances: pallet_balances::{Pallet, Call, Event<T>, Config<T>},
+			Elections: elections_phragmen::{Pallet, Call, Event<T>, Config<T>},
 		}
 	);
 
@@ -1308,7 +1308,6 @@ mod tests {
 	}
 
 	fn has_lock(who: &u64) -> u64 {
-		dbg!(Balances::locks(who));
 		Balances::locks(who)
 			.get(0)
 			.cloned()
diff --git a/frame/elections-phragmen/src/migrations_3_0_0.rs b/frame/elections-phragmen/src/migrations_3_0_0.rs
index 8adc4c1a69f7c..8afc9ed66920b 100644
--- a/frame/elections-phragmen/src/migrations_3_0_0.rs
+++ b/frame/elections-phragmen/src/migrations_3_0_0.rs
@@ -21,7 +21,6 @@ use codec::{Encode, Decode, FullCodec};
 use sp_std::prelude::*;
 use frame_support::{
 	RuntimeDebug, weights::Weight, Twox64Concat,
-	storage::types::{StorageMap, StorageValue},
 	traits::{GetPalletVersion, PalletVersion},
 };
 
@@ -51,38 +50,21 @@ pub trait V2ToV3 {
 	type Balance: 'static + FullCodec + Copy;
 }
 
-struct __Candidates;
-impl frame_support::traits::StorageInstance for __Candidates {
-	fn pallet_prefix() -> &'static str { "PhragmenElection" }
-	const STORAGE_PREFIX: &'static str = "Candidates";
-}
-
-#[allow(type_alias_bounds)]
-type Candidates<T: V2ToV3> = StorageValue<__Candidates, Vec<(T::AccountId, T::Balance)>>;
-
-struct __Members;
-impl frame_support::traits::StorageInstance for __Members {
-	fn pallet_prefix() -> &'static str { "PhragmenElection" }
-	const STORAGE_PREFIX: &'static str = "Members";
-}
-#[allow(type_alias_bounds)]
-type Members<T: V2ToV3> = StorageValue<__Members, Vec<SeatHolder<T::AccountId, T::Balance>>>;
-
-struct __RunnersUp;
-impl frame_support::traits::StorageInstance for __RunnersUp {
-	fn pallet_prefix() -> &'static str { "PhragmenElection" }
-	const STORAGE_PREFIX: &'static str = "RunnersUp";
-}
-#[allow(type_alias_bounds)]
-type RunnersUp<T: V2ToV3> = StorageValue<__RunnersUp, Vec<SeatHolder<T::AccountId, T::Balance>>>;
-
-struct __Voting;
-impl frame_support::traits::StorageInstance for __Voting {
-	fn pallet_prefix() -> &'static str { "PhragmenElection" }
-	const STORAGE_PREFIX: &'static str = "Voting";
-}
-#[allow(type_alias_bounds)]
-type Voting<T: V2ToV3> = StorageMap<__Voting, Twox64Concat, T::AccountId, Voter<T::AccountId, T::Balance>>;
+frame_support::generate_storage_alias!(
+	PhragmenElection, Candidates<T: V2ToV3> => Value<Vec<(T::AccountId, T::Balance)>>
+);
+frame_support::generate_storage_alias!(
+	PhragmenElection, Members<T: V2ToV3> => Value<Vec<SeatHolder<T::AccountId, T::Balance>>>
+);
+frame_support::generate_storage_alias!(
+	PhragmenElection, RunnersUp<T: V2ToV3> => Value<Vec<SeatHolder<T::AccountId, T::Balance>>>
+);
+frame_support::generate_storage_alias!(
+	PhragmenElection, Voting<T: V2ToV3> => Map<
+		(Twox64Concat, T::AccountId),
+		Voter<T::AccountId, T::Balance>
+	>
+);
 
 /// Apply all of the migrations from 2_0_0 to 3_0_0.
 ///
diff --git a/frame/elections/src/lib.rs b/frame/elections/src/lib.rs
index 6eaa2dfad3732..d6b68bbf5a043 100644
--- a/frame/elections/src/lib.rs
+++ b/frame/elections/src/lib.rs
@@ -713,7 +713,7 @@ decl_event!(
 		BadReaperSlashed(AccountId),
 		/// A tally (for approval votes of \[seats\]) has started.
 		TallyStarted(u32),
-		/// A tally (for approval votes of seat(s)) has ended (with one or more new members). 
+		/// A tally (for approval votes of seat(s)) has ended (with one or more new members).
 		/// \[incoming, outgoing\]
 		TallyFinalized(Vec<AccountId>, Vec<AccountId>),
 	}
@@ -759,7 +759,7 @@ impl<T: Config> Module<T> {
 					// if there's a tally in progress, then next tally can begin immediately afterwards
 					(tally_end, c.len() - leavers.len() + comers as usize, comers)
 				} else {
-					(<frame_system::Module<T>>::block_number(), c.len(), 0)
+					(<frame_system::Pallet<T>>::block_number(), c.len(), 0)
 				};
 			if count < desired_seats as usize {
 				Some(next_possible)
@@ -914,7 +914,7 @@ impl<T: Config> Module<T> {
 	fn start_tally() {
 		let members = Self::members();
 		let desired_seats = Self::desired_seats() as usize;
-		let number = <frame_system::Module<T>>::block_number();
+		let number = <frame_system::Pallet<T>>::block_number();
 		let expiring =
 			members.iter().take_while(|i| i.1 <= number).map(|i| i.0.clone()).collect::<Vec<_>>();
 		let retaining_seats = members.len() - expiring.len();
@@ -942,7 +942,7 @@ impl<T: Config> Module<T> {
 				.ok_or("finalize can only be called after a tally is started.")?;
 		let leaderboard: Vec<(BalanceOf<T>, T::AccountId)> = <Leaderboard<T>>::take()
 			.unwrap_or_default();
-		let new_expiry = <frame_system::Module<T>>::block_number() + Self::term_duration();
+		let new_expiry = <frame_system::Pallet<T>>::block_number() + Self::term_duration();
 
 		// return bond to winners.
 		let candidacy_bond = T::CandidacyBond::get();
diff --git a/frame/elections/src/mock.rs b/frame/elections/src/mock.rs
index 31d3f5a1c28a5..287eaa27b196a 100644
--- a/frame/elections/src/mock.rs
+++ b/frame/elections/src/mock.rs
@@ -135,9 +135,9 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic
 	{
-		System: system::{Module, Call, Event<T>},
-		Balances: pallet_balances::{Module, Call, Event<T>, Config<T>},
-		Elections: elections::{Module, Call, Event<T>, Config<T>},
+		System: system::{Pallet, Call, Event<T>},
+		Balances: pallet_balances::{Pallet, Call, Event<T>, Config<T>},
+		Elections: elections::{Pallet, Call, Event<T>, Config<T>},
 	}
 );
 
diff --git a/frame/example-offchain-worker/src/tests.rs b/frame/example-offchain-worker/src/tests.rs
index 7707e7d61e629..e91b374adbe1d 100644
--- a/frame/example-offchain-worker/src/tests.rs
+++ b/frame/example-offchain-worker/src/tests.rs
@@ -49,8 +49,8 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Example: example_offchain_worker::{Module, Call, Storage, Event<T>, ValidateUnsigned},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Example: example_offchain_worker::{Pallet, Call, Storage, Event<T>, ValidateUnsigned},
 	}
 );
 
diff --git a/frame/example-parallel/src/tests.rs b/frame/example-parallel/src/tests.rs
index da2892c67d42a..e82d75e632068 100644
--- a/frame/example-parallel/src/tests.rs
+++ b/frame/example-parallel/src/tests.rs
@@ -33,8 +33,8 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Example: pallet_example_parallel::{Module, Call, Storage},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Example: pallet_example_parallel::{Pallet, Call, Storage},
 	}
 );
 
diff --git a/frame/example/Cargo.toml b/frame/example/Cargo.toml
index de741294b9c16..e24616bc84cf3 100644
--- a/frame/example/Cargo.toml
+++ b/frame/example/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "pallet-example"
-version = "2.0.0"
+version = "3.0.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
 license = "Unlicense"
@@ -21,8 +21,8 @@ pallet-balances = { version = "3.0.0", default-features = false, path = "../bala
 sp-runtime = { version = "3.0.0", default-features = false, path = "../../primitives/runtime" }
 sp-std = { version = "3.0.0", default-features = false, path = "../../primitives/std" }
 sp-io = { version = "3.0.0", default-features = false, path = "../../primitives/io" }
-
 frame-benchmarking = { version = "3.1.0", default-features = false, path = "../benchmarking", optional = true }
+log = { version = "0.4.14", default-features = false }
 
 [dev-dependencies]
 sp-core = { version = "3.0.0", path = "../../primitives/core", default-features = false }
@@ -30,14 +30,15 @@ sp-core = { version = "3.0.0", path = "../../primitives/core", default-features
 [features]
 default = ["std"]
 std = [
-	"serde",
 	"codec/std",
-	"sp-runtime/std",
 	"frame-benchmarking/std",
 	"frame-support/std",
 	"frame-system/std",
+	"log/std",
 	"pallet-balances/std",
+	"serde",
 	"sp-io/std",
+	"sp-runtime/std",
 	"sp-std/std"
 ]
 runtime-benchmarks = ["frame-benchmarking"]
diff --git a/frame/example/src/benchmarking.rs b/frame/example/src/benchmarking.rs
new file mode 100644
index 0000000000000..64602ca41cee9
--- /dev/null
+++ b/frame/example/src/benchmarking.rs
@@ -0,0 +1,76 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Benchmarking for pallet-example.
+
+#![cfg(feature = "runtime-benchmarks")]
+
+use crate::*;
+use frame_benchmarking::{benchmarks, whitelisted_caller, impl_benchmark_test_suite};
+use frame_system::RawOrigin;
+
+// To actually run this benchmark on pallet-example, we need to put this pallet into the
+//   runtime and compile it with `runtime-benchmarks` feature. The detail procedures are
+//   documented at:
+//   https://substrate.dev/docs/en/knowledgebase/runtime/benchmarking#how-to-benchmark
+//
+// The auto-generated weight estimate of this pallet is copied over to the `weights.rs` file.
+// The exact command of how the estimate generated is printed at the top of the file.
+
+// Details on using the benchmarks macro can be seen at:
+//   https://substrate.dev/rustdocs/v3.0.0/frame_benchmarking/macro.benchmarks.html
+benchmarks!{
+	// This will measure the execution time of `set_dummy` for b in [1..1000] range.
+	set_dummy_benchmark {
+		// This is the benchmark setup phase
+		let b in 1 .. 1000;
+	}: set_dummy(RawOrigin::Root, b.into()) // The execution phase is just running `set_dummy` extrinsic call
+	verify {
+		// This is the optional benchmark verification phase, asserting certain states.
+		assert_eq!(Pallet::<T>::dummy(), Some(b.into()))
+	}
+
+	// This will measure the execution time of `accumulate_dummy` for b in [1..1000] range.
+	// The benchmark execution phase is shorthanded. When the name of the benchmark case is the same
+	// as the extrinsic call. `_(...)` is used to represent the extrinsic name.
+	// The benchmark verification phase is omitted.
+	accumulate_dummy {
+		let b in 1 .. 1000;
+		// The caller account is whitelisted for DB reads/write by the benchmarking macro.
+		let caller: T::AccountId = whitelisted_caller();
+	}: _(RawOrigin::Signed(caller), b.into())
+
+	// This will measure the execution time of sorting a vector.
+	sort_vector {
+		let x in 0 .. 10000;
+		let mut m = Vec::<u32>::new();
+		for i in (0..x).rev() {
+			m.push(i);
+		}
+	}: {
+		// The benchmark execution phase could also be a closure with custom code
+		m.sort();
+	}
+}
+
+// This line generates test cases for benchmarking, and could be run by:
+//   `cargo test -p pallet-example --all-features`, you will see an additional line of:
+//   `test benchmarking::benchmark_tests::test_benchmarks ... ok` in the result.
+//
+// The line generates three steps per benchmark, with repeat=1 and the three steps are
+//   [low, mid, high] of the range.
+impl_benchmark_test_suite!(Pallet, crate::tests::new_test_ext(), crate::tests::Test);
diff --git a/frame/example/src/lib.rs b/frame/example/src/lib.rs
index 7a537f4522abf..fd1bc292ac8aa 100644
--- a/frame/example/src/lib.rs
+++ b/frame/example/src/lib.rs
@@ -255,28 +255,45 @@
 // Ensure we're `no_std` when compiling for Wasm.
 #![cfg_attr(not(feature = "std"), no_std)]
 
-use sp_std::marker::PhantomData;
+use sp_std::{
+	prelude::*,
+	marker::PhantomData
+};
 use frame_support::{
 	dispatch::DispatchResult, traits::IsSubType,
 	weights::{DispatchClass, ClassifyDispatch, WeighData, Weight, PaysFee, Pays},
 };
-use sp_std::prelude::*;
 use frame_system::{ensure_signed};
 use codec::{Encode, Decode};
 use sp_runtime::{
 	traits::{
-		SignedExtension, Bounded, SaturatedConversion, DispatchInfoOf,
+		SignedExtension, Bounded, SaturatedConversion, DispatchInfoOf, Saturating
 	},
 	transaction_validity::{
 		ValidTransaction, TransactionValidityError, InvalidTransaction, TransactionValidity,
 	},
 };
+use log::info;
+
+// Re-export pallet items so that they can be accessed from the crate namespace.
+pub use pallet::*;
+
+#[cfg(test)]
+mod tests;
+
+mod benchmarking;
+pub mod weights;
+pub use weights::*;
+
+/// A type alias for the balance type from this pallet's point of view.
+type BalanceOf<T> = <T as pallet_balances::Config>::Balance;
+const MILLICENTS: u32 = 1_000_000_000;
 
 // A custom weight calculator tailored for the dispatch call `set_dummy()`. This actually examines
 // the arguments and makes a decision based upon them.
 //
 // The `WeightData<T>` trait has access to the arguments of the dispatch that it wants to assign a
-// weight to. Nonetheless, the trait itself can not make any assumptions about what the generic type
+// weight to. Nonetheless, the trait itself cannot make any assumptions about what the generic type
 // of the arguments (`T`) is. Based on our needs, we could replace `T` with a more concrete type
 // while implementing the trait. The `pallet::weight` expects whatever implements `WeighData<T>` to
 // replace `T` with a tuple of the dispatch arguments. This is exactly how we will craft the
@@ -286,13 +303,22 @@ use sp_runtime::{
 // - The final weight of each dispatch is calculated as the argument of the call multiplied by the
 //   parameter given to the `WeightForSetDummy`'s constructor.
 // - assigns a dispatch class `operational` if the argument of the call is more than 1000.
+//
+// More information can be read at:
+//   - https://substrate.dev/docs/en/knowledgebase/learn-substrate/weight
+//   - https://substrate.dev/docs/en/knowledgebase/runtime/fees#default-weight-annotations
+//
+// Manually configuring weight is an advanced operation and what you really need may well be
+//   fulfilled by running the benchmarking toolchain. Refer to `benchmarking.rs` file.
 struct WeightForSetDummy<T: pallet_balances::Config>(BalanceOf<T>);
 
 impl<T: pallet_balances::Config> WeighData<(&BalanceOf<T>,)> for WeightForSetDummy<T>
 {
 	fn weigh_data(&self, target: (&BalanceOf<T>,)) -> Weight {
 		let multiplier = self.0;
-		(*target.0 * multiplier).saturated_into::<Weight>()
+		// *target.0 is the amount passed into the extrinsic
+		let cents = *target.0 / <BalanceOf<T>>::from(MILLICENTS);
+		(cents * multiplier).saturated_into::<Weight>()
 	}
 }
 
@@ -312,12 +338,6 @@ impl<T: pallet_balances::Config> PaysFee<(&BalanceOf<T>,)> for WeightForSetDummy
 	}
 }
 
-/// A type alias for the balance type from this pallet's point of view.
-type BalanceOf<T> = <T as pallet_balances::Config>::Balance;
-
-// Re-export pallet items so that they can be accessed from the crate namespace.
-pub use pallet::*;
-
 // Definition of the pallet logic, to be aggregated at runtime definition through
 // `construct_runtime`.
 #[frame_support::pallet]
@@ -334,8 +354,15 @@ pub mod pallet {
 	/// `frame_system::Config` should always be included.
 	#[pallet::config]
 	pub trait Config: pallet_balances::Config + frame_system::Config {
+		// Setting a constant config parameter from the runtime
+		#[pallet::constant]
+		type MagicNumber: Get<Self::Balance>;
+
 		/// The overarching event type.
 		type Event: From<Event<Self>> + IsType<<Self as frame_system::Config>::Event>;
+
+		/// Type representing the weight of this pallet
+		type WeightInfo: WeightInfo;
 	}
 
 	// Simple declaration of the `Pallet` type. It is placeholder we use to implement traits and
@@ -354,14 +381,12 @@ pub mod pallet {
 		fn on_initialize(_n: T::BlockNumber) -> Weight {
 			// Anything that needs to be done at the start of the block.
 			// We don't do anything here.
-
 			0
 		}
 
 		// `on_finalize` is executed at the end of block after all extrinsic are dispatched.
 		fn on_finalize(_n: T::BlockNumber) {
-			// We just kill our dummy storage item.
-			<Dummy<T>>::kill();
+			// Perform necessary data/state clean up here.
 		}
 
 		// A runtime code run after every block and have access to extended set of APIs.
@@ -370,7 +395,9 @@ pub mod pallet {
 		fn offchain_worker(_n: T::BlockNumber) {
 			// We don't do anything here.
 			// but we could dispatch extrinsic (transaction/unsigned/inherent) using
-			// sp_io::submit_extrinsic
+			// sp_io::submit_extrinsic.
+			// To see example on offchain worker, please refer to example-offchain-worker pallet
+		 	// accompanied in this repository.
 		}
 	}
 
@@ -455,11 +482,16 @@ pub mod pallet {
 		// difficulty) of the transaction and the latter demonstrates the [`DispatchClass`] of the
 		// call. A higher weight means a larger transaction (less of which can be placed in a
 		// single block).
-		#[pallet::weight(0)]
+		//
+		// The weight for this extrinsic we rely on the auto-generated `WeightInfo` from the benchmark
+		// toolchain.
+		#[pallet::weight(
+			<T as pallet::Config>::WeightInfo::accumulate_dummy((*increase_by).saturated_into())
+		)]
 		pub(super) fn accumulate_dummy(
 			origin: OriginFor<T>,
 			increase_by: T::Balance
-		) -> DispatchResultWithPostInfo {
+		) -> DispatchResult {
 			// This is a public call, so we ensure that the origin is some signed account.
 			let _sender = ensure_signed(origin)?;
 
@@ -478,15 +510,16 @@ pub mod pallet {
 
 			// Here's the new one of read and then modify the value.
 			<Dummy<T>>::mutate(|dummy| {
-				let new_dummy = dummy.map_or(increase_by, |dummy| dummy + increase_by);
+				// Using `saturating_add` instead of a regular `+` to avoid overflowing
+				let new_dummy = dummy.map_or(increase_by, |d| d.saturating_add(increase_by));
 				*dummy = Some(new_dummy);
 			});
 
 			// Let's deposit an event to let the outside world know this happened.
-			Self::deposit_event(Event::Dummy(increase_by));
+			Self::deposit_event(Event::AccumulateDummy(increase_by));
 
 			// All good, no refund.
-			Ok(().into())
+			Ok(())
 		}
 
 		/// A privileged call; in this case it resets our dummy value to something new.
@@ -496,17 +529,28 @@ pub mod pallet {
 		// calls to be executed - we don't need to care why. Because it's privileged, we can
 		// assume it's a one-off operation and substantial processing/storage/memory can be used
 		// without worrying about gameability or attack scenarios.
+		//
+		// The weight for this extrinsic we use our own weight object `WeightForSetDummy` to determine
+		// its weight
 		#[pallet::weight(WeightForSetDummy::<T>(<BalanceOf<T>>::from(100u32)))]
-		fn set_dummy(
+		pub(super) fn set_dummy(
 			origin: OriginFor<T>,
 			#[pallet::compact] new_value: T::Balance,
-		) -> DispatchResultWithPostInfo {
+		) -> DispatchResult {
 			ensure_root(origin)?;
+
+			// Print out log or debug message in the console via log::{error, warn, info, debug, trace},
+			// accepting format strings similar to `println!`.
+			// https://substrate.dev/rustdocs/v3.0.0/log/index.html
+			info!("New value is now: {:?}", new_value);
+
 			// Put the new value into storage.
 			<Dummy<T>>::put(new_value);
 
+			Self::deposit_event(Event::SetDummy(new_value));
+
 			// All good, no refund.
-			Ok(().into())
+			Ok(())
 		}
 	}
 
@@ -520,7 +564,9 @@ pub mod pallet {
 	pub enum Event<T: Config> {
 		// Just a normal `enum`, here's a dummy event to ensure it compiles.
 		/// Dummy event, just here so there's a generic type that's used.
-		Dummy(BalanceOf<T>),
+		AccumulateDummy(BalanceOf<T>),
+		SetDummy(BalanceOf<T>),
+		SetBar(T::AccountId, BalanceOf<T>),
 	}
 
 	// pallet::storage attributes allow for type-safe usage of the Substrate storage database,
@@ -545,14 +591,13 @@ pub mod pallet {
 	// A map that has enumerable entries.
 	#[pallet::storage]
 	#[pallet::getter(fn bar)]
-	pub(super) type Bar<T: Config> = StorageMap<_, Blake2_128Concat, T::AccountId, T::Balance, ValueQuery>;
+	pub(super) type Bar<T: Config> = StorageMap<_, Blake2_128Concat, T::AccountId, T::Balance>;
 
 	// this one uses the query kind: `ValueQuery`, we'll demonstrate the usage of 'mutate' API.
 	#[pallet::storage]
 	#[pallet::getter(fn foo)]
 	pub(super) type Foo<T: Config> = StorageValue<_, T::Balance, ValueQuery>;
 
-
 	// The genesis config type.
 	#[pallet::genesis_config]
 	pub struct GenesisConfig<T: Config> {
@@ -600,7 +645,7 @@ impl<T: Config> Pallet<T> {
 		let prev = <Foo<T>>::get();
 		// Because Foo has 'default', the type of 'foo' in closure is the raw type instead of an Option<> type.
 		let result = <Foo<T>>::mutate(|foo| {
-			*foo = *foo + increase_by;
+			*foo = foo.saturating_add(increase_by);
 			*foo
 		});
 		assert!(prev + increase_by == result);
@@ -640,11 +685,11 @@ impl<T: Config> Pallet<T> {
 // types defined in the runtime. Lookup `pub type SignedExtra = (...)` in `node/runtime` and
 // `node-template` for an example of this.
 
-/// A simple signed extension that checks for the `set_dummy` call. In that case, it increases the
-/// priority and prints some log.
-///
-/// Additionally, it drops any transaction with an encoded length higher than 200 bytes. No
-/// particular reason why, just to demonstrate the power of signed extensions.
+// A simple signed extension that checks for the `set_dummy` call. In that case, it increases the
+// priority and prints some log.
+//
+// Additionally, it drops any transaction with an encoded length higher than 200 bytes. No
+// particular reason why, just to demonstrate the power of signed extensions.
 #[derive(Encode, Decode, Clone, Eq, PartialEq)]
 pub struct WatchDummy<T: Config + Send + Sync>(PhantomData<T>);
 
@@ -691,201 +736,3 @@ where
 		}
 	}
 }
-
-#[cfg(feature = "runtime-benchmarks")]
-mod benchmarking {
-	use super::*;
-	use frame_benchmarking::{benchmarks, account, impl_benchmark_test_suite};
-	use frame_system::RawOrigin;
-
-	benchmarks!{
-		// This will measure the execution time of `accumulate_dummy` for b in [1..1000] range.
-		accumulate_dummy {
-			let b in 1 .. 1000;
-			let caller = account("caller", 0, 0);
-		}: _ (RawOrigin::Signed(caller), b.into())
-
-		// This will measure the execution time of `set_dummy` for b in [1..1000] range.
-		set_dummy {
-			let b in 1 .. 1000;
-		}: set_dummy (RawOrigin::Root, b.into())
-
-		// This will measure the execution time of `set_dummy` for b in [1..10] range.
-		another_set_dummy {
-			let b in 1 .. 10;
-		}: set_dummy (RawOrigin::Root, b.into())
-
-		// This will measure the execution time of sorting a vector.
-		sort_vector {
-			let x in 0 .. 10000;
-			let mut m = Vec::<u32>::new();
-			for i in (0..x).rev() {
-				m.push(i);
-			}
-		}: {
-			m.sort();
-		}
-	}
-
-	impl_benchmark_test_suite!(Pallet, crate::tests::new_test_ext(), crate::tests::Test);
-}
-
-#[cfg(test)]
-mod tests {
-	use super::*;
-
-	use frame_support::{
-		assert_ok, parameter_types,
-		weights::{DispatchInfo, GetDispatchInfo}, traits::{OnInitialize, OnFinalize}
-	};
-	use sp_core::H256;
-	// The testing primitives are very useful for avoiding having to work with signatures
-	// or public keys. `u64` is used as the `AccountId` and no `Signature`s are required.
-	use sp_runtime::{
-		testing::Header, BuildStorage,
-		traits::{BlakeTwo256, IdentityLookup},
-	};
-	// Reexport crate as its pallet name for construct_runtime.
-	use crate as pallet_example;
-
-	type UncheckedExtrinsic = frame_system::mocking::MockUncheckedExtrinsic<Test>;
-	type Block = frame_system::mocking::MockBlock<Test>;
-
-	// For testing the pallet, we construct a mock runtime.
-	frame_support::construct_runtime!(
-		pub enum Test where
-			Block = Block,
-			NodeBlock = Block,
-			UncheckedExtrinsic = UncheckedExtrinsic,
-		{
-			System: frame_system::{Module, Call, Config, Storage, Event<T>},
-			Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
-			Example: pallet_example::{Module, Call, Storage, Config<T>, Event<T>},
-		}
-	);
-
-	parameter_types! {
-		pub const BlockHashCount: u64 = 250;
-		pub BlockWeights: frame_system::limits::BlockWeights =
-			frame_system::limits::BlockWeights::simple_max(1024);
-	}
-	impl frame_system::Config for Test {
-		type BaseCallFilter = ();
-		type BlockWeights = ();
-		type BlockLength = ();
-		type DbWeight = ();
-		type Origin = Origin;
-		type Index = u64;
-		type BlockNumber = u64;
-		type Hash = H256;
-		type Call = Call;
-		type Hashing = BlakeTwo256;
-		type AccountId = u64;
-		type Lookup = IdentityLookup<Self::AccountId>;
-		type Header = Header;
-		type Event = Event;
-		type BlockHashCount = BlockHashCount;
-		type Version = ();
-		type PalletInfo = PalletInfo;
-		type AccountData = pallet_balances::AccountData<u64>;
-		type OnNewAccount = ();
-		type OnKilledAccount = ();
-		type SystemWeightInfo = ();
-		type SS58Prefix = ();
-	}
-	parameter_types! {
-		pub const ExistentialDeposit: u64 = 1;
-	}
-	impl pallet_balances::Config for Test {
-		type MaxLocks = ();
-		type Balance = u64;
-		type DustRemoval = ();
-		type Event = Event;
-		type ExistentialDeposit = ExistentialDeposit;
-		type AccountStore = System;
-		type WeightInfo = ();
-	}
-	impl Config for Test {
-		type Event = Event;
-	}
-
-	// This function basically just builds a genesis storage key/value store according to
-	// our desired mockup.
-	pub fn new_test_ext() -> sp_io::TestExternalities {
-		let t = GenesisConfig {
-			// We use default for brevity, but you can configure as desired if needed.
-			frame_system: Default::default(),
-			pallet_balances: Default::default(),
-			pallet_example: pallet_example::GenesisConfig {
-				dummy: 42,
-				// we configure the map with (key, value) pairs.
-				bar: vec![(1, 2), (2, 3)],
-				foo: 24,
-			},
-		}.build_storage().unwrap();
-		t.into()
-	}
-
-	#[test]
-	fn it_works_for_optional_value() {
-		new_test_ext().execute_with(|| {
-			// Check that GenesisBuilder works properly.
-			assert_eq!(Example::dummy(), Some(42));
-
-			// Check that accumulate works when we have Some value in Dummy already.
-			assert_ok!(Example::accumulate_dummy(Origin::signed(1), 27));
-			assert_eq!(Example::dummy(), Some(69));
-
-			// Check that finalizing the block removes Dummy from storage.
-			<Example as OnFinalize<u64>>::on_finalize(1);
-			assert_eq!(Example::dummy(), None);
-
-			// Check that accumulate works when we Dummy has None in it.
-			<Example as OnInitialize<u64>>::on_initialize(2);
-			assert_ok!(Example::accumulate_dummy(Origin::signed(1), 42));
-			assert_eq!(Example::dummy(), Some(42));
-		});
-	}
-
-	#[test]
-	fn it_works_for_default_value() {
-		new_test_ext().execute_with(|| {
-			assert_eq!(Example::foo(), 24);
-			assert_ok!(Example::accumulate_foo(Origin::signed(1), 1));
-			assert_eq!(Example::foo(), 25);
-		});
-	}
-
-	#[test]
-	fn signed_ext_watch_dummy_works() {
-		new_test_ext().execute_with(|| {
-			let call = <pallet_example::Call<Test>>::set_dummy(10).into();
-			let info = DispatchInfo::default();
-
-			assert_eq!(
-				WatchDummy::<Test>(PhantomData).validate(&1, &call, &info, 150)
-					.unwrap()
-					.priority,
-				u64::max_value(),
-			);
-			assert_eq!(
-				WatchDummy::<Test>(PhantomData).validate(&1, &call, &info, 250),
-				InvalidTransaction::ExhaustsResources.into(),
-			);
-		})
-	}
-
-	#[test]
-	fn weights_work() {
-		// must have a defined weight.
-		let default_call = <pallet_example::Call<Test>>::accumulate_dummy(10);
-		let info = default_call.get_dispatch_info();
-		// aka. `let info = <Call<Test> as GetDispatchInfo>::get_dispatch_info(&default_call);`
-		assert_eq!(info.weight, 0);
-
-		// must have a custom weight of `100 * arg = 2000`
-		let custom_call = <pallet_example::Call<Test>>::set_dummy(20);
-		let info = custom_call.get_dispatch_info();
-		assert_eq!(info.weight, 2000);
-	}
-}
diff --git a/frame/example/src/tests.rs b/frame/example/src/tests.rs
new file mode 100644
index 0000000000000..ed866344a4b18
--- /dev/null
+++ b/frame/example/src/tests.rs
@@ -0,0 +1,189 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Tests for pallet-example.
+
+use crate::*;
+use frame_support::{
+	assert_ok, parameter_types,
+	weights::{DispatchInfo, GetDispatchInfo}, traits::OnInitialize
+};
+use sp_core::H256;
+// The testing primitives are very useful for avoiding having to work with signatures
+// or public keys. `u64` is used as the `AccountId` and no `Signature`s are required.
+use sp_runtime::{
+	testing::Header, BuildStorage,
+	traits::{BlakeTwo256, IdentityLookup},
+};
+// Reexport crate as its pallet name for construct_runtime.
+use crate as pallet_example;
+
+type UncheckedExtrinsic = frame_system::mocking::MockUncheckedExtrinsic<Test>;
+type Block = frame_system::mocking::MockBlock<Test>;
+
+// For testing the pallet, we construct a mock runtime.
+frame_support::construct_runtime!(
+	pub enum Test where
+		Block = Block,
+		NodeBlock = Block,
+		UncheckedExtrinsic = UncheckedExtrinsic,
+	{
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
+		Example: pallet_example::{Pallet, Call, Storage, Config<T>, Event<T>},
+	}
+);
+
+parameter_types! {
+	pub const BlockHashCount: u64 = 250;
+	pub BlockWeights: frame_system::limits::BlockWeights =
+		frame_system::limits::BlockWeights::simple_max(1024);
+}
+impl frame_system::Config for Test {
+	type BaseCallFilter = ();
+	type BlockWeights = ();
+	type BlockLength = ();
+	type DbWeight = ();
+	type Origin = Origin;
+	type Index = u64;
+	type BlockNumber = u64;
+	type Hash = H256;
+	type Call = Call;
+	type Hashing = BlakeTwo256;
+	type AccountId = u64;
+	type Lookup = IdentityLookup<Self::AccountId>;
+	type Header = Header;
+	type Event = Event;
+	type BlockHashCount = BlockHashCount;
+	type Version = ();
+	type PalletInfo = PalletInfo;
+	type AccountData = pallet_balances::AccountData<u64>;
+	type OnNewAccount = ();
+	type OnKilledAccount = ();
+	type SystemWeightInfo = ();
+	type SS58Prefix = ();
+}
+parameter_types! {
+	pub const ExistentialDeposit: u64 = 1;
+}
+impl pallet_balances::Config for Test {
+	type MaxLocks = ();
+	type Balance = u64;
+	type DustRemoval = ();
+	type Event = Event;
+	type ExistentialDeposit = ExistentialDeposit;
+	type AccountStore = System;
+	type WeightInfo = ();
+}
+
+parameter_types! {
+	pub const MagicNumber: u64 = 1_000_000_000;
+}
+impl Config for Test {
+	type MagicNumber = MagicNumber;
+	type Event = Event;
+	type WeightInfo = ();
+}
+
+// This function basically just builds a genesis storage key/value store according to
+// our desired mockup.
+pub fn new_test_ext() -> sp_io::TestExternalities {
+	let t = GenesisConfig {
+		// We use default for brevity, but you can configure as desired if needed.
+		frame_system: Default::default(),
+		pallet_balances: Default::default(),
+		pallet_example: pallet_example::GenesisConfig {
+			dummy: 42,
+			// we configure the map with (key, value) pairs.
+			bar: vec![(1, 2), (2, 3)],
+			foo: 24,
+		},
+	}.build_storage().unwrap();
+	t.into()
+}
+
+#[test]
+fn it_works_for_optional_value() {
+	new_test_ext().execute_with(|| {
+		// Check that GenesisBuilder works properly.
+		let val1 = 42;
+		let val2 = 27;
+		assert_eq!(Example::dummy(), Some(val1));
+
+		// Check that accumulate works when we have Some value in Dummy already.
+		assert_ok!(Example::accumulate_dummy(Origin::signed(1), val2));
+		assert_eq!(Example::dummy(), Some(val1 + val2));
+
+		// Check that accumulate works when we Dummy has None in it.
+		<Example as OnInitialize<u64>>::on_initialize(2);
+		assert_ok!(Example::accumulate_dummy(Origin::signed(1), val1));
+		assert_eq!(Example::dummy(), Some(val1 + val2 + val1));
+	});
+}
+
+#[test]
+fn it_works_for_default_value() {
+	new_test_ext().execute_with(|| {
+		assert_eq!(Example::foo(), 24);
+		assert_ok!(Example::accumulate_foo(Origin::signed(1), 1));
+		assert_eq!(Example::foo(), 25);
+	});
+}
+
+#[test]
+fn set_dummy_works() {
+	new_test_ext().execute_with(|| {
+		let test_val = 133;
+		assert_ok!(Example::set_dummy(Origin::root(), test_val.into()));
+		assert_eq!(Example::dummy(), Some(test_val));
+	});
+}
+
+#[test]
+fn signed_ext_watch_dummy_works() {
+	new_test_ext().execute_with(|| {
+		let call = <pallet_example::Call<Test>>::set_dummy(10).into();
+		let info = DispatchInfo::default();
+
+		assert_eq!(
+			WatchDummy::<Test>(PhantomData).validate(&1, &call, &info, 150)
+				.unwrap()
+				.priority,
+			u64::max_value(),
+		);
+		assert_eq!(
+			WatchDummy::<Test>(PhantomData).validate(&1, &call, &info, 250),
+			InvalidTransaction::ExhaustsResources.into(),
+		);
+	})
+}
+
+#[test]
+fn weights_work() {
+	// must have a defined weight.
+	let default_call = <pallet_example::Call<Test>>::accumulate_dummy(10);
+	let info1 = default_call.get_dispatch_info();
+	// aka. `let info = <Call<Test> as GetDispatchInfo>::get_dispatch_info(&default_call);`
+	assert!(info1.weight > 0);
+
+
+	// `set_dummy` is simpler than `accumulate_dummy`, and the weight
+	//   should be less.
+	let custom_call = <pallet_example::Call<Test>>::set_dummy(20);
+	let info2 = custom_call.get_dispatch_info();
+	assert!(info1.weight > info2.weight);
+}
diff --git a/frame/example/src/weights.rs b/frame/example/src/weights.rs
new file mode 100644
index 0000000000000..db6491335c76f
--- /dev/null
+++ b/frame/example/src/weights.rs
@@ -0,0 +1,100 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Autogenerated weights for pallet_example
+//!
+//! THIS FILE WAS AUTO-GENERATED USING THE SUBSTRATE BENCHMARK CLI VERSION 3.0.0
+//! DATE: 2021-03-15, STEPS: `[100, ]`, REPEAT: 10, LOW RANGE: `[]`, HIGH RANGE: `[]`
+//! EXECUTION: Some(Wasm), WASM-EXECUTION: Compiled, CHAIN: Some("dev"), DB CACHE: 128
+
+// Executed Command:
+// ./target/release/substrate
+// benchmark
+// --chain
+// dev
+// --execution
+// wasm
+// --wasm-execution
+// compiled
+// --pallet
+// pallet_example
+// --extrinsic
+// *
+// --steps
+// 100
+// --repeat
+// 10
+// --raw
+// --output
+// ./
+// --template
+// ./.maintain/frame-weight-template.hbs
+
+
+#![allow(unused_parens)]
+#![allow(unused_imports)]
+
+use frame_support::{traits::Get, weights::{Weight, constants::RocksDbWeight}};
+use sp_std::marker::PhantomData;
+
+/// Weight functions needed for pallet_example.
+pub trait WeightInfo {
+	fn set_dummy_benchmark(b: u32, ) -> Weight;
+	fn accumulate_dummy(b: u32, ) -> Weight;
+	fn sort_vector(x: u32, ) -> Weight;
+}
+
+/// Weights for pallet_example using the Substrate node and recommended hardware.
+pub struct SubstrateWeight<T>(PhantomData<T>);
+impl<T: frame_system::Config> WeightInfo for SubstrateWeight<T> {
+	fn set_dummy_benchmark(b: u32, ) -> Weight {
+		(5_834_000 as Weight)
+			.saturating_add((24_000 as Weight).saturating_mul(b as Weight))
+			.saturating_add(T::DbWeight::get().writes(1 as Weight))
+	}
+	fn accumulate_dummy(b: u32, ) -> Weight {
+		(51_353_000 as Weight)
+			.saturating_add((14_000 as Weight).saturating_mul(b as Weight))
+			.saturating_add(T::DbWeight::get().reads(1 as Weight))
+			.saturating_add(T::DbWeight::get().writes(1 as Weight))
+	}
+	fn sort_vector(x: u32, ) -> Weight {
+		(2_569_000 as Weight)
+			// Standard Error: 0
+			.saturating_add((4_000 as Weight).saturating_mul(x as Weight))
+	}
+}
+
+// For backwards compatibility and tests
+impl WeightInfo for () {
+	fn set_dummy_benchmark(b: u32, ) -> Weight {
+		(5_834_000 as Weight)
+			.saturating_add((24_000 as Weight).saturating_mul(b as Weight))
+			.saturating_add(RocksDbWeight::get().writes(1 as Weight))
+	}
+	fn accumulate_dummy(b: u32, ) -> Weight {
+		(51_353_000 as Weight)
+			.saturating_add((14_000 as Weight).saturating_mul(b as Weight))
+			.saturating_add(RocksDbWeight::get().reads(1 as Weight))
+			.saturating_add(RocksDbWeight::get().writes(1 as Weight))
+	}
+	fn sort_vector(x: u32, ) -> Weight {
+		(2_569_000 as Weight)
+			// Standard Error: 0
+			.saturating_add((4_000 as Weight).saturating_mul(x as Weight))
+	}
+}
diff --git a/frame/executive/README.md b/frame/executive/README.md
index 183e32b2ff8a9..ae3bbf1a9d994 100644
--- a/frame/executive/README.md
+++ b/frame/executive/README.md
@@ -35,7 +35,7 @@ The default Substrate node template declares the [`Executive`](https://docs.rs/f
 ```rust
 #
 /// Executive: handles dispatch to the various modules.
-pub type Executive = executive::Executive<Runtime, Block, Context, Runtime, AllModules>;
+pub type Executive = executive::Executive<Runtime, Block, Context, Runtime, AllPallets>;
 ```
 
 ### Custom `OnRuntimeUpgrade` logic
@@ -54,7 +54,7 @@ impl frame_support::traits::OnRuntimeUpgrade for CustomOnRuntimeUpgrade {
     }
 }
 
-pub type Executive = executive::Executive<Runtime, Block, Context, Runtime, AllModules, CustomOnRuntimeUpgrade>;
+pub type Executive = executive::Executive<Runtime, Block, Context, Runtime, AllPallets, CustomOnRuntimeUpgrade>;
 ```
 
 License: Apache-2.0
diff --git a/frame/executive/src/lib.rs b/frame/executive/src/lib.rs
index f48fda4841d26..277b20cf20bfa 100644
--- a/frame/executive/src/lib.rs
+++ b/frame/executive/src/lib.rs
@@ -59,7 +59,7 @@
 //! # type Context = frame_system::ChainContext<Runtime>;
 //! # pub type Block = generic::Block<Header, UncheckedExtrinsic>;
 //! # pub type Balances = u64;
-//! # pub type AllModules = u64;
+//! # pub type AllPallets = u64;
 //! # pub enum Runtime {};
 //! # use sp_runtime::transaction_validity::{
 //! #    TransactionValidity, UnknownTransaction, TransactionSource,
@@ -73,7 +73,7 @@
 //! #     }
 //! # }
 //! /// Executive: handles dispatch to the various modules.
-//! pub type Executive = executive::Executive<Runtime, Block, Context, Runtime, AllModules>;
+//! pub type Executive = executive::Executive<Runtime, Block, Context, Runtime, AllPallets>;
 //! ```
 //!
 //! ### Custom `OnRuntimeUpgrade` logic
@@ -90,7 +90,7 @@
 //! # type Context = frame_system::ChainContext<Runtime>;
 //! # pub type Block = generic::Block<Header, UncheckedExtrinsic>;
 //! # pub type Balances = u64;
-//! # pub type AllModules = u64;
+//! # pub type AllPallets = u64;
 //! # pub enum Runtime {};
 //! # use sp_runtime::transaction_validity::{
 //! #    TransactionValidity, UnknownTransaction, TransactionSource,
@@ -111,7 +111,7 @@
 //!     }
 //! }
 //!
-//! pub type Executive = executive::Executive<Runtime, Block, Context, Runtime, AllModules, CustomOnRuntimeUpgrade>;
+//! pub type Executive = executive::Executive<Runtime, Block, Context, Runtime, AllPallets, CustomOnRuntimeUpgrade>;
 //! ```
 
 #![cfg_attr(not(feature = "std"), no_std)]
@@ -144,12 +144,12 @@ pub type OriginOf<E, C> = <CallOf<E, C> as Dispatchable>::Origin;
 /// - `Block`: The block type of the runtime
 /// - `Context`: The context that is used when checking an extrinsic.
 /// - `UnsignedValidator`: The unsigned transaction validator of the runtime.
-/// - `AllModules`: Tuple that contains all modules. Will be used to call e.g. `on_initialize`.
+/// - `AllPallets`: Tuple that contains all modules. Will be used to call e.g. `on_initialize`.
 /// - `OnRuntimeUpgrade`: Custom logic that should be called after a runtime upgrade. Modules are
-///                       already called by `AllModules`. It will be called before all modules will
+///                       already called by `AllPallets`. It will be called before all modules will
 ///                       be called.
-pub struct Executive<System, Block, Context, UnsignedValidator, AllModules, OnRuntimeUpgrade = ()>(
-	PhantomData<(System, Block, Context, UnsignedValidator, AllModules, OnRuntimeUpgrade)>
+pub struct Executive<System, Block, Context, UnsignedValidator, AllPallets, OnRuntimeUpgrade = ()>(
+	PhantomData<(System, Block, Context, UnsignedValidator, AllPallets, OnRuntimeUpgrade)>
 );
 
 impl<
@@ -157,7 +157,7 @@ impl<
 	Block: traits::Block<Header=System::Header, Hash=System::Hash>,
 	Context: Default,
 	UnsignedValidator,
-	AllModules:
+	AllPallets:
 		OnRuntimeUpgrade +
 		OnInitialize<System::BlockNumber> +
 		OnIdle<System::BlockNumber> +
@@ -165,7 +165,7 @@ impl<
 		OffchainWorker<System::BlockNumber>,
 	COnRuntimeUpgrade: OnRuntimeUpgrade,
 > ExecuteBlock<Block> for
-	Executive<System, Block, Context, UnsignedValidator, AllModules, COnRuntimeUpgrade>
+	Executive<System, Block, Context, UnsignedValidator, AllPallets, COnRuntimeUpgrade>
 where
 	Block::Extrinsic: Checkable<Context> + Codec,
 	CheckedOf<Block::Extrinsic, Context>:
@@ -176,7 +176,7 @@ where
 	UnsignedValidator: ValidateUnsigned<Call=CallOf<Block::Extrinsic, Context>>,
 {
 	fn execute_block(block: Block) {
-		Executive::<System, Block, Context, UnsignedValidator, AllModules>::execute_block(block);
+		Executive::<System, Block, Context, UnsignedValidator, AllPallets>::execute_block(block);
 	}
 }
 
@@ -185,13 +185,13 @@ impl<
 		Block: traits::Block<Header = System::Header, Hash = System::Hash>,
 		Context: Default,
 		UnsignedValidator,
-		AllModules: OnRuntimeUpgrade
+		AllPallets: OnRuntimeUpgrade
 			+ OnInitialize<System::BlockNumber>
 			+ OnIdle<System::BlockNumber>
 			+ OnFinalize<System::BlockNumber>
 			+ OffchainWorker<System::BlockNumber>,
 		COnRuntimeUpgrade: OnRuntimeUpgrade,
-	> Executive<System, Block, Context, UnsignedValidator, AllModules, COnRuntimeUpgrade>
+	> Executive<System, Block, Context, UnsignedValidator, AllPallets, COnRuntimeUpgrade>
 where
 	Block::Extrinsic: Checkable<Context> + Codec,
 	CheckedOf<Block::Extrinsic, Context>: Applyable + GetDispatchInfo,
@@ -204,10 +204,10 @@ where
 	pub fn execute_on_runtime_upgrade() -> frame_support::weights::Weight {
 		let mut weight = 0;
 		weight = weight.saturating_add(
-			<frame_system::Module<System> as OnRuntimeUpgrade>::on_runtime_upgrade(),
+			<frame_system::Pallet<System> as OnRuntimeUpgrade>::on_runtime_upgrade(),
 		);
 		weight = weight.saturating_add(COnRuntimeUpgrade::on_runtime_upgrade());
-		weight = weight.saturating_add(<AllModules as OnRuntimeUpgrade>::on_runtime_upgrade());
+		weight = weight.saturating_add(<AllPallets as OnRuntimeUpgrade>::on_runtime_upgrade());
 
 		weight
 	}
@@ -218,7 +218,7 @@ where
 	#[cfg(feature = "try-runtime")]
 	pub fn try_runtime_upgrade() -> Result<frame_support::weights::Weight, &'static str> {
 		<
-			(frame_system::Module::<System>, COnRuntimeUpgrade, AllModules)
+			(frame_system::Pallet::<System>, COnRuntimeUpgrade, AllPallets)
 			as
 			OnRuntimeUpgrade
 		>::pre_upgrade()?;
@@ -226,7 +226,7 @@ where
 		let weight = Self::execute_on_runtime_upgrade();
 
 		<
-			(frame_system::Module::<System>, COnRuntimeUpgrade, AllModules)
+			(frame_system::Pallet::<System>, COnRuntimeUpgrade, AllPallets)
 			as
 			OnRuntimeUpgrade
 		>::post_upgrade()?;
@@ -265,24 +265,24 @@ where
 		if Self::runtime_upgraded() {
 			weight = weight.saturating_add(Self::execute_on_runtime_upgrade());
 		}
-		<frame_system::Module<System>>::initialize(
+		<frame_system::Pallet<System>>::initialize(
 			block_number,
 			parent_hash,
 			digest,
 			frame_system::InitKind::Full,
 		);
 		weight = weight.saturating_add(
-			<frame_system::Module<System> as OnInitialize<System::BlockNumber>>::on_initialize(*block_number)
+			<frame_system::Pallet<System> as OnInitialize<System::BlockNumber>>::on_initialize(*block_number)
 		);
 		weight = weight.saturating_add(
-			<AllModules as OnInitialize<System::BlockNumber>>::on_initialize(*block_number)
+			<AllPallets as OnInitialize<System::BlockNumber>>::on_initialize(*block_number)
 		);
 		weight = weight.saturating_add(
 			<System::BlockWeights as frame_support::traits::Get<_>>::get().base_block
 		);
-		<frame_system::Module::<System>>::register_extra_weight_unchecked(weight, DispatchClass::Mandatory);
+		<frame_system::Pallet::<System>>::register_extra_weight_unchecked(weight, DispatchClass::Mandatory);
 
-		frame_system::Module::<System>::note_finished_initialize();
+		frame_system::Pallet::<System>::note_finished_initialize();
 	}
 
 	/// Returns if the runtime was upgraded since the last time this function was called.
@@ -308,7 +308,7 @@ where
 		let n = header.number().clone();
 		assert!(
 			n > System::BlockNumber::zero()
-			&& <frame_system::Module<System>>::block_hash(n - System::BlockNumber::one()) == *header.parent_hash(),
+			&& <frame_system::Pallet<System>>::block_hash(n - System::BlockNumber::one()) == *header.parent_hash(),
 			"Parent hash should be valid.",
 		);
 	}
@@ -350,7 +350,7 @@ where
 		});
 
 		// post-extrinsics book-keeping
-		<frame_system::Module<System>>::note_finished_extrinsics();
+		<frame_system::Pallet<System>>::note_finished_extrinsics();
 
 		Self::idle_and_finalize_hook(block_number);
 	}
@@ -360,36 +360,36 @@ where
 	pub fn finalize_block() -> System::Header {
 		sp_io::init_tracing();
 		sp_tracing::enter_span!( sp_tracing::Level::TRACE, "finalize_block" );
-		<frame_system::Module<System>>::note_finished_extrinsics();
-		let block_number = <frame_system::Module<System>>::block_number();
+		<frame_system::Pallet<System>>::note_finished_extrinsics();
+		let block_number = <frame_system::Pallet<System>>::block_number();
 
 		Self::idle_and_finalize_hook(block_number);
 
-		<frame_system::Module<System>>::finalize()
+		<frame_system::Pallet<System>>::finalize()
 	}
 
 	fn idle_and_finalize_hook(block_number: NumberFor<Block>) {
-		let weight =  <frame_system::Module<System>>::block_weight();
+		let weight =  <frame_system::Pallet<System>>::block_weight();
 		let max_weight =  <System::BlockWeights as frame_support::traits::Get<_>>::get().max_block;
 		let mut remaining_weight = max_weight.saturating_sub(weight.total());
 
 		if remaining_weight > 0 {
 			let mut used_weight =
-				<frame_system::Module<System> as OnIdle<System::BlockNumber>>::on_idle(
+				<frame_system::Pallet<System> as OnIdle<System::BlockNumber>>::on_idle(
 					block_number,
 					remaining_weight
 				);
 			remaining_weight = remaining_weight.saturating_sub(used_weight);
-			used_weight = <AllModules as OnIdle<System::BlockNumber>>::on_idle(
+			used_weight = <AllPallets as OnIdle<System::BlockNumber>>::on_idle(
 				block_number,
 				remaining_weight
 			)
 			.saturating_add(used_weight);
-			<frame_system::Module::<System>>::register_extra_weight_unchecked(used_weight, DispatchClass::Mandatory);
+			<frame_system::Pallet::<System>>::register_extra_weight_unchecked(used_weight, DispatchClass::Mandatory);
 		}
 
-		<frame_system::Module<System> as OnFinalize<System::BlockNumber>>::on_finalize(block_number);
-		<AllModules as OnFinalize<System::BlockNumber>>::on_finalize(block_number);
+		<frame_system::Pallet<System> as OnFinalize<System::BlockNumber>>::on_finalize(block_number);
+		<AllPallets as OnFinalize<System::BlockNumber>>::on_finalize(block_number);
 	}
 
 	/// Apply extrinsic outside of the block execution function.
@@ -419,7 +419,7 @@ where
 		// We don't need to make sure to `note_extrinsic` only after we know it's going to be
 		// executed to prevent it from leaking in storage since at this point, it will either
 		// execute or panic (and revert storage changes).
-		<frame_system::Module<System>>::note_extrinsic(to_note);
+		<frame_system::Pallet<System>>::note_extrinsic(to_note);
 
 		// AUDIT: Under no circumstances may this function panic from here onwards.
 
@@ -427,7 +427,7 @@ where
 		let dispatch_info = xt.get_dispatch_info();
 		let r = Applyable::apply::<UnsignedValidator>(xt, &dispatch_info, encoded_len)?;
 
-		<frame_system::Module<System>>::note_applied_extrinsic(&r, dispatch_info);
+		<frame_system::Pallet<System>>::note_applied_extrinsic(&r, dispatch_info);
 
 		Ok(r.map(|_| ()).map_err(|e| e.error))
 	}
@@ -435,7 +435,7 @@ where
 	fn final_checks(header: &System::Header) {
 		sp_tracing::enter_span!(sp_tracing::Level::TRACE, "final_checks");
 		// remove temporaries
-		let new_header = <frame_system::Module<System>>::finalize();
+		let new_header = <frame_system::Pallet<System>>::finalize();
 
 		// check digest
 		assert_eq!(
@@ -499,7 +499,7 @@ where
 		// OffchainWorker RuntimeApi should skip initialization.
 		let digests = header.digest().clone();
 
-		<frame_system::Module<System>>::initialize(
+		<frame_system::Pallet<System>>::initialize(
 			header.number(),
 			header.parent_hash(),
 			&digests,
@@ -511,7 +511,7 @@ where
 		// as well.
 		frame_system::BlockHash::<System>::insert(header.number(), header.hash());
 
-		<AllModules as OffchainWorker<System::BlockNumber>>::offchain_worker(*header.number())
+		<AllPallets as OffchainWorker<System::BlockNumber>>::offchain_worker(*header.number())
 	}
 }
 
@@ -628,9 +628,9 @@ mod tests {
 			NodeBlock = TestBlock,
 			UncheckedExtrinsic = TestUncheckedExtrinsic
 		{
-			System: frame_system::{Module, Call, Config, Storage, Event<T>},
-			Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
-			Custom: custom::{Module, Call, ValidateUnsigned},
+			System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+			Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
+			Custom: custom::{Pallet, Call, ValidateUnsigned},
 		}
 	);
 
@@ -741,7 +741,7 @@ mod tests {
 		Block<TestXt>,
 		ChainContext<Runtime>,
 		Runtime,
-		AllModules,
+		AllPallets,
 		CustomOnRuntimeUpgrade
 	>;
 
@@ -780,8 +780,8 @@ mod tests {
 			));
 			let r = Executive::apply_extrinsic(xt);
 			assert!(r.is_ok());
-			assert_eq!(<pallet_balances::Module<Runtime>>::total_balance(&1), 142 - fee);
-			assert_eq!(<pallet_balances::Module<Runtime>>::total_balance(&2), 69);
+			assert_eq!(<pallet_balances::Pallet<Runtime>>::total_balance(&1), 142 - fee);
+			assert_eq!(<pallet_balances::Pallet<Runtime>>::total_balance(&2), 69);
 		});
 	}
 
@@ -857,7 +857,7 @@ mod tests {
 				Digest::default(),
 			));
 			assert!(Executive::apply_extrinsic(xt).is_err());
-			assert_eq!(<frame_system::Module<Runtime>>::extrinsic_index(), Some(0));
+			assert_eq!(<frame_system::Pallet<Runtime>>::extrinsic_index(), Some(0));
 		});
 	}
 
@@ -883,7 +883,7 @@ mod tests {
 				Digest::default(),
 			));
 			// Base block execution weight + `on_initialize` weight from the custom module.
-			assert_eq!(<frame_system::Module<Runtime>>::block_weight().total(), base_block_weight);
+			assert_eq!(<frame_system::Pallet<Runtime>>::block_weight().total(), base_block_weight);
 
 			for nonce in 0..=num_to_exhaust_block {
 				let xt = TestXt::new(
@@ -893,11 +893,11 @@ mod tests {
 				if nonce != num_to_exhaust_block {
 					assert!(res.is_ok());
 					assert_eq!(
-						<frame_system::Module<Runtime>>::block_weight().total(),
+						<frame_system::Pallet<Runtime>>::block_weight().total(),
 						//--------------------- on_initialize + block_execution + extrinsic_base weight
 						(encoded_len + 5) * (nonce + 1) + base_block_weight,
 					);
-					assert_eq!(<frame_system::Module<Runtime>>::extrinsic_index(), Some(nonce as u32 + 1));
+					assert_eq!(<frame_system::Pallet<Runtime>>::extrinsic_index(), Some(nonce as u32 + 1));
 				} else {
 					assert_eq!(res, Err(InvalidTransaction::ExhaustsResources.into()));
 				}
@@ -924,8 +924,8 @@ mod tests {
 				Digest::default(),
 			));
 
-			assert_eq!(<frame_system::Module<Runtime>>::block_weight().total(), base_block_weight);
-			assert_eq!(<frame_system::Module<Runtime>>::all_extrinsics_len(), 0);
+			assert_eq!(<frame_system::Pallet<Runtime>>::block_weight().total(), base_block_weight);
+			assert_eq!(<frame_system::Pallet<Runtime>>::all_extrinsics_len(), 0);
 
 			assert!(Executive::apply_extrinsic(xt.clone()).unwrap().is_ok());
 			assert!(Executive::apply_extrinsic(x1.clone()).unwrap().is_ok());
@@ -935,14 +935,14 @@ mod tests {
 			let extrinsic_weight = len as Weight + <Runtime as frame_system::Config>::BlockWeights
 				::get().get(DispatchClass::Normal).base_extrinsic;
 			assert_eq!(
-				<frame_system::Module<Runtime>>::block_weight().total(),
+				<frame_system::Pallet<Runtime>>::block_weight().total(),
 				base_block_weight + 3 * extrinsic_weight,
 			);
-			assert_eq!(<frame_system::Module<Runtime>>::all_extrinsics_len(), 3 * len);
+			assert_eq!(<frame_system::Pallet<Runtime>>::all_extrinsics_len(), 3 * len);
 
-			let _ = <frame_system::Module<Runtime>>::finalize();
+			let _ = <frame_system::Pallet<Runtime>>::finalize();
 			// All extrinsics length cleaned on `System::finalize`
-			assert_eq!(<frame_system::Module<Runtime>>::all_extrinsics_len(), 0);
+			assert_eq!(<frame_system::Pallet<Runtime>>::all_extrinsics_len(), 0);
 
 			// New Block
 			Executive::initialize_block(&Header::new(
@@ -954,7 +954,7 @@ mod tests {
 			));
 
 			// Block weight cleaned up on `System::initialize`
-			assert_eq!(<frame_system::Module<Runtime>>::block_weight().total(), base_block_weight);
+			assert_eq!(<frame_system::Pallet<Runtime>>::block_weight().total(), base_block_weight);
 		});
 	}
 
@@ -989,7 +989,7 @@ mod tests {
 		let execute_with_lock = |lock: WithdrawReasons| {
 			let mut t = new_test_ext(1);
 			t.execute_with(|| {
-				<pallet_balances::Module<Runtime> as LockableCurrency<Balance>>::set_lock(
+				<pallet_balances::Pallet<Runtime> as LockableCurrency<Balance>>::set_lock(
 					id,
 					&1,
 					110,
@@ -1017,13 +1017,13 @@ mod tests {
 				if lock == WithdrawReasons::except(WithdrawReasons::TRANSACTION_PAYMENT) {
 					assert!(Executive::apply_extrinsic(xt).unwrap().is_ok());
 					// tx fee has been deducted.
-					assert_eq!(<pallet_balances::Module<Runtime>>::total_balance(&1), 111 - fee);
+					assert_eq!(<pallet_balances::Pallet<Runtime>>::total_balance(&1), 111 - fee);
 				} else {
 					assert_eq!(
 						Executive::apply_extrinsic(xt),
 						Err(InvalidTransaction::Payment.into()),
 					);
-					assert_eq!(<pallet_balances::Module<Runtime>>::total_balance(&1), 111);
+					assert_eq!(<pallet_balances::Pallet<Runtime>>::total_balance(&1), 111);
 				}
 			});
 		};
@@ -1041,7 +1041,7 @@ mod tests {
 			// NOTE: might need updates over time if new weights are introduced.
 			// For now it only accounts for the base block execution weight and
 			// the `on_initialize` weight defined in the custom test module.
-			assert_eq!(<frame_system::Module<Runtime>>::block_weight().total(), 175 + 175  + 10);
+			assert_eq!(<frame_system::Pallet<Runtime>>::block_weight().total(), 175 + 175  + 10);
 		})
 	}
 
@@ -1159,16 +1159,16 @@ mod tests {
 			));
 
 			// All weights that show up in the `initialize_block_impl`
-			let frame_system_upgrade_weight = frame_system::Module::<Runtime>::on_runtime_upgrade();
+			let frame_system_upgrade_weight = frame_system::Pallet::<Runtime>::on_runtime_upgrade();
 			let custom_runtime_upgrade_weight = CustomOnRuntimeUpgrade::on_runtime_upgrade();
-			let runtime_upgrade_weight = <AllModules as OnRuntimeUpgrade>::on_runtime_upgrade();
-			let frame_system_on_initialize_weight = frame_system::Module::<Runtime>::on_initialize(block_number);
-			let on_initialize_weight = <AllModules as OnInitialize<u64>>::on_initialize(block_number);
+			let runtime_upgrade_weight = <AllPallets as OnRuntimeUpgrade>::on_runtime_upgrade();
+			let frame_system_on_initialize_weight = frame_system::Pallet::<Runtime>::on_initialize(block_number);
+			let on_initialize_weight = <AllPallets as OnInitialize<u64>>::on_initialize(block_number);
 			let base_block_weight = <Runtime as frame_system::Config>::BlockWeights::get().base_block;
 
 			// Weights are recorded correctly
 			assert_eq!(
-				frame_system::Module::<Runtime>::block_weight().total(),
+				frame_system::Pallet::<Runtime>::block_weight().total(),
 				frame_system_upgrade_weight +
 				custom_runtime_upgrade_weight +
 				runtime_upgrade_weight +
diff --git a/frame/gilt/src/lib.rs b/frame/gilt/src/lib.rs
index ab35ce76742bc..23596a8b6e147 100644
--- a/frame/gilt/src/lib.rs
+++ b/frame/gilt/src/lib.rs
@@ -78,7 +78,7 @@ pub mod weights;
 pub mod pallet {
 	use sp_std::prelude::*;
 	use sp_arithmetic::{Perquintill, PerThing};
-	use sp_runtime::traits::{Zero, Saturating, SaturatedConversion};
+	use sp_runtime::traits::{Zero, Saturating};
 	use frame_support::traits::{Currency, OnUnbalanced, ReservableCurrency};
 	use frame_support::pallet_prelude::*;
 	use frame_system::pallet_prelude::*;
@@ -96,7 +96,13 @@ pub mod pallet {
 		type Event: From<Event<Self>> + IsType<<Self as frame_system::Config>::Event>;
 
 		/// Currency type that this works on.
-		type Currency: ReservableCurrency<Self::AccountId>;
+		type Currency: ReservableCurrency<Self::AccountId, Balance=Self::CurrencyBalance>;
+
+		/// Just the `Currency::Balance` type; we have this item to allow us to constrain it to
+		/// `From<u64>`.
+		type CurrencyBalance:
+			sp_runtime::traits::AtLeast32BitUnsigned + codec::FullCodec + Copy
+				+ MaybeSerializeDeserialize + sp_std::fmt::Debug + Default + From<u64>;
 
 		/// Origin required for setting the target proportion to be under gilt.
 		type AdminOrigin: EnsureOrigin<Self::Origin>;
@@ -440,7 +446,7 @@ pub mod pallet {
 			let gilt = Active::<T>::get(index).ok_or(Error::<T>::Unknown)?;
 			// If found, check the owner is `who`.
 			ensure!(gilt.who == who, Error::<T>::NotOwner);
-			let now = frame_system::Module::<T>::block_number();
+			let now = frame_system::Pallet::<T>::block_number();
 			ensure!(now >= gilt.expiry, Error::<T>::NotExpired);
 			// Remove it
 			Active::<T>::remove(index);
@@ -448,11 +454,10 @@ pub mod pallet {
 			// Multiply the proportion it is by the total issued.
 			let total_issuance = T::Currency::total_issuance().saturating_sub(T::IgnoredIssuance::get());
 			ActiveTotal::<T>::mutate(|totals| {
-				let nongilt_issuance: u128 = total_issuance.saturating_sub(totals.frozen)
-					.saturated_into();
+				let nongilt_issuance = total_issuance.saturating_sub(totals.frozen);
 				let effective_issuance = totals.proportion.left_from_one()
 					.saturating_reciprocal_mul(nongilt_issuance);
-				let gilt_value: BalanceOf<T> = (gilt.proportion * effective_issuance).saturated_into();
+				let gilt_value = gilt.proportion * effective_issuance;
 
 				totals.frozen = totals.frozen.saturating_sub(gilt.amount);
 				totals.proportion = totals.proportion.saturating_sub(gilt.proportion);
@@ -488,7 +493,40 @@ pub mod pallet {
 		}
 	}
 
+	/// Issuance information returned by `issuance()`.
+	pub struct IssuanceInfo<Balance> {
+		/// The balance held in reserve over all active gilts.
+		pub reserved: Balance,
+		/// The issuance not held in reserve for active gilts. Together with `reserved` this sums to
+		/// `Currency::total_issuance`.
+		pub non_gilt: Balance,
+		/// The balance that `reserved` is effectively worth, at present. This is not issued funds
+		/// and could be less than `reserved` (though in most cases should be greater).
+		pub effective: Balance,
+	}
+
 	impl<T: Config> Pallet<T> {
+		/// Get the target amount of Gilts that we're aiming for.
+		pub fn target() -> Perquintill {
+			ActiveTotal::<T>::get().target
+		}
+
+		/// Returns information on the issuance of gilts.
+		pub fn issuance() -> IssuanceInfo<BalanceOf<T>> {
+			let totals = ActiveTotal::<T>::get();
+
+			let total_issuance = T::Currency::total_issuance();
+			let non_gilt = total_issuance.saturating_sub(totals.frozen);
+			let effective = totals.proportion.left_from_one()
+				.saturating_reciprocal_mul(non_gilt);
+
+			IssuanceInfo {
+				reserved: totals.frozen,
+				non_gilt,
+				effective,
+			}
+		}
+
 		/// Attempt to enlarge our gilt-set from bids in order to satisfy our desired target amount
 		/// of funds frozen into gilts.
 		pub fn pursue_target(max_bids: u32) -> Weight {
@@ -497,11 +535,10 @@ pub mod pallet {
 				let missing = totals.target.saturating_sub(totals.proportion);
 
 				let total_issuance = T::Currency::total_issuance().saturating_sub(T::IgnoredIssuance::get());
-				let nongilt_issuance: u128 = total_issuance.saturating_sub(totals.frozen)
-					.saturated_into();
+				let nongilt_issuance = total_issuance.saturating_sub(totals.frozen);
 				let effective_issuance = totals.proportion.left_from_one()
 					.saturating_reciprocal_mul(nongilt_issuance);
-				let intake: BalanceOf<T> = (missing * effective_issuance).saturated_into();
+				let intake = missing * effective_issuance;
 
 				let (bids_taken, queues_hit) = Self::enlarge(intake, max_bids);
 				let first_from_each_queue = T::WeightInfo::pursue_target_per_queue(queues_hit);
@@ -525,7 +562,7 @@ pub mod pallet {
 			let mut remaining = amount;
 			let mut bids_taken = 0;
 			let mut queues_hit = 0;
-			let now = frame_system::Module::<T>::block_number();
+			let now = frame_system::Pallet::<T>::block_number();
 
 			ActiveTotal::<T>::mutate(|totals| {
 				QueueTotals::<T>::mutate(|qs| {
@@ -550,13 +587,12 @@ pub mod pallet {
 								qs[queue_index].1 = qs[queue_index].1.saturating_sub(bid.amount);
 
 								// Now to activate the bid...
-								let nongilt_issuance: u128 = total_issuance.saturating_sub(totals.frozen)
-									.saturated_into();
+								let nongilt_issuance = total_issuance.saturating_sub(totals.frozen);
 								let effective_issuance = totals.proportion.left_from_one()
 									.saturating_reciprocal_mul(nongilt_issuance);
-								let n: u128 = amount.saturated_into();
+								let n = amount;
 								let d = effective_issuance;
-								let proportion = Perquintill::from_rational_approximation(n, d);
+								let proportion = Perquintill::from_rational(n, d);
 								let who = bid.who;
 								let index = totals.index;
 								totals.frozen += bid.amount;
diff --git a/frame/gilt/src/mock.rs b/frame/gilt/src/mock.rs
index ca4ccaff73c58..1abb92ed3dfac 100644
--- a/frame/gilt/src/mock.rs
+++ b/frame/gilt/src/mock.rs
@@ -36,9 +36,9 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Balances: pallet_balances::{Module, Call, Config<T>, Storage, Event<T>},
-		Gilt: pallet_gilt::{Module, Call, Config, Storage, Event<T>},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Balances: pallet_balances::{Pallet, Call, Config<T>, Storage, Event<T>},
+		Gilt: pallet_gilt::{Pallet, Call, Config, Storage, Event<T>},
 	}
 );
 
@@ -103,6 +103,7 @@ ord_parameter_types! {
 impl pallet_gilt::Config for Test {
 	type Event = Event;
 	type Currency = Balances;
+	type CurrencyBalance = <Self as pallet_balances::Config>::Balance;
 	type AdminOrigin = frame_system::EnsureSignedBy<One, Self::AccountId>;
 	type Deficit = ();
 	type Surplus = ();
diff --git a/frame/grandpa/Cargo.toml b/frame/grandpa/Cargo.toml
index 2bf7306f58e15..547e3966d52a4 100644
--- a/frame/grandpa/Cargo.toml
+++ b/frame/grandpa/Cargo.toml
@@ -39,7 +39,7 @@ pallet-offences = { version = "3.0.0", path = "../offences" }
 pallet-staking = { version = "3.0.0", path = "../staking" }
 pallet-staking-reward-curve = { version = "3.0.0", path = "../staking/reward-curve" }
 pallet-timestamp = { version = "3.0.0", path = "../timestamp" }
-sp-election-providers = { version = "3.0.0", path = "../../primitives/election-providers" }
+frame-election-provider-support = { version = "3.0.0", path = "../election-provider-support" }
 
 [features]
 default = ["std"]
diff --git a/frame/grandpa/src/equivocation.rs b/frame/grandpa/src/equivocation.rs
index 37496fdeb8592..8ab86b2fed065 100644
--- a/frame/grandpa/src/equivocation.rs
+++ b/frame/grandpa/src/equivocation.rs
@@ -358,7 +358,7 @@ impl<FullIdentification: Clone> Offence<FullIdentification>
 
 	fn slash_fraction(offenders_count: u32, validator_set_count: u32) -> Perbill {
 		// the formula is min((3k / n)^2, 1)
-		let x = Perbill::from_rational_approximation(3 * offenders_count, validator_set_count);
+		let x = Perbill::from_rational(3 * offenders_count, validator_set_count);
 		// _ ^ 2
 		x.square()
 	}
diff --git a/frame/grandpa/src/lib.rs b/frame/grandpa/src/lib.rs
index b68624df7b5dc..eb3dc4f110acb 100644
--- a/frame/grandpa/src/lib.rs
+++ b/frame/grandpa/src/lib.rs
@@ -390,7 +390,7 @@ impl<T: Config> Module<T> {
 	/// Cannot be done when already paused.
 	pub fn schedule_pause(in_blocks: T::BlockNumber) -> DispatchResult {
 		if let StoredState::Live = <State<T>>::get() {
-			let scheduled_at = <frame_system::Module<T>>::block_number();
+			let scheduled_at = <frame_system::Pallet<T>>::block_number();
 			<State<T>>::put(StoredState::PendingPause {
 				delay: in_blocks,
 				scheduled_at,
@@ -405,7 +405,7 @@ impl<T: Config> Module<T> {
 	/// Schedule a resume of GRANDPA after pausing.
 	pub fn schedule_resume(in_blocks: T::BlockNumber) -> DispatchResult {
 		if let StoredState::Paused = <State<T>>::get() {
-			let scheduled_at = <frame_system::Module<T>>::block_number();
+			let scheduled_at = <frame_system::Pallet<T>>::block_number();
 			<State<T>>::put(StoredState::PendingResume {
 				delay: in_blocks,
 				scheduled_at,
@@ -437,7 +437,7 @@ impl<T: Config> Module<T> {
 		forced: Option<T::BlockNumber>,
 	) -> DispatchResult {
 		if !<PendingChange<T>>::exists() {
-			let scheduled_at = <frame_system::Module<T>>::block_number();
+			let scheduled_at = <frame_system::Pallet<T>>::block_number();
 
 			if let Some(_) = forced {
 				if Self::next_forced().map_or(false, |next| next > scheduled_at) {
@@ -465,7 +465,7 @@ impl<T: Config> Module<T> {
 	/// Deposit one of this module's logs.
 	fn deposit_log(log: ConsensusLog<T::BlockNumber>) {
 		let log: DigestItem<T::Hash> = DigestItem::Consensus(GRANDPA_ENGINE_ID, log.encode());
-		<frame_system::Module<T>>::deposit_log(log.into());
+		<frame_system::Pallet<T>>::deposit_log(log.into());
 	}
 
 	// Perform module initialization, abstracted so that it can be called either through genesis
diff --git a/frame/grandpa/src/mock.rs b/frame/grandpa/src/mock.rs
index 0a24a2344547e..3f450e18bc783 100644
--- a/frame/grandpa/src/mock.rs
+++ b/frame/grandpa/src/mock.rs
@@ -40,7 +40,7 @@ use sp_runtime::{
 };
 use sp_staking::SessionIndex;
 use pallet_session::historical as pallet_session_historical;
-use sp_election_providers::onchain;
+use frame_election_provider_support::onchain;
 
 type UncheckedExtrinsic = frame_system::mocking::MockUncheckedExtrinsic<Test>;
 type Block = frame_system::mocking::MockBlock<Test>;
@@ -51,14 +51,14 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Timestamp: pallet_timestamp::{Module, Call, Storage, Inherent},
-		Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
-		Staking: pallet_staking::{Module, Call, Config<T>, Storage, Event<T>, ValidateUnsigned},
-		Session: pallet_session::{Module, Call, Storage, Event, Config<T>},
-		Grandpa: pallet_grandpa::{Module, Call, Storage, Config, Event, ValidateUnsigned},
-		Offences: pallet_offences::{Module, Call, Storage, Event},
-		Historical: pallet_session_historical::{Module},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Timestamp: pallet_timestamp::{Pallet, Call, Storage, Inherent},
+		Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
+		Staking: pallet_staking::{Pallet, Call, Config<T>, Storage, Event<T>},
+		Session: pallet_session::{Pallet, Call, Storage, Event, Config<T>},
+		Grandpa: pallet_grandpa::{Pallet, Call, Storage, Config, Event, ValidateUnsigned},
+		Offences: pallet_offences::{Pallet, Call, Storage, Event},
+		Historical: pallet_session_historical::{Pallet},
 	}
 );
 
@@ -193,11 +193,13 @@ parameter_types! {
 impl onchain::Config for Test {
 	type AccountId = <Self as frame_system::Config>::AccountId;
 	type BlockNumber = <Self as frame_system::Config>::BlockNumber;
+	type BlockWeights = ();
 	type Accuracy = Perbill;
 	type DataProvider = Staking;
 }
 
 impl pallet_staking::Config for Test {
+	const MAX_NOMINATIONS: u32 = 16;
 	type RewardRemainder = ();
 	type CurrencyToVote = frame_support::traits::SaturatingCurrencyToVote;
 	type Event = Event;
@@ -209,16 +211,10 @@ impl pallet_staking::Config for Test {
 	type SlashDeferDuration = SlashDeferDuration;
 	type SlashCancelOrigin = frame_system::EnsureRoot<Self::AccountId>;
 	type SessionInterface = Self;
-	type UnixTime = pallet_timestamp::Module<Test>;
-	type RewardCurve = RewardCurve;
+	type UnixTime = pallet_timestamp::Pallet<Test>;
+	type EraPayout = pallet_staking::ConvertCurve<RewardCurve>;
 	type MaxNominatorRewardedPerValidator = MaxNominatorRewardedPerValidator;
 	type NextNewSession = Session;
-	type ElectionLookahead = ElectionLookahead;
-	type Call = Call;
-	type UnsignedPriority = StakingUnsignedPriority;
-	type MaxIterations = ();
-	type MinSolutionScoreBump = ();
-	type OffchainSolutionWeightLimit = ();
 	type ElectionProvider = onchain::OnChainSequentialPhragmen<Self>;
 	type WeightInfo = ();
 }
diff --git a/frame/identity/src/benchmarking.rs b/frame/identity/src/benchmarking.rs
index 645b3817d6ec9..372abc72a97dd 100644
--- a/frame/identity/src/benchmarking.rs
+++ b/frame/identity/src/benchmarking.rs
@@ -25,12 +25,12 @@ use frame_system::{EventRecord, RawOrigin};
 use frame_benchmarking::{benchmarks, account, whitelisted_caller, impl_benchmark_test_suite};
 use sp_runtime::traits::Bounded;
 
-use crate::Module as Identity;
+use crate::Pallet as Identity;
 
 const SEED: u32 = 0;
 
 fn assert_last_event<T: Config>(generic_event: <T as Config>::Event) {
-	let events = frame_system::Module::<T>::events();
+	let events = frame_system::Pallet::<T>::events();
 	let system_event: <T as frame_system::Config>::Event = generic_event.into();
 	// compare to the last event record
 	let EventRecord { event, .. } = &events[events.len() - 1];
diff --git a/frame/identity/src/lib.rs b/frame/identity/src/lib.rs
index fed32afa2e62f..880d202795922 100644
--- a/frame/identity/src/lib.rs
+++ b/frame/identity/src/lib.rs
@@ -17,8 +17,8 @@
 
 //! # Identity Module
 //!
-//! - [`identity::Config`](./trait.Config.html)
-//! - [`Call`](./enum.Call.html)
+//! - [`Config`]
+//! - [`Call`]
 //!
 //! ## Overview
 //!
@@ -598,7 +598,8 @@ decl_module! {
 				T::Currency::reserve(&sender, id.deposit - old_deposit)?;
 			}
 			if old_deposit > id.deposit {
-				let _ = T::Currency::unreserve(&sender, old_deposit - id.deposit);
+				let err_amount = T::Currency::unreserve(&sender, old_deposit - id.deposit);
+				debug_assert!(err_amount.is_zero());
 			}
 
 			let judgements = id.judgements.len();
@@ -655,7 +656,8 @@ decl_module! {
 			if old_deposit < new_deposit {
 				T::Currency::reserve(&sender, new_deposit - old_deposit)?;
 			} else if old_deposit > new_deposit {
-				let _ = T::Currency::unreserve(&sender, old_deposit - new_deposit);
+				let err_amount = T::Currency::unreserve(&sender, old_deposit - new_deposit);
+				debug_assert!(err_amount.is_zero());
 			}
 			// do nothing if they're equal.
 
@@ -713,7 +715,8 @@ decl_module! {
 				<SuperOf<T>>::remove(sub);
 			}
 
-			let _ = T::Currency::unreserve(&sender, deposit.clone());
+			let err_amount = T::Currency::unreserve(&sender, deposit.clone());
+			debug_assert!(err_amount.is_zero());
 
 			Self::deposit_event(RawEvent::IdentityCleared(sender, deposit));
 
@@ -819,7 +822,8 @@ decl_module! {
 				Err(Error::<T>::JudgementGiven)?
 			};
 
-			let _ = T::Currency::unreserve(&sender, fee);
+			let err_amount = T::Currency::unreserve(&sender, fee);
+			debug_assert!(err_amount.is_zero());
 			let judgements = id.judgements.len();
 			let extra_fields = id.info.additional.len();
 			<IdentityOf<T>>::insert(&sender, id);
@@ -1095,7 +1099,8 @@ decl_module! {
 				sub_ids.retain(|x| x != &sub);
 				let deposit = T::SubAccountDeposit::get().min(*subs_deposit);
 				*subs_deposit -= deposit;
-				let _ = T::Currency::unreserve(&sender, deposit);
+				let err_amount = T::Currency::unreserve(&sender, deposit);
+				debug_assert!(err_amount.is_zero());
 				Self::deposit_event(RawEvent::SubIdentityRemoved(sub, sender, deposit));
 			});
 		}
diff --git a/frame/identity/src/tests.rs b/frame/identity/src/tests.rs
index 230079a21ea0d..a996c989a9185 100644
--- a/frame/identity/src/tests.rs
+++ b/frame/identity/src/tests.rs
@@ -37,9 +37,9 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
-		Identity: pallet_identity::{Module, Call, Storage, Event<T>},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
+		Identity: pallet_identity::{Pallet, Call, Storage, Event<T>},
 	}
 );
 
diff --git a/frame/im-online/src/lib.rs b/frame/im-online/src/lib.rs
index e00b5aa9d1395..d8f3fdc854b16 100644
--- a/frame/im-online/src/lib.rs
+++ b/frame/im-online/src/lib.rs
@@ -30,9 +30,9 @@
 //! as the [NetworkState](../../client/offchain/struct.NetworkState.html).
 //! It is submitted as an Unsigned Transaction via off-chain workers.
 //!
-//! - [`im_online::Config`](./trait.Config.html)
-//! - [`Call`](./enum.Call.html)
-//! - [`Module`](./struct.Module.html)
+//! - [`Config`]
+//! - [`Call`]
+//! - [`Module`]
 //!
 //! ## Interface
 //!
@@ -100,11 +100,7 @@ use frame_support::{
 	},
 	Parameter,
 };
-use frame_system::ensure_none;
-use frame_system::offchain::{
-	SendTransactionTypes,
-	SubmitTransaction,
-};
+use frame_system::{ensure_none, offchain::{SendTransactionTypes, SubmitTransaction}};
 pub use weights::WeightInfo;
 
 pub mod sr25519 {
@@ -672,7 +668,7 @@ impl<T: Config> OneSessionHandler<T::AccountId> for Module<T> {
 		// Tell the offchain worker to start making the next session's heartbeats.
 		// Since we consider producing blocks as being online,
 		// the heartbeat is deferred a bit to prevent spamming.
-		let block_number = <frame_system::Module<T>>::block_number();
+		let block_number = <frame_system::Pallet<T>>::block_number();
 		let half_session = T::NextSessionRotation::average_session_length() / 2u32.into();
 		<HeartbeatAfter<T>>::put(block_number + half_session);
 
@@ -813,7 +809,7 @@ impl<Offender: Clone> Offence<Offender> for UnresponsivenessOffence<Offender> {
 		// basically, 10% can be offline with no slash, but after that, it linearly climbs up to 7%
 		// when 13/30 are offline (around 5% when 1/3 are offline).
 		if let Some(threshold) = offenders.checked_sub(validator_set_count / 10 + 1) {
-			let x = Perbill::from_rational_approximation(3 * threshold, validator_set_count);
+			let x = Perbill::from_rational(3 * threshold, validator_set_count);
 			x.saturating_mul(Perbill::from_percent(7))
 		} else {
 			Perbill::default()
diff --git a/frame/im-online/src/mock.rs b/frame/im-online/src/mock.rs
index f8346aa536248..35028dd89df4e 100644
--- a/frame/im-online/src/mock.rs
+++ b/frame/im-online/src/mock.rs
@@ -44,10 +44,10 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Session: pallet_session::{Module, Call, Storage, Event, Config<T>},
-		ImOnline: imonline::{Module, Call, Storage, Config<T>, Event<T>},
-		Historical: pallet_session_historical::{Module},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Session: pallet_session::{Pallet, Call, Storage, Event, Config<T>},
+		ImOnline: imonline::{Pallet, Call, Storage, Config<T>, Event<T>},
+		Historical: pallet_session_historical::{Pallet},
 	}
 );
 
diff --git a/frame/indices/src/mock.rs b/frame/indices/src/mock.rs
index 06c73b1a9bc27..01db4b50f5085 100644
--- a/frame/indices/src/mock.rs
+++ b/frame/indices/src/mock.rs
@@ -33,9 +33,9 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
-		Indices: pallet_indices::{Module, Call, Storage, Config<T>, Event<T>},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
+		Indices: pallet_indices::{Pallet, Call, Storage, Config<T>, Event<T>},
 	}
 );
 
diff --git a/frame/lottery/src/lib.rs b/frame/lottery/src/lib.rs
index 8248caa06708e..94b7dd459889a 100644
--- a/frame/lottery/src/lib.rs
+++ b/frame/lottery/src/lib.rs
@@ -277,7 +277,7 @@ decl_module! {
 				ensure!(lottery.is_none(), Error::<T>::InProgress);
 				let index = LotteryIndex::get();
 				let new_index = index.checked_add(1).ok_or(Error::<T>::Overflow)?;
-				let start = frame_system::Module::<T>::block_number();
+				let start = frame_system::Pallet::<T>::block_number();
 				// Use new_index to more easily track everything with the current state.
 				*lottery = Some(LotteryConfig {
 					price,
@@ -324,7 +324,8 @@ decl_module! {
 						let winning_number = Self::choose_winner(ticket_count);
 						let winner = Tickets::<T>::get(winning_number).unwrap_or(lottery_account);
 						// Not much we can do if this fails...
-						let _ = T::Currency::transfer(&Self::account_id(), &winner, lottery_balance, KeepAlive);
+						let res = T::Currency::transfer(&Self::account_id(), &winner, lottery_balance, KeepAlive);
+						debug_assert!(res.is_ok());
 
 						Self::deposit_event(RawEvent::Winner(winner, lottery_balance));
 
@@ -392,7 +393,7 @@ impl<T: Config> Module<T> {
 	fn do_buy_ticket(caller: &T::AccountId, call: &<T as Config>::Call) -> DispatchResult {
 		// Check the call is valid lottery
 		let config = Lottery::<T>::get().ok_or(Error::<T>::NotConfigured)?;
-		let block_number = frame_system::Module::<T>::block_number();
+		let block_number = frame_system::Pallet::<T>::block_number();
 		ensure!(block_number < config.start.saturating_add(config.length), Error::<T>::AlreadyEnded);
 		ensure!(T::ValidateCall::validate_call(call), Error::<T>::InvalidCall);
 		let call_index = Self::call_to_index(call)?;
diff --git a/frame/lottery/src/mock.rs b/frame/lottery/src/mock.rs
index 44691427c8e59..a776896921a7f 100644
--- a/frame/lottery/src/mock.rs
+++ b/frame/lottery/src/mock.rs
@@ -42,9 +42,9 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
-		Lottery: pallet_lottery::{Module, Call, Storage, Event<T>},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
+		Lottery: pallet_lottery::{Pallet, Call, Storage, Event<T>},
 	}
 );
 
diff --git a/frame/membership/src/lib.rs b/frame/membership/src/lib.rs
index f080938095445..e26af3ce9b71a 100644
--- a/frame/membership/src/lib.rs
+++ b/frame/membership/src/lib.rs
@@ -293,8 +293,8 @@ mod tests {
 			NodeBlock = Block,
 			UncheckedExtrinsic = UncheckedExtrinsic,
 		{
-			System: frame_system::{Module, Call, Config, Storage, Event<T>},
-			Membership: pallet_membership::{Module, Call, Storage, Config<T>, Event<T>},
+			System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+			Membership: pallet_membership::{Pallet, Call, Storage, Config<T>, Event<T>},
 		}
 	);
 
diff --git a/frame/merkle-mountain-range/primitives/src/lib.rs b/frame/merkle-mountain-range/primitives/src/lib.rs
index 0887535dca0ef..73d4d3ecc1fc3 100644
--- a/frame/merkle-mountain-range/primitives/src/lib.rs
+++ b/frame/merkle-mountain-range/primitives/src/lib.rs
@@ -51,10 +51,10 @@ impl LeafDataProvider for () {
 /// so that any point in time in the future we can receive a proof about some past
 /// blocks without using excessive on-chain storage.
 ///
-/// Hence we implement the [LeafDataProvider] for [frame_system::Module]. Since the
+/// Hence we implement the [LeafDataProvider] for [frame_system::Pallet]. Since the
 /// current block hash is not available (since the block is not finished yet),
 /// we use the `parent_hash` here along with parent block number.
-impl<T: frame_system::Config> LeafDataProvider for frame_system::Module<T> {
+impl<T: frame_system::Config> LeafDataProvider for frame_system::Pallet<T> {
 	type LeafData = (
 		<T as frame_system::Config>::BlockNumber,
 		<T as frame_system::Config>::Hash
diff --git a/frame/merkle-mountain-range/src/mock.rs b/frame/merkle-mountain-range/src/mock.rs
index 0adb0294d5080..072724a58afe5 100644
--- a/frame/merkle-mountain-range/src/mock.rs
+++ b/frame/merkle-mountain-range/src/mock.rs
@@ -40,8 +40,8 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		MMR: pallet_mmr::{Module, Call, Storage},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		MMR: pallet_mmr::{Pallet, Call, Storage},
 	}
 );
 
@@ -78,7 +78,7 @@ impl Config for Test {
 
 	type Hashing = Keccak256;
 	type Hash = H256;
-	type LeafData = Compact<Keccak256, (frame_system::Module<Test>, LeafData)>;
+	type LeafData = Compact<Keccak256, (frame_system::Pallet<Test>, LeafData)>;
 	type OnNewRoot = ();
 	type WeightInfo = ();
 }
diff --git a/frame/merkle-mountain-range/src/tests.rs b/frame/merkle-mountain-range/src/tests.rs
index ea522dc51cd03..dfaf60ef2eab6 100644
--- a/frame/merkle-mountain-range/src/tests.rs
+++ b/frame/merkle-mountain-range/src/tests.rs
@@ -39,11 +39,11 @@ fn register_offchain_ext(ext: &mut sp_io::TestExternalities) {
 }
 
 fn new_block() -> u64 {
-	let number = frame_system::Module::<Test>::block_number() + 1;
+	let number = frame_system::Pallet::<Test>::block_number() + 1;
 	let hash = H256::repeat_byte(number as u8);
 	LEAF_DATA.with(|r| r.borrow_mut().a = number);
 
-	frame_system::Module::<Test>::initialize(
+	frame_system::Pallet::<Test>::initialize(
 		&number,
 		&hash,
 		&Default::default(),
diff --git a/frame/multisig/src/lib.rs b/frame/multisig/src/lib.rs
index aa72d2d1ad3ca..8c8e1c0dbc436 100644
--- a/frame/multisig/src/lib.rs
+++ b/frame/multisig/src/lib.rs
@@ -18,8 +18,8 @@
 //! # Multisig Module
 //! A module for doing multisig dispatch.
 //!
-//! - [`multisig::Config`](./trait.Config.html)
-//! - [`Call`](./enum.Call.html)
+//! - [`Config`]
+//! - [`Call`]
 //!
 //! ## Overview
 //!
@@ -436,7 +436,8 @@ decl_module! {
 			ensure!(m.when == timepoint, Error::<T>::WrongTimepoint);
 			ensure!(m.depositor == who, Error::<T>::NotOwner);
 
-			let _ = T::Currency::unreserve(&m.depositor, m.deposit);
+			let err_amount = T::Currency::unreserve(&m.depositor, m.deposit);
+			debug_assert!(err_amount.is_zero());
 			<Multisigs<T>>::remove(&id, &call_hash);
 			Self::clear_call(&call_hash);
 
@@ -638,8 +639,8 @@ impl<T: Config> Module<T> {
 	/// The current `Timepoint`.
 	pub fn timepoint() -> Timepoint<T::BlockNumber> {
 		Timepoint {
-			height: <system::Module<T>>::block_number(),
-			index: <system::Module<T>>::extrinsic_index().unwrap_or_default(),
+			height: <system::Pallet<T>>::block_number(),
+			index: <system::Pallet<T>>::extrinsic_index().unwrap_or_default(),
 		}
 	}
 
diff --git a/frame/multisig/src/tests.rs b/frame/multisig/src/tests.rs
index a3f47a26e6422..a3a3edc34f1a9 100644
--- a/frame/multisig/src/tests.rs
+++ b/frame/multisig/src/tests.rs
@@ -37,9 +37,9 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
-		Multisig: pallet_multisig::{Module, Call, Storage, Event<T>},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
+		Multisig: pallet_multisig::{Pallet, Call, Storage, Event<T>},
 	}
 );
 
@@ -124,7 +124,7 @@ pub fn new_test_ext() -> sp_io::TestExternalities {
 }
 
 fn last_event() -> Event {
-	system::Module::<Test>::events().pop().map(|e| e.event).expect("Event expected")
+	system::Pallet::<Test>::events().pop().map(|e| e.event).expect("Event expected")
 }
 
 fn expect_event<E: Into<Event>>(e: E) {
diff --git a/frame/nicks/src/lib.rs b/frame/nicks/src/lib.rs
index 681a45626fbca..67e62a09da64a 100644
--- a/frame/nicks/src/lib.rs
+++ b/frame/nicks/src/lib.rs
@@ -17,8 +17,8 @@
 
 //! # Nicks Module
 //!
-//! - [`nicks::Config`](./trait.Config.html)
-//! - [`Call`](./enum.Call.html)
+//! - [`Config`]
+//! - [`Call`]
 //!
 //! ## Overview
 //!
@@ -179,7 +179,8 @@ decl_module! {
 
 			let deposit = <NameOf<T>>::take(&sender).ok_or(Error::<T>::Unnamed)?.1;
 
-			let _ = T::Currency::unreserve(&sender, deposit.clone());
+			let err_amount = T::Currency::unreserve(&sender, deposit.clone());
+			debug_assert!(err_amount.is_zero());
 
 			Self::deposit_event(RawEvent::NameCleared(sender, deposit));
 		}
@@ -257,9 +258,9 @@ mod tests {
 			NodeBlock = Block,
 			UncheckedExtrinsic = UncheckedExtrinsic,
 		{
-			System: frame_system::{Module, Call, Config, Storage, Event<T>},
-			Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
-			Nicks: pallet_nicks::{Module, Call, Storage, Event<T>},
+			System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+			Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
+			Nicks: pallet_nicks::{Pallet, Call, Storage, Event<T>},
 		}
 	);
 
diff --git a/frame/node-authorization/Cargo.toml b/frame/node-authorization/Cargo.toml
index 245db9176f740..786eb84d1e523 100644
--- a/frame/node-authorization/Cargo.toml
+++ b/frame/node-authorization/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "pallet-node-authorization"
-version = "2.0.0"
+version = "3.0.0"
 authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
 license = "Apache-2.0"
diff --git a/frame/node-authorization/src/lib.rs b/frame/node-authorization/src/lib.rs
index 090be28492630..5f233549c73ca 100644
--- a/frame/node-authorization/src/lib.rs
+++ b/frame/node-authorization/src/lib.rs
@@ -37,117 +37,137 @@
 // Ensure we're `no_std` when compiling for Wasm.
 #![cfg_attr(not(feature = "std"), no_std)]
 
+#[cfg(test)]
+mod mock;
+#[cfg(test)]
+mod tests;
+
+pub mod weights;
+
 use sp_core::OpaquePeerId as PeerId;
 use sp_std::{
 	collections::btree_set::BTreeSet,
 	iter::FromIterator,
 	prelude::*,
 };
-use codec::Decode;
-use frame_support::{
-	decl_module, decl_storage, decl_event, decl_error,
-	ensure, weights::{DispatchClass, Weight}, traits::{Get, EnsureOrigin},
-};
-use frame_system::ensure_signed;
-
-pub trait WeightInfo {
-	fn add_well_known_node() -> Weight;
-	fn remove_well_known_node() -> Weight;
-	fn swap_well_known_node() -> Weight;
-	fn reset_well_known_nodes() -> Weight;
-	fn claim_node() -> Weight;
-	fn remove_claim() -> Weight;
-	fn transfer_node() -> Weight;
-	fn add_connections() -> Weight;
-	fn remove_connections() -> Weight;
-}
+pub use pallet::*;
+pub use weights::WeightInfo;
 
-impl WeightInfo for () {
-	fn add_well_known_node() -> Weight { 50_000_000 }
-	fn remove_well_known_node() -> Weight { 50_000_000 }
-	fn swap_well_known_node() -> Weight { 50_000_000 }
-	fn reset_well_known_nodes() -> Weight { 50_000_000 }
-	fn claim_node() -> Weight { 50_000_000 }
-	fn remove_claim() -> Weight { 50_000_000 }
-	fn transfer_node() -> Weight { 50_000_000 }
-	fn add_connections() -> Weight { 50_000_000 }
-	fn remove_connections() -> Weight { 50_000_000 }
-}
-
-pub trait Config: frame_system::Config {
-	/// The event type of this module.
-	type Event: From<Event<Self>> + Into<<Self as frame_system::Config>::Event>;
+#[frame_support::pallet]
+pub mod pallet {
+	use super::*;
+	use frame_support::{
+		dispatch::DispatchResult,
+		pallet_prelude::*,
+	};
+	use frame_system::pallet_prelude::*;
+
+	#[pallet::pallet]
+	#[pallet::generate_store(pub(super) trait Store)]
+	pub struct Pallet<T>(_);
+
+	/// The module configuration trait
+	#[pallet::config]
+	pub trait Config: frame_system::Config {
+		/// The overarching event type.
+		type Event: From<Event<Self>> + IsType<<Self as frame_system::Config>::Event>;
+
+		/// The maximum number of well known nodes that are allowed to set
+		#[pallet::constant]
+		type MaxWellKnownNodes: Get<u32>;
 
-	/// The maximum number of well known nodes that are allowed to set
-	type MaxWellKnownNodes: Get<u32>;
+		/// The maximum length in bytes of PeerId
+		#[pallet::constant]
+		type MaxPeerIdLength: Get<u32>;
 
-	/// The maximum length in bytes of PeerId
-	type MaxPeerIdLength: Get<u32>;
+		/// The origin which can add a well known node.
+		type AddOrigin: EnsureOrigin<Self::Origin>;
 
-	/// The origin which can add a well known node.
-	type AddOrigin: EnsureOrigin<Self::Origin>;
+		/// The origin which can remove a well known node.
+		type RemoveOrigin: EnsureOrigin<Self::Origin>;
 
-	/// The origin which can remove a well known node.
-	type RemoveOrigin: EnsureOrigin<Self::Origin>;
+		/// The origin which can swap the well known nodes.
+		type SwapOrigin: EnsureOrigin<Self::Origin>;
 
-	/// The origin which can swap the well known nodes.
-	type SwapOrigin: EnsureOrigin<Self::Origin>;
+		/// The origin which can reset the well known nodes.
+		type ResetOrigin: EnsureOrigin<Self::Origin>;
 
-	/// The origin which can reset the well known nodes.
-	type ResetOrigin: EnsureOrigin<Self::Origin>;
+		/// Weight information for extrinsics in this pallet.
+		type WeightInfo: WeightInfo;
+	}
 
-	/// Weight information for extrinsics in this pallet.
-	type WeightInfo: WeightInfo;
-}
+	/// The set of well known nodes. This is stored sorted (just by value).
+	#[pallet::storage]
+	#[pallet::getter(fn well_known_nodes)]
+	pub type WellKnownNodes<T> = StorageValue<_, BTreeSet<PeerId>, ValueQuery>;
+
+	/// A map that maintains the ownership of each node.
+	#[pallet::storage]
+	#[pallet::getter(fn owners)]
+	pub type Owners<T: Config> = StorageMap<
+		_,
+		Blake2_128Concat,
+		PeerId,
+		T::AccountId,
+	>;
+
+	/// The additional adapative connections of each node.
+	#[pallet::storage]
+	#[pallet::getter(fn additional_connection)]
+	pub type AdditionalConnections<T> = StorageMap<
+		_,
+		Blake2_128Concat,
+		PeerId,
+		BTreeSet<PeerId>,
+		ValueQuery,
+	>;
+
+	#[pallet::genesis_config]
+	pub struct GenesisConfig<T: Config> {
+		pub nodes: Vec<(PeerId, T::AccountId)>,
+	}
 
-decl_storage! {
-	trait Store for Module<T: Config> as NodeAuthorization {
-		/// The set of well known nodes. This is stored sorted (just by value).
-		pub WellKnownNodes get(fn well_known_nodes): BTreeSet<PeerId>;
-		/// A map that maintains the ownership of each node.
-		pub Owners get(fn owners):
-			map hasher(blake2_128_concat) PeerId => T::AccountId;
-		/// The additional adapative connections of each node.
-		pub AdditionalConnections get(fn additional_connection):
-			map hasher(blake2_128_concat) PeerId => BTreeSet<PeerId>;
+	#[cfg(feature = "std")]
+	impl<T: Config> Default for GenesisConfig<T> {
+		fn default() -> Self {
+			Self { nodes: Vec::new() }
+		}
 	}
-	add_extra_genesis {
-		config(nodes): Vec<(PeerId, T::AccountId)>;
-		build(|config: &GenesisConfig<T>| {
-			<Module<T>>::initialize_nodes(&config.nodes)
-		})
+
+	#[pallet::genesis_build]
+	impl<T: Config> GenesisBuild<T> for GenesisConfig<T> {
+		fn build(&self) {
+			Pallet::<T>::initialize_nodes(&self.nodes);
+		}
 	}
-}
 
-decl_event! {
-	pub enum Event<T> where
-		<T as frame_system::Config>::AccountId,
-	{
+	#[pallet::event]
+	#[pallet::generate_deposit(pub(super) fn deposit_event)]
+	#[pallet::metadata(T::AccountId = "AccountId")]
+	pub enum Event<T: Config> {
 		/// The given well known node was added.
-		NodeAdded(PeerId, AccountId),
+		NodeAdded(PeerId, T::AccountId),
 		/// The given well known node was removed.
 		NodeRemoved(PeerId),
 		/// The given well known node was swapped; first item was removed,
 		/// the latter was added.
 		NodeSwapped(PeerId, PeerId),
 		/// The given well known nodes were reset.
-		NodesReset(Vec<(PeerId, AccountId)>),
+		NodesReset(Vec<(PeerId, T::AccountId)>),
 		/// The given node was claimed by a user.
-		NodeClaimed(PeerId, AccountId),
+		NodeClaimed(PeerId, T::AccountId),
 		/// The given claim was removed by its owner.
-		ClaimRemoved(PeerId, AccountId),
+		ClaimRemoved(PeerId, T::AccountId),
 		/// The node was transferred to another account.
-		NodeTransferred(PeerId, AccountId),
+		NodeTransferred(PeerId, T::AccountId),
 		/// The allowed connections were added to a node.
 		ConnectionsAdded(PeerId, Vec<PeerId>),
 		/// The allowed connections were removed from a node.
 		ConnectionsRemoved(PeerId, Vec<PeerId>),
 	}
-}
 
-decl_error! {
-	/// Error for the node authorization module.
-	pub enum Error for Module<T: Config> {
+	#[pallet::error]
+	pub enum Error<T> {
 		/// The PeerId is too long.
 		PeerIdTooLong,
 		/// Too many well known nodes.
@@ -165,41 +185,65 @@ decl_error! {
 		/// No permisson to perform specific operation.
 		PermissionDenied,
 	}
-}
 
-decl_module! {
-	pub struct Module<T: Config> for enum Call where origin: T::Origin {
-		/// The maximum number of authorized well known nodes
-		const MaxWellKnownNodes: u32 = T::MaxWellKnownNodes::get();
-
-		/// The maximum length in bytes of PeerId
-		const MaxPeerIdLength: u32 = T::MaxPeerIdLength::get();
-
-		type Error = Error<T>;
-
-		fn deposit_event() = default;
+	#[pallet::hooks]
+	impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {
+		/// Set reserved node every block. It may not be enabled depends on the offchain
+		/// worker settings when starting the node.
+		fn offchain_worker(now: T::BlockNumber) {
+			let network_state = sp_io::offchain::network_state();
+			match network_state {
+				Err(_) => log::error!(
+					target: "runtime::node-authorization",
+					"Error: failed to get network state of node at {:?}",
+					now,
+				),
+				Ok(state) => {
+					let encoded_peer = state.peer_id.0;
+					match Decode::decode(&mut &encoded_peer[..]) {
+						Err(_) => log::error!(
+							target: "runtime::node-authorization",
+							"Error: failed to decode PeerId at {:?}",
+							now,
+						),
+						Ok(node) => sp_io::offchain::set_authorized_nodes(
+							Self::get_authorized_nodes(&PeerId(node)),
+							true
+						)
+					}
+				}
+			}
+		}
+	}
 
+	#[pallet::call]
+	impl<T: Config> Pallet<T> {
 		/// Add a node to the set of well known nodes. If the node is already claimed, the owner
 		/// will be updated and keep the existing additional connection unchanged.
 		///
 		/// May only be called from `T::AddOrigin`.
 		///
 		/// - `node`: identifier of the node.
-		#[weight = (T::WeightInfo::add_well_known_node(), DispatchClass::Operational)]
-		pub fn add_well_known_node(origin, node: PeerId, owner: T::AccountId) {
+		#[pallet::weight((T::WeightInfo::add_well_known_node(), DispatchClass::Operational))]
+		pub fn add_well_known_node(
+			origin: OriginFor<T>,
+			node: PeerId,
+			owner: T::AccountId
+		) -> DispatchResult {
 			T::AddOrigin::ensure_origin(origin)?;
 			ensure!(node.0.len() < T::MaxPeerIdLength::get() as usize, Error::<T>::PeerIdTooLong);
 
-			let mut nodes = WellKnownNodes::get();
+			let mut nodes = WellKnownNodes::<T>::get();
 			ensure!(nodes.len() < T::MaxWellKnownNodes::get() as usize, Error::<T>::TooManyNodes);
 			ensure!(!nodes.contains(&node), Error::<T>::AlreadyJoined);
 
 			nodes.insert(node.clone());
 
-			WellKnownNodes::put(&nodes);
+			WellKnownNodes::<T>::put(&nodes);
 			<Owners<T>>::insert(&node, &owner);
 
-			Self::deposit_event(RawEvent::NodeAdded(node, owner));
+			Self::deposit_event(Event::NodeAdded(node, owner));
+			Ok(())
 		}
 
 		/// Remove a node from the set of well known nodes. The ownership and additional
@@ -208,21 +252,22 @@ decl_module! {
 		/// May only be called from `T::RemoveOrigin`.
 		///
 		/// - `node`: identifier of the node.
-		#[weight = (T::WeightInfo::remove_well_known_node(), DispatchClass::Operational)]
-		pub fn remove_well_known_node(origin, node: PeerId) {
+		#[pallet::weight((T::WeightInfo::remove_well_known_node(), DispatchClass::Operational))]
+		pub fn remove_well_known_node(origin: OriginFor<T>, node: PeerId) -> DispatchResult {
 			T::RemoveOrigin::ensure_origin(origin)?;
 			ensure!(node.0.len() < T::MaxPeerIdLength::get() as usize, Error::<T>::PeerIdTooLong);
 
-			let mut nodes = WellKnownNodes::get();
+			let mut nodes = WellKnownNodes::<T>::get();
 			ensure!(nodes.contains(&node), Error::<T>::NotExist);
 
 			nodes.remove(&node);
 
-			WellKnownNodes::put(&nodes);
+			WellKnownNodes::<T>::put(&nodes);
 			<Owners<T>>::remove(&node);
-			AdditionalConnections::remove(&node);
+			AdditionalConnections::<T>::remove(&node);
 
-			Self::deposit_event(RawEvent::NodeRemoved(node));
+			Self::deposit_event(Event::NodeRemoved(node));
+			Ok(())
 		}
 
 		/// Swap a well known node to another. Both the ownership and additional connections
@@ -232,26 +277,34 @@ decl_module! {
 		///
 		/// - `remove`: the node which will be moved out from the list.
 		/// - `add`: the node which will be put in the list.
-		#[weight = (T::WeightInfo::swap_well_known_node(), DispatchClass::Operational)]
-		pub fn swap_well_known_node(origin, remove: PeerId, add: PeerId) {
+		#[pallet::weight((T::WeightInfo::swap_well_known_node(), DispatchClass::Operational))]
+		pub fn swap_well_known_node(
+			origin: OriginFor<T>,
+			remove: PeerId,
+			add: PeerId
+		) -> DispatchResult {
 			T::SwapOrigin::ensure_origin(origin)?;
-			ensure!(remove.0.len() < T::MaxPeerIdLength::get() as usize, Error::<T>::PeerIdTooLong);
+			ensure!(
+				remove.0.len() < T::MaxPeerIdLength::get() as usize,
+				Error::<T>::PeerIdTooLong
+			);
 			ensure!(add.0.len() < T::MaxPeerIdLength::get() as usize, Error::<T>::PeerIdTooLong);
 
 			if remove == add { return Ok(()) }
 
-			let mut nodes = WellKnownNodes::get();
+			let mut nodes = WellKnownNodes::<T>::get();
 			ensure!(nodes.contains(&remove), Error::<T>::NotExist);
 			ensure!(!nodes.contains(&add), Error::<T>::AlreadyJoined);
 
 			nodes.remove(&remove);
 			nodes.insert(add.clone());
 
-			WellKnownNodes::put(&nodes);
+			WellKnownNodes::<T>::put(&nodes);
 			Owners::<T>::swap(&remove, &add);
-			AdditionalConnections::swap(&remove, &add);
+			AdditionalConnections::<T>::swap(&remove, &add);
 
-			Self::deposit_event(RawEvent::NodeSwapped(remove, add));
+			Self::deposit_event(Event::NodeSwapped(remove, add));
+			Ok(())
 		}
 
 		/// Reset all the well known nodes. This will not remove the ownership and additional
@@ -261,29 +314,34 @@ decl_module! {
 		/// May only be called from `T::ResetOrigin`.
 		///
 		/// - `nodes`: the new nodes for the allow list.
-		#[weight = (T::WeightInfo::reset_well_known_nodes(), DispatchClass::Operational)]
-		pub fn reset_well_known_nodes(origin, nodes: Vec<(PeerId, T::AccountId)>) {
+		#[pallet::weight((T::WeightInfo::reset_well_known_nodes(), DispatchClass::Operational))]
+		pub fn reset_well_known_nodes(
+			origin: OriginFor<T>,
+			nodes: Vec<(PeerId, T::AccountId)>
+		) -> DispatchResult {
 			T::ResetOrigin::ensure_origin(origin)?;
 			ensure!(nodes.len() < T::MaxWellKnownNodes::get() as usize, Error::<T>::TooManyNodes);
 
 			Self::initialize_nodes(&nodes);
 
-			Self::deposit_event(RawEvent::NodesReset(nodes));
+			Self::deposit_event(Event::NodesReset(nodes));
+			Ok(())
 		}
 
 		/// A given node can be claimed by anyone. The owner should be the first to know its
 		/// PeerId, so claim it right away!
 		///
 		/// - `node`: identifier of the node.
-		#[weight = T::WeightInfo::claim_node()]
-		pub fn claim_node(origin, node: PeerId) {
+		#[pallet::weight(T::WeightInfo::claim_node())]
+		pub fn claim_node(origin: OriginFor<T>, node: PeerId) -> DispatchResult {
 			let sender = ensure_signed(origin)?;
 
 			ensure!(node.0.len() < T::MaxPeerIdLength::get() as usize, Error::<T>::PeerIdTooLong);
 			ensure!(!Owners::<T>::contains_key(&node),Error::<T>::AlreadyClaimed);
 
 			Owners::<T>::insert(&node, &sender);
-			Self::deposit_event(RawEvent::NodeClaimed(node, sender));
+			Self::deposit_event(Event::NodeClaimed(node, sender));
+			Ok(())
 		}
 
 		/// A claim can be removed by its owner and get back the reservation. The additional
@@ -291,55 +349,61 @@ decl_module! {
 		/// needs to reach consensus among the network participants.
 		///
 		/// - `node`: identifier of the node.
-		#[weight = T::WeightInfo::remove_claim()]
-		pub fn remove_claim(origin, node: PeerId) {
+		#[pallet::weight(T::WeightInfo::remove_claim())]
+		pub fn remove_claim(origin: OriginFor<T>, node: PeerId) -> DispatchResult {
 			let sender = ensure_signed(origin)?;
 
 			ensure!(node.0.len() < T::MaxPeerIdLength::get() as usize, Error::<T>::PeerIdTooLong);
-			ensure!(Owners::<T>::contains_key(&node), Error::<T>::NotClaimed);
-			ensure!(Owners::<T>::get(&node) == sender, Error::<T>::NotOwner);
-			ensure!(!WellKnownNodes::get().contains(&node), Error::<T>::PermissionDenied);
+			let owner = Owners::<T>::get(&node).ok_or(Error::<T>::NotClaimed)?;
+			ensure!(owner == sender, Error::<T>::NotOwner);
+			ensure!(!WellKnownNodes::<T>::get().contains(&node), Error::<T>::PermissionDenied);
 
 			Owners::<T>::remove(&node);
-			AdditionalConnections::remove(&node);
+			AdditionalConnections::<T>::remove(&node);
 
-			Self::deposit_event(RawEvent::ClaimRemoved(node, sender));
+			Self::deposit_event(Event::ClaimRemoved(node, sender));
+			Ok(())
 		}
 
 		/// A node can be transferred to a new owner.
 		///
 		/// - `node`: identifier of the node.
 		/// - `owner`: new owner of the node.
-		#[weight = T::WeightInfo::transfer_node()]
-		pub fn transfer_node(origin, node: PeerId, owner: T::AccountId) {
+		#[pallet::weight(T::WeightInfo::transfer_node())]
+		pub fn transfer_node(
+			origin: OriginFor<T>,
+			node: PeerId,
+			owner: T::AccountId
+		) -> DispatchResult {
 			let sender = ensure_signed(origin)?;
 
 			ensure!(node.0.len() < T::MaxPeerIdLength::get() as usize, Error::<T>::PeerIdTooLong);
-			ensure!(Owners::<T>::contains_key(&node), Error::<T>::NotClaimed);
-			ensure!(Owners::<T>::get(&node) == sender, Error::<T>::NotOwner);
+			let pre_owner = Owners::<T>::get(&node).ok_or(Error::<T>::NotClaimed)?;
+			ensure!(pre_owner == sender, Error::<T>::NotOwner);
 
 			Owners::<T>::insert(&node, &owner);
 
-			Self::deposit_event(RawEvent::NodeTransferred(node, owner));
+			Self::deposit_event(Event::NodeTransferred(node, owner));
+			Ok(())
 		}
 
 		/// Add additional connections to a given node.
 		///
 		/// - `node`: identifier of the node.
 		/// - `connections`: additonal nodes from which the connections are allowed.
-		#[weight = T::WeightInfo::add_connections()]
+		#[pallet::weight(T::WeightInfo::add_connections())]
 		pub fn add_connections(
-			origin,
+			origin: OriginFor<T>,
 			node: PeerId,
 			connections: Vec<PeerId>
-		) {
+		) -> DispatchResult {
 			let sender = ensure_signed(origin)?;
 
 			ensure!(node.0.len() < T::MaxPeerIdLength::get() as usize, Error::<T>::PeerIdTooLong);
-			ensure!(Owners::<T>::contains_key(&node), Error::<T>::NotClaimed);
-			ensure!(Owners::<T>::get(&node) == sender, Error::<T>::NotOwner);
+			let owner = Owners::<T>::get(&node).ok_or(Error::<T>::NotClaimed)?;
+			ensure!(owner == sender, Error::<T>::NotOwner);
 
-			let mut nodes = AdditionalConnections::get(&node);
+			let mut nodes = AdditionalConnections::<T>::get(&node);
 
 			for add_node in connections.iter() {
 				if *add_node == node {
@@ -348,73 +412,48 @@ decl_module! {
 				nodes.insert(add_node.clone());
 			}
 
-			AdditionalConnections::insert(&node, nodes);
+			AdditionalConnections::<T>::insert(&node, nodes);
 
-			Self::deposit_event(RawEvent::ConnectionsAdded(node, connections));
+			Self::deposit_event(Event::ConnectionsAdded(node, connections));
+			Ok(())
 		}
 
 		/// Remove additional connections of a given node.
 		///
 		/// - `node`: identifier of the node.
 		/// - `connections`: additonal nodes from which the connections are not allowed anymore.
-		#[weight = T::WeightInfo::remove_connections()]
+		#[pallet::weight(T::WeightInfo::remove_connections())]
 		pub fn remove_connections(
-			origin,
+			origin: OriginFor<T>,
 			node: PeerId,
 			connections: Vec<PeerId>
-		) {
+		) -> DispatchResult {
 			let sender = ensure_signed(origin)?;
 
 			ensure!(node.0.len() < T::MaxPeerIdLength::get() as usize, Error::<T>::PeerIdTooLong);
-			ensure!(Owners::<T>::contains_key(&node), Error::<T>::NotClaimed);
-			ensure!(Owners::<T>::get(&node) == sender, Error::<T>::NotOwner);
+			let owner = Owners::<T>::get(&node).ok_or(Error::<T>::NotClaimed)?;
+			ensure!(owner == sender, Error::<T>::NotOwner);
 
-			let mut nodes = AdditionalConnections::get(&node);
+			let mut nodes = AdditionalConnections::<T>::get(&node);
 
 			for remove_node in connections.iter() {
 				nodes.remove(remove_node);
 			}
 
-			AdditionalConnections::insert(&node, nodes);
+			AdditionalConnections::<T>::insert(&node, nodes);
 
-			Self::deposit_event(RawEvent::ConnectionsRemoved(node, connections));
-		}
-
-		/// Set reserved node every block. It may not be enabled depends on the offchain
-		/// worker settings when starting the node.
-		fn offchain_worker(now: T::BlockNumber) {
-			let network_state = sp_io::offchain::network_state();
-			match network_state {
-				Err(_) => log::error!(
-					target: "runtime::node-authorization",
-					"Error: failed to get network state of node at {:?}",
-					now,
-				),
-				Ok(state) => {
-					let encoded_peer = state.peer_id.0;
-					match Decode::decode(&mut &encoded_peer[..]) {
-						Err(_) => log::error!(
-							target: "runtime::node-authorization",
-							"Error: failed to decode PeerId at {:?}",
-							now,
-						),
-						Ok(node) => sp_io::offchain::set_authorized_nodes(
-							Self::get_authorized_nodes(&PeerId(node)),
-							true
-						)
-					}
-				}
-			}
+			Self::deposit_event(Event::ConnectionsRemoved(node, connections));
+			Ok(())
 		}
 	}
 }
 
-impl<T: Config> Module<T> {
+impl<T: Config> Pallet<T> {
 	fn initialize_nodes(nodes: &Vec<(PeerId, T::AccountId)>) {
 		let peer_ids = nodes.iter()
 			.map(|item| item.0.clone())
 			.collect::<BTreeSet<PeerId>>();
-		WellKnownNodes::put(&peer_ids);
+		WellKnownNodes::<T>::put(&peer_ids);
 
 		for (node, who) in nodes.iter() {
 			Owners::<T>::insert(node, who);
@@ -422,9 +461,9 @@ impl<T: Config> Module<T> {
 	}
 
 	fn get_authorized_nodes(node: &PeerId) -> Vec<PeerId> {
-		let mut nodes = AdditionalConnections::get(node);
+		let mut nodes = AdditionalConnections::<T>::get(node);
 
-		let mut well_known_nodes = WellKnownNodes::get();
+		let mut well_known_nodes = WellKnownNodes::<T>::get();
 		if well_known_nodes.contains(node) {
 			well_known_nodes.remove(node);
 			nodes.extend(well_known_nodes);
@@ -433,434 +472,3 @@ impl<T: Config> Module<T> {
 		Vec::from_iter(nodes)
 	}
 }
-
-#[cfg(test)]
-mod tests {
-	use super::*;
-	use crate as pallet_node_authorization;
-
-	use frame_support::{assert_ok, assert_noop, parameter_types, ord_parameter_types};
-	use frame_system::EnsureSignedBy;
-	use sp_core::H256;
-	use sp_runtime::{traits::{BlakeTwo256, IdentityLookup, BadOrigin}, testing::Header};
-
-	type UncheckedExtrinsic = frame_system::mocking::MockUncheckedExtrinsic<Test>;
-	type Block = frame_system::mocking::MockBlock<Test>;
-
-	frame_support::construct_runtime!(
-		pub enum Test where
-			Block = Block,
-			NodeBlock = Block,
-			UncheckedExtrinsic = UncheckedExtrinsic,
-		{
-			System: frame_system::{Module, Call, Config, Storage, Event<T>},
-			NodeAuthorization: pallet_node_authorization::{
-				Module, Call, Storage, Config<T>, Event<T>,
-			},
-		}
-	);
-
-	parameter_types! {
-		pub const BlockHashCount: u64 = 250;
-	}
-	impl frame_system::Config for Test {
-		type BaseCallFilter = ();
-		type DbWeight = ();
-		type BlockWeights = ();
-		type BlockLength = ();
-		type Origin = Origin;
-		type Index = u64;
-		type BlockNumber = u64;
-		type Hash = H256;
-		type Call = Call;
-		type Hashing = BlakeTwo256;
-		type AccountId = u64;
-		type Lookup = IdentityLookup<Self::AccountId>;
-		type Header = Header;
-		type Event = Event;
-		type BlockHashCount = BlockHashCount;
-		type Version = ();
-		type PalletInfo = PalletInfo;
-		type AccountData = ();
-		type OnNewAccount = ();
-		type OnKilledAccount = ();
-		type SystemWeightInfo = ();
-		type SS58Prefix = ();
-	}
-
-	ord_parameter_types! {
-		pub const One: u64 = 1;
-		pub const Two: u64 = 2;
-		pub const Three: u64 = 3;
-		pub const Four: u64 = 4;
-	}
-	parameter_types! {
-		pub const MaxWellKnownNodes: u32 = 4;
-		pub const MaxPeerIdLength: u32 = 2;
-	}
-	impl Config for Test {
-		type Event = Event;
-		type MaxWellKnownNodes = MaxWellKnownNodes;
-		type MaxPeerIdLength = MaxPeerIdLength;
-		type AddOrigin = EnsureSignedBy<One, u64>;
-		type RemoveOrigin = EnsureSignedBy<Two, u64>;
-		type SwapOrigin = EnsureSignedBy<Three, u64>;
-		type ResetOrigin = EnsureSignedBy<Four, u64>;
-		type WeightInfo = ();
-	}
-
-	fn test_node(id: u8) -> PeerId {
-		PeerId(vec![id])
-	}
-
-	fn new_test_ext() -> sp_io::TestExternalities {
-		let mut t = frame_system::GenesisConfig::default().build_storage::<Test>().unwrap();
-		pallet_node_authorization::GenesisConfig::<Test> {
-			nodes: vec![(test_node(10), 10), (test_node(20), 20), (test_node(30), 30)],
-		}.assimilate_storage(&mut t).unwrap();
-		t.into()
-	}
-
-	#[test]
-	fn add_well_known_node_works() {
-		new_test_ext().execute_with(|| {
-			assert_noop!(
-				NodeAuthorization::add_well_known_node(Origin::signed(2), test_node(15), 15),
-				BadOrigin
-			);
-			assert_noop!(
-				NodeAuthorization::add_well_known_node(Origin::signed(1), PeerId(vec![1, 2, 3]), 15),
-				Error::<Test>::PeerIdTooLong
-			);
-			assert_noop!(
-				NodeAuthorization::add_well_known_node(Origin::signed(1), test_node(20), 20),
-				Error::<Test>::AlreadyJoined
-			);
-
-			assert_ok!(
-				NodeAuthorization::add_well_known_node(Origin::signed(1), test_node(15), 15)
-			);
-			assert_eq!(
-				WellKnownNodes::get(),
-				BTreeSet::from_iter(vec![test_node(10), test_node(15), test_node(20), test_node(30)])
-			);
-			assert_eq!(Owners::<Test>::get(test_node(10)), 10);
-			assert_eq!(Owners::<Test>::get(test_node(20)), 20);
-			assert_eq!(Owners::<Test>::get(test_node(30)), 30);
-			assert_eq!(Owners::<Test>::get(test_node(15)), 15);
-
-			assert_noop!(
-				NodeAuthorization::add_well_known_node(Origin::signed(1), test_node(25), 25),
-				Error::<Test>::TooManyNodes
-			);
-		});
-	}
-
-	#[test]
-	fn remove_well_known_node_works() {
-		new_test_ext().execute_with(|| {
-			assert_noop!(
-				NodeAuthorization::remove_well_known_node(Origin::signed(3), test_node(20)),
-				BadOrigin
-			);
-			assert_noop!(
-				NodeAuthorization::remove_well_known_node(Origin::signed(2), PeerId(vec![1, 2, 3])),
-				Error::<Test>::PeerIdTooLong
-			);
-			assert_noop!(
-				NodeAuthorization::remove_well_known_node(Origin::signed(2), test_node(40)),
-				Error::<Test>::NotExist
-			);
-
-			AdditionalConnections::insert(
-				test_node(20),
-				BTreeSet::from_iter(vec![test_node(40)])
-			);
-			assert!(AdditionalConnections::contains_key(test_node(20)));
-
-			assert_ok!(
-				NodeAuthorization::remove_well_known_node(Origin::signed(2), test_node(20))
-			);
-			assert_eq!(
-				WellKnownNodes::get(),
-				BTreeSet::from_iter(vec![test_node(10), test_node(30)])
-			);
-			assert!(!Owners::<Test>::contains_key(test_node(20)));
-			assert!(!AdditionalConnections::contains_key(test_node(20)));
-		});
-	}
-
-	#[test]
-	fn swap_well_known_node_works() {
-		new_test_ext().execute_with(|| {
-			assert_noop!(
-				NodeAuthorization::swap_well_known_node(
-					Origin::signed(4), test_node(20), test_node(5)
-				),
-				BadOrigin
-			);
-			assert_noop!(
-				NodeAuthorization::swap_well_known_node(
-					Origin::signed(3), PeerId(vec![1, 2, 3]), test_node(20)
-				),
-				Error::<Test>::PeerIdTooLong
-			);
-			assert_noop!(
-				NodeAuthorization::swap_well_known_node(
-					Origin::signed(3), test_node(20), PeerId(vec![1, 2, 3])
-				),
-				Error::<Test>::PeerIdTooLong
-			);
-
-			assert_ok!(
-				NodeAuthorization::swap_well_known_node(
-					Origin::signed(3), test_node(20), test_node(20)
-				)
-			);
-			assert_eq!(
-				WellKnownNodes::get(),
-				BTreeSet::from_iter(vec![test_node(10), test_node(20), test_node(30)])
-			);
-
-			assert_noop!(
-				NodeAuthorization::swap_well_known_node(
-					Origin::signed(3), test_node(15), test_node(5)
-				),
-				Error::<Test>::NotExist
-			);
-			assert_noop!(
-				NodeAuthorization::swap_well_known_node(
-					Origin::signed(3), test_node(20), test_node(30)
-				),
-				Error::<Test>::AlreadyJoined
-			);
-
-			AdditionalConnections::insert(
-				test_node(20),
-				BTreeSet::from_iter(vec![test_node(15)])
-			);
-			assert_ok!(
-				NodeAuthorization::swap_well_known_node(
-					Origin::signed(3), test_node(20), test_node(5)
-				)
-			);
-			assert_eq!(
-				WellKnownNodes::get(),
-				BTreeSet::from_iter(vec![test_node(5), test_node(10), test_node(30)])
-			);
-			assert!(!Owners::<Test>::contains_key(test_node(20)));
-			assert_eq!(Owners::<Test>::get(test_node(5)), 20);
-			assert!(!AdditionalConnections::contains_key(test_node(20)));
-			assert_eq!(
-				AdditionalConnections::get(test_node(5)),
-				BTreeSet::from_iter(vec![test_node(15)])
-			);
-		});
-	}
-
-	#[test]
-	fn reset_well_known_nodes_works() {
-		new_test_ext().execute_with(|| {
-			assert_noop!(
-				NodeAuthorization::reset_well_known_nodes(
-					Origin::signed(3),
-					vec![(test_node(15), 15), (test_node(5), 5), (test_node(20), 20)]
-				),
-				BadOrigin
-			);
-			assert_noop!(
-				NodeAuthorization::reset_well_known_nodes(
-					Origin::signed(4),
-					vec![
-						(test_node(15), 15),
-						(test_node(5), 5),
-						(test_node(20), 20),
-						(test_node(25), 25),
-					]
-				),
-				Error::<Test>::TooManyNodes
-			);
-
-			assert_ok!(
-				NodeAuthorization::reset_well_known_nodes(
-					Origin::signed(4),
-					vec![(test_node(15), 15), (test_node(5), 5), (test_node(20), 20)]
-				)
-			);
-			assert_eq!(
-				WellKnownNodes::get(),
-				BTreeSet::from_iter(vec![test_node(5), test_node(15), test_node(20)])
-			);
-			assert_eq!(Owners::<Test>::get(test_node(5)), 5);
-			assert_eq!(Owners::<Test>::get(test_node(15)), 15);
-			assert_eq!(Owners::<Test>::get(test_node(20)), 20);
-		});
-	}
-
-	#[test]
-	fn claim_node_works() {
-		new_test_ext().execute_with(|| {
-			assert_noop!(
-				NodeAuthorization::claim_node(Origin::signed(1), PeerId(vec![1, 2, 3])),
-				Error::<Test>::PeerIdTooLong
-			);
-			assert_noop!(
-				NodeAuthorization::claim_node(Origin::signed(1), test_node(20)),
-				Error::<Test>::AlreadyClaimed
-			);
-
-			assert_ok!(NodeAuthorization::claim_node(Origin::signed(15), test_node(15)));
-			assert_eq!(Owners::<Test>::get(test_node(15)), 15);
-		});
-	}
-
-	#[test]
-	fn remove_claim_works() {
-		new_test_ext().execute_with(|| {
-			assert_noop!(
-				NodeAuthorization::remove_claim(Origin::signed(15), PeerId(vec![1, 2, 3])),
-				Error::<Test>::PeerIdTooLong
-			);
-			assert_noop!(
-				NodeAuthorization::remove_claim(Origin::signed(15), test_node(15)),
-				Error::<Test>::NotClaimed
-			);
-
-			assert_noop!(
-				NodeAuthorization::remove_claim(Origin::signed(15), test_node(20)),
-				Error::<Test>::NotOwner
-			);
-
-			assert_noop!(
-				NodeAuthorization::remove_claim(Origin::signed(20), test_node(20)),
-				Error::<Test>::PermissionDenied
-			);
-
-			Owners::<Test>::insert(test_node(15), 15);
-			AdditionalConnections::insert(
-				test_node(15),
-				BTreeSet::from_iter(vec![test_node(20)])
-			);
-			assert_ok!(NodeAuthorization::remove_claim(Origin::signed(15), test_node(15)));
-			assert!(!Owners::<Test>::contains_key(test_node(15)));
-			assert!(!AdditionalConnections::contains_key(test_node(15)));
-		});
-	}
-
-	#[test]
-	fn transfer_node_works() {
-		new_test_ext().execute_with(|| {
-			assert_noop!(
-				NodeAuthorization::transfer_node(Origin::signed(15), PeerId(vec![1, 2, 3]), 10),
-				Error::<Test>::PeerIdTooLong
-			);
-			assert_noop!(
-				NodeAuthorization::transfer_node(Origin::signed(15), test_node(15), 10),
-				Error::<Test>::NotClaimed
-			);
-
-			assert_noop!(
-				NodeAuthorization::transfer_node(Origin::signed(15), test_node(20), 10),
-				Error::<Test>::NotOwner
-			);
-
-			assert_ok!(NodeAuthorization::transfer_node(Origin::signed(20), test_node(20), 15));
-			assert_eq!(Owners::<Test>::get(test_node(20)), 15);
-		});
-	}
-
-	#[test]
-	fn add_connections_works() {
-		new_test_ext().execute_with(|| {
-			assert_noop!(
-				NodeAuthorization::add_connections(
-					Origin::signed(15), PeerId(vec![1, 2, 3]), vec![test_node(5)]
-				),
-				Error::<Test>::PeerIdTooLong
-			);
-			assert_noop!(
-				NodeAuthorization::add_connections(
-					Origin::signed(15), test_node(15), vec![test_node(5)]
-				),
-				Error::<Test>::NotClaimed
-			);
-
-			assert_noop!(
-				NodeAuthorization::add_connections(
-					Origin::signed(15), test_node(20), vec![test_node(5)]
-				),
-				Error::<Test>::NotOwner
-			);
-
-			assert_ok!(
-				NodeAuthorization::add_connections(
-					Origin::signed(20),
-					test_node(20),
-					vec![test_node(15), test_node(5), test_node(25), test_node(20)]
-				)
-			);
-			assert_eq!(
-				AdditionalConnections::get(test_node(20)),
-				BTreeSet::from_iter(vec![test_node(5), test_node(15), test_node(25)])
-			);
-		});
-	}
-
-	#[test]
-	fn remove_connections_works() {
-		new_test_ext().execute_with(|| {
-			assert_noop!(
-				NodeAuthorization::remove_connections(
-					Origin::signed(15), PeerId(vec![1, 2, 3]), vec![test_node(5)]
-				),
-				Error::<Test>::PeerIdTooLong
-			);
-			assert_noop!(
-				NodeAuthorization::remove_connections(
-					Origin::signed(15), test_node(15), vec![test_node(5)]
-				),
-				Error::<Test>::NotClaimed
-			);
-
-			assert_noop!(
-				NodeAuthorization::remove_connections(
-					Origin::signed(15), test_node(20), vec![test_node(5)]
-				),
-				Error::<Test>::NotOwner
-			);
-
-			AdditionalConnections::insert(
-				test_node(20),
-				BTreeSet::from_iter(vec![test_node(5), test_node(15), test_node(25)])
-			);
-			assert_ok!(
-				NodeAuthorization::remove_connections(
-					Origin::signed(20),
-					test_node(20),
-					vec![test_node(15), test_node(5)]
-				)
-			);
-			assert_eq!(
-				AdditionalConnections::get(test_node(20)),
-				BTreeSet::from_iter(vec![test_node(25)])
-			);
-		});
-	}
-
-	#[test]
-	fn get_authorized_nodes_works() {
-		new_test_ext().execute_with(|| {
-			AdditionalConnections::insert(
-				test_node(20),
-				BTreeSet::from_iter(vec![test_node(5), test_node(15), test_node(25)])
-			);
-
-			let mut authorized_nodes = Module::<Test>::get_authorized_nodes(&test_node(20));
-			authorized_nodes.sort();
-			assert_eq!(
-				authorized_nodes,
-				vec![test_node(5), test_node(10), test_node(15), test_node(25), test_node(30)]
-			);
-		});
-	}
-}
diff --git a/frame/node-authorization/src/mock.rs b/frame/node-authorization/src/mock.rs
new file mode 100644
index 0000000000000..5118f07c7694e
--- /dev/null
+++ b/frame/node-authorization/src/mock.rs
@@ -0,0 +1,106 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Test environment for node-authorization pallet.
+
+use super::*;
+use crate as pallet_node_authorization;
+
+use frame_support::{
+	parameter_types, ord_parameter_types,
+	traits::GenesisBuild,
+};
+use frame_system::EnsureSignedBy;
+use sp_core::H256;
+use sp_runtime::{traits::{BlakeTwo256, IdentityLookup}, testing::Header};
+
+type UncheckedExtrinsic = frame_system::mocking::MockUncheckedExtrinsic<Test>;
+type Block = frame_system::mocking::MockBlock<Test>;
+
+frame_support::construct_runtime!(
+	pub enum Test where
+		Block = Block,
+		NodeBlock = Block,
+		UncheckedExtrinsic = UncheckedExtrinsic,
+	{
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		NodeAuthorization: pallet_node_authorization::{
+			Pallet, Call, Storage, Config<T>, Event<T>,
+		},
+	}
+);
+
+parameter_types! {
+	pub const BlockHashCount: u64 = 250;
+}
+impl frame_system::Config for Test {
+	type BaseCallFilter = ();
+	type DbWeight = ();
+	type BlockWeights = ();
+	type BlockLength = ();
+	type Origin = Origin;
+	type Index = u64;
+	type BlockNumber = u64;
+	type Hash = H256;
+	type Call = Call;
+	type Hashing = BlakeTwo256;
+	type AccountId = u64;
+	type Lookup = IdentityLookup<Self::AccountId>;
+	type Header = Header;
+	type Event = Event;
+	type BlockHashCount = BlockHashCount;
+	type Version = ();
+	type PalletInfo = PalletInfo;
+	type AccountData = ();
+	type OnNewAccount = ();
+	type OnKilledAccount = ();
+	type SystemWeightInfo = ();
+	type SS58Prefix = ();
+}
+
+ord_parameter_types! {
+	pub const One: u64 = 1;
+	pub const Two: u64 = 2;
+	pub const Three: u64 = 3;
+	pub const Four: u64 = 4;
+}
+parameter_types! {
+	pub const MaxWellKnownNodes: u32 = 4;
+	pub const MaxPeerIdLength: u32 = 2;
+}
+impl Config for Test {
+	type Event = Event;
+	type MaxWellKnownNodes = MaxWellKnownNodes;
+	type MaxPeerIdLength = MaxPeerIdLength;
+	type AddOrigin = EnsureSignedBy<One, u64>;
+	type RemoveOrigin = EnsureSignedBy<Two, u64>;
+	type SwapOrigin = EnsureSignedBy<Three, u64>;
+	type ResetOrigin = EnsureSignedBy<Four, u64>;
+	type WeightInfo = ();
+}
+
+pub fn test_node(id: u8) -> PeerId {
+	PeerId(vec![id])
+}
+
+pub fn new_test_ext() -> sp_io::TestExternalities {
+	let mut t = frame_system::GenesisConfig::default().build_storage::<Test>().unwrap();
+	pallet_node_authorization::GenesisConfig::<Test> {
+		nodes: vec![(test_node(10), 10), (test_node(20), 20), (test_node(30), 30)],
+	}.assimilate_storage(&mut t).unwrap();
+	t.into()
+}
diff --git a/frame/node-authorization/src/tests.rs b/frame/node-authorization/src/tests.rs
new file mode 100644
index 0000000000000..15a286fbc2390
--- /dev/null
+++ b/frame/node-authorization/src/tests.rs
@@ -0,0 +1,366 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Tests for node-authorization pallet.
+
+use super::*;
+use crate::mock::*;
+use frame_support::{assert_ok, assert_noop};
+use sp_runtime::traits::BadOrigin;
+
+#[test]
+fn add_well_known_node_works() {
+	new_test_ext().execute_with(|| {
+		assert_noop!(
+			NodeAuthorization::add_well_known_node(Origin::signed(2), test_node(15), 15),
+			BadOrigin
+		);
+		assert_noop!(
+			NodeAuthorization::add_well_known_node(Origin::signed(1), PeerId(vec![1, 2, 3]), 15),
+			Error::<Test>::PeerIdTooLong
+		);
+		assert_noop!(
+			NodeAuthorization::add_well_known_node(Origin::signed(1), test_node(20), 20),
+			Error::<Test>::AlreadyJoined
+		);
+
+		assert_ok!(
+			NodeAuthorization::add_well_known_node(Origin::signed(1), test_node(15), 15)
+		);
+		assert_eq!(
+			WellKnownNodes::<Test>::get(),
+			BTreeSet::from_iter(vec![test_node(10), test_node(15), test_node(20), test_node(30)])
+		);
+		assert_eq!(Owners::<Test>::get(test_node(10)), Some(10));
+		assert_eq!(Owners::<Test>::get(test_node(20)), Some(20));
+		assert_eq!(Owners::<Test>::get(test_node(30)), Some(30));
+		assert_eq!(Owners::<Test>::get(test_node(15)), Some(15));
+
+		assert_noop!(
+			NodeAuthorization::add_well_known_node(Origin::signed(1), test_node(25), 25),
+			Error::<Test>::TooManyNodes
+		);
+	});
+}
+
+#[test]
+fn remove_well_known_node_works() {
+	new_test_ext().execute_with(|| {
+		assert_noop!(
+			NodeAuthorization::remove_well_known_node(Origin::signed(3), test_node(20)),
+			BadOrigin
+		);
+		assert_noop!(
+			NodeAuthorization::remove_well_known_node(Origin::signed(2), PeerId(vec![1, 2, 3])),
+			Error::<Test>::PeerIdTooLong
+		);
+		assert_noop!(
+			NodeAuthorization::remove_well_known_node(Origin::signed(2), test_node(40)),
+			Error::<Test>::NotExist
+		);
+
+		AdditionalConnections::<Test>::insert(
+			test_node(20),
+			BTreeSet::from_iter(vec![test_node(40)])
+		);
+		assert!(AdditionalConnections::<Test>::contains_key(test_node(20)));
+
+		assert_ok!(
+			NodeAuthorization::remove_well_known_node(Origin::signed(2), test_node(20))
+		);
+		assert_eq!(
+			WellKnownNodes::<Test>::get(),
+			BTreeSet::from_iter(vec![test_node(10), test_node(30)])
+		);
+		assert!(!Owners::<Test>::contains_key(test_node(20)));
+		assert!(!AdditionalConnections::<Test>::contains_key(test_node(20)));
+	});
+}
+
+#[test]
+fn swap_well_known_node_works() {
+	new_test_ext().execute_with(|| {
+		assert_noop!(
+			NodeAuthorization::swap_well_known_node(
+				Origin::signed(4), test_node(20), test_node(5)
+			),
+			BadOrigin
+		);
+		assert_noop!(
+			NodeAuthorization::swap_well_known_node(
+				Origin::signed(3), PeerId(vec![1, 2, 3]), test_node(20)
+			),
+			Error::<Test>::PeerIdTooLong
+		);
+		assert_noop!(
+			NodeAuthorization::swap_well_known_node(
+				Origin::signed(3), test_node(20), PeerId(vec![1, 2, 3])
+			),
+			Error::<Test>::PeerIdTooLong
+		);
+
+		assert_ok!(
+			NodeAuthorization::swap_well_known_node(
+				Origin::signed(3), test_node(20), test_node(20)
+			)
+		);
+		assert_eq!(
+			WellKnownNodes::<Test>::get(),
+			BTreeSet::from_iter(vec![test_node(10), test_node(20), test_node(30)])
+		);
+
+		assert_noop!(
+			NodeAuthorization::swap_well_known_node(
+				Origin::signed(3), test_node(15), test_node(5)
+			),
+			Error::<Test>::NotExist
+		);
+		assert_noop!(
+			NodeAuthorization::swap_well_known_node(
+				Origin::signed(3), test_node(20), test_node(30)
+			),
+			Error::<Test>::AlreadyJoined
+		);
+
+		AdditionalConnections::<Test>::insert(
+			test_node(20),
+			BTreeSet::from_iter(vec![test_node(15)])
+		);
+		assert_ok!(
+			NodeAuthorization::swap_well_known_node(
+				Origin::signed(3), test_node(20), test_node(5)
+			)
+		);
+		assert_eq!(
+			WellKnownNodes::<Test>::get(),
+			BTreeSet::from_iter(vec![test_node(5), test_node(10), test_node(30)])
+		);
+		assert!(!Owners::<Test>::contains_key(test_node(20)));
+		assert_eq!(Owners::<Test>::get(test_node(5)), Some(20));
+		assert!(!AdditionalConnections::<Test>::contains_key(test_node(20)));
+		assert_eq!(
+			AdditionalConnections::<Test>::get(test_node(5)),
+			BTreeSet::from_iter(vec![test_node(15)])
+		);
+	});
+}
+
+#[test]
+fn reset_well_known_nodes_works() {
+	new_test_ext().execute_with(|| {
+		assert_noop!(
+			NodeAuthorization::reset_well_known_nodes(
+				Origin::signed(3),
+				vec![(test_node(15), 15), (test_node(5), 5), (test_node(20), 20)]
+			),
+			BadOrigin
+		);
+		assert_noop!(
+			NodeAuthorization::reset_well_known_nodes(
+				Origin::signed(4),
+				vec![
+					(test_node(15), 15),
+					(test_node(5), 5),
+					(test_node(20), 20),
+					(test_node(25), 25),
+				]
+			),
+			Error::<Test>::TooManyNodes
+		);
+
+		assert_ok!(
+			NodeAuthorization::reset_well_known_nodes(
+				Origin::signed(4),
+				vec![(test_node(15), 15), (test_node(5), 5), (test_node(20), 20)]
+			)
+		);
+		assert_eq!(
+			WellKnownNodes::<Test>::get(),
+			BTreeSet::from_iter(vec![test_node(5), test_node(15), test_node(20)])
+		);
+		assert_eq!(Owners::<Test>::get(test_node(5)), Some(5));
+		assert_eq!(Owners::<Test>::get(test_node(15)), Some(15));
+		assert_eq!(Owners::<Test>::get(test_node(20)), Some(20));
+	});
+}
+
+#[test]
+fn claim_node_works() {
+	new_test_ext().execute_with(|| {
+		assert_noop!(
+			NodeAuthorization::claim_node(Origin::signed(1), PeerId(vec![1, 2, 3])),
+			Error::<Test>::PeerIdTooLong
+		);
+		assert_noop!(
+			NodeAuthorization::claim_node(Origin::signed(1), test_node(20)),
+			Error::<Test>::AlreadyClaimed
+		);
+
+		assert_ok!(NodeAuthorization::claim_node(Origin::signed(15), test_node(15)));
+		assert_eq!(Owners::<Test>::get(test_node(15)), Some(15));
+	});
+}
+
+#[test]
+fn remove_claim_works() {
+	new_test_ext().execute_with(|| {
+		assert_noop!(
+			NodeAuthorization::remove_claim(Origin::signed(15), PeerId(vec![1, 2, 3])),
+			Error::<Test>::PeerIdTooLong
+		);
+		assert_noop!(
+			NodeAuthorization::remove_claim(Origin::signed(15), test_node(15)),
+			Error::<Test>::NotClaimed
+		);
+
+		assert_noop!(
+			NodeAuthorization::remove_claim(Origin::signed(15), test_node(20)),
+			Error::<Test>::NotOwner
+		);
+
+		assert_noop!(
+			NodeAuthorization::remove_claim(Origin::signed(20), test_node(20)),
+			Error::<Test>::PermissionDenied
+		);
+
+		Owners::<Test>::insert(test_node(15), 15);
+		AdditionalConnections::<Test>::insert(
+			test_node(15),
+			BTreeSet::from_iter(vec![test_node(20)])
+		);
+		assert_ok!(NodeAuthorization::remove_claim(Origin::signed(15), test_node(15)));
+		assert!(!Owners::<Test>::contains_key(test_node(15)));
+		assert!(!AdditionalConnections::<Test>::contains_key(test_node(15)));
+	});
+}
+
+#[test]
+fn transfer_node_works() {
+	new_test_ext().execute_with(|| {
+		assert_noop!(
+			NodeAuthorization::transfer_node(Origin::signed(15), PeerId(vec![1, 2, 3]), 10),
+			Error::<Test>::PeerIdTooLong
+		);
+		assert_noop!(
+			NodeAuthorization::transfer_node(Origin::signed(15), test_node(15), 10),
+			Error::<Test>::NotClaimed
+		);
+
+		assert_noop!(
+			NodeAuthorization::transfer_node(Origin::signed(15), test_node(20), 10),
+			Error::<Test>::NotOwner
+		);
+
+		assert_ok!(NodeAuthorization::transfer_node(Origin::signed(20), test_node(20), 15));
+		assert_eq!(Owners::<Test>::get(test_node(20)), Some(15));
+	});
+}
+
+#[test]
+fn add_connections_works() {
+	new_test_ext().execute_with(|| {
+		assert_noop!(
+			NodeAuthorization::add_connections(
+				Origin::signed(15), PeerId(vec![1, 2, 3]), vec![test_node(5)]
+			),
+			Error::<Test>::PeerIdTooLong
+		);
+		assert_noop!(
+			NodeAuthorization::add_connections(
+				Origin::signed(15), test_node(15), vec![test_node(5)]
+			),
+			Error::<Test>::NotClaimed
+		);
+
+		assert_noop!(
+			NodeAuthorization::add_connections(
+				Origin::signed(15), test_node(20), vec![test_node(5)]
+			),
+			Error::<Test>::NotOwner
+		);
+
+		assert_ok!(
+			NodeAuthorization::add_connections(
+				Origin::signed(20),
+				test_node(20),
+				vec![test_node(15), test_node(5), test_node(25), test_node(20)]
+			)
+		);
+		assert_eq!(
+			AdditionalConnections::<Test>::get(test_node(20)),
+			BTreeSet::from_iter(vec![test_node(5), test_node(15), test_node(25)])
+		);
+	});
+}
+
+#[test]
+fn remove_connections_works() {
+	new_test_ext().execute_with(|| {
+		assert_noop!(
+			NodeAuthorization::remove_connections(
+				Origin::signed(15), PeerId(vec![1, 2, 3]), vec![test_node(5)]
+			),
+			Error::<Test>::PeerIdTooLong
+		);
+		assert_noop!(
+			NodeAuthorization::remove_connections(
+				Origin::signed(15), test_node(15), vec![test_node(5)]
+			),
+			Error::<Test>::NotClaimed
+		);
+
+		assert_noop!(
+			NodeAuthorization::remove_connections(
+				Origin::signed(15), test_node(20), vec![test_node(5)]
+			),
+			Error::<Test>::NotOwner
+		);
+
+		AdditionalConnections::<Test>::insert(
+			test_node(20),
+			BTreeSet::from_iter(vec![test_node(5), test_node(15), test_node(25)])
+		);
+		assert_ok!(
+			NodeAuthorization::remove_connections(
+				Origin::signed(20),
+				test_node(20),
+				vec![test_node(15), test_node(5)]
+			)
+		);
+		assert_eq!(
+			AdditionalConnections::<Test>::get(test_node(20)),
+			BTreeSet::from_iter(vec![test_node(25)])
+		);
+	});
+}
+
+#[test]
+fn get_authorized_nodes_works() {
+	new_test_ext().execute_with(|| {
+		AdditionalConnections::<Test>::insert(
+			test_node(20),
+			BTreeSet::from_iter(vec![test_node(5), test_node(15), test_node(25)])
+		);
+
+		let mut authorized_nodes = Pallet::<Test>::get_authorized_nodes(&test_node(20));
+		authorized_nodes.sort();
+		assert_eq!(
+			authorized_nodes,
+			vec![test_node(5), test_node(10), test_node(15), test_node(25), test_node(30)]
+		);
+	});
+}
diff --git a/frame/node-authorization/src/weights.rs b/frame/node-authorization/src/weights.rs
new file mode 100644
index 0000000000000..3d01e40d67ac3
--- /dev/null
+++ b/frame/node-authorization/src/weights.rs
@@ -0,0 +1,48 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Autogenerated weights for pallet_node_authorization
+
+#![allow(unused_parens)]
+#![allow(unused_imports)]
+
+use frame_support::{traits::Get, weights::{Weight, constants::RocksDbWeight}};
+use sp_std::marker::PhantomData;
+
+pub trait WeightInfo {
+	fn add_well_known_node() -> Weight;
+	fn remove_well_known_node() -> Weight;
+	fn swap_well_known_node() -> Weight;
+	fn reset_well_known_nodes() -> Weight;
+	fn claim_node() -> Weight;
+	fn remove_claim() -> Weight;
+	fn transfer_node() -> Weight;
+	fn add_connections() -> Weight;
+	fn remove_connections() -> Weight;
+}
+
+impl WeightInfo for () {
+	fn add_well_known_node() -> Weight { 50_000_000 }
+	fn remove_well_known_node() -> Weight { 50_000_000 }
+	fn swap_well_known_node() -> Weight { 50_000_000 }
+	fn reset_well_known_nodes() -> Weight { 50_000_000 }
+	fn claim_node() -> Weight { 50_000_000 }
+	fn remove_claim() -> Weight { 50_000_000 }
+	fn transfer_node() -> Weight { 50_000_000 }
+	fn add_connections() -> Weight { 50_000_000 }
+	fn remove_connections() -> Weight { 50_000_000 }
+}
diff --git a/frame/offences/benchmarking/Cargo.toml b/frame/offences/benchmarking/Cargo.toml
index 6be2787734a4f..6c249ebcc61d8 100644
--- a/frame/offences/benchmarking/Cargo.toml
+++ b/frame/offences/benchmarking/Cargo.toml
@@ -27,7 +27,7 @@ pallet-staking = { version = "3.0.0", default-features = false, features = ["run
 sp-runtime = { version = "3.0.0", default-features = false, path = "../../../primitives/runtime" }
 sp-staking = { version = "3.0.0", default-features = false, path = "../../../primitives/staking" }
 sp-std = { version = "3.0.0", default-features = false, path = "../../../primitives/std" }
-sp-election-providers = { version = "3.0.0", default-features = false, path = "../../../primitives/election-providers" }
+frame-election-provider-support = { version = "3.0.0", default-features = false, path = "../../election-provider-support" }
 
 [dev-dependencies]
 pallet-staking-reward-curve = { version = "3.0.0", path = "../../staking/reward-curve" }
@@ -51,7 +51,7 @@ std = [
 	"pallet-staking/std",
 	"sp-runtime/std",
 	"sp-staking/std",
-	"sp-election-providers/std",
+	"frame-election-provider-support/std",
 	"sp-std/std",
 	"codec/std",
 ]
diff --git a/frame/offences/benchmarking/src/lib.rs b/frame/offences/benchmarking/src/lib.rs
index 0ceebaecd91ae..08517a4ac8df0 100644
--- a/frame/offences/benchmarking/src/lib.rs
+++ b/frame/offences/benchmarking/src/lib.rs
@@ -24,11 +24,14 @@ mod mock;
 use sp_std::prelude::*;
 use sp_std::vec;
 
-use frame_system::{RawOrigin, Module as System, Config as SystemConfig};
+use frame_system::{RawOrigin, Pallet as System, Config as SystemConfig};
 use frame_benchmarking::{benchmarks, account, impl_benchmark_test_suite};
 use frame_support::traits::{Currency, OnInitialize, ValidatorSet, ValidatorSetWithIdentification};
 
-use sp_runtime::{Perbill, traits::{Convert, StaticLookup, Saturating, UniqueSaturatedInto}};
+use sp_runtime::{
+	Perbill,
+	traits::{Convert, StaticLookup, Saturating, UniqueSaturatedInto},
+};
 use sp_staking::offence::{ReportOffence, Offence, OffenceDetails};
 
 use pallet_balances::Config as BalancesConfig;
@@ -39,8 +42,8 @@ use pallet_offences::{Config as OffencesConfig, Module as Offences};
 use pallet_session::historical::{Config as HistoricalConfig, IdentificationTuple};
 use pallet_session::{Config as SessionConfig, SessionManager};
 use pallet_staking::{
-	Module as Staking, Config as StakingConfig, RewardDestination, ValidatorPrefs,
-	Exposure, IndividualExposure, ElectionStatus, MAX_NOMINATIONS, Event as StakingEvent
+	Module as Staking, Config as StakingConfig, RewardDestination, ValidatorPrefs, Exposure,
+	IndividualExposure, Event as StakingEvent,
 };
 
 const SEED: u32 = 0;
@@ -50,7 +53,7 @@ const MAX_OFFENDERS: u32 = 100;
 const MAX_NOMINATORS: u32 = 100;
 const MAX_DEFERRED_OFFENCES: u32 = 100;
 
-pub struct Module<T: Config>(Offences<T>);
+pub struct Pallet<T: Config>(Offences<T>);
 
 pub trait Config:
 	SessionConfig
@@ -236,7 +239,7 @@ benchmarks! {
 		let r in 1 .. MAX_REPORTERS;
 		// we skip 1 offender, because in such case there is no slashing
 		let o in 2 .. MAX_OFFENDERS;
-		let n in 0 .. MAX_NOMINATORS.min(MAX_NOMINATIONS as u32);
+		let n in 0 .. MAX_NOMINATORS.min(<T as pallet_staking::Config>::MAX_NOMINATIONS);
 
 		// Make r reporters
 		let mut reporters = vec![];
@@ -310,7 +313,7 @@ benchmarks! {
 	}
 
 	report_offence_grandpa {
-		let n in 0 .. MAX_NOMINATORS.min(MAX_NOMINATIONS as u32);
+		let n in 0 .. MAX_NOMINATORS.min(<T as pallet_staking::Config>::MAX_NOMINATIONS);
 
 		// for grandpa equivocation reports the number of reporters
 		// and offenders is always 1
@@ -346,7 +349,7 @@ benchmarks! {
 	}
 
 	report_offence_babe {
-		let n in 0 .. MAX_NOMINATORS.min(MAX_NOMINATIONS as u32);
+		let n in 0 .. MAX_NOMINATORS.min(<T as pallet_staking::Config>::MAX_NOMINATIONS);
 
 		// for babe equivocation reports the number of reporters
 		// and offenders is always 1
@@ -386,8 +389,6 @@ benchmarks! {
 		let o = 10;
 		let n = 100;
 
-		Staking::<T>::put_election_status(ElectionStatus::Closed);
-
 		let mut deferred_offences = vec![];
 		let offenders = make_offenders::<T>(o, n)?.0;
 		let offence_details = offenders.into_iter()
@@ -421,7 +422,7 @@ benchmarks! {
 }
 
 impl_benchmark_test_suite!(
-	Module,
+	Pallet,
 	crate::mock::new_test_ext(),
 	crate::mock::Test,
 );
diff --git a/frame/offences/benchmarking/src/mock.rs b/frame/offences/benchmarking/src/mock.rs
index 54d649381eea6..223d6d4d477a6 100644
--- a/frame/offences/benchmarking/src/mock.rs
+++ b/frame/offences/benchmarking/src/mock.rs
@@ -29,7 +29,7 @@ use sp_runtime::{
 	traits::IdentityLookup,
 	testing::{Header, UintAuthorityId},
 };
-use sp_election_providers::onchain;
+use frame_election_provider_support::onchain;
 use pallet_session::historical as pallet_session_historical;
 
 type AccountId = u64;
@@ -152,13 +152,15 @@ pub type Extrinsic = sp_runtime::testing::TestXt<Call, ()>;
 impl onchain::Config for Test {
 	type AccountId = AccountId;
 	type BlockNumber = BlockNumber;
+	type BlockWeights = ();
 	type Accuracy = Perbill;
 	type DataProvider = Staking;
 }
 
 impl pallet_staking::Config for Test {
+	const MAX_NOMINATIONS: u32 = 16;
 	type Currency = Balances;
-	type UnixTime = pallet_timestamp::Module<Self>;
+	type UnixTime = pallet_timestamp::Pallet<Self>;
 	type CurrencyToVote = frame_support::traits::SaturatingCurrencyToVote;
 	type RewardRemainder = ();
 	type Event = Event;
@@ -169,15 +171,9 @@ impl pallet_staking::Config for Test {
 	type SlashCancelOrigin = frame_system::EnsureRoot<Self::AccountId>;
 	type BondingDuration = ();
 	type SessionInterface = Self;
-	type RewardCurve = RewardCurve;
+	type EraPayout = pallet_staking::ConvertCurve<RewardCurve>;
 	type NextNewSession = Session;
-	type ElectionLookahead = ();
-	type Call = Call;
 	type MaxNominatorRewardedPerValidator = MaxNominatorRewardedPerValidator;
-	type UnsignedPriority = ();
-	type MaxIterations = ();
-	type MinSolutionScoreBump = ();
-	type OffchainSolutionWeightLimit = ();
 	type ElectionProvider = onchain::OnChainSequentialPhragmen<Self>;
 	type WeightInfo = ();
 }
@@ -219,13 +215,13 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic
 	{
-		System: system::{Module, Call, Event<T>},
-		Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
-		Staking: pallet_staking::{Module, Call, Config<T>, Storage, Event<T>, ValidateUnsigned},
-		Session: pallet_session::{Module, Call, Storage, Event, Config<T>},
-		ImOnline: pallet_im_online::{Module, Call, Storage, Event<T>, ValidateUnsigned, Config<T>},
-		Offences: pallet_offences::{Module, Call, Storage, Event},
-		Historical: pallet_session_historical::{Module},
+		System: system::{Pallet, Call, Event<T>},
+		Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
+		Staking: pallet_staking::{Pallet, Call, Config<T>, Storage, Event<T>},
+		Session: pallet_session::{Pallet, Call, Storage, Event, Config<T>},
+		ImOnline: pallet_im_online::{Pallet, Call, Storage, Event<T>, ValidateUnsigned, Config<T>},
+		Offences: pallet_offences::{Pallet, Call, Storage, Event},
+		Historical: pallet_session_historical::{Pallet},
 	}
 );
 
diff --git a/frame/offences/src/mock.rs b/frame/offences/src/mock.rs
index c47a9cf943c18..ab45bb0837b56 100644
--- a/frame/offences/src/mock.rs
+++ b/frame/offences/src/mock.rs
@@ -91,8 +91,8 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Offences: offences::{Module, Call, Storage, Event},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Offences: offences::{Pallet, Call, Storage, Event},
 	}
 );
 
diff --git a/frame/proxy/src/benchmarking.rs b/frame/proxy/src/benchmarking.rs
index 130c980011871..4027fcbafa0d6 100644
--- a/frame/proxy/src/benchmarking.rs
+++ b/frame/proxy/src/benchmarking.rs
@@ -23,12 +23,12 @@ use super::*;
 use frame_system::{RawOrigin, EventRecord};
 use frame_benchmarking::{benchmarks, account, whitelisted_caller, impl_benchmark_test_suite};
 use sp_runtime::traits::Bounded;
-use crate::Module as Proxy;
+use crate::Pallet as Proxy;
 
 const SEED: u32 = 0;
 
 fn assert_last_event<T: Config>(generic_event: <T as Config>::Event) {
-	let events = frame_system::Module::<T>::events();
+	let events = frame_system::Pallet::<T>::events();
 	let system_event: <T as frame_system::Config>::Event = generic_event.into();
 	// compare to the last event record
 	let EventRecord { event, .. } = &events[events.len() - 1];
@@ -90,7 +90,7 @@ benchmarks! {
 		let call: <T as Config>::Call = frame_system::Call::<T>::remark(vec![]).into();
 	}: _(RawOrigin::Signed(caller), real, Some(T::ProxyType::default()), Box::new(call))
 	verify {
-		assert_last_event::<T>(RawEvent::ProxyExecuted(Ok(())).into())
+		assert_last_event::<T>(Event::ProxyExecuted(Ok(())).into())
 	}
 
 	proxy_announced {
@@ -111,7 +111,7 @@ benchmarks! {
 		add_announcements::<T>(a, Some(delegate.clone()), None)?;
 	}: _(RawOrigin::Signed(caller), delegate, real, Some(T::ProxyType::default()), Box::new(call))
 	verify {
-		assert_last_event::<T>(RawEvent::ProxyExecuted(Ok(())).into())
+		assert_last_event::<T>(Event::ProxyExecuted(Ok(())).into())
 	}
 
 	remove_announcement {
@@ -169,7 +169,7 @@ benchmarks! {
 		let call_hash = T::CallHasher::hash_of(&call);
 	}: _(RawOrigin::Signed(caller.clone()), real.clone(), call_hash)
 	verify {
-		assert_last_event::<T>(RawEvent::Announced(real, caller, call_hash).into());
+		assert_last_event::<T>(Event::Announced(real, caller, call_hash).into());
 	}
 
 	add_proxy {
@@ -219,8 +219,8 @@ benchmarks! {
 		0
 	)
 	verify {
-		let anon_account = Module::<T>::anonymous_account(&caller, &T::ProxyType::default(), 0, None);
-		assert_last_event::<T>(RawEvent::AnonymousCreated(
+		let anon_account = Pallet::<T>::anonymous_account(&caller, &T::ProxyType::default(), 0, None);
+		assert_last_event::<T>(Event::AnonymousCreated(
 			anon_account,
 			caller,
 			T::ProxyType::default(),
@@ -233,15 +233,15 @@ benchmarks! {
 
 		let caller: T::AccountId = whitelisted_caller();
 		T::Currency::make_free_balance_be(&caller, BalanceOf::<T>::max_value());
-		Module::<T>::anonymous(
+		Pallet::<T>::anonymous(
 			RawOrigin::Signed(whitelisted_caller()).into(),
 			T::ProxyType::default(),
 			T::BlockNumber::zero(),
 			0
 		)?;
-		let height = system::Module::<T>::block_number();
-		let ext_index = system::Module::<T>::extrinsic_index().unwrap_or(0);
-		let anon = Module::<T>::anonymous_account(&caller, &T::ProxyType::default(), 0, None);
+		let height = system::Pallet::<T>::block_number();
+		let ext_index = system::Pallet::<T>::extrinsic_index().unwrap_or(0);
+		let anon = Pallet::<T>::anonymous_account(&caller, &T::ProxyType::default(), 0, None);
 
 		add_proxies::<T>(p, Some(anon.clone()))?;
 		ensure!(Proxies::<T>::contains_key(&anon), "anon proxy not created");
diff --git a/frame/proxy/src/lib.rs b/frame/proxy/src/lib.rs
index 1e5aaadcc62d3..5e63e0cd8d3d9 100644
--- a/frame/proxy/src/lib.rs
+++ b/frame/proxy/src/lib.rs
@@ -15,25 +15,16 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//! # Proxy Module
-//! A module allowing accounts to give permission to other accounts to dispatch types of calls from
+//! # Proxy Pallet
+//! A pallet allowing accounts to give permission to other accounts to dispatch types of calls from
 //! their signed origin.
 //!
-//! The accounts to which permission is delegated may be requied to announce the action that they
+//! The accounts to which permission is delegated may be required to announce the action that they
 //! wish to execute some duration prior to execution happens. In this case, the target account may
 //! reject the announcement and in doing so, veto the execution.
 //!
-//! - [`proxy::Config`](./trait.Config.html)
-//! - [`Call`](./enum.Call.html)
-//!
-//! ## Overview
-//!
-//! ## Interface
-//!
-//! ### Dispatchable Functions
-//!
-//! [`Call`]: ./enum.Call.html
-//! [`Config`]: ./trait.Config.html
+//! - [`Config`]
+//! - [`Call`]
 
 // Ensure we're `no_std` when compiling for Wasm.
 #![cfg_attr(not(feature = "std"), no_std)]
@@ -45,73 +36,25 @@ pub mod weights;
 use sp_std::prelude::*;
 use codec::{Encode, Decode};
 use sp_io::hashing::blake2_256;
-use sp_runtime::{DispatchResult, traits::{Dispatchable, Zero, Hash, Member, Saturating}};
+use sp_runtime::{
+	DispatchResult,
+	traits::{Dispatchable, Zero, Hash, Saturating}
+};
 use frame_support::{
-	decl_module, decl_event, decl_error, decl_storage, Parameter, ensure, RuntimeDebug, traits::{
-		Get, ReservableCurrency, Currency, InstanceFilter, OriginTrait, IsType, IsSubType,
-	}, weights::{Weight, GetDispatchInfo}, dispatch::PostDispatchInfo, storage::IterableStorageMap,
+		RuntimeDebug, ensure,
+		dispatch::{DispatchResultWithPostInfo, PostDispatchInfo},
+		traits::{Get, ReservableCurrency, Currency, InstanceFilter, OriginTrait, IsType, IsSubType},
+		weights::{Weight, GetDispatchInfo}
 };
-use frame_system::{self as system, ensure_signed};
+use frame_system::{self as system};
 use frame_support::dispatch::DispatchError;
 pub use weights::WeightInfo;
 
-type BalanceOf<T> = <<T as Config>::Currency as Currency<<T as frame_system::Config>::AccountId>>::Balance;
-
-/// Configuration trait.
-pub trait Config: frame_system::Config {
-	/// The overarching event type.
-	type Event: From<Event<Self>> + Into<<Self as frame_system::Config>::Event>;
+pub use pallet::*;
 
-	/// The overarching call type.
-	type Call: Parameter + Dispatchable<Origin=Self::Origin, PostInfo=PostDispatchInfo>
-		+ GetDispatchInfo + From<frame_system::Call<Self>> + IsSubType<Call<Self>>
-		+ IsType<<Self as frame_system::Config>::Call>;
-
-	/// The currency mechanism.
-	type Currency: ReservableCurrency<Self::AccountId>;
-
-	/// A kind of proxy; specified with the proxy and passed in to the `IsProxyable` fitler.
-	/// The instance filter determines whether a given call may be proxied under this type.
-	///
-	/// IMPORTANT: `Default` must be provided and MUST BE the the *most permissive* value.
-	type ProxyType: Parameter + Member + Ord + PartialOrd + InstanceFilter<<Self as Config>::Call>
-		+ Default;
-
-	/// The base amount of currency needed to reserve for creating a proxy.
-	///
-	/// This is held for an additional storage item whose value size is
-	/// `sizeof(Balance)` bytes and whose key size is `sizeof(AccountId)` bytes.
-	type ProxyDepositBase: Get<BalanceOf<Self>>;
-
-	/// The amount of currency needed per proxy added.
-	///
-	/// This is held for adding 32 bytes plus an instance of `ProxyType` more into a pre-existing
-	/// storage value.
-	type ProxyDepositFactor: Get<BalanceOf<Self>>;
-
-	/// The maximum amount of proxies allowed for a single account.
-	type MaxProxies: Get<u16>;
-
-	/// Weight information for extrinsics in this pallet.
-	type WeightInfo: WeightInfo;
-
-	/// The maximum amount of time-delayed announcements that are allowed to be pending.
-	type MaxPending: Get<u32>;
-
-	/// The type of hash used for hashing the call.
-	type CallHasher: Hash;
-
-	/// The base amount of currency needed to reserve for creating an announcement.
-	///
-	/// This is held when a new storage item holding a `Balance` is created (typically 16 bytes).
-	type AnnouncementDepositBase: Get<BalanceOf<Self>>;
+type CallHashOf<T> = <<T as Config>::CallHasher as Hash>::Output;
 
-	/// The amount of currency needed per announcement made.
-	///
-	/// This is held for adding an `AccountId`, `Hash` and `BlockNumber` (typically 68 bytes)
-	/// into a pre-existing storage value.
-	type AnnouncementDepositFactor: Get<BalanceOf<Self>>;
-}
+type BalanceOf<T> = <<T as Config>::Currency as Currency<<T as frame_system::Config>::AccountId>>::Balance;
 
 /// The parameters under which a particular account has a proxy relationship with some other
 /// account.
@@ -137,84 +80,85 @@ pub struct Announcement<AccountId, Hash, BlockNumber> {
 	height: BlockNumber,
 }
 
-type CallHashOf<T> = <<T as Config>::CallHasher as Hash>::Output;
-
-decl_storage! {
-	trait Store for Module<T: Config> as Proxy {
-		/// The set of account proxies. Maps the account which has delegated to the accounts
-		/// which are being delegated to, together with the amount held on deposit.
-		pub Proxies get(fn proxies): map hasher(twox_64_concat) T::AccountId
-			=> (Vec<ProxyDefinition<T::AccountId, T::ProxyType, T::BlockNumber>>, BalanceOf<T>);
+#[frame_support::pallet]
+pub mod pallet {
+	use frame_support::pallet_prelude::*;
+	use frame_system::pallet_prelude::*;
+	use super::{*, DispatchResult};
 
-		/// The announcements made by the proxy (key).
-		pub Announcements get(fn announcements): map hasher(twox_64_concat) T::AccountId
-			=> (Vec<Announcement<T::AccountId, CallHashOf<T>, T::BlockNumber>>, BalanceOf<T>);
-	}
-}
+	#[pallet::pallet]
+	#[pallet::generate_store(pub(super) trait Store)]
+	pub struct Pallet<T>(_);
 
-decl_error! {
-	pub enum Error for Module<T: Config> {
-		/// There are too many proxies registered or too many announcements pending.
-		TooMany,
-		/// Proxy registration not found.
-		NotFound,
-		/// Sender is not a proxy of the account to be proxied.
-		NotProxy,
-		/// A call which is incompatible with the proxy type's filter was attempted.
-		Unproxyable,
-		/// Account is already a proxy.
-		Duplicate,
-		/// Call may not be made by proxy because it may escalate its privileges.
-		NoPermission,
-		/// Announcement, if made at all, was made too recently.
-		Unannounced,
-		/// Cannot add self as proxy.
-		NoSelfProxy,
-	}
-}
+	/// Configuration trait.
+	#[pallet::config]
+	pub trait Config: frame_system::Config {
+		/// The overarching event type.
+		type Event: From<Event<Self>> + IsType<<Self as frame_system::Config>::Event>;
 
-decl_event! {
-	/// Events type.
-	pub enum Event<T> where
-		AccountId = <T as frame_system::Config>::AccountId,
-		ProxyType = <T as Config>::ProxyType,
-		Hash = CallHashOf<T>,
-	{
-		/// A proxy was executed correctly, with the given \[result\].
-		ProxyExecuted(DispatchResult),
-		/// Anonymous account has been created by new proxy with given
-		/// disambiguation index and proxy type. \[anonymous, who, proxy_type, disambiguation_index\]
-		AnonymousCreated(AccountId, AccountId, ProxyType, u16),
-		/// An announcement was placed to make a call in the future. \[real, proxy, call_hash\]
-		Announced(AccountId, AccountId, Hash),
-	}
-}
+		/// The overarching call type.
+		type Call: Parameter + Dispatchable<Origin=Self::Origin, PostInfo=PostDispatchInfo>
+			+ GetDispatchInfo + From<frame_system::Call<Self>> + IsSubType<Call<Self>>
+			+ IsType<<Self as frame_system::Config>::Call>;
 
-decl_module! {
-	pub struct Module<T: Config> for enum Call where origin: T::Origin {
-		type Error = Error<T>;
+		/// The currency mechanism.
+		type Currency: ReservableCurrency<Self::AccountId>;
 
-		/// Deposit one of this module's events by using the default implementation.
-		fn deposit_event() = default;
+		/// A kind of proxy; specified with the proxy and passed in to the `IsProxyable` fitler.
+		/// The instance filter determines whether a given call may be proxied under this type.
+		///
+		/// IMPORTANT: `Default` must be provided and MUST BE the the *most permissive* value.
+		type ProxyType: Parameter + Member + Ord + PartialOrd + InstanceFilter<<Self as Config>::Call>
+			+ Default;
 
 		/// The base amount of currency needed to reserve for creating a proxy.
-		const ProxyDepositBase: BalanceOf<T> = T::ProxyDepositBase::get();
+		///
+		/// This is held for an additional storage item whose value size is
+		/// `sizeof(Balance)` bytes and whose key size is `sizeof(AccountId)` bytes.
+		#[pallet::constant]
+		type ProxyDepositBase: Get<BalanceOf<Self>>;
 
 		/// The amount of currency needed per proxy added.
-		const ProxyDepositFactor: BalanceOf<T> = T::ProxyDepositFactor::get();
+		///
+		/// This is held for adding 32 bytes plus an instance of `ProxyType` more into a pre-existing
+		/// storage value. Thus, when configuring `ProxyDepositFactor` one should take into account
+		/// `32 + proxy_type.encode().len()` bytes of data.
+		#[pallet::constant]
+		type ProxyDepositFactor: Get<BalanceOf<Self>>;
 
 		/// The maximum amount of proxies allowed for a single account.
-		const MaxProxies: u16 = T::MaxProxies::get();
+		#[pallet::constant]
+		type MaxProxies: Get<u16>;
+
+		/// Weight information for extrinsics in this pallet.
+		type WeightInfo: WeightInfo;
 
-		/// `MaxPending` metadata shadow.
-		const MaxPending: u32 = T::MaxPending::get();
+		/// The maximum amount of time-delayed announcements that are allowed to be pending.
+		#[pallet::constant]
+		type MaxPending: Get<u32>;
+
+		/// The type of hash used for hashing the call.
+		type CallHasher: Hash;
+
+		/// The base amount of currency needed to reserve for creating an announcement.
+		///
+		/// This is held when a new storage item holding a `Balance` is created (typically 16 bytes).
+		#[pallet::constant]
+		type AnnouncementDepositBase: Get<BalanceOf<Self>>;
 
-		/// `AnnouncementDepositBase` metadata shadow.
-		const AnnouncementDepositBase: BalanceOf<T> = T::AnnouncementDepositBase::get();
+		/// The amount of currency needed per announcement made.
+		///
+		/// This is held for adding an `AccountId`, `Hash` and `BlockNumber` (typically 68 bytes)
+		/// into a pre-existing storage value.
+		#[pallet::constant]
+		type AnnouncementDepositFactor: Get<BalanceOf<Self>>;
+	}
 
-		/// `AnnouncementDepositFactor` metadata shadow.
-		const AnnouncementDepositFactor: BalanceOf<T> = T::AnnouncementDepositFactor::get();
+	#[pallet::hooks]
+	impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {}
 
+	#[pallet::call]
+	impl<T: Config> Pallet<T> {
 		/// Dispatch the given `call` from an account that the sender is authorised for through
 		/// `add_proxy`.
 		///
@@ -230,24 +174,27 @@ decl_module! {
 		/// # <weight>
 		/// Weight is a function of the number of proxies the user has (P).
 		/// # </weight>
-		#[weight = {
+		#[pallet::weight({
 			let di = call.get_dispatch_info();
 			(T::WeightInfo::proxy(T::MaxProxies::get().into())
 				.saturating_add(di.weight)
 				 // AccountData for inner call origin accountdata.
 				.saturating_add(T::DbWeight::get().reads_writes(1, 1)),
 			di.class)
-		}]
-		fn proxy(origin,
+		})]
+		pub(super) fn proxy(
+			origin: OriginFor<T>,
 			real: T::AccountId,
 			force_proxy_type: Option<T::ProxyType>,
 			call: Box<<T as Config>::Call>,
-		) {
+		) -> DispatchResultWithPostInfo {
 			let who = ensure_signed(origin)?;
 			let def = Self::find_proxy(&real, &who, force_proxy_type)?;
 			ensure!(def.delay.is_zero(), Error::<T>::Unannounced);
 
 			Self::do_proxy(def, real, *call);
+
+			Ok(().into())
 		}
 
 		/// Register a proxy account for the sender that is able to make calls on its behalf.
@@ -263,12 +210,13 @@ decl_module! {
 		/// # <weight>
 		/// Weight is a function of the number of proxies the user has (P).
 		/// # </weight>
-		#[weight = T::WeightInfo::add_proxy(T::MaxProxies::get().into())]
-		fn add_proxy(origin,
+		#[pallet::weight(T::WeightInfo::add_proxy(T::MaxProxies::get().into()))]
+		pub(super) fn add_proxy(
+			origin: OriginFor<T>,
 			delegate: T::AccountId,
 			proxy_type: T::ProxyType,
 			delay: T::BlockNumber,
-		) -> DispatchResult {
+		) -> DispatchResultWithPostInfo {
 			let who = ensure_signed(origin)?;
 			Self::add_proxy_delegate(&who, delegate, proxy_type, delay)
 		}
@@ -284,12 +232,13 @@ decl_module! {
 		/// # <weight>
 		/// Weight is a function of the number of proxies the user has (P).
 		/// # </weight>
-		#[weight = T::WeightInfo::remove_proxy(T::MaxProxies::get().into())]
-		fn remove_proxy(origin,
+		#[pallet::weight(T::WeightInfo::remove_proxy(T::MaxProxies::get().into()))]
+		pub(super) fn remove_proxy(
+			origin: OriginFor<T>,
 			delegate: T::AccountId,
 			proxy_type: T::ProxyType,
 			delay: T::BlockNumber,
-		) -> DispatchResult {
+		) -> DispatchResultWithPostInfo {
 			let who = ensure_signed(origin)?;
 			Self::remove_proxy_delegate(&who, delegate, proxy_type, delay)
 		}
@@ -304,11 +253,13 @@ decl_module! {
 		/// # <weight>
 		/// Weight is a function of the number of proxies the user has (P).
 		/// # </weight>
-		#[weight = T::WeightInfo::remove_proxies(T::MaxProxies::get().into())]
-		fn remove_proxies(origin) {
+		#[pallet::weight(T::WeightInfo::remove_proxies(T::MaxProxies::get().into()))]
+		pub(super) fn remove_proxies(origin: OriginFor<T>) -> DispatchResultWithPostInfo {
 			let who = ensure_signed(origin)?;
 			let (_, old_deposit) = Proxies::<T>::take(&who);
 			T::Currency::unreserve(&who, old_deposit);
+
+			Ok(().into())
 		}
 
 		/// Spawn a fresh new account that is guaranteed to be otherwise inaccessible, and
@@ -334,8 +285,13 @@ decl_module! {
 		/// Weight is a function of the number of proxies the user has (P).
 		/// # </weight>
 		/// TODO: Might be over counting 1 read
-		#[weight = T::WeightInfo::anonymous(T::MaxProxies::get().into())]
-		fn anonymous(origin, proxy_type: T::ProxyType, delay: T::BlockNumber, index: u16) {
+		#[pallet::weight(T::WeightInfo::anonymous(T::MaxProxies::get().into()))]
+		pub(super) fn anonymous(
+			origin: OriginFor<T>,
+			proxy_type: T::ProxyType,
+			delay: T::BlockNumber,
+			index: u16
+		) -> DispatchResultWithPostInfo {
 			let who = ensure_signed(origin)?;
 
 			let anonymous = Self::anonymous_account(&who, &proxy_type, index, None);
@@ -348,7 +304,9 @@ decl_module! {
 				delay,
 			};
 			Proxies::<T>::insert(&anonymous, (vec![proxy_def], deposit));
-			Self::deposit_event(RawEvent::AnonymousCreated(anonymous, who, proxy_type, index));
+			Self::deposit_event(Event::AnonymousCreated(anonymous, who, proxy_type, index));
+
+			Ok(().into())
 		}
 
 		/// Removes a previously spawned anonymous proxy.
@@ -371,14 +329,15 @@ decl_module! {
 		/// # <weight>
 		/// Weight is a function of the number of proxies the user has (P).
 		/// # </weight>
-		#[weight = T::WeightInfo::kill_anonymous(T::MaxProxies::get().into())]
-		fn kill_anonymous(origin,
+		#[pallet::weight(T::WeightInfo::kill_anonymous(T::MaxProxies::get().into()))]
+		pub(super) fn kill_anonymous(
+			origin: OriginFor<T>,
 			spawner: T::AccountId,
 			proxy_type: T::ProxyType,
 			index: u16,
-			#[compact] height: T::BlockNumber,
-			#[compact] ext_index: u32,
-		) {
+			#[pallet::compact] height: T::BlockNumber,
+			#[pallet::compact] ext_index: u32,
+		) -> DispatchResultWithPostInfo {
 			let who = ensure_signed(origin)?;
 
 			let when = (height, ext_index);
@@ -387,6 +346,8 @@ decl_module! {
 
 			let (_, deposit) = Proxies::<T>::take(&who);
 			T::Currency::unreserve(&spawner, deposit);
+
+			Ok(().into())
 		}
 
 		/// Publish the hash of a proxy-call that will be made in the future.
@@ -410,8 +371,12 @@ decl_module! {
 		/// - A: the number of announcements made.
 		/// - P: the number of proxies the user has.
 		/// # </weight>
-		#[weight = T::WeightInfo::announce(T::MaxPending::get(), T::MaxProxies::get().into())]
-		fn announce(origin, real: T::AccountId, call_hash: CallHashOf<T>) {
+		#[pallet::weight(T::WeightInfo::announce(T::MaxPending::get(), T::MaxProxies::get().into()))]
+		pub(super) fn announce(
+			origin: OriginFor<T>,
+			real: T::AccountId,
+			call_hash: CallHashOf<T>
+		) -> DispatchResultWithPostInfo{
 			let who = ensure_signed(origin)?;
 			Proxies::<T>::get(&real).0.into_iter()
 				.find(|x| &x.delegate == &who)
@@ -420,7 +385,7 @@ decl_module! {
 			let announcement = Announcement {
 				real: real.clone(),
 				call_hash: call_hash.clone(),
-				height: system::Module::<T>::block_number(),
+				height: system::Pallet::<T>::block_number(),
 			};
 
 			Announcements::<T>::try_mutate(&who, |(ref mut pending, ref mut deposit)| {
@@ -435,7 +400,9 @@ decl_module! {
 				).map(|d| d.expect("Just pushed; pending.len() > 0; rejig_deposit returns Some; qed"))
 				.map(|d| *deposit = d)
 			})?;
-			Self::deposit_event(RawEvent::Announced(real, who, call_hash));
+			Self::deposit_event(Event::Announced(real, who, call_hash));
+
+			Ok(().into())
 		}
 
 		/// Remove a given announcement.
@@ -454,10 +421,18 @@ decl_module! {
 		/// - A: the number of announcements made.
 		/// - P: the number of proxies the user has.
 		/// # </weight>
-		#[weight = T::WeightInfo::remove_announcement(T::MaxPending::get(), T::MaxProxies::get().into())]
-		fn remove_announcement(origin, real: T::AccountId, call_hash: CallHashOf<T>) {
+		#[pallet::weight(
+			T::WeightInfo::remove_announcement(T::MaxPending::get(), T::MaxProxies::get().into())
+		)]
+		pub(super) fn remove_announcement(
+			origin: OriginFor<T>,
+			real: T::AccountId,
+			call_hash: CallHashOf<T>
+		) -> DispatchResultWithPostInfo {
 			let who = ensure_signed(origin)?;
 			Self::edit_announcements(&who, |ann| ann.real != real || ann.call_hash != call_hash)?;
+
+			Ok(().into())
 		}
 
 		/// Remove the given announcement of a delegate.
@@ -476,13 +451,21 @@ decl_module! {
 		/// - A: the number of announcements made.
 		/// - P: the number of proxies the user has.
 		/// # </weight>
-		#[weight = T::WeightInfo::reject_announcement(T::MaxPending::get(), T::MaxProxies::get().into())]
-		fn reject_announcement(origin, delegate: T::AccountId, call_hash: CallHashOf<T>) {
+		#[pallet::weight(
+			T::WeightInfo::reject_announcement(T::MaxPending::get(), T::MaxProxies::get().into())
+		)]
+		pub(super) fn reject_announcement(
+			origin: OriginFor<T>,
+			delegate: T::AccountId,
+			call_hash: CallHashOf<T>
+		) -> DispatchResultWithPostInfo {
 			let who = ensure_signed(origin)?;
 			Self::edit_announcements(&delegate, |ann| ann.real != who || ann.call_hash != call_hash)?;
+
+			Ok(().into())
 		}
 
-		/// Dispatch the given `call` from an account that the sender is authorised for through
+		/// Dispatch the given `call` from an account that the sender is authorized for through
 		/// `add_proxy`.
 		///
 		/// Removes any corresponding announcement(s).
@@ -499,35 +482,100 @@ decl_module! {
 		/// - A: the number of announcements made.
 		/// - P: the number of proxies the user has.
 		/// # </weight>
-		#[weight = {
+		#[pallet::weight({
 			let di = call.get_dispatch_info();
 			(T::WeightInfo::proxy_announced(T::MaxPending::get(), T::MaxProxies::get().into())
 				.saturating_add(di.weight)
 				 // AccountData for inner call origin accountdata.
 				.saturating_add(T::DbWeight::get().reads_writes(1, 1)),
 			di.class)
-		}]
-		fn proxy_announced(origin,
+		})]
+		pub(super) fn proxy_announced(
+			origin: OriginFor<T>,
 			delegate: T::AccountId,
 			real: T::AccountId,
 			force_proxy_type: Option<T::ProxyType>,
 			call: Box<<T as Config>::Call>,
-		) {
+		) -> DispatchResultWithPostInfo {
 			ensure_signed(origin)?;
 			let def = Self::find_proxy(&real, &delegate, force_proxy_type)?;
 
 			let call_hash = T::CallHasher::hash_of(&call);
-			let now = system::Module::<T>::block_number();
+			let now = system::Pallet::<T>::block_number();
 			Self::edit_announcements(&delegate, |ann|
 				ann.real != real || ann.call_hash != call_hash || now.saturating_sub(ann.height) < def.delay
 			).map_err(|_| Error::<T>::Unannounced)?;
 
 			Self::do_proxy(def, real, *call);
+
+			Ok(().into())
 		}
 	}
+
+	#[pallet::event]
+	#[pallet::metadata(T::AccountId = "AccountId", T::ProxyType = "ProxyType", CallHashOf<T> = "Hash")]
+	#[pallet::generate_deposit(pub(super) fn deposit_event)]
+	pub enum Event<T: Config>
+	{
+		/// A proxy was executed correctly, with the given \[result\].
+		ProxyExecuted(DispatchResult),
+		/// Anonymous account has been created by new proxy with given
+		/// disambiguation index and proxy type. \[anonymous, who, proxy_type, disambiguation_index\]
+		AnonymousCreated(T::AccountId, T::AccountId, T::ProxyType, u16),
+		/// An announcement was placed to make a call in the future. \[real, proxy, call_hash\]
+		Announced(T::AccountId, T::AccountId, CallHashOf<T>),
+	}
+
+	/// Old name generated by `decl_event`.
+	#[deprecated(note="use `Event` instead")]
+	pub type RawEvent<T> = Event<T>;
+
+	 #[pallet::error]
+	pub enum Error<T> {
+		/// There are too many proxies registered or too many announcements pending.
+		TooMany,
+		/// Proxy registration not found.
+		NotFound,
+		/// Sender is not a proxy of the account to be proxied.
+		NotProxy,
+		/// A call which is incompatible with the proxy type's filter was attempted.
+		Unproxyable,
+		/// Account is already a proxy.
+		Duplicate,
+		/// Call may not be made by proxy because it may escalate its privileges.
+		NoPermission,
+		/// Announcement, if made at all, was made too recently.
+		Unannounced,
+		/// Cannot add self as proxy.
+		NoSelfProxy,
+	}
+
+	/// The set of account proxies. Maps the account which has delegated to the accounts
+	/// which are being delegated to, together with the amount held on deposit.
+	#[pallet::storage]
+	#[pallet::getter(fn proxies)]
+	pub type Proxies<T: Config> = StorageMap<
+		_,
+		Twox64Concat,
+		T::AccountId,
+		(Vec<ProxyDefinition<T::AccountId, T::ProxyType, T::BlockNumber>>, BalanceOf<T>),
+		ValueQuery
+	>;
+
+	/// The announcements made by the proxy (key).
+	#[pallet::storage]
+	#[pallet::getter(fn announcements)]
+	pub type Announcements<T: Config> = StorageMap<
+		_,
+		Twox64Concat,
+		T::AccountId,
+		(Vec<Announcement<T::AccountId, CallHashOf<T>, T::BlockNumber>>, BalanceOf<T>),
+		ValueQuery
+	>;
+
 }
 
-impl<T: Config> Module<T> {
+impl<T: Config> Pallet<T> {
 
 	/// Calculate the address of an anonymous account.
 	///
@@ -547,8 +595,8 @@ impl<T: Config> Module<T> {
 		maybe_when: Option<(T::BlockNumber, u32)>,
 	) -> T::AccountId {
 		let (height, ext_index) = maybe_when.unwrap_or_else(|| (
-			system::Module::<T>::block_number(),
-			system::Module::<T>::extrinsic_index().unwrap_or_default()
+			system::Pallet::<T>::block_number(),
+			system::Pallet::<T>::extrinsic_index().unwrap_or_default()
 		));
 		let entropy = (b"modlpy/proxy____", who, height, ext_index, proxy_type, index)
 			.using_encoded(blake2_256);
@@ -568,7 +616,7 @@ impl<T: Config> Module<T> {
 		delegatee: T::AccountId,
 		proxy_type: T::ProxyType,
 		delay: T::BlockNumber,
-	) -> DispatchResult {
+	) -> DispatchResultWithPostInfo {
 		ensure!(delegator != &delegatee, Error::<T>::NoSelfProxy);
 		Proxies::<T>::try_mutate(delegator, |(ref mut proxies, ref mut deposit)| {
 			ensure!(proxies.len() < T::MaxProxies::get() as usize, Error::<T>::TooMany);
@@ -582,7 +630,7 @@ impl<T: Config> Module<T> {
 				T::Currency::unreserve(delegator, *deposit - new_deposit);
 			}
 			*deposit = new_deposit;
-			Ok(())
+			Ok(().into())
 		})
 	}
 
@@ -599,7 +647,7 @@ impl<T: Config> Module<T> {
 		delegatee: T::AccountId,
 		proxy_type: T::ProxyType,
 		delay: T::BlockNumber,
-	) -> DispatchResult {
+	) -> DispatchResultWithPostInfo {
 		Proxies::<T>::try_mutate_exists(delegator, |x| {
 			let (mut proxies, old_deposit) = x.take().ok_or(Error::<T>::NotFound)?;
 			let proxy_def = ProxyDefinition { delegate: delegatee, proxy_type, delay };
@@ -614,7 +662,7 @@ impl<T: Config> Module<T> {
 			if !proxies.is_empty() {
 				*x = Some((proxies, new_deposit))
 			}
-			Ok(())
+			Ok(().into())
 		})
 	}
 
@@ -701,7 +749,7 @@ impl<T: Config> Module<T> {
 			}
 		});
 		let e = call.dispatch(origin);
-		Self::deposit_event(RawEvent::ProxyExecuted(e.map(|_| ()).map_err(|e| e.error)));
+		Self::deposit_event(Event::ProxyExecuted(e.map(|_| ()).map_err(|e| e.error)));
 	}
 }
 
diff --git a/frame/proxy/src/tests.rs b/frame/proxy/src/tests.rs
index b31ef1dfdb2fe..797a5ee3d4694 100644
--- a/frame/proxy/src/tests.rs
+++ b/frame/proxy/src/tests.rs
@@ -38,10 +38,10 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
-		Proxy: proxy::{Module, Call, Storage, Event<T>},
-		Utility: pallet_utility::{Module, Call, Event},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
+		Proxy: proxy::{Pallet, Call, Storage, Event<T>},
+		Utility: pallet_utility::{Pallet, Call, Event},
 	}
 );
 
@@ -150,6 +150,7 @@ use pallet_balances::Error as BalancesError;
 use pallet_balances::Event as BalancesEvent;
 use pallet_utility::Call as UtilityCall;
 use pallet_utility::Event as UtilityEvent;
+use super::Event as ProxyEvent;
 use super::Call as ProxyCall;
 
 pub fn new_test_ext() -> sp_io::TestExternalities {
@@ -163,7 +164,7 @@ pub fn new_test_ext() -> sp_io::TestExternalities {
 }
 
 fn last_event() -> Event {
-	system::Module::<Test>::events().pop().expect("Event expected").event
+	system::Pallet::<Test>::events().pop().expect("Event expected").event
 }
 
 fn expect_event<E: Into<Event>>(e: E) {
@@ -171,7 +172,7 @@ fn expect_event<E: Into<Event>>(e: E) {
 }
 
 fn last_events(n: usize) -> Vec<Event> {
-	system::Module::<Test>::events().into_iter().rev().take(n).rev().map(|e| e.event).collect()
+	system::Pallet::<Test>::events().into_iter().rev().take(n).rev().map(|e| e.event).collect()
 }
 
 fn expect_events(e: Vec<Event>) {
@@ -270,7 +271,7 @@ fn delayed_requires_pre_announcement() {
 		assert_noop!(Proxy::proxy_announced(Origin::signed(0), 2, 1, None, call.clone()), e);
 		let call_hash = BlakeTwo256::hash_of(&call);
 		assert_ok!(Proxy::announce(Origin::signed(2), 1, call_hash));
-		system::Module::<Test>::set_block_number(2);
+		system::Pallet::<Test>::set_block_number(2);
 		assert_ok!(Proxy::proxy_announced(Origin::signed(0), 2, 1, None, call.clone()));
 	});
 }
@@ -288,7 +289,7 @@ fn proxy_announced_removes_announcement_and_returns_deposit() {
 		let e = Error::<Test>::Unannounced;
 		assert_noop!(Proxy::proxy_announced(Origin::signed(0), 3, 1, None, call.clone()), e);
 
-		system::Module::<Test>::set_block_number(2);
+		system::Pallet::<Test>::set_block_number(2);
 		assert_ok!(Proxy::proxy_announced(Origin::signed(0), 3, 1, None, call.clone()));
 		assert_eq!(Announcements::<Test>::get(3), (vec![Announcement {
 			real: 2,
@@ -309,11 +310,11 @@ fn filtering_works() {
 
 		let call = Box::new(Call::Balances(BalancesCall::transfer(6, 1)));
 		assert_ok!(Proxy::proxy(Origin::signed(2), 1, None, call.clone()));
-		expect_event(RawEvent::ProxyExecuted(Ok(())));
+		expect_event(ProxyEvent::ProxyExecuted(Ok(())));
 		assert_ok!(Proxy::proxy(Origin::signed(3), 1, None, call.clone()));
-		expect_event(RawEvent::ProxyExecuted(Ok(())));
+		expect_event(ProxyEvent::ProxyExecuted(Ok(())));
 		assert_ok!(Proxy::proxy(Origin::signed(4), 1, None, call.clone()));
-		expect_event(RawEvent::ProxyExecuted(Err(DispatchError::BadOrigin)));
+		expect_event(ProxyEvent::ProxyExecuted(Err(DispatchError::BadOrigin)));
 
 		let derivative_id = Utility::derivative_account_id(1, 0);
 		assert!(Balances::mutate_account(&derivative_id, |a| a.free = 1000).is_ok());
@@ -321,42 +322,42 @@ fn filtering_works() {
 
 		let call = Box::new(Call::Utility(UtilityCall::as_derivative(0, inner.clone())));
 		assert_ok!(Proxy::proxy(Origin::signed(2), 1, None, call.clone()));
-		expect_event(RawEvent::ProxyExecuted(Ok(())));
+		expect_event(ProxyEvent::ProxyExecuted(Ok(())));
 		assert_ok!(Proxy::proxy(Origin::signed(3), 1, None, call.clone()));
-		expect_event(RawEvent::ProxyExecuted(Err(DispatchError::BadOrigin)));
+		expect_event(ProxyEvent::ProxyExecuted(Err(DispatchError::BadOrigin)));
 		assert_ok!(Proxy::proxy(Origin::signed(4), 1, None, call.clone()));
-		expect_event(RawEvent::ProxyExecuted(Err(DispatchError::BadOrigin)));
+		expect_event(ProxyEvent::ProxyExecuted(Err(DispatchError::BadOrigin)));
 
 		let call = Box::new(Call::Utility(UtilityCall::batch(vec![*inner])));
 		assert_ok!(Proxy::proxy(Origin::signed(2), 1, None, call.clone()));
-		expect_events(vec![UtilityEvent::BatchCompleted.into(), RawEvent::ProxyExecuted(Ok(())).into()]);
+		expect_events(vec![UtilityEvent::BatchCompleted.into(), ProxyEvent::ProxyExecuted(Ok(())).into()]);
 		assert_ok!(Proxy::proxy(Origin::signed(3), 1, None, call.clone()));
-		expect_event(RawEvent::ProxyExecuted(Err(DispatchError::BadOrigin)));
+		expect_event(ProxyEvent::ProxyExecuted(Err(DispatchError::BadOrigin)));
 		assert_ok!(Proxy::proxy(Origin::signed(4), 1, None, call.clone()));
 		expect_events(vec![
 			UtilityEvent::BatchInterrupted(0, DispatchError::BadOrigin).into(),
-			RawEvent::ProxyExecuted(Ok(())).into(),
+			ProxyEvent::ProxyExecuted(Ok(())).into(),
 		]);
 
 		let inner = Box::new(Call::Proxy(ProxyCall::add_proxy(5, ProxyType::Any, 0)));
 		let call = Box::new(Call::Utility(UtilityCall::batch(vec![*inner])));
 		assert_ok!(Proxy::proxy(Origin::signed(2), 1, None, call.clone()));
-		expect_events(vec![UtilityEvent::BatchCompleted.into(), RawEvent::ProxyExecuted(Ok(())).into()]);
+		expect_events(vec![UtilityEvent::BatchCompleted.into(), ProxyEvent::ProxyExecuted(Ok(())).into()]);
 		assert_ok!(Proxy::proxy(Origin::signed(3), 1, None, call.clone()));
-		expect_event(RawEvent::ProxyExecuted(Err(DispatchError::BadOrigin)));
+		expect_event(ProxyEvent::ProxyExecuted(Err(DispatchError::BadOrigin)));
 		assert_ok!(Proxy::proxy(Origin::signed(4), 1, None, call.clone()));
 		expect_events(vec![
 			UtilityEvent::BatchInterrupted(0, DispatchError::BadOrigin).into(),
-			RawEvent::ProxyExecuted(Ok(())).into(),
+			ProxyEvent::ProxyExecuted(Ok(())).into(),
 		]);
 
 		let call = Box::new(Call::Proxy(ProxyCall::remove_proxies()));
 		assert_ok!(Proxy::proxy(Origin::signed(3), 1, None, call.clone()));
-		expect_event(RawEvent::ProxyExecuted(Err(DispatchError::BadOrigin)));
+		expect_event(ProxyEvent::ProxyExecuted(Err(DispatchError::BadOrigin)));
 		assert_ok!(Proxy::proxy(Origin::signed(4), 1, None, call.clone()));
-		expect_event(RawEvent::ProxyExecuted(Err(DispatchError::BadOrigin)));
+		expect_event(ProxyEvent::ProxyExecuted(Err(DispatchError::BadOrigin)));
 		assert_ok!(Proxy::proxy(Origin::signed(2), 1, None, call.clone()));
-		expect_events(vec![BalancesEvent::<Test>::Unreserved(1, 5).into(), RawEvent::ProxyExecuted(Ok(())).into()]);
+		expect_events(vec![BalancesEvent::<Test>::Unreserved(1, 5).into(), ProxyEvent::ProxyExecuted(Ok(())).into()]);
 	});
 }
 
@@ -411,18 +412,18 @@ fn proxying_works() {
 			Error::<Test>::NotProxy
 		);
 		assert_ok!(Proxy::proxy(Origin::signed(2), 1, None, call.clone()));
-		expect_event(RawEvent::ProxyExecuted(Ok(())));
+		expect_event(ProxyEvent::ProxyExecuted(Ok(())));
 		assert_eq!(Balances::free_balance(6), 1);
 
 		let call = Box::new(Call::System(SystemCall::set_code(vec![])));
 		assert_ok!(Proxy::proxy(Origin::signed(3), 1, None, call.clone()));
-		expect_event(RawEvent::ProxyExecuted(Err(DispatchError::BadOrigin)));
+		expect_event(ProxyEvent::ProxyExecuted(Err(DispatchError::BadOrigin)));
 
 		let call = Box::new(Call::Balances(BalancesCall::transfer_keep_alive(6, 1)));
 		assert_ok!(Call::Proxy(super::Call::proxy(1, None, call.clone())).dispatch(Origin::signed(2)));
-		expect_event(RawEvent::ProxyExecuted(Err(DispatchError::BadOrigin)));
+		expect_event(ProxyEvent::ProxyExecuted(Err(DispatchError::BadOrigin)));
 		assert_ok!(Proxy::proxy(Origin::signed(3), 1, None, call.clone()));
-		expect_event(RawEvent::ProxyExecuted(Ok(())));
+		expect_event(ProxyEvent::ProxyExecuted(Ok(())));
 		assert_eq!(Balances::free_balance(6), 2);
 	});
 }
@@ -432,7 +433,7 @@ fn anonymous_works() {
 	new_test_ext().execute_with(|| {
 		assert_ok!(Proxy::anonymous(Origin::signed(1), ProxyType::Any, 0, 0));
 		let anon = Proxy::anonymous_account(&1, &ProxyType::Any, 0, None);
-		expect_event(RawEvent::AnonymousCreated(anon.clone(), 1, ProxyType::Any, 0));
+		expect_event(ProxyEvent::AnonymousCreated(anon.clone(), 1, ProxyType::Any, 0));
 
 		// other calls to anonymous allowed as long as they're not exactly the same.
 		assert_ok!(Proxy::anonymous(Origin::signed(1), ProxyType::JustTransfer, 0, 0));
@@ -449,13 +450,13 @@ fn anonymous_works() {
 		let call = Box::new(Call::Balances(BalancesCall::transfer(6, 1)));
 		assert_ok!(Balances::transfer(Origin::signed(3), anon, 5));
 		assert_ok!(Proxy::proxy(Origin::signed(1), anon, None, call));
-		expect_event(RawEvent::ProxyExecuted(Ok(())));
+		expect_event(ProxyEvent::ProxyExecuted(Ok(())));
 		assert_eq!(Balances::free_balance(6), 1);
 
 		let call = Box::new(Call::Proxy(ProxyCall::kill_anonymous(1, ProxyType::Any, 0, 1, 0)));
 		assert_ok!(Proxy::proxy(Origin::signed(2), anon2, None, call.clone()));
 		let de = DispatchError::from(Error::<Test>::NoPermission).stripped();
-		expect_event(RawEvent::ProxyExecuted(Err(de)));
+		expect_event(ProxyEvent::ProxyExecuted(Err(de)));
 		assert_noop!(
 			Proxy::kill_anonymous(Origin::signed(1), 1, ProxyType::Any, 0, 1, 0),
 			Error::<Test>::NoPermission
diff --git a/frame/randomness-collective-flip/src/lib.rs b/frame/randomness-collective-flip/src/lib.rs
index 57e95ccb141df..5ef76a33c21f4 100644
--- a/frame/randomness-collective-flip/src/lib.rs
+++ b/frame/randomness-collective-flip/src/lib.rs
@@ -25,7 +25,7 @@
 //!
 //! ## Public Functions
 //!
-//! See the [`Module`](./struct.Module.html) struct for details of publicly available functions.
+//! See the [`Module`] struct for details of publicly available functions.
 //!
 //! ## Usage
 //!
@@ -76,7 +76,7 @@ fn block_number_to_index<T: Config>(block_number: T::BlockNumber) -> usize {
 decl_module! {
 	pub struct Module<T: Config> for enum Call where origin: T::Origin {
 		fn on_initialize(block_number: T::BlockNumber) -> Weight {
-			let parent_hash = <frame_system::Module<T>>::parent_hash();
+			let parent_hash = <frame_system::Pallet<T>>::parent_hash();
 
 			<RandomMaterial<T>>::mutate(|ref mut values| if values.len() < RANDOM_MATERIAL_LEN as usize {
 				values.push(parent_hash)
@@ -111,7 +111,7 @@ impl<T: Config> Randomness<T::Hash, T::BlockNumber> for Module<T> {
 	/// and mean that all bits of the resulting value are entirely manipulatable by the author of
 	/// the parent block, who can determine the value of `parent_hash`.
 	fn random(subject: &[u8]) -> (T::Hash, T::BlockNumber) {
-		let block_number = <frame_system::Module<T>>::block_number();
+		let block_number = <frame_system::Pallet<T>>::block_number();
 		let index = block_number_to_index::<T>(block_number);
 
 		let hash_series = <RandomMaterial<T>>::get();
@@ -157,8 +157,8 @@ mod tests {
 			NodeBlock = Block,
 			UncheckedExtrinsic = UncheckedExtrinsic,
 		{
-			System: frame_system::{Module, Call, Config, Storage, Event<T>},
-			CollectiveFlip: pallet_randomness_collective_flip::{Module, Call, Storage},
+			System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+			CollectiveFlip: pallet_randomness_collective_flip::{Pallet, Call, Storage},
 		}
 	);
 
diff --git a/frame/recovery/src/lib.rs b/frame/recovery/src/lib.rs
index 00cd6ff2a7f79..cb991e64945a1 100644
--- a/frame/recovery/src/lib.rs
+++ b/frame/recovery/src/lib.rs
@@ -17,8 +17,8 @@
 
 //! # Recovery Pallet
 //!
-//! - [`recovery::Config`](./trait.Config.html)
-//! - [`Call`](./enum.Call.html)
+//! - [`Config`]
+//! - [`Call`]
 //!
 //! ## Overview
 //!
@@ -496,7 +496,7 @@ decl_module! {
 			T::Currency::reserve(&who, recovery_deposit)?;
 			// Create an active recovery status
 			let recovery_status = ActiveRecovery {
-				created: <system::Module<T>>::block_number(),
+				created: <system::Pallet<T>>::block_number(),
 				deposit: recovery_deposit,
 				friends: vec![],
 			};
@@ -578,7 +578,7 @@ decl_module! {
 			let active_recovery = Self::active_recovery(&account, &who).ok_or(Error::<T>::NotStarted)?;
 			ensure!(!Proxy::<T>::contains_key(&who), Error::<T>::AlreadyProxy);
 			// Make sure the delay period has passed
-			let current_block_number = <system::Module<T>>::block_number();
+			let current_block_number = <system::Pallet<T>>::block_number();
 			let recoverable_block_number = active_recovery.created
 				.checked_add(&recovery_config.delay_period)
 				.ok_or(Error::<T>::Overflow)?;
@@ -588,7 +588,7 @@ decl_module! {
 				recovery_config.threshold as usize <= active_recovery.friends.len(),
 				Error::<T>::Threshold
 			);
-			system::Module::<T>::inc_consumers(&who).map_err(|_| Error::<T>::BadState)?;
+			system::Pallet::<T>::inc_consumers(&who).map_err(|_| Error::<T>::BadState)?;
 			// Create the recovery storage item
 			Proxy::<T>::insert(&who, &account);
 			Self::deposit_event(RawEvent::AccountRecovered(account, who));
@@ -677,7 +677,7 @@ decl_module! {
 			// Check `who` is allowed to make a call on behalf of `account`
 			ensure!(Self::proxy(&who) == Some(account), Error::<T>::NotAllowed);
 			Proxy::<T>::remove(&who);
-			system::Module::<T>::dec_consumers(&who);
+			system::Pallet::<T>::dec_consumers(&who);
 		}
 	}
 }
diff --git a/frame/recovery/src/mock.rs b/frame/recovery/src/mock.rs
index ee38b0e24cc60..301dd8dba8ddd 100644
--- a/frame/recovery/src/mock.rs
+++ b/frame/recovery/src/mock.rs
@@ -35,9 +35,9 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
-		Recovery: recovery::{Module, Call, Storage, Event<T>},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
+		Recovery: recovery::{Pallet, Call, Storage, Event<T>},
 	}
 );
 
diff --git a/frame/scheduler/src/benchmarking.rs b/frame/scheduler/src/benchmarking.rs
index 37ccb900a824a..563a1ba89c86f 100644
--- a/frame/scheduler/src/benchmarking.rs
+++ b/frame/scheduler/src/benchmarking.rs
@@ -26,7 +26,7 @@ use frame_support::{ensure, traits::OnInitialize};
 use frame_benchmarking::{benchmarks, impl_benchmark_test_suite};
 
 use crate::Module as Scheduler;
-use frame_system::Module as System;
+use frame_system::Pallet as System;
 
 const BLOCK_NUMBER: u32 = 2;
 
diff --git a/frame/scheduler/src/lib.rs b/frame/scheduler/src/lib.rs
index 5cab10b0aff38..9848c9853d0bf 100644
--- a/frame/scheduler/src/lib.rs
+++ b/frame/scheduler/src/lib.rs
@@ -18,9 +18,9 @@
 //! # Scheduler
 //! A module for scheduling dispatches.
 //!
-//! - [`scheduler::Config`](./trait.Config.html)
-//! - [`Call`](./enum.Call.html)
-//! - [`Module`](./struct.Module.html)
+//! - [`Config`]
+//! - [`Call`]
+//! - [`Module`]
 //!
 //! ## Overview
 //!
@@ -465,7 +465,7 @@ impl<T: Config> Module<T> {
 	}
 
 	fn resolve_time(when: DispatchTime<T::BlockNumber>) -> Result<T::BlockNumber, DispatchError> {
-		let now = frame_system::Module::<T>::block_number();
+		let now = frame_system::Pallet::<T>::block_number();
 
 		let when = match when {
 			DispatchTime::At(x) => x,
@@ -793,9 +793,9 @@ mod tests {
 			NodeBlock = Block,
 			UncheckedExtrinsic = UncheckedExtrinsic,
 		{
-			System: frame_system::{Module, Call, Config, Storage, Event<T>},
-			Logger: logger::{Module, Call, Event},
-			Scheduler: scheduler::{Module, Call, Storage, Event<T>},
+			System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+			Logger: logger::{Pallet, Call, Event},
+			Scheduler: scheduler::{Pallet, Call, Storage, Event<T>},
 		}
 	);
 
diff --git a/frame/scored-pool/src/lib.rs b/frame/scored-pool/src/lib.rs
index ce2279b150050..da26872a0071a 100644
--- a/frame/scored-pool/src/lib.rs
+++ b/frame/scored-pool/src/lib.rs
@@ -37,9 +37,9 @@
 //! from the `Pool` and `Members`; the entity is immediately replaced
 //! by the next highest scoring candidate in the pool, if available.
 //!
-//! - [`scored_pool::Config`](./trait.Config.html)
-//! - [`Call`](./enum.Call.html)
-//! - [`Module`](./struct.Module.html)
+//! - [`Config`]
+//! - [`Call`]
+//! - [`Module`]
 //!
 //! ## Interface
 //!
diff --git a/frame/scored-pool/src/mock.rs b/frame/scored-pool/src/mock.rs
index 3c4263b813e41..76f9dd848d6c0 100644
--- a/frame/scored-pool/src/mock.rs
+++ b/frame/scored-pool/src/mock.rs
@@ -37,9 +37,9 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
-		ScoredPool: pallet_scored_pool::{Module, Call, Storage, Config<T>, Event<T>},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
+		ScoredPool: pallet_scored_pool::{Pallet, Call, Storage, Config<T>, Event<T>},
 	}
 );
 
diff --git a/frame/scored-pool/src/tests.rs b/frame/scored-pool/src/tests.rs
index 8f33f30f6ed8e..e24ee91164973 100644
--- a/frame/scored-pool/src/tests.rs
+++ b/frame/scored-pool/src/tests.rs
@@ -24,8 +24,8 @@ use frame_support::{assert_ok, assert_noop, traits::OnInitialize};
 use sp_runtime::traits::BadOrigin;
 
 type ScoredPool = Module<Test>;
-type System = frame_system::Module<Test>;
-type Balances = pallet_balances::Module<Test>;
+type System = frame_system::Pallet<Test>;
+type Balances = pallet_balances::Pallet<Test>;
 
 #[test]
 fn query_membership_works() {
diff --git a/frame/session/benchmarking/Cargo.toml b/frame/session/benchmarking/Cargo.toml
index 47265ed5ef7a8..0c83347b1991f 100644
--- a/frame/session/benchmarking/Cargo.toml
+++ b/frame/session/benchmarking/Cargo.toml
@@ -31,14 +31,14 @@ pallet-staking-reward-curve = { version = "3.0.0", path = "../../staking/reward-
 sp-io ={ version = "3.0.0", path = "../../../primitives/io" }
 pallet-timestamp = { version = "3.0.0", path = "../../timestamp" }
 pallet-balances = { version = "3.0.0", path = "../../balances" }
-sp-election-providers = { version = "3.0.0", path = "../../../primitives/election-providers" }
+frame-election-provider-support = { version = "3.0.0", path = "../../election-provider-support" }
 
 [features]
 default = ["std"]
 std = [
 	"sp-std/std",
 	"sp-session/std",
-	"sp-election-providers/std",
+	"frame-election-provider-support/std",
 	"sp-runtime/std",
 	"frame-system/std",
 	"frame-benchmarking/std",
diff --git a/frame/session/benchmarking/src/lib.rs b/frame/session/benchmarking/src/lib.rs
index 8546800ee4fdc..fff3717607f8f 100644
--- a/frame/session/benchmarking/src/lib.rs
+++ b/frame/session/benchmarking/src/lib.rs
@@ -35,16 +35,16 @@ use frame_system::RawOrigin;
 use pallet_session::{historical::Module as Historical, Module as Session, *};
 use pallet_staking::{
 	benchmarking::create_validator_with_nominators, testing_utils::create_validators,
-	MAX_NOMINATIONS, RewardDestination,
+	RewardDestination,
 };
 use sp_runtime::traits::{One, StaticLookup};
 
 const MAX_VALIDATORS: u32 = 1000;
 
-pub struct Module<T: Config>(pallet_session::Module<T>);
+pub struct Pallet<T: Config>(pallet_session::Module<T>);
 pub trait Config: pallet_session::Config + pallet_session::historical::Config + pallet_staking::Config {}
 
-impl<T: Config> OnInitialize<T::BlockNumber> for Module<T> {
+impl<T: Config> OnInitialize<T::BlockNumber> for Pallet<T> {
 	fn on_initialize(n: T::BlockNumber) -> frame_support::weights::Weight {
 		pallet_session::Module::<T>::on_initialize(n)
 	}
@@ -52,10 +52,10 @@ impl<T: Config> OnInitialize<T::BlockNumber> for Module<T> {
 
 benchmarks! {
 	set_keys {
-		let n = MAX_NOMINATIONS as u32;
+		let n = <T as pallet_staking::Config>::MAX_NOMINATIONS;
 		let (v_stash, _) = create_validator_with_nominators::<T>(
 			n,
-			MAX_NOMINATIONS as u32,
+			<T as pallet_staking::Config>::MAX_NOMINATIONS,
 			false,
 			RewardDestination::Staked,
 		)?;
@@ -68,10 +68,10 @@ benchmarks! {
 	}: _(RawOrigin::Signed(v_controller), keys, proof)
 
 	purge_keys {
-		let n = MAX_NOMINATIONS as u32;
+		let n = <T as pallet_staking::Config>::MAX_NOMINATIONS;
 		let (v_stash, _) = create_validator_with_nominators::<T>(
 			n,
-			MAX_NOMINATIONS as u32,
+			<T as pallet_staking::Config>::MAX_NOMINATIONS,
 			false,
 			RewardDestination::Staked
 		)?;
@@ -157,7 +157,7 @@ fn check_membership_proof_setup<T: Config>(
 		Session::<T>::set_keys(RawOrigin::Signed(controller).into(), keys, proof).unwrap();
 	}
 
-	Module::<T>::on_initialize(T::BlockNumber::one());
+	Pallet::<T>::on_initialize(T::BlockNumber::one());
 
 	// skip sessions until the new validator set is enacted
 	while Session::<T>::validators().len() < n as usize {
@@ -170,7 +170,7 @@ fn check_membership_proof_setup<T: Config>(
 }
 
 impl_benchmark_test_suite!(
-	Module,
+	Pallet,
 	crate::mock::new_test_ext(),
 	crate::mock::Test,
 	extra = false,
diff --git a/frame/session/benchmarking/src/mock.rs b/frame/session/benchmarking/src/mock.rs
index 0eba5452b28d0..53afeb620c260 100644
--- a/frame/session/benchmarking/src/mock.rs
+++ b/frame/session/benchmarking/src/mock.rs
@@ -20,7 +20,7 @@
 #![cfg(test)]
 
 use sp_runtime::traits::IdentityLookup;
-use sp_election_providers::onchain;
+use frame_election_provider_support::onchain;
 use frame_support::parameter_types;
 
 type AccountId = u64;
@@ -37,10 +37,10 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
-		Staking: pallet_staking::{Module, Call, Config<T>, Storage, Event<T>, ValidateUnsigned},
-		Session: pallet_session::{Module, Call, Storage, Event, Config<T>},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
+		Staking: pallet_staking::{Pallet, Call, Config<T>, Storage, Event<T>},
+		Session: pallet_session::{Pallet, Call, Storage, Event, Config<T>},
 	}
 );
 
@@ -157,13 +157,15 @@ where
 impl onchain::Config for Test {
 	type AccountId = AccountId;
 	type BlockNumber = BlockNumber;
+	type BlockWeights = ();
 	type Accuracy = sp_runtime::Perbill;
 	type DataProvider = Staking;
 }
 
 impl pallet_staking::Config for Test {
+	const MAX_NOMINATIONS: u32 = 16;
 	type Currency = Balances;
-	type UnixTime = pallet_timestamp::Module<Self>;
+	type UnixTime = pallet_timestamp::Pallet<Self>;
 	type CurrencyToVote = frame_support::traits::SaturatingCurrencyToVote;
 	type RewardRemainder = ();
 	type Event = Event;
@@ -174,15 +176,9 @@ impl pallet_staking::Config for Test {
 	type SlashCancelOrigin = frame_system::EnsureRoot<Self::AccountId>;
 	type BondingDuration = ();
 	type SessionInterface = Self;
-	type RewardCurve = RewardCurve;
+	type EraPayout = pallet_staking::ConvertCurve<RewardCurve>;
 	type NextNewSession = Session;
-	type ElectionLookahead = ();
-	type Call = Call;
 	type MaxNominatorRewardedPerValidator = MaxNominatorRewardedPerValidator;
-	type UnsignedPriority = UnsignedPriority;
-	type MaxIterations = ();
-	type MinSolutionScoreBump = ();
-	type OffchainSolutionWeightLimit = ();
 	type ElectionProvider = onchain::OnChainSequentialPhragmen<Self>;
 	type WeightInfo = ();
 }
diff --git a/frame/session/src/historical/mod.rs b/frame/session/src/historical/mod.rs
index 9b4d2704cf456..8902ebe551f6c 100644
--- a/frame/session/src/historical/mod.rs
+++ b/frame/session/src/historical/mod.rs
@@ -358,7 +358,7 @@ pub(crate) mod tests {
 		);
 		BasicExternalities::execute_with_storage(&mut t, || {
 			for (ref k, ..) in &keys {
-				frame_system::Module::<Test>::inc_providers(k);
+				frame_system::Pallet::<Test>::inc_providers(k);
 			}
 		});
 		crate::GenesisConfig::<Test> { keys }.assimilate_storage(&mut t).unwrap();
diff --git a/frame/session/src/historical/offchain.rs b/frame/session/src/historical/offchain.rs
index f095be9e44e24..f675d878c1e28 100644
--- a/frame/session/src/historical/offchain.rs
+++ b/frame/session/src/historical/offchain.rs
@@ -28,7 +28,7 @@
 use sp_runtime::{offchain::storage::StorageValueRef, KeyTypeId};
 use sp_session::MembershipProof;
 
-use super::super::{Module as SessionModule, SessionIndex};
+use super::super::{Pallet as SessionModule, SessionIndex};
 use super::{IdentificationTuple, ProvingTrie, Config};
 
 use super::shared;
@@ -167,7 +167,7 @@ mod tests {
 		);
 		BasicExternalities::execute_with_storage(&mut t, || {
 			for (ref k, ..) in &keys {
-				frame_system::Module::<Test>::inc_providers(k);
+				frame_system::Pallet::<Test>::inc_providers(k);
 			}
 		});
 
diff --git a/frame/session/src/historical/onchain.rs b/frame/session/src/historical/onchain.rs
index 3b933bf262a00..8fe63a79e1c59 100644
--- a/frame/session/src/historical/onchain.rs
+++ b/frame/session/src/historical/onchain.rs
@@ -21,7 +21,7 @@ use codec::Encode;
 use sp_runtime::traits::Convert;
 
 use super::super::Config as SessionConfig;
-use super::super::{Module as SessionModule, SessionIndex};
+use super::super::{Pallet as SessionModule, SessionIndex};
 use super::Config as HistoricalConfig;
 
 use super::shared;
diff --git a/frame/session/src/lib.rs b/frame/session/src/lib.rs
index 45f3ae9dfce47..e7b16808f7239 100644
--- a/frame/session/src/lib.rs
+++ b/frame/session/src/lib.rs
@@ -20,9 +20,9 @@
 //! The Session module allows validators to manage their session keys, provides a function for
 //! changing the session length, and handles session rotation.
 //!
-//! - [`session::Config`](./trait.Config.html)
-//! - [`Call`](./enum.Call.html)
-//! - [`Module`](./struct.Module.html)
+//! - [`Config`]
+//! - [`Call`]
+//! - [`Module`]
 //!
 //! ## Overview
 //!
@@ -177,12 +177,12 @@ impl<
 		// (0% is never returned).
 		let progress = if now >= offset {
 			let current = (now - offset) % period.clone() + One::one();
-			Some(Percent::from_rational_approximation(
+			Some(Percent::from_rational(
 				current.clone(),
 				period.clone(),
 			))
 		} else {
-			Some(Percent::from_rational_approximation(
+			Some(Percent::from_rational(
 				now + One::one(),
 				offset,
 			))
@@ -442,7 +442,11 @@ decl_storage! {
 			for (account, val, keys) in config.keys.iter().cloned() {
 				<Module<T>>::inner_set_keys(&val, keys)
 					.expect("genesis config must not contain duplicates; qed");
-				assert!(frame_system::Module::<T>::inc_consumers(&account).is_ok());
+				assert!(
+					frame_system::Pallet::<T>::inc_consumers(&account).is_ok(),
+					"Account ({:?}) does not exist at genesis to set key. Account not endowed?",
+					account,
+				);
 			}
 
 			let initial_validators_0 = T::SessionManager::new_session(0)
@@ -746,10 +750,10 @@ impl<T: Config> Module<T> {
 		let who = T::ValidatorIdOf::convert(account.clone())
 			.ok_or(Error::<T>::NoAssociatedValidatorId)?;
 
-		frame_system::Module::<T>::inc_consumers(&account).map_err(|_| Error::<T>::NoAccount)?;
+		frame_system::Pallet::<T>::inc_consumers(&account).map_err(|_| Error::<T>::NoAccount)?;
 		let old_keys = Self::inner_set_keys(&who, keys)?;
 		if old_keys.is_some() {
-			let _ = frame_system::Module::<T>::dec_consumers(&account);
+			let _ = frame_system::Pallet::<T>::dec_consumers(&account);
 			// ^^^ Defensive only; Consumers were incremented just before, so should never fail.
 		}
 
@@ -798,7 +802,7 @@ impl<T: Config> Module<T> {
 			let key_data = old_keys.get_raw(*id);
 			Self::clear_key_owner(*id, key_data);
 		}
-		frame_system::Module::<T>::dec_consumers(&account);
+		frame_system::Pallet::<T>::dec_consumers(&account);
 
 		Ok(())
 	}
diff --git a/frame/session/src/mock.rs b/frame/session/src/mock.rs
index 73499bf739b87..b64359fccee32 100644
--- a/frame/session/src/mock.rs
+++ b/frame/session/src/mock.rs
@@ -78,9 +78,9 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Session: pallet_session::{Module, Call, Storage, Event, Config<T>},
-		Historical: pallet_session_historical::{Module},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Session: pallet_session::{Pallet, Call, Storage, Event, Config<T>},
+		Historical: pallet_session_historical::{Pallet},
 	}
 );
 
@@ -91,8 +91,8 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Session: pallet_session::{Module, Call, Storage, Event, Config<T>},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Session: pallet_session::{Pallet, Call, Storage, Event, Config<T>},
 	}
 );
 
@@ -210,11 +210,11 @@ pub fn new_test_ext() -> sp_io::TestExternalities {
 	);
 	BasicExternalities::execute_with_storage(&mut t, || {
 		for (ref k, ..) in &keys {
-			frame_system::Module::<Test>::inc_providers(k);
+			frame_system::Pallet::<Test>::inc_providers(k);
 		}
-		frame_system::Module::<Test>::inc_providers(&4);
+		frame_system::Pallet::<Test>::inc_providers(&4);
 		// An additional identity that we use.
-		frame_system::Module::<Test>::inc_providers(&69);
+		frame_system::Pallet::<Test>::inc_providers(&69);
 	});
 	pallet_session::GenesisConfig::<Test> { keys }.assimilate_storage(&mut t).unwrap();
 	sp_io::TestExternalities::new(t)
diff --git a/frame/society/src/lib.rs b/frame/society/src/lib.rs
index 66d89d67dd6e7..64caf328002af 100644
--- a/frame/society/src/lib.rs
+++ b/frame/society/src/lib.rs
@@ -17,8 +17,8 @@
 
 //! # Society Module
 //!
-//! - [`society::Config`](./trait.Config.html)
-//! - [`Call`](./enum.Call.html)
+//! - [`Config`]
+//! - [`Call`]
 //!
 //! ## Overview
 //!
@@ -272,7 +272,7 @@ type BalanceOf<T, I> = <<T as Config<I>>::Currency as Currency<<T as system::Con
 type NegativeImbalanceOf<T> = <<T as Config>::Currency as Currency<<T as frame_system::Config>::AccountId>>::NegativeImbalance;
 
 /// The module's configuration trait.
-pub trait Config<I=DefaultInstance>: system::Config {
+pub trait Config<I = DefaultInstance>: system::Config {
 	/// The overarching event type.
 	type Event: From<Event<Self, I>> + Into<<Self as system::Config>::Event>;
 
@@ -316,6 +316,9 @@ pub trait Config<I=DefaultInstance>: system::Config {
 
 	/// The number of blocks between membership challenges.
 	type ChallengePeriod: Get<Self::BlockNumber>;
+
+	/// The maximum number of candidates that we accept per round.
+	type MaxCandidateIntake: Get<u32>;
 }
 
 /// A vote by a member on a candidate application.
@@ -497,6 +500,9 @@ decl_module! {
 		/// The societies's module id
 		const ModuleId: ModuleId = T::ModuleId::get();
 
+		/// Maximum candidate intake per round.
+		const MaxCandidateIntake: u32 = T::MaxCandidateIntake::get();
+
 		// Used for handling module events.
 		fn deposit_event() = default;
 
@@ -584,7 +590,8 @@ decl_module! {
 					// no reason that either should fail.
 					match b.remove(pos).kind {
 						BidKind::Deposit(deposit) => {
-							let _ = T::Currency::unreserve(&who, deposit);
+							let err_amount = T::Currency::unreserve(&who, deposit);
+							debug_assert!(err_amount.is_zero());
 						}
 						BidKind::Vouch(voucher, _) => {
 							<Vouching<T, I>>::remove(&voucher);
@@ -793,7 +800,7 @@ decl_module! {
 
 			let mut payouts = <Payouts<T, I>>::get(&who);
 			if let Some((when, amount)) = payouts.first() {
-				if when <= &<system::Module<T>>::block_number() {
+				if when <= &<system::Pallet<T>>::block_number() {
 					T::Currency::transfer(&Self::payouts(), &who, *amount, AllowDeath)?;
 					payouts.remove(0);
 					if payouts.is_empty() {
@@ -981,7 +988,7 @@ decl_module! {
 						// Reduce next pot by payout
 						<Pot<T, I>>::put(pot - value);
 						// Add payout for new candidate
-						let maturity = <system::Module<T>>::block_number()
+						let maturity = <system::Pallet<T>>::block_number()
 							+ Self::lock_duration(Self::members().len() as u32);
 						Self::pay_accepted_candidate(&who, value, kind, maturity);
 					}
@@ -1235,7 +1242,8 @@ impl<T: Config<I>, I: Instance> Module<T, I> {
 			let Bid { who: popped, kind, .. } = bids.pop().expect("b.len() > 1000; qed");
 			match kind {
 				BidKind::Deposit(deposit) => {
-					let _ = T::Currency::unreserve(&popped, deposit);
+					let err_amount = T::Currency::unreserve(&popped, deposit);
+					debug_assert!(err_amount.is_zero());
 				}
 				BidKind::Vouch(voucher, _) => {
 					<Vouching<T, I>>::remove(&voucher);
@@ -1324,7 +1332,7 @@ impl<T: Config<I>, I: Instance> Module<T, I> {
 			// critical issues or side-effects. This is auto-correcting as members fall out of society.
 			members.reserve(candidates.len());
 
-			let maturity = <system::Module<T>>::block_number()
+			let maturity = <system::Pallet<T>>::block_number()
 				+ Self::lock_duration(members.len() as u32);
 
 			let mut rewardees = Vec::new();
@@ -1402,7 +1410,8 @@ impl<T: Config<I>, I: Instance> Module<T, I> {
 					Self::bump_payout(winner, maturity, total_slash);
 				} else {
 					// Move the slashed amount back from payouts account to local treasury.
-					let _ = T::Currency::transfer(&Self::payouts(), &Self::account_id(), total_slash, AllowDeath);
+					let res = T::Currency::transfer(&Self::payouts(), &Self::account_id(), total_slash, AllowDeath);
+					debug_assert!(res.is_ok());
 				}
 			}
 
@@ -1413,7 +1422,8 @@ impl<T: Config<I>, I: Instance> Module<T, I> {
 
 				// this should never fail since we ensure we can afford the payouts in a previous
 				// block, but there's not much we can do to recover if it fails anyway.
-				let _ = T::Currency::transfer(&Self::account_id(), &Self::payouts(), total_payouts, AllowDeath);
+				let res = T::Currency::transfer(&Self::account_id(), &Self::payouts(), total_payouts, AllowDeath);
+				debug_assert!(res.is_ok());
 			}
 
 			// if at least one candidate was accepted...
@@ -1514,7 +1524,8 @@ impl<T: Config<I>, I: Instance> Module<T, I> {
 			BidKind::Deposit(deposit) => {
 				// In the case that a normal deposit bid is accepted we unreserve
 				// the deposit.
-				let _ = T::Currency::unreserve(candidate, deposit);
+				let err_amount = T::Currency::unreserve(candidate, deposit);
+				debug_assert!(err_amount.is_zero());
 				value
 			}
 			BidKind::Vouch(voucher, tip) => {
@@ -1615,11 +1626,11 @@ impl<T: Config<I>, I: Instance> Module<T, I> {
 	/// May be empty.
 	pub fn take_selected(
 		members_len: usize,
-		pot: BalanceOf<T, I>
+		pot: BalanceOf<T, I>,
 	) -> Vec<Bid<T::AccountId, BalanceOf<T, I>>> {
 		let max_members = MaxMembers::<I>::get() as usize;
-		// No more than 10 will be returned.
-		let mut max_selections: usize = 10.min(max_members.saturating_sub(members_len));
+		let mut max_selections: usize =
+			(T::MaxCandidateIntake::get() as usize).min(max_members.saturating_sub(members_len));
 
 		if max_selections > 0 {
 			// Get the number of left-most bidders whose bids add up to less than `pot`.
diff --git a/frame/society/src/mock.rs b/frame/society/src/mock.rs
index 0a684b2a8dc89..ff80b50b6d358 100644
--- a/frame/society/src/mock.rs
+++ b/frame/society/src/mock.rs
@@ -41,9 +41,9 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
-		Society: pallet_society::{Module, Call, Storage, Event<T>, Config<T>},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
+		Society: pallet_society::{Pallet, Call, Storage, Event<T>, Config<T>},
 	}
 );
 
@@ -57,6 +57,7 @@ parameter_types! {
 	pub const ChallengePeriod: u64 = 8;
 	pub const BlockHashCount: u64 = 250;
 	pub const ExistentialDeposit: u64 = 1;
+	pub const MaxCandidateIntake: u32 = 10;
 	pub const SocietyModuleId: ModuleId = ModuleId(*b"py/socie");
 	pub BlockWeights: frame_system::limits::BlockWeights =
 		frame_system::limits::BlockWeights::simple_max(1024);
@@ -104,7 +105,7 @@ impl pallet_balances::Config for Test {
 
 impl Config for Test {
 	type Event = Event;
-	type Currency = pallet_balances::Module<Self>;
+	type Currency = pallet_balances::Pallet<Self>;
 	type Randomness = TestRandomness<Self>;
 	type CandidateDeposit = CandidateDeposit;
 	type WrongSideDeduction = WrongSideDeduction;
@@ -116,6 +117,7 @@ impl Config for Test {
 	type FounderSetOrigin = EnsureSignedBy<FounderSetAccount, u128>;
 	type SuspensionJudgementOrigin = EnsureSignedBy<SuspensionJudgementSetAccount, u128>;
 	type ChallengePeriod = ChallengePeriod;
+	type MaxCandidateIntake = MaxCandidateIntake;
 	type ModuleId = SocietyModuleId;
 }
 
diff --git a/frame/staking/Cargo.toml b/frame/staking/Cargo.toml
index 1f9f29570a223..908e361e667e3 100644
--- a/frame/staking/Cargo.toml
+++ b/frame/staking/Cargo.toml
@@ -17,8 +17,6 @@ static_assertions = "1.1.0"
 serde = { version = "1.0.101", optional = true }
 codec = { package = "parity-scale-codec", version = "2.0.0", default-features = false, features = ["derive"] }
 sp-std = { version = "3.0.0", default-features = false, path = "../../primitives/std" }
-# TWO_PHASE_NOTE:: ideally we should be able to get rid of this.
-sp-npos-elections = { version = "3.0.0", default-features = false, path = "../../primitives/npos-elections" }
 sp-io ={ version = "3.0.0", default-features = false, path = "../../primitives/io" }
 sp-runtime = { version = "3.0.0", default-features = false, path = "../../primitives/runtime" }
 sp-staking = { version = "3.0.0", default-features = false, path = "../../primitives/staking" }
@@ -27,8 +25,9 @@ frame-system = { version = "3.0.0", default-features = false, path = "../system"
 pallet-session = { version = "3.0.0", default-features = false, features = ["historical"], path = "../session" }
 pallet-authorship = { version = "3.0.0", default-features = false, path = "../authorship" }
 sp-application-crypto = { version = "3.0.0", default-features = false, path = "../../primitives/application-crypto" }
+frame-election-provider-support = { version = "3.0.0", default-features = false, path = "../election-provider-support" }
 log = { version = "0.4.14", default-features = false }
-sp-election-providers = { version = "3.0.0", default-features = false, path = "../../primitives/election-providers" }
+paste = "1.0"
 
 # Optional imports for benchmarking
 frame-benchmarking = { version = "3.1.0", default-features = false, path = "../benchmarking", optional = true }
@@ -43,7 +42,7 @@ pallet-timestamp = { version = "3.0.0", path = "../timestamp" }
 pallet-staking-reward-curve = { version = "3.0.0",  path = "../staking/reward-curve" }
 substrate-test-utils = { version = "3.0.0", path = "../../test-utils" }
 frame-benchmarking = { version = "3.1.0", path = "../benchmarking" }
-sp-election-providers = { version = "3.0.0", features = ["runtime-benchmarks"], path = "../../primitives/election-providers" }
+frame-election-provider-support = { version = "3.0.0", features = ["runtime-benchmarks"], path = "../election-provider-support" }
 rand_chacha = { version = "0.2" }
 parking_lot = "0.11.1"
 hex = "0.4"
@@ -54,7 +53,6 @@ std = [
 	"serde",
 	"codec/std",
 	"sp-std/std",
-	"sp-npos-elections/std",
 	"sp-io/std",
 	"frame-support/std",
 	"sp-runtime/std",
@@ -64,11 +62,11 @@ std = [
 	"pallet-authorship/std",
 	"sp-application-crypto/std",
 	"log/std",
-	"sp-election-providers/std",
+	"frame-election-provider-support/std",
 ]
 runtime-benchmarks = [
 	"frame-benchmarking",
-	"sp-election-providers/runtime-benchmarks",
+	"frame-election-provider-support/runtime-benchmarks",
 	"rand_chacha",
 ]
 try-runtime = ["frame-support/try-runtime"]
diff --git a/frame/staking/fuzzer/.gitignore b/frame/staking/fuzzer/.gitignore
deleted file mode 100644
index 3ebcb104d4a50..0000000000000
--- a/frame/staking/fuzzer/.gitignore
+++ /dev/null
@@ -1,2 +0,0 @@
-hfuzz_target
-hfuzz_workspace
diff --git a/frame/staking/fuzzer/Cargo.lock b/frame/staking/fuzzer/Cargo.lock
deleted file mode 100644
index e451e12d10131..0000000000000
--- a/frame/staking/fuzzer/Cargo.lock
+++ /dev/null
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diff --git a/frame/staking/fuzzer/Cargo.toml b/frame/staking/fuzzer/Cargo.toml
deleted file mode 100644
index 84758c6bf65ce..0000000000000
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-homepage = "https://substrate.dev"
-repository = "https://github.com/paritytech/substrate/"
-description = "FRAME pallet staking fuzzing"
-
-[package.metadata.docs.rs]
-targets = ["x86_64-unknown-linux-gnu"]
-
-[dependencies]
-honggfuzz = "0.5"
-codec = { package = "parity-scale-codec", version = "2.0.0", default-features = false, features = ["derive"] }
-pallet-staking = { version = "3.0.0", path = "..", features = ["runtime-benchmarks"] }
-pallet-staking-reward-curve = { version = "3.0.0",  path = "../reward-curve" }
-pallet-session = { version = "3.0.0", path = "../../session" }
-pallet-indices = { version = "3.0.0", path = "../../indices" }
-pallet-balances = { version = "3.0.0", path = "../../balances" }
-pallet-timestamp = { version = "3.0.0", path = "../../timestamp" }
-frame-system = { version = "3.0.0", path = "../../system" }
-frame-support = { version = "3.0.0", path = "../../support" }
-sp-std = { version = "3.0.0", path = "../../../primitives/std" }
-sp-io ={ version = "3.0.0", path = "../../../primitives/io" }
-sp-core = { version = "3.0.0", path = "../../../primitives/core" }
-sp-npos-elections = { version = "3.0.0", path = "../../../primitives/npos-elections" }
-sp-runtime = { version = "3.0.0", path = "../../../primitives/runtime" }
-sp-election-providers = { version = "3.0.0", path = "../../../primitives/election-providers" }
-serde = "1.0.101"
-
-[features]
-# Note feature std is required so that impl_opaque_keys derive serde.
-default = ["std"]
-std = []
-
-[[bin]]
-name = "submit_solution"
-path = "src/submit_solution.rs"
diff --git a/frame/staking/fuzzer/src/mock.rs b/frame/staking/fuzzer/src/mock.rs
index 05d001d23858e..8fe7975cef068 100644
--- a/frame/staking/fuzzer/src/mock.rs
+++ b/frame/staking/fuzzer/src/mock.rs
@@ -33,11 +33,11 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
-		Staking: pallet_staking::{Module, Call, Config<T>, Storage, Event<T>, ValidateUnsigned},
-		Indices: pallet_indices::{Module, Call, Storage, Config<T>, Event<T>},
-		Session: pallet_session::{Module, Call, Storage, Event, Config<T>},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
+		Staking: pallet_staking::{Pallet, Call, Config<T>, Storage, Event<T>, ValidateUnsigned},
+		Indices: pallet_indices::{Pallet, Call, Storage, Config<T>, Event<T>},
+		Session: pallet_session::{Pallet, Call, Storage, Event, Config<T>},
 	}
 );
 
@@ -158,18 +158,23 @@ where
 }
 
 pub struct MockElectionProvider;
-impl sp_election_providers::ElectionProvider<AccountId, BlockNumber> for MockElectionProvider {
+impl frame_election_provider_support::ElectionProvider<AccountId, BlockNumber>
+	for MockElectionProvider
+{
 	type Error = ();
 	type DataProvider = pallet_staking::Module<Test>;
 
-	fn elect() -> Result<sp_npos_elections::Supports<AccountId>, Self::Error> {
+	fn elect() -> Result<
+		(sp_npos_elections::Supports<AccountId>, frame_support::weights::Weight),
+		Self::Error
+	> {
 		Err(())
 	}
 }
 
 impl pallet_staking::Config for Test {
 	type Currency = Balances;
-	type UnixTime = pallet_timestamp::Module<Self>;
+	type UnixTime = pallet_timestamp::Pallet<Self>;
 	type CurrencyToVote = frame_support::traits::SaturatingCurrencyToVote;
 	type RewardRemainder = ();
 	type Event = Event;
@@ -180,7 +185,7 @@ impl pallet_staking::Config for Test {
 	type SlashCancelOrigin = frame_system::EnsureRoot<Self::AccountId>;
 	type BondingDuration = ();
 	type SessionInterface = Self;
-	type RewardCurve = RewardCurve;
+	type EraPayout = pallet_staking::ConvertCurve<RewardCurve>;
 	type NextNewSession = Session;
 	type ElectionLookahead = ();
 	type Call = Call;
diff --git a/frame/staking/fuzzer/src/submit_solution.rs b/frame/staking/fuzzer/src/submit_solution.rs
deleted file mode 100644
index 63ec189d44b07..0000000000000
--- a/frame/staking/fuzzer/src/submit_solution.rs
+++ /dev/null
@@ -1,183 +0,0 @@
-// This file is part of Substrate.
-
-// Copyright (C) 2020-2021 Parity Technologies (UK) Ltd.
-// SPDX-License-Identifier: Apache-2.0
-
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// 	http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-//! Fuzzing for staking pallet.
-//!
-//! HFUZZ_RUN_ARGS="-n 8" cargo hfuzz run submit_solution
-
-use honggfuzz::fuzz;
-
-use mock::Test;
-use pallet_staking::testing_utils::*;
-use frame_support::{assert_ok, storage::StorageValue, traits::UnfilteredDispatchable};
-use frame_system::RawOrigin;
-use sp_runtime::DispatchError;
-use sp_core::offchain::{testing::TestOffchainExt, OffchainWorkerExt, OffchainDbExt};
-use pallet_staking::{EraElectionStatus, ElectionStatus, Module as Staking, Call as StakingCall};
-
-mod mock;
-
-#[repr(u32)]
-#[allow(dead_code)]
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-enum Mode {
-	/// Initial submission. This will be rather cheap.
-	InitialSubmission,
-	/// A better submission that will replace the previous ones. This is the most expensive.
-	StrongerSubmission,
-	/// A weak submission that will be rejected. This will be rather cheap.
-	WeakerSubmission,
-}
-
-pub fn new_test_ext(iterations: u32) -> sp_io::TestExternalities {
-	let mut ext: sp_io::TestExternalities = frame_system::GenesisConfig::default()
-		.build_storage::<mock::Test>()
-		.map(Into::into)
-		.expect("Failed to create test externalities.");
-
-	let (offchain, offchain_state) = TestOffchainExt::new();
-
-	let mut seed = [0u8; 32];
-	seed[0..4].copy_from_slice(&iterations.to_le_bytes());
-	offchain_state.write().seed = seed;
-
-	ext.register_extension(OffchainDbExt::new(offchain.clone()));
-	ext.register_extension(OffchainWorkerExt::new(offchain));
-
-	ext
-}
-
-fn main() {
-	let to_range = |x: u32, a: u32, b: u32| {
-		let collapsed = x % b;
-		if collapsed >= a {
-			collapsed
-		} else {
-			collapsed + a
-		}
-	};
-	loop {
-		fuzz!(|data: (u32, u32, u32, u32, u32)| {
-			let (mut num_validators, mut num_nominators, mut edge_per_voter, mut to_elect, mode_u32) = data;
-			// always run with 5 iterations.
-			let mut ext = new_test_ext(5);
-			let mode: Mode = unsafe { std::mem::transmute(mode_u32) };
-			num_validators = to_range(num_validators, 50, 1000);
-			num_nominators = to_range(num_nominators, 50, 2000);
-			edge_per_voter = to_range(edge_per_voter, 1, 16);
-			to_elect = to_range(to_elect, 20, num_validators);
-
-			let do_reduce = true;
-
-			println!("+++ instance with params {} / {} / {} / {} / {:?}({})",
-				num_nominators,
-				num_validators,
-				edge_per_voter,
-				to_elect,
-				mode,
-				mode_u32,
-			);
-
-			ext.execute_with(|| {
-				// initial setup
-				init_active_era();
-
-				assert_ok!(create_validators_with_nominators_for_era::<Test>(
-					num_validators,
-					num_nominators,
-					edge_per_voter as usize,
-					true,
-					None,
-				));
-
-				<EraElectionStatus<Test>>::put(ElectionStatus::Open(1));
-				assert!(<Staking<Test>>::create_stakers_snapshot().0);
-
-				let origin = RawOrigin::Signed(create_funded_user::<Test>("fuzzer", 0, 100));
-
-				// stuff to submit
-				let (winners, compact, score, size) = match mode {
-					Mode::InitialSubmission => {
-						// No need to setup anything
-						get_seq_phragmen_solution::<Test>(do_reduce)
-					},
-					Mode::StrongerSubmission => {
-						let (winners, compact, score, size) = get_weak_solution::<Test>(false);
-						println!("Weak on chain score = {:?}", score);
-						assert_ok!(
-							<Staking<Test>>::submit_election_solution(
-								origin.clone().into(),
-								winners,
-								compact,
-								score,
-								current_era::<Test>(),
-								size,
-							)
-						);
-						get_seq_phragmen_solution::<Test>(do_reduce)
-					},
-					Mode::WeakerSubmission => {
-						let (winners, compact, score, size) = get_seq_phragmen_solution::<Test>(do_reduce);
-						println!("Strong on chain score = {:?}", score);
-						assert_ok!(
-							<Staking<Test>>::submit_election_solution(
-								origin.clone().into(),
-								winners,
-								compact,
-								score,
-								current_era::<Test>(),
-								size,
-							)
-						);
-						get_weak_solution::<Test>(false)
-					}
-				};
-
-				// must have chosen correct number of winners.
-				assert_eq!(winners.len() as u32, <Staking<Test>>::validator_count());
-
-				// final call and origin
-				let call = StakingCall::<Test>::submit_election_solution(
-					winners,
-					compact,
-					score,
-					current_era::<Test>(),
-					size,
-				);
-
-				// actually submit
-				match mode {
-					Mode::WeakerSubmission => {
-						assert_eq!(
-							call.dispatch_bypass_filter(origin.into()).unwrap_err().error,
-							DispatchError::Module {
-								index: 2,
-								error: 16,
-								message: Some("OffchainElectionWeakSubmission"),
-							},
-						);
-					},
-					// NOTE: so exhaustive pattern doesn't work here.. maybe some rust issue?
-					// or due to `#[repr(u32)]`?
-					Mode::InitialSubmission | Mode::StrongerSubmission => {
-						assert_ok!(call.dispatch_bypass_filter(origin.into()));
-					}
-				};
-			})
-		});
-	}
-}
diff --git a/frame/staking/reward-fn/Cargo.toml b/frame/staking/reward-fn/Cargo.toml
new file mode 100644
index 0000000000000..15b17a5e716c3
--- /dev/null
+++ b/frame/staking/reward-fn/Cargo.toml
@@ -0,0 +1,25 @@
+[package]
+name = "pallet-staking-reward-fn"
+version = "3.0.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+edition = "2018"
+license = "Apache-2.0"
+homepage = "https://substrate.dev"
+repository = "https://github.com/paritytech/substrate/"
+description = "Reward function for FRAME staking pallet"
+
+[package.metadata.docs.rs]
+targets = ["x86_64-unknown-linux-gnu"]
+
+[lib]
+
+[dependencies]
+sp-arithmetic = { version = "3.0.0", default-features = false, path = "../../../primitives/arithmetic" }
+log = { version = "0.4.14", default-features = false }
+
+[features]
+default = ["std"]
+std = [
+	"sp-arithmetic/std",
+	"log/std",
+]
diff --git a/frame/staking/reward-fn/src/lib.rs b/frame/staking/reward-fn/src/lib.rs
new file mode 100644
index 0000000000000..205f0207673a3
--- /dev/null
+++ b/frame/staking/reward-fn/src/lib.rs
@@ -0,0 +1,236 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#![cfg_attr(not(feature = "std"), no_std)]
+
+//! Useful function for inflation for nominated proof of stake.
+
+use sp_arithmetic::{Perquintill, PerThing, biguint::BigUint, traits::{Zero, SaturatedConversion}};
+use core::convert::TryFrom;
+
+/// Compute yearly inflation using function
+///
+/// ```ignore
+/// I(x) = for x between 0 and x_ideal: x / x_ideal,
+/// for x between x_ideal and 1: 2^((x_ideal - x) / d)
+/// ```
+///
+/// where:
+/// * x is the stake rate, i.e. fraction of total issued tokens that actively staked behind
+///   validators.
+/// * d is the falloff or `decay_rate`
+/// * x_ideal: the ideal stake rate.
+///
+/// The result is meant to be scaled with minimum inflation and maximum inflation.
+///
+/// (as detailed
+/// [here](https://research.web3.foundation/en/latest/polkadot/economics/1-token-economics.html#inflation-model-with-parachains))
+///
+/// Arguments are:
+/// * `stake`:
+///   The fraction of total issued tokens that actively staked behind
+///   validators. Known as `x` in the literature.
+///   Must be between 0 and 1.
+/// * `ideal_stake`:
+///   The fraction of total issued tokens that should be actively staked behind
+///   validators. Known as `x_ideal` in the literature.
+///   Must be between 0 and 1.
+/// * `falloff`:
+///   Known as `decay_rate` in the literature. A co-efficient dictating the strength of
+///   the global incentivization to get the `ideal_stake`. A higher number results in less typical
+///   inflation at the cost of greater volatility for validators.
+///   Must be more than 0.01.
+pub fn compute_inflation<P: PerThing>(
+	stake: P,
+	ideal_stake: P,
+	falloff: P,
+) -> P {
+	if stake < ideal_stake {
+		// ideal_stake is more than 0 because it is strictly more than stake
+		return stake / ideal_stake
+	}
+
+	if falloff < P::from_percent(1.into()) {
+		log::error!("Invalid inflation computation: falloff less than 1% is not supported");
+		return PerThing::zero()
+	}
+
+	let accuracy = {
+		let mut a = BigUint::from(Into::<u128>::into(P::ACCURACY));
+		a.lstrip();
+		a
+	};
+
+	let mut falloff = BigUint::from(falloff.deconstruct().into());
+	falloff.lstrip();
+
+	let ln2 = {
+		/// `ln(2)` expressed in as perquintillionth.
+		const LN2: u64 = 0_693_147_180_559_945_309;
+		let ln2 = P::from_rational(LN2.into(), Perquintill::ACCURACY.into());
+		BigUint::from(ln2.deconstruct().into())
+	};
+
+	// falloff is stripped above.
+	let ln2_div_d = div_by_stripped(ln2.mul(&accuracy), &falloff);
+
+	let inpos_param = INPoSParam {
+		x_ideal: BigUint::from(ideal_stake.deconstruct().into()),
+		x: BigUint::from(stake.deconstruct().into()),
+		accuracy,
+		ln2_div_d,
+	};
+
+	let res = compute_taylor_serie_part(&inpos_param);
+
+	match u128::try_from(res.clone()) {
+		Ok(res) if res <= Into::<u128>::into(P::ACCURACY) => {
+			P::from_parts(res.saturated_into())
+		},
+		// If result is beyond bounds there is nothing we can do
+		_ => {
+			log::error!("Invalid inflation computation: unexpected result {:?}", res);
+			P::zero()
+		},
+	}
+}
+
+
+/// Internal struct holding parameter info alongside other cached value.
+///
+/// All expressed in part from `accuracy`
+struct INPoSParam {
+	ln2_div_d: BigUint,
+	x_ideal: BigUint,
+	x: BigUint,
+	/// Must be stripped and have no leading zeros.
+	accuracy: BigUint,
+}
+
+/// Compute `2^((x_ideal - x) / d)` using taylor serie.
+///
+/// x must be strictly more than x_ideal.
+///
+/// result is expressed with accuracy `INPoSParam.accuracy`
+fn compute_taylor_serie_part(p: &INPoSParam) -> BigUint {
+	// The last computed taylor term.
+	let mut last_taylor_term = p.accuracy.clone();
+
+	// Whereas taylor sum is positive.
+	let mut taylor_sum_positive = true;
+
+	// The sum of all taylor term.
+	let mut taylor_sum = last_taylor_term.clone();
+
+	for k in 1..300 {
+		last_taylor_term = compute_taylor_term(k, &last_taylor_term, p);
+
+		if last_taylor_term.is_zero() {
+			break
+		}
+
+		let last_taylor_term_positive = k % 2 == 0;
+
+		if taylor_sum_positive == last_taylor_term_positive {
+			taylor_sum = taylor_sum.add(&last_taylor_term);
+		} else {
+			if taylor_sum >= last_taylor_term {
+				taylor_sum = taylor_sum.sub(&last_taylor_term)
+					// NOTE: Should never happen as checked above
+					.unwrap_or_else(|e| e);
+			} else {
+				taylor_sum_positive = !taylor_sum_positive;
+				taylor_sum = last_taylor_term.clone().sub(&taylor_sum)
+					// NOTE: Should never happen as checked above
+					.unwrap_or_else(|e| e);
+			}
+		}
+	}
+
+	if !taylor_sum_positive {
+		return BigUint::zero()
+	}
+
+	taylor_sum.lstrip();
+	taylor_sum
+}
+
+/// Return the absolute value of k-th taylor term of `2^((x_ideal - x))/d` i.e.
+/// `((x - x_ideal) * ln(2) / d)^k / k!`
+///
+/// x must be strictly more x_ideal.
+///
+/// We compute the term from the last term using this formula:
+///
+/// `((x - x_ideal) * ln(2) / d)^k / k! == previous_term * (x - x_ideal) * ln(2) / d / k`
+///
+/// `previous_taylor_term` and result are expressed with accuracy `INPoSParam.accuracy`
+fn compute_taylor_term(k: u32, previous_taylor_term: &BigUint, p: &INPoSParam) -> BigUint {
+	let x_minus_x_ideal = p.x.clone().sub(&p.x_ideal)
+		// NOTE: Should never happen, as x must be more than x_ideal
+		.unwrap_or_else(|_| BigUint::zero());
+
+	let res = previous_taylor_term.clone()
+		.mul(&x_minus_x_ideal)
+		.mul(&p.ln2_div_d)
+		.div_unit(k);
+
+	// p.accuracy is stripped by definition.
+	let res = div_by_stripped(res, &p.accuracy);
+	let mut res = div_by_stripped(res, &p.accuracy);
+
+	res.lstrip();
+	res
+}
+
+/// Compute a div b.
+///
+/// requires `b` to be stripped and have no leading zeros.
+fn div_by_stripped(mut a: BigUint, b: &BigUint) -> BigUint {
+	a.lstrip();
+
+	if b.len() == 0 {
+		log::error!("Computation error: Invalid division");
+		return BigUint::zero()
+	}
+
+	if b.len() == 1 {
+		return a.div_unit(b.checked_get(0).unwrap_or(1))
+	}
+
+	if b.len() > a.len() {
+		return BigUint::zero()
+	}
+
+	if b.len() == a.len() {
+		// 100_000^2 is more than 2^32-1, thus `new_a` has more limbs than `b`.
+		let mut new_a = a.mul(&BigUint::from(100_000u64.pow(2)));
+		new_a.lstrip();
+
+		debug_assert!(new_a.len() > b.len());
+		return new_a
+			.div(b, false)
+			.map(|res| res.0)
+			.unwrap_or_else(|| BigUint::zero())
+			.div_unit(100_000)
+			.div_unit(100_000)
+	}
+
+	a.div(b, false)
+		.map(|res| res.0)
+		.unwrap_or_else(|| BigUint::zero())
+}
diff --git a/frame/staking/reward-fn/tests/test.rs b/frame/staking/reward-fn/tests/test.rs
new file mode 100644
index 0000000000000..32daf9d09a76d
--- /dev/null
+++ b/frame/staking/reward-fn/tests/test.rs
@@ -0,0 +1,101 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use sp_arithmetic::{PerThing, Perbill, PerU16, Percent, Perquintill};
+
+/// This test the precision and panics if error too big error.
+///
+/// error is asserted to be less or equal to 8/accuracy or 8*f64::EPSILON
+fn test_precision<P: PerThing>(stake: P, ideal_stake: P, falloff: P) {
+	let accuracy_f64 = Into::<u128>::into(P::ACCURACY) as f64;
+	let res = pallet_staking_reward_fn::compute_inflation(stake, ideal_stake, falloff);
+	let res = Into::<u128>::into(res.deconstruct()) as f64 / accuracy_f64;
+
+	let expect = float_i_npos(stake, ideal_stake, falloff);
+
+	let error = (res - expect).abs();
+
+	if error > 8f64 / accuracy_f64 && error > 8.0 * f64::EPSILON {
+		panic!(
+			"stake: {:?}, ideal_stake: {:?}, falloff: {:?}, res: {}, expect: {}",
+			stake, ideal_stake, falloff, res , expect
+		);
+	}
+}
+
+/// compute the inflation using floats
+fn float_i_npos<P: PerThing>(stake: P, ideal_stake: P, falloff: P) -> f64 {
+	let accuracy_f64 = Into::<u128>::into(P::ACCURACY) as f64;
+
+	let ideal_stake = Into::<u128>::into(ideal_stake.deconstruct()) as f64 / accuracy_f64;
+	let stake = Into::<u128>::into(stake.deconstruct()) as f64 / accuracy_f64;
+	let falloff = Into::<u128>::into(falloff.deconstruct()) as f64 / accuracy_f64;
+
+	let x_ideal = ideal_stake;
+	let x = stake;
+	let d = falloff;
+
+	if x < x_ideal {
+		x / x_ideal
+	} else {
+		2_f64.powf((x_ideal - x) / d)
+	}
+}
+
+#[test]
+fn test_precision_for_minimum_falloff() {
+	fn test_falloff_precision_for_minimum_falloff<P: PerThing>() {
+		for stake in 0..1_000 {
+			let stake = P::from_rational(stake, 1_000);
+			let ideal_stake = P::zero();
+			let falloff = P::from_rational(1, 100);
+			test_precision(stake, ideal_stake, falloff);
+		}
+	}
+
+	test_falloff_precision_for_minimum_falloff::<Perquintill>();
+
+	test_falloff_precision_for_minimum_falloff::<PerU16>();
+
+	test_falloff_precision_for_minimum_falloff::<Perbill>();
+
+	test_falloff_precision_for_minimum_falloff::<Percent>();
+}
+
+#[test]
+fn compute_inflation_works() {
+	fn compute_inflation_works<P: PerThing>() {
+		for stake in 0..100 {
+			for ideal_stake in 0..10 {
+				for falloff in 1..10 {
+					let stake = P::from_rational(stake, 100);
+					let ideal_stake = P::from_rational(ideal_stake, 10);
+					let falloff = P::from_rational(falloff, 100);
+					test_precision(stake, ideal_stake, falloff);
+				}
+			}
+		}
+	}
+
+	compute_inflation_works::<Perquintill>();
+
+	compute_inflation_works::<PerU16>();
+
+	compute_inflation_works::<Perbill>();
+
+	compute_inflation_works::<Percent>();
+}
diff --git a/frame/staking/src/benchmarking.rs b/frame/staking/src/benchmarking.rs
index ecaa9889b5fb2..1d8a5c1fd6451 100644
--- a/frame/staking/src/benchmarking.rs
+++ b/frame/staking/src/benchmarking.rs
@@ -21,16 +21,12 @@ use super::*;
 use crate::Module as Staking;
 use testing_utils::*;
 
-use sp_npos_elections::CompactSolution;
 use sp_runtime::traits::One;
 use frame_system::RawOrigin;
 pub use frame_benchmarking::{
-	benchmarks,
-	account,
-	whitelisted_caller,
-	whitelist_account,
-	impl_benchmark_test_suite,
+	benchmarks, account, whitelisted_caller, whitelist_account, impl_benchmark_test_suite,
 };
+
 const SEED: u32 = 0;
 const MAX_SPANS: u32 = 100;
 const MAX_VALIDATORS: u32 = 1000;
@@ -97,8 +93,8 @@ pub fn create_validator_with_nominators<T: Config>(
 	// Start a new Era
 	let new_validators = Staking::<T>::new_era(SessionIndex::one()).unwrap();
 
-	assert!(new_validators.len() == 1);
-	assert!(new_validators[0] == v_stash, "Our validator was not selected!");
+	assert_eq!(new_validators.len(), 1);
+	assert_eq!(new_validators[0], v_stash, "Our validator was not selected!");
 
 	// Give Era Points
 	let reward = EraRewardPoints::<T::AccountId> {
@@ -208,16 +204,20 @@ benchmarks! {
 	kick {
 		// scenario: we want to kick `k` nominators from nominating us (we are a validator).
 		// we'll assume that `k` is under 128 for the purposes of determining the slope.
-		// each nominator should have `MAX_NOMINATIONS` validators nominated, and our validator
+		// each nominator should have `T::MAX_NOMINATIONS` validators nominated, and our validator
 		// should be somewhere in there.
 		let k in 1 .. 128;
 
-		// these are the other validators; there are `MAX_NOMINATIONS - 1` of them, so there are a
-		// total of `MAX_NOMINATIONS` validators in the system.
-		let rest_of_validators = create_validators::<T>(MAX_NOMINATIONS as u32 - 1, 100)?;
+		// these are the other validators; there are `T::MAX_NOMINATIONS - 1` of them, so
+		// there are a total of `T::MAX_NOMINATIONS` validators in the system.
+		let rest_of_validators = create_validators::<T>(T::MAX_NOMINATIONS - 1, 100)?;
 
 		// this is the validator that will be kicking.
-		let (stash, controller) = create_stash_controller::<T>(MAX_NOMINATIONS as u32 - 1, 100, Default::default())?;
+		let (stash, controller) = create_stash_controller::<T>(
+			T::MAX_NOMINATIONS - 1,
+			100,
+			Default::default(),
+		)?;
 		let stash_lookup: <T::Lookup as StaticLookup>::Source = T::Lookup::unlookup(stash.clone());
 
 		// they start validating.
@@ -228,7 +228,11 @@ benchmarks! {
 		let mut nominator_stashes = Vec::with_capacity(k as usize);
 		for i in 0 .. k {
 			// create a nominator stash.
-			let (n_stash, n_controller) = create_stash_controller::<T>(MAX_NOMINATIONS as u32 + i, 100, Default::default())?;
+			let (n_stash, n_controller) = create_stash_controller::<T>(
+				T::MAX_NOMINATIONS + i,
+				100,
+				Default::default(),
+			)?;
 
 			// bake the nominations; we first clone them from the rest of the validators.
 			let mut nominations = rest_of_validators.clone();
@@ -260,9 +264,9 @@ benchmarks! {
 		}
 	}
 
-	// Worst case scenario, MAX_NOMINATIONS
+	// Worst case scenario, T::MAX_NOMINATIONS
 	nominate {
-		let n in 1 .. MAX_NOMINATIONS as u32;
+		let n in 1 .. T::MAX_NOMINATIONS;
 		let (stash, controller) = create_stash_controller::<T>(n + 1, 100, Default::default())?;
 		let validators = create_validators::<T>(n, 100)?;
 		whitelist_account!(controller);
@@ -471,7 +475,13 @@ benchmarks! {
 		let v in 1 .. 10;
 		let n in 1 .. 100;
 
-		create_validators_with_nominators_for_era::<T>(v, n, MAX_NOMINATIONS, false, None)?;
+		create_validators_with_nominators_for_era::<T>(
+			v,
+			n,
+			<T as Config>::MAX_NOMINATIONS as usize,
+			false,
+			None,
+		)?;
 		let session_index = SessionIndex::one();
 	}: {
 		let validators = Staking::<T>::new_era(session_index).ok_or("`new_era` failed")?;
@@ -482,7 +492,13 @@ benchmarks! {
 	payout_all {
 		let v in 1 .. 10;
 		let n in 1 .. 100;
-		create_validators_with_nominators_for_era::<T>(v, n, MAX_NOMINATIONS, false, None)?;
+		create_validators_with_nominators_for_era::<T>(
+			v,
+			n,
+			<T as Config>::MAX_NOMINATIONS as usize,
+			false,
+			None,
+		)?;
 		// Start a new Era
 		let new_validators = Staking::<T>::new_era(SessionIndex::one()).unwrap();
 		assert!(new_validators.len() == v as usize);
@@ -544,229 +560,37 @@ benchmarks! {
 		assert!(balance_before > balance_after);
 	}
 
-	// This benchmark create `v` validators intent, `n` nominators intent, in total creating `e`
-	// edges.
-	#[extra]
-	submit_solution_initial {
-		// number of validator intention. This will be equal to `ElectionSize::validators`.
-		let v in 200 .. 400;
-		// number of nominator intention. This will be equal to `ElectionSize::nominators`.
-		let n in 500 .. 1000;
-		// number of assignments. Basically, number of active nominators. This will be equal to
-		// `compact.len()`.
-		let a in 200 .. 400;
-		// number of winners, also ValidatorCount. This will be equal to `winner.len()`.
-		let w in 16 .. 100;
-
-		ensure!(w as usize >= MAX_NOMINATIONS, "doesn't support lower value");
-
-		let winners = create_validators_with_nominators_for_era::<T>(
-			v,
-			n,
-			MAX_NOMINATIONS,
-			false,
-			Some(w),
-		)?;
-
-		// needed for the solution to be generates.
-		assert!(<Staking<T>>::create_stakers_snapshot().0);
-
-		// set number of winners
-		ValidatorCount::put(w);
-
-		// create a assignments in total for the w winners.
-		let (winners, assignments) = create_assignments_for_offchain::<T>(a, winners)?;
-
-		let (
-			winners,
-			compact,
-			score,
-			size
-		) = offchain_election::prepare_submission::<T>(
-			assignments,
-			winners,
-			false,
-			T::BlockWeights::get().max_block,
-		).unwrap();
-
-		assert_eq!(
-			winners.len(), compact.unique_targets().len(),
-			"unique targets ({}) and winners ({}) count not same. This solution is not valid.",
-			compact.unique_targets().len(),
-			winners.len(),
-		);
-
-		// needed for the solution to be accepted
-		<EraElectionStatus<T>>::put(ElectionStatus::Open(T::BlockNumber::from(1u32)));
-
-		let era = <Staking<T>>::current_era().unwrap_or(0);
-		let caller: T::AccountId = account("caller", n, SEED);
-		whitelist_account!(caller);
-	}: {
-		let result = <Staking<T>>::submit_election_solution(
-			RawOrigin::Signed(caller.clone()).into(),
-			winners,
-			compact,
-			score.clone(),
-			era,
-			size,
-		);
-		assert!(result.is_ok());
-	}
-	verify {
-		// new solution has been accepted.
-		assert_eq!(<Staking<T>>::queued_score().unwrap(), score);
-	}
-
-	// same as submit_solution_initial but we place a very weak solution on chian first.
-	submit_solution_better {
+	get_npos_voters {
 		// number of validator intention.
 		let v in 200 .. 400;
 		// number of nominator intention.
-		let n in 500 .. 1000;
-		// number of assignments. Basically, number of active nominators.
-		let a in 200 .. 400;
-		// number of winners, also ValidatorCount.
-		let w in 16 .. 100;
+		let n in 200 .. 400;
+		// total number of slashing spans. Assigned to validators randomly.
+		let s in 1 .. 20;
 
-		ensure!(w as usize >= MAX_NOMINATIONS, "doesn't support lower value");
-
-		let winners = create_validators_with_nominators_for_era::<T>(
-			v,
-			n,
-			MAX_NOMINATIONS,
-			false,
-			Some(w),
-		)?;
-
-		// needed for the solution to be generates.
-		assert!(<Staking<T>>::create_stakers_snapshot().0);
-
-		// set number of winners
-		ValidatorCount::put(w);
-
-		// create a assignments in total for the w winners.
-		let (winners, assignments) = create_assignments_for_offchain::<T>(a, winners)?;
-
-		let single_winner = winners[0].0.clone();
-
-		let (
-			winners,
-			compact,
-			score,
-			size
-		) = offchain_election::prepare_submission::<T>(
-			assignments,
-			winners,
-			false,
-			T::BlockWeights::get().max_block,
-		).unwrap();
-
-		assert_eq!(
-			winners.len(), compact.unique_targets().len(),
-			"unique targets ({}) and winners ({}) count not same. This solution is not valid.",
-			compact.unique_targets().len(),
-			winners.len(),
-		);
+		let validators = create_validators_with_nominators_for_era::<T>(v, n, T::MAX_NOMINATIONS as usize, false, None)?
+			.into_iter()
+			.map(|v| T::Lookup::lookup(v).unwrap())
+			.collect::<Vec<_>>();
 
-		// needed for the solution to be accepted
-		<EraElectionStatus<T>>::put(ElectionStatus::Open(T::BlockNumber::from(1u32)));
-
-		let era = <Staking<T>>::current_era().unwrap_or(0);
-		let caller: T::AccountId = account("caller", n, SEED);
-		whitelist_account!(caller);
-
-		// submit a very bad solution on-chain
-		{
-			// this is needed to fool the chain to accept this solution.
-			ValidatorCount::put(1);
-			let (winners, compact, score, size) = get_single_winner_solution::<T>(single_winner)?;
-			assert!(
-				<Staking<T>>::submit_election_solution(
-					RawOrigin::Signed(caller.clone()).into(),
-					winners,
-					compact,
-					score.clone(),
-					era,
-					size,
-			).is_ok());
-
-			// new solution has been accepted.
-			assert_eq!(<Staking<T>>::queued_score().unwrap(), score);
-			ValidatorCount::put(w);
-		}
+		(0..s).for_each(|index| {
+			add_slashing_spans::<T>(&validators[index as usize], 10);
+		});
 	}: {
-		let result = <Staking<T>>::submit_election_solution(
-			RawOrigin::Signed(caller.clone()).into(),
-			winners,
-			compact,
-			score.clone(),
-			era,
-			size,
-		);
-		assert!(result.is_ok());
-	}
-	verify {
-		// new solution has been accepted.
-		assert_eq!(<Staking<T>>::queued_score().unwrap(), score);
+		let voters = <Staking<T>>::get_npos_voters();
+		assert_eq!(voters.len() as u32, v + n);
 	}
 
-	// This will be early rejected based on the score.
-	#[extra]
-	submit_solution_weaker {
+	get_npos_targets {
 		// number of validator intention.
 		let v in 200 .. 400;
 		// number of nominator intention.
-		let n in 500 .. 1000;
-
-		create_validators_with_nominators_for_era::<T>(v, n, MAX_NOMINATIONS, false, None)?;
-
-		// needed for the solution to be generates.
-		assert!(<Staking<T>>::create_stakers_snapshot().0);
-
-		// needed for the solution to be accepted
-		<EraElectionStatus<T>>::put(ElectionStatus::Open(T::BlockNumber::from(1u32)));
-		let era = <Staking<T>>::current_era().unwrap_or(0);
-		let caller: T::AccountId = account("caller", n, SEED);
-		whitelist_account!(caller);
-
-		// submit a seq-phragmen with all the good stuff on chain.
-		{
-			let (winners, compact, score, size) = get_seq_phragmen_solution::<T>(true);
-			assert_eq!(
-				winners.len(), compact.unique_targets().len(),
-				"unique targets ({}) and winners ({}) count not same. This solution is not valid.",
-				compact.unique_targets().len(),
-				winners.len(),
-			);
-			assert!(
-				<Staking<T>>::submit_election_solution(
-					RawOrigin::Signed(caller.clone()).into(),
-					winners,
-					compact,
-					score.clone(),
-					era,
-					size,
-				).is_ok()
-			);
-
-			// new solution has been accepted.
-			assert_eq!(<Staking<T>>::queued_score().unwrap(), score);
-		}
+		let n = 500;
 
-		// prepare a bad solution. This will be very early rejected.
-		let (winners, compact, score, size) = get_weak_solution::<T>(true);
+		let _ = create_validators_with_nominators_for_era::<T>(v, n, T::MAX_NOMINATIONS as usize, false, None)?;
 	}: {
-		assert!(
-			<Staking<T>>::submit_election_solution(
-				RawOrigin::Signed(caller.clone()).into(),
-				winners,
-				compact,
-				score.clone(),
-				era,
-				size,
-			).is_err()
-		);
+		let targets = <Staking<T>>::get_npos_targets();
+		assert_eq!(targets.len() as u32, v);
 	}
 }
 
@@ -782,8 +606,13 @@ mod tests {
 			let v = 10;
 			let n = 100;
 
-			create_validators_with_nominators_for_era::<Test>(v, n, MAX_NOMINATIONS, false, None)
-				.unwrap();
+			create_validators_with_nominators_for_era::<Test>(
+				v,
+				n,
+				<Test as Config>::MAX_NOMINATIONS as usize,
+				false,
+				None,
+			).unwrap();
 
 			let count_validators = Validators::<Test>::iter().count();
 			let count_nominators = Nominators::<Test>::iter().count();
@@ -866,16 +695,6 @@ mod tests {
 			assert_ok!(closure_to_benchmark());
 		});
 	}
-
-	#[test]
-	#[ignore]
-	fn test_benchmarks_offchain() {
-		ExtBuilder::default().has_stakers(false).build().execute_with(|| {
-			assert_ok!(test_benchmark_submit_solution_better::<Test>());
-			assert_ok!(test_benchmark_submit_solution_weaker::<Test>());
-		});
-	}
-
 }
 
 impl_benchmark_test_suite!(
diff --git a/frame/staking/src/inflation.rs b/frame/staking/src/inflation.rs
index bd9d1f8bbdb30..e5259543fd4ba 100644
--- a/frame/staking/src/inflation.rs
+++ b/frame/staking/src/inflation.rs
@@ -38,7 +38,7 @@ pub fn compute_total_payout<N>(
 	// Milliseconds per year for the Julian year (365.25 days).
 	const MILLISECONDS_PER_YEAR: u64 = 1000 * 3600 * 24 * 36525 / 100;
 
-	let portion = Perbill::from_rational_approximation(era_duration as u64, MILLISECONDS_PER_YEAR);
+	let portion = Perbill::from_rational(era_duration as u64, MILLISECONDS_PER_YEAR);
 	let payout = portion * yearly_inflation.calculate_for_fraction_times_denominator(
 		npos_token_staked,
 		total_tokens.clone(),
diff --git a/frame/staking/src/lib.rs b/frame/staking/src/lib.rs
index 05511be63bb07..c28dbc87bccdd 100644
--- a/frame/staking/src/lib.rs
+++ b/frame/staking/src/lib.rs
@@ -19,9 +19,9 @@
 //!
 //! The Staking module is used to manage funds at stake by network maintainers.
 //!
-//! - [`staking::Config`](./trait.Config.html)
-//! - [`Call`](./enum.Call.html)
-//! - [`Module`](./struct.Module.html)
+//! - [`Config`]
+//! - [`Call`]
+//! - [`Module`]
 //!
 //! ## Overview
 //!
@@ -65,16 +65,16 @@
 //! is paired with an active **controller** account, which issues instructions on how they shall be
 //! used.
 //!
-//! An account pair can become bonded using the [`bond`](./enum.Call.html#variant.bond) call.
+//! An account pair can become bonded using the [`bond`](Call::bond) call.
 //!
 //! Stash accounts can change their associated controller using the
-//! [`set_controller`](./enum.Call.html#variant.set_controller) call.
+//! [`set_controller`](Call::set_controller) call.
 //!
 //! There are three possible roles that any staked account pair can be in: `Validator`, `Nominator`
-//! and `Idle` (defined in [`StakerStatus`](./enum.StakerStatus.html)). There are three
+//! and `Idle` (defined in [`StakerStatus`]). There are three
 //! corresponding instructions to change between roles, namely:
-//! [`validate`](./enum.Call.html#variant.validate),
-//! [`nominate`](./enum.Call.html#variant.nominate), and [`chill`](./enum.Call.html#variant.chill).
+//! [`validate`](Call::validate),
+//! [`nominate`](Call::nominate), and [`chill`](Call::chill).
 //!
 //! #### Validating
 //!
@@ -86,7 +86,7 @@
 //! by nominators and their votes.
 //!
 //! An account can become a validator candidate via the
-//! [`validate`](./enum.Call.html#variant.validate) call.
+//! [`validate`](Call::validate) call.
 //!
 //! #### Nomination
 //!
@@ -98,7 +98,7 @@
 //! the misbehaving/offline validators as much as possible, simply because the nominators will also
 //! lose funds if they vote poorly.
 //!
-//! An account can become a nominator via the [`nominate`](enum.Call.html#variant.nominate) call.
+//! An account can become a nominator via the [`nominate`](Call::nominate) call.
 //!
 //! #### Rewards and Slash
 //!
@@ -127,7 +127,7 @@
 //! This means that if they are a nominator, they will not be considered as voters anymore and if
 //! they are validators, they will no longer be a candidate for the next election.
 //!
-//! An account can step back via the [`chill`](enum.Call.html#variant.chill) call.
+//! An account can step back via the [`chill`](Call::chill) call.
 //!
 //! ### Session managing
 //!
@@ -175,7 +175,7 @@
 //! ### Era payout
 //!
 //! The era payout is computed using yearly inflation curve defined at
-//! [`T::RewardCurve`](./trait.Config.html#associatedtype.RewardCurve) as such:
+//! [`Config::EraPayout`] as such:
 //!
 //! ```nocompile
 //! staker_payout = yearly_inflation(npos_token_staked / total_tokens) * total_tokens / era_per_year
@@ -186,7 +186,7 @@
 //! remaining_payout = max_yearly_inflation * total_tokens / era_per_year - staker_payout
 //! ```
 //! The remaining reward is send to the configurable end-point
-//! [`T::RewardRemainder`](./trait.Config.html#associatedtype.RewardRemainder).
+//! [`Config::RewardRemainder`].
 //!
 //! ### Reward Calculation
 //!
@@ -198,29 +198,28 @@
 //!
 //! Total reward is split among validators and their nominators depending on the number of points
 //! they received during the era. Points are added to a validator using
-//! [`reward_by_ids`](./enum.Call.html#variant.reward_by_ids) or
-//! [`reward_by_indices`](./enum.Call.html#variant.reward_by_indices).
+//! [`reward_by_ids`](Module::reward_by_ids).
 //!
-//! [`Module`](./struct.Module.html) implements
-//! [`pallet_authorship::EventHandler`](../pallet_authorship/trait.EventHandler.html) to add reward
+//! [`Module`] implements
+//! [`pallet_authorship::EventHandler`] to add reward
 //! points to block producer and block producer of referenced uncles.
 //!
 //! The validator and its nominator split their reward as following:
 //!
 //! The validator can declare an amount, named
-//! [`commission`](./struct.ValidatorPrefs.html#structfield.commission), that does not get shared
+//! [`commission`](ValidatorPrefs::commission), that does not get shared
 //! with the nominators at each reward payout through its
-//! [`ValidatorPrefs`](./struct.ValidatorPrefs.html). This value gets deducted from the total reward
+//! [`ValidatorPrefs`]. This value gets deducted from the total reward
 //! that is paid to the validator and its nominators. The remaining portion is split among the
 //! validator and all of the nominators that nominated the validator, proportional to the value
 //! staked behind this validator (_i.e._ dividing the
-//! [`own`](./struct.Exposure.html#structfield.own) or
-//! [`others`](./struct.Exposure.html#structfield.others) by
-//! [`total`](./struct.Exposure.html#structfield.total) in [`Exposure`](./struct.Exposure.html)).
+//! [`own`](Exposure::own) or
+//! [`others`](Exposure::others) by
+//! [`total`](Exposure::total) in [`Exposure`]).
 //!
 //! All entities who receive a reward have the option to choose their reward destination through the
-//! [`Payee`](./struct.Payee.html) storage item (see
-//! [`set_payee`](enum.Call.html#variant.set_payee)), to be one of the following:
+//! [`Payee`] storage item (see
+//! [`set_payee`](Call::set_payee)), to be one of the following:
 //!
 //! - Controller account, (obviously) not increasing the staked value.
 //! - Stash account, not increasing the staked value.
@@ -231,15 +230,15 @@
 //! Any funds already placed into stash can be the target of the following operations:
 //!
 //! The controller account can free a portion (or all) of the funds using the
-//! [`unbond`](enum.Call.html#variant.unbond) call. Note that the funds are not immediately
+//! [`unbond`](Call::unbond) call. Note that the funds are not immediately
 //! accessible. Instead, a duration denoted by
-//! [`BondingDuration`](./trait.Config.html#associatedtype.BondingDuration) (in number of eras) must
+//! [`Config::BondingDuration`] (in number of eras) must
 //! pass until the funds can actually be removed. Once the `BondingDuration` is over, the
-//! [`withdraw_unbonded`](./enum.Call.html#variant.withdraw_unbonded) call can be used to actually
+//! [`withdraw_unbonded`](Call::withdraw_unbonded) call can be used to actually
 //! withdraw the funds.
 //!
 //! Note that there is a limitation to the number of fund-chunks that can be scheduled to be
-//! unlocked in the future via [`unbond`](enum.Call.html#variant.unbond). In case this maximum
+//! unlocked in the future via [`unbond`](Call::unbond). In case this maximum
 //! (`MAX_UNLOCKING_CHUNKS`) is reached, the bonded account _must_ first wait until a successful
 //! call to `withdraw_unbonded` to remove some of the chunks.
 //!
@@ -256,7 +255,7 @@
 //!
 //! ## GenesisConfig
 //!
-//! The Staking module depends on the [`GenesisConfig`](./struct.GenesisConfig.html). The
+//! The Staking module depends on the [`GenesisConfig`]. The
 //! `GenesisConfig` is optional and allow to set some initial stakers.
 //!
 //! ## Related Modules
@@ -278,7 +277,6 @@ pub mod testing_utils;
 pub mod benchmarking;
 
 pub mod slashing;
-pub mod offchain_election;
 pub mod inflation;
 pub mod weights;
 
@@ -286,34 +284,29 @@ use sp_std::{
 	result,
 	prelude::*,
 	collections::btree_map::BTreeMap,
-	convert::{TryInto, From},
-	mem::size_of,
+	convert::From,
 };
 use codec::{HasCompact, Encode, Decode};
 use frame_support::{
 	decl_module, decl_event, decl_storage, ensure, decl_error,
-	weights::{Weight, constants::{WEIGHT_PER_MICROS, WEIGHT_PER_NANOS}},
-	storage::IterableStorageMap,
-	dispatch::{
-		DispatchResult, DispatchResultWithPostInfo, DispatchErrorWithPostInfo,
-		WithPostDispatchInfo,
+	weights::{
+		Weight, WithPostDispatchInfo,
+		constants::{WEIGHT_PER_MICROS, WEIGHT_PER_NANOS},
 	},
+	storage::IterableStorageMap,
+	dispatch::{DispatchResult, DispatchResultWithPostInfo},
 	traits::{
 		Currency, LockIdentifier, LockableCurrency, WithdrawReasons, OnUnbalanced, Imbalance, Get,
-		UnixTime, EstimateNextNewSession, EnsureOrigin, CurrencyToVote, IsSubType,
-	}
+		UnixTime, EstimateNextNewSession, EnsureOrigin, CurrencyToVote,
+	},
 };
 use pallet_session::historical;
 use sp_runtime::{
-	Percent, Perbill, PerU16, RuntimeDebug, DispatchError,
+	Percent, Perbill, RuntimeDebug, DispatchError,
 	curve::PiecewiseLinear,
 	traits::{
 		Convert, Zero, StaticLookup, CheckedSub, Saturating, SaturatedConversion,
-		AtLeast32BitUnsigned, Dispatchable,
-	},
-	transaction_validity::{
-		TransactionValidityError, TransactionValidity, ValidTransaction, InvalidTransaction,
-		TransactionSource, TransactionPriority,
+		AtLeast32BitUnsigned,
 	},
 };
 use sp_staking::{
@@ -323,15 +316,10 @@ use sp_staking::{
 #[cfg(feature = "std")]
 use sp_runtime::{Serialize, Deserialize};
 use frame_system::{
-	self as system, ensure_signed, ensure_root, ensure_none,
+	self as system, ensure_signed, ensure_root,
 	offchain::SendTransactionTypes,
 };
-use sp_npos_elections::{
-	ExtendedBalance, Assignment, ElectionScore, ElectionResult as PrimitiveElectionResult,
-	to_supports, EvaluateSupport, seq_phragmen, generate_solution_type, is_score_better, Supports,
-	VoteWeight, CompactSolution, PerThing128,
-};
-use sp_election_providers::ElectionProvider;
+use frame_election_provider_support::{ElectionProvider, VoteWeight, Supports, data_provider};
 pub use weights::WeightInfo;
 
 const STAKING_ID: LockIdentifier = *b"staking ";
@@ -343,29 +331,11 @@ macro_rules! log {
 	($level:tt, $patter:expr $(, $values:expr)* $(,)?) => {
 		log::$level!(
 			target: crate::LOG_TARGET,
-			concat!("💸 ", $patter) $(, $values)*
+			concat!("[{:?}] 💸 ", $patter), <frame_system::Pallet<T>>::block_number() $(, $values)*
 		)
 	};
 }
 
-/// Data type used to index nominators in the compact type
-pub type NominatorIndex = u32;
-
-/// Data type used to index validators in the compact type.
-pub type ValidatorIndex = u16;
-
-// Ensure the size of both ValidatorIndex and NominatorIndex. They both need to be well below usize.
-static_assertions::const_assert!(size_of::<ValidatorIndex>() <= size_of::<usize>());
-static_assertions::const_assert!(size_of::<NominatorIndex>() <= size_of::<usize>());
-static_assertions::const_assert!(size_of::<ValidatorIndex>() <= size_of::<u32>());
-static_assertions::const_assert!(size_of::<NominatorIndex>() <= size_of::<u32>());
-
-/// Maximum number of stakers that can be stored in a snapshot.
-pub(crate) const MAX_VALIDATORS: usize = ValidatorIndex::max_value() as usize;
-pub(crate) const MAX_NOMINATORS: usize = NominatorIndex::max_value() as usize;
-pub const MAX_NOMINATIONS: usize =
-	<CompactAssignments as sp_npos_elections::CompactSolution>::LIMIT;
-
 pub const MAX_UNLOCKING_CHUNKS: usize = 32;
 
 /// Counter for the number of eras that have passed.
@@ -374,18 +344,6 @@ pub type EraIndex = u32;
 /// Counter for the number of "reward" points earned by a given validator.
 pub type RewardPoint = u32;
 
-// Note: Maximum nomination limit is set here -- 16.
-generate_solution_type!(
-	#[compact]
-	pub struct CompactAssignments::<NominatorIndex, ValidatorIndex, OffchainAccuracy>(16)
-);
-
-/// Accuracy used for on-chain election.
-pub type ChainAccuracy = Perbill;
-
-/// Accuracy used for off-chain election. This better be small.
-pub type OffchainAccuracy = PerU16;
-
 /// The balance type of this module.
 pub type BalanceOf<T> =
 	<<T as Config>::Currency as Currency<<T as frame_system::Config>::AccountId>>::Balance;
@@ -670,78 +628,6 @@ pub struct UnappliedSlash<AccountId, Balance: HasCompact> {
 	payout: Balance,
 }
 
-/// Indicate how an election round was computed.
-#[derive(PartialEq, Eq, Clone, Copy, Encode, Decode, RuntimeDebug)]
-pub enum ElectionCompute {
-	/// Result was forcefully computed on chain at the end of the session.
-	OnChain,
-	/// Result was submitted and accepted to the chain via a signed transaction.
-	Signed,
-	/// Result was submitted and accepted to the chain via an unsigned transaction (by an
-	/// authority).
-	Unsigned,
-}
-
-/// The result of an election round.
-#[derive(PartialEq, Eq, Clone, Encode, Decode, RuntimeDebug)]
-pub struct ElectionResult<AccountId, Balance: HasCompact> {
-	/// Flat list of validators who have been elected.
-	elected_stashes: Vec<AccountId>,
-	/// Flat list of new exposures, to be updated in the [`Exposure`] storage.
-	exposures: Vec<(AccountId, Exposure<AccountId, Balance>)>,
-	/// Type of the result. This is kept on chain only to track and report the best score's
-	/// submission type. An optimisation could remove this.
-	compute: ElectionCompute,
-}
-
-/// The status of the upcoming (offchain) election.
-#[derive(PartialEq, Eq, Clone, Encode, Decode, RuntimeDebug)]
-pub enum ElectionStatus<BlockNumber> {
-	/// Nothing has and will happen for now. submission window is not open.
-	Closed,
-	/// The submission window has been open since the contained block number.
-	Open(BlockNumber),
-}
-
-/// Some indications about the size of the election. This must be submitted with the solution.
-///
-/// Note that these values must reflect the __total__ number, not only those that are present in the
-/// solution. In short, these should be the same size as the size of the values dumped in
-/// `SnapshotValidators` and `SnapshotNominators`.
-#[derive(PartialEq, Eq, Clone, Copy, Encode, Decode, RuntimeDebug, Default)]
-pub struct ElectionSize {
-	/// Number of validators in the snapshot of the current election round.
-	#[codec(compact)]
-	pub validators: ValidatorIndex,
-	/// Number of nominators in the snapshot of the current election round.
-	#[codec(compact)]
-	pub nominators: NominatorIndex,
-}
-
-
-impl<BlockNumber: PartialEq> ElectionStatus<BlockNumber> {
-	pub fn is_open_at(&self, n: BlockNumber) -> bool {
-		*self == Self::Open(n)
-	}
-
-	pub fn is_closed(&self) -> bool {
-		match self {
-			Self::Closed => true,
-			_ => false
-		}
-	}
-
-	pub fn is_open(&self) -> bool {
-		!self.is_closed()
-	}
-}
-
-impl<BlockNumber> Default for ElectionStatus<BlockNumber> {
-	fn default() -> Self {
-		Self::Closed
-	}
-}
-
 /// Means for interacting with a specialized version of the `session` trait.
 ///
 /// This is needed because `Staking` sets the `ValidatorIdOf` of the `pallet_session::Config`
@@ -782,6 +668,53 @@ impl<T: Config> SessionInterface<<T as frame_system::Config>::AccountId> for T w
 	}
 }
 
+/// Handler for determining how much of a balance should be paid out on the current era.
+pub trait EraPayout<Balance> {
+	/// Determine the payout for this era.
+	///
+	/// Returns the amount to be paid to stakers in this era, as well as whatever else should be
+	/// paid out ("the rest").
+	fn era_payout(
+		total_staked: Balance,
+		total_issuance: Balance,
+		era_duration_millis: u64,
+	) -> (Balance, Balance);
+}
+
+impl<Balance: Default> EraPayout<Balance> for () {
+	fn era_payout(
+		_total_staked: Balance,
+		_total_issuance: Balance,
+		_era_duration_millis: u64,
+	) -> (Balance, Balance) {
+		(Default::default(), Default::default())
+	}
+}
+
+/// Adaptor to turn a `PiecewiseLinear` curve definition into an `EraPayout` impl, used for
+/// backwards compatibility.
+pub struct ConvertCurve<T>(sp_std::marker::PhantomData<T>);
+impl<
+	Balance: AtLeast32BitUnsigned + Clone,
+	T: Get<&'static PiecewiseLinear<'static>>,
+> EraPayout<Balance> for ConvertCurve<T> {
+	fn era_payout(
+		total_staked: Balance,
+		total_issuance: Balance,
+		era_duration_millis: u64,
+	) -> (Balance, Balance) {
+		let (validator_payout, max_payout) = inflation::compute_total_payout(
+			&T::get(),
+			total_staked,
+			total_issuance,
+			// Duration of era; more than u64::MAX is rewarded as u64::MAX.
+			era_duration_millis,
+		);
+		let rest = max_payout.saturating_sub(validator_payout.clone());
+		(validator_payout, rest)
+	}
+}
+
 pub trait Config: frame_system::Config + SendTransactionTypes<Call<Self>> {
 	/// The staking balance.
 	type Currency: LockableCurrency<Self::AccountId, Moment = Self::BlockNumber>;
@@ -800,13 +733,16 @@ pub trait Config: frame_system::Config + SendTransactionTypes<Call<Self>> {
 	type CurrencyToVote: CurrencyToVote<BalanceOf<Self>>;
 
 	/// Something that provides the election functionality.
-	type ElectionProvider: sp_election_providers::ElectionProvider<
+	type ElectionProvider: frame_election_provider_support::ElectionProvider<
 		Self::AccountId,
 		Self::BlockNumber,
 		// we only accept an election provider that has staking as data provider.
 		DataProvider = Module<Self>,
 	>;
 
+	/// Maximum number of nominations per nominator.
+	const MAX_NOMINATIONS: u32;
+
 	/// Tokens have been minted and are unused for validator-reward.
 	/// See [Era payout](./index.html#era-payout).
 	type RewardRemainder: OnUnbalanced<NegativeImbalanceOf<Self>>;
@@ -838,52 +774,19 @@ pub trait Config: frame_system::Config + SendTransactionTypes<Call<Self>> {
 	/// Interface for interacting with a session module.
 	type SessionInterface: self::SessionInterface<Self::AccountId>;
 
-	/// The NPoS reward curve used to define yearly inflation.
+	/// The payout for validators and the system for the current era.
 	/// See [Era payout](./index.html#era-payout).
-	type RewardCurve: Get<&'static PiecewiseLinear<'static>>;
+	type EraPayout: EraPayout<BalanceOf<Self>>;
 
 	/// Something that can estimate the next session change, accurately or as a best effort guess.
 	type NextNewSession: EstimateNextNewSession<Self::BlockNumber>;
 
-	/// The number of blocks before the end of the era from which election submissions are allowed.
-	///
-	/// Setting this to zero will disable the offchain compute and only on-chain seq-phragmen will
-	/// be used.
-	///
-	/// This is bounded by being within the last session. Hence, setting it to a value more than the
-	/// length of a session will be pointless.
-	type ElectionLookahead: Get<Self::BlockNumber>;
-
-	/// The overarching call type.
-	type Call: Dispatchable + From<Call<Self>> + IsSubType<Call<Self>> + Clone;
-
-	/// Maximum number of balancing iterations to run in the offchain submission.
-	///
-	/// If set to 0, balance_solution will not be executed at all.
-	type MaxIterations: Get<u32>;
-
-	/// The threshold of improvement that should be provided for a new solution to be accepted.
-	type MinSolutionScoreBump: Get<Perbill>;
-
 	/// The maximum number of nominators rewarded for each validator.
 	///
 	/// For each validator only the `$MaxNominatorRewardedPerValidator` biggest stakers can claim
 	/// their reward. This used to limit the i/o cost for the nominator payout.
 	type MaxNominatorRewardedPerValidator: Get<u32>;
 
-	/// A configuration for base priority of unsigned transactions.
-	///
-	/// This is exposed so that it can be tuned for particular runtime, when
-	/// multiple pallets send unsigned transactions.
-	type UnsignedPriority: Get<TransactionPriority>;
-
-	/// Maximum weight that the unsigned transaction can have.
-	///
-	/// Chose this value with care. On one hand, it should be as high as possible, so the solution
-	/// can contain as many nominators/validators as possible. On the other hand, it should be small
-	/// enough to fit in the block.
-	type OffchainSolutionWeightLimit: Get<Weight>;
-
 	/// Weight information for extrinsics in this pallet.
 	type WeightInfo: WeightInfo;
 }
@@ -917,12 +820,13 @@ enum Releases {
 	V2_0_0,
 	V3_0_0,
 	V4_0_0,
-	V5_0_0,
+	V5_0_0, // blockable validators.
+	V6_0_0, // removal of all storage associated with offchain phragmen.
 }
 
 impl Default for Releases {
 	fn default() -> Self {
-		Releases::V5_0_0
+		Releases::V6_0_0
 	}
 }
 
@@ -1087,47 +991,11 @@ decl_storage! {
 		/// This is basically in sync with the call to [`SessionManager::new_session`].
 		pub CurrentPlannedSession get(fn current_planned_session): SessionIndex;
 
-		/// Snapshot of validators at the beginning of the current election window. This should only
-		/// have a value when [`EraElectionStatus`] == `ElectionStatus::Open(_)`.
-		///
-		/// TWO_PHASE_NOTE: should be removed once we switch to multi-phase.
-		pub SnapshotValidators get(fn snapshot_validators): Option<Vec<T::AccountId>>;
-
-		/// Snapshot of nominators at the beginning of the current election window. This should only
-		/// have a value when [`EraElectionStatus`] == `ElectionStatus::Open(_)`.
-		///
-		/// TWO_PHASE_NOTE: should be removed once we switch to multi-phase.
-		pub SnapshotNominators get(fn snapshot_nominators): Option<Vec<T::AccountId>>;
-
-		/// The next validator set. At the end of an era, if this is available (potentially from the
-		/// result of an offchain worker), it is immediately used. Otherwise, the on-chain election
-		/// is executed.
-		///
-		/// TWO_PHASE_NOTE: should be removed once we switch to multi-phase.
-		pub QueuedElected get(fn queued_elected): Option<ElectionResult<T::AccountId, BalanceOf<T>>>;
-
-		/// The score of the current [`QueuedElected`].
-		///
-		/// TWO_PHASE_NOTE: should be removed once we switch to multi-phase.
-		pub QueuedScore get(fn queued_score): Option<ElectionScore>;
-
-		/// Flag to control the execution of the offchain election. When `Open(_)`, we accept
-		/// solutions to be submitted.
-		///
-		/// TWO_PHASE_NOTE: should be removed once we switch to multi-phase.
-		pub EraElectionStatus get(fn era_election_status): ElectionStatus<T::BlockNumber>;
-
-		/// True if the current **planned** session is final. Note that this does not take era
-		/// forcing into account.
-		///
-		/// TWO_PHASE_NOTE: should be removed once we switch to multi-phase.
-		pub IsCurrentSessionFinal get(fn is_current_session_final): bool = false;
-
 		/// True if network has been upgraded to this version.
 		/// Storage version of the pallet.
 		///
-		/// This is set to v5.0.0 for new networks.
-		StorageVersion build(|_: &GenesisConfig<T>| Releases::V5_0_0): Releases;
+		/// This is set to v6.0.0 for new networks.
+		StorageVersion build(|_: &GenesisConfig<T>| Releases::V6_0_0): Releases;
 	}
 	add_extra_genesis {
 		config(stakers):
@@ -1166,23 +1034,46 @@ decl_storage! {
 pub mod migrations {
 	use super::*;
 
-	#[derive(Decode)]
-	struct OldValidatorPrefs {
-		#[codec(compact)]
-		pub commission: Perbill
-	}
-	impl OldValidatorPrefs {
-		fn upgraded(self) -> ValidatorPrefs {
-			ValidatorPrefs {
-				commission: self.commission,
-				.. Default::default()
-			}
+	pub mod v6 {
+		use super::*;
+		use frame_support::{traits::Get, weights::Weight, generate_storage_alias};
+
+		// NOTE: value type doesn't matter, we just set it to () here.
+		generate_storage_alias!(Staking, SnapshotValidators => Value<()>);
+		generate_storage_alias!(Staking, SnapshotNominators => Value<()>);
+		generate_storage_alias!(Staking, QueuedElected => Value<()>);
+		generate_storage_alias!(Staking, QueuedScore => Value<()>);
+		generate_storage_alias!(Staking, EraElectionStatus => Value<()>);
+		generate_storage_alias!(Staking, IsCurrentSessionFinal => Value<()>);
+
+		/// check to execute prior to migration.
+		pub fn pre_migrate<T: Config>() -> Result<(), &'static str> {
+			// these may or may not exist.
+			log!(info, "SnapshotValidators.exits()? {:?}", SnapshotValidators::exists());
+			log!(info, "SnapshotNominators.exits()? {:?}", SnapshotNominators::exists());
+			log!(info, "QueuedElected.exits()? {:?}", QueuedElected::exists());
+			log!(info, "QueuedScore.exits()? {:?}", QueuedScore::exists());
+			// these must exist.
+			assert!(IsCurrentSessionFinal::exists(), "IsCurrentSessionFinal storage item not found!");
+			assert!(EraElectionStatus::exists(), "EraElectionStatus storage item not found!");
+			Ok(())
+		}
+
+		/// Migrate storage to v6.
+		pub fn migrate<T: Config>() -> Weight {
+			log!(info, "Migrating staking to Releases::V6_0_0");
+
+			SnapshotValidators::kill();
+			SnapshotNominators::kill();
+			QueuedElected::kill();
+			QueuedScore::kill();
+			EraElectionStatus::kill();
+			IsCurrentSessionFinal::kill();
+
+			StorageVersion::put(Releases::V6_0_0);
+			log!(info, "Done.");
+			T::DbWeight::get().writes(6 + 1)
 		}
-	}
-	pub fn migrate_to_blockable<T: Config>() -> frame_support::weights::Weight {
-		Validators::<T>::translate::<OldValidatorPrefs, _>(|_, p| Some(p.upgraded()));
-		ErasValidatorPrefs::<T>::translate::<OldValidatorPrefs, _>(|_, _, p| Some(p.upgraded()));
-		T::BlockWeights::get().max_block
 	}
 }
 
@@ -1200,10 +1091,8 @@ decl_event!(
 		/// An old slashing report from a prior era was discarded because it could
 		/// not be processed. \[session_index\]
 		OldSlashingReportDiscarded(SessionIndex),
-		/// A new set of stakers was elected with the given \[compute\].
-		StakingElection(ElectionCompute),
-		/// A new solution for the upcoming election has been stored. \[compute\]
-		SolutionStored(ElectionCompute),
+		/// A new set of stakers was elected.
+		StakingElection,
 		/// An account has bonded this amount. \[stash, amount\]
 		///
 		/// NOTE: This event is only emitted when funds are bonded via a dispatchable. Notably,
@@ -1252,37 +1141,6 @@ decl_error! {
 		NotSortedAndUnique,
 		/// Rewards for this era have already been claimed for this validator.
 		AlreadyClaimed,
-		/// The submitted result is received out of the open window.
-		OffchainElectionEarlySubmission,
-		/// The submitted result is not as good as the one stored on chain.
-		OffchainElectionWeakSubmission,
-		/// The snapshot data of the current window is missing.
-		SnapshotUnavailable,
-		/// Incorrect number of winners were presented.
-		OffchainElectionBogusWinnerCount,
-		/// One of the submitted winners is not an active candidate on chain (index is out of range
-		/// in snapshot).
-		OffchainElectionBogusWinner,
-		/// Error while building the assignment type from the compact. This can happen if an index
-		/// is invalid, or if the weights _overflow_.
-		OffchainElectionBogusCompact,
-		/// One of the submitted nominators is not an active nominator on chain.
-		OffchainElectionBogusNominator,
-		/// One of the submitted nominators has an edge to which they have not voted on chain.
-		OffchainElectionBogusNomination,
-		/// One of the submitted nominators has an edge which is submitted before the last non-zero
-		/// slash of the target.
-		OffchainElectionSlashedNomination,
-		/// A self vote must only be originated from a validator to ONLY themselves.
-		OffchainElectionBogusSelfVote,
-		/// The submitted result has unknown edges that are not among the presented winners.
-		OffchainElectionBogusEdge,
-		/// The claimed score does not match with the one computed from the data.
-		OffchainElectionBogusScore,
-		/// The election size is invalid.
-		OffchainElectionBogusElectionSize,
-		/// The call is not allowed at the given time due to restrictions of election period.
-		CallNotAllowed,
 		/// Incorrect previous history depth input provided.
 		IncorrectHistoryDepth,
 		/// Incorrect number of slashing spans provided.
@@ -1311,110 +1169,30 @@ decl_module! {
 		/// intervention.
 		const SlashDeferDuration: EraIndex = T::SlashDeferDuration::get();
 
-		/// The number of blocks before the end of the era from which election submissions are allowed.
-		///
-		/// Setting this to zero will disable the offchain compute and only on-chain seq-phragmen will
-		/// be used.
-		///
-		/// This is bounded by being within the last session. Hence, setting it to a value more than the
-		/// length of a session will be pointless.
-		const ElectionLookahead: T::BlockNumber = T::ElectionLookahead::get();
-
-		/// Maximum number of balancing iterations to run in the offchain submission.
-		///
-		/// If set to 0, balance_solution will not be executed at all.
-		const MaxIterations: u32 = T::MaxIterations::get();
-
-		/// The threshold of improvement that should be provided for a new solution to be accepted.
-		const MinSolutionScoreBump: Perbill = T::MinSolutionScoreBump::get();
-
 		/// The maximum number of nominators rewarded for each validator.
 		///
 		/// For each validator only the `$MaxNominatorRewardedPerValidator` biggest stakers can claim
 		/// their reward. This used to limit the i/o cost for the nominator payout.
 		const MaxNominatorRewardedPerValidator: u32 = T::MaxNominatorRewardedPerValidator::get();
 
+		/// Maximum number of nominations per nominator.
+		const MaxNominations: u32 = T::MAX_NOMINATIONS;
+
 		type Error = Error<T>;
 
 		fn deposit_event() = default;
 
-		fn on_runtime_upgrade() -> frame_support::weights::Weight {
-			if StorageVersion::get() == Releases::V4_0_0 {
-				StorageVersion::put(Releases::V5_0_0);
-				migrations::migrate_to_blockable::<T>()
+		fn on_runtime_upgrade() -> Weight {
+			if StorageVersion::get() == Releases::V5_0_0 {
+				migrations::v6::migrate::<T>()
 			} else {
-				0
+				T::DbWeight::get().reads(1)
 			}
 		}
 
-		/// sets `ElectionStatus` to `Open(now)` where `now` is the block number at which the
-		/// election window has opened, if we are at the last session and less blocks than
-		/// `T::ElectionLookahead` is remaining until the next new session schedule. The offchain
-		/// worker, if applicable, will execute at the end of the current block, and solutions may
-		/// be submitted.
-		fn on_initialize(now: T::BlockNumber) -> Weight {
-			let mut consumed_weight = 0;
-			let mut add_weight = |reads, writes, weight| {
-				consumed_weight += T::DbWeight::get().reads_writes(reads, writes);
-				consumed_weight += weight;
-			};
-
-			if
-				// if we don't have any ongoing offchain compute.
-				Self::era_election_status().is_closed() &&
-				// either current session final based on the plan, or we're forcing.
-				(Self::is_current_session_final() || Self::will_era_be_forced())
-			{
-				let (maybe_next_session_change, estimate_next_new_session_weight) =
-					T::NextNewSession::estimate_next_new_session(now);
-
-				if let Some(next_session_change) = maybe_next_session_change {
-					if let Some(remaining) = next_session_change.checked_sub(&now) {
-						if remaining <= T::ElectionLookahead::get() && !remaining.is_zero() {
-							// create snapshot.
-							let (did_snapshot, snapshot_weight) = Self::create_stakers_snapshot();
-							add_weight(0, 0, snapshot_weight);
-							if did_snapshot {
-								// Set the flag to make sure we don't waste any compute here in the same era
-								// after we have triggered the offline compute.
-								<EraElectionStatus<T>>::put(
-									ElectionStatus::<T::BlockNumber>::Open(now)
-								);
-								add_weight(0, 1, 0);
-								log!(info, "Election window is Open({:?}). Snapshot created", now);
-							} else {
-								log!(warn, "Failed to create snapshot at {:?}.", now);
-							}
-						}
-					}
-				} else {
-					log!(warn, "Estimating next session change failed.");
-				}
-				add_weight(0, 0, estimate_next_new_session_weight)
-			}
-			// For `era_election_status`, `is_current_session_final`, `will_era_be_forced`
-			add_weight(3, 0, 0);
-			// Additional read from `on_finalize`
-			add_weight(1, 0, 0);
-			consumed_weight
-		}
-
-		/// Check if the current block number is the one at which the election window has been set
-		/// to open. If so, it runs the offchain worker code.
-		fn offchain_worker(now: T::BlockNumber) {
-			use offchain_election::{set_check_offchain_execution_status, compute_offchain_election};
-			if Self::era_election_status().is_open_at(now) {
-				let offchain_status = set_check_offchain_execution_status::<T>(now);
-				if let Err(why) = offchain_status {
-					log!(warn, "skipping offchain worker in open election window due to [{}]", why);
-				} else {
-					if let Err(e) = compute_offchain_election::<T>() {
-						log!(error, "Error in election offchain worker: {:?}", e);
-					} else {
-						log!(debug, "Executed offchain worker thread without errors.");
-					}
-				}
-			}
+		fn on_initialize(_now: T::BlockNumber) -> Weight {
+			// just return the weight of the on_finalize.
+			T::DbWeight::get().reads(1)
 		}
 
 		fn on_finalize() {
@@ -1439,25 +1217,6 @@ decl_module! {
 					T::BondingDuration::get(),
 				)
 			);
-
-			use sp_runtime::UpperOf;
-			// see the documentation of `Assignment::try_normalize`. Now we can ensure that this
-			// will always return `Ok`.
-			// 1. Maximum sum of Vec<ChainAccuracy> must fit into `UpperOf<ChainAccuracy>`.
-			assert!(
-				<usize as TryInto<UpperOf<ChainAccuracy>>>::try_into(MAX_NOMINATIONS)
-				.unwrap()
-				.checked_mul(<ChainAccuracy>::one().deconstruct().try_into().unwrap())
-				.is_some()
-			);
-
-			// 2. Maximum sum of Vec<OffchainAccuracy> must fit into `UpperOf<OffchainAccuracy>`.
-			assert!(
-				<usize as TryInto<UpperOf<OffchainAccuracy>>>::try_into(MAX_NOMINATIONS)
-				.unwrap()
-				.checked_mul(<OffchainAccuracy>::one().deconstruct().try_into().unwrap())
-				.is_some()
-			);
 		}
 
 		/// Take the origin account as a stash and lock up `value` of its balance. `controller` will
@@ -1505,7 +1264,7 @@ decl_module! {
 				Err(Error::<T>::InsufficientValue)?
 			}
 
-			system::Module::<T>::inc_consumers(&stash).map_err(|_| Error::<T>::BadState)?;
+			system::Pallet::<T>::inc_consumers(&stash).map_err(|_| Error::<T>::BadState)?;
 
 			// You're auto-bonded forever, here. We might improve this by only bonding when
 			// you actually validate/nominate and remove once you unbond __everything__.
@@ -1552,7 +1311,6 @@ decl_module! {
 		/// # </weight>
 		#[weight = T::WeightInfo::bond_extra()]
 		fn bond_extra(origin, #[compact] max_additional: BalanceOf<T>) {
-			ensure!(Self::era_election_status().is_closed(), Error::<T>::CallNotAllowed);
 			let stash = ensure_signed(origin)?;
 
 			let controller = Self::bonded(&stash).ok_or(Error::<T>::NotStash)?;
@@ -1605,7 +1363,6 @@ decl_module! {
 		/// </weight>
 		#[weight = T::WeightInfo::unbond()]
 		fn unbond(origin, #[compact] value: BalanceOf<T>) {
-			ensure!(Self::era_election_status().is_closed(), Error::<T>::CallNotAllowed);
 			let controller = ensure_signed(origin)?;
 			let mut ledger = Self::ledger(&controller).ok_or(Error::<T>::NotController)?;
 			ensure!(
@@ -1665,7 +1422,6 @@ decl_module! {
 		/// # </weight>
 		#[weight = T::WeightInfo::withdraw_unbonded_kill(*num_slashing_spans)]
 		fn withdraw_unbonded(origin, num_slashing_spans: u32) -> DispatchResultWithPostInfo {
-			ensure!(Self::era_election_status().is_closed(), Error::<T>::CallNotAllowed);
 			let controller = ensure_signed(origin)?;
 			let mut ledger = Self::ledger(&controller).ok_or(Error::<T>::NotController)?;
 			let (stash, old_total) = (ledger.stash.clone(), ledger.total);
@@ -1720,7 +1476,6 @@ decl_module! {
 		/// # </weight>
 		#[weight = T::WeightInfo::validate()]
 		pub fn validate(origin, prefs: ValidatorPrefs) {
-			ensure!(Self::era_election_status().is_closed(), Error::<T>::CallNotAllowed);
 			let controller = ensure_signed(origin)?;
 			let ledger = Self::ledger(&controller).ok_or(Error::<T>::NotController)?;
 			let stash = &ledger.stash;
@@ -1749,12 +1504,11 @@ decl_module! {
 		/// # </weight>
 		#[weight = T::WeightInfo::nominate(targets.len() as u32)]
 		pub fn nominate(origin, targets: Vec<<T::Lookup as StaticLookup>::Source>) {
-			ensure!(Self::era_election_status().is_closed(), Error::<T>::CallNotAllowed);
 			let controller = ensure_signed(origin)?;
 			let ledger = Self::ledger(&controller).ok_or(Error::<T>::NotController)?;
 			let stash = &ledger.stash;
 			ensure!(!targets.is_empty(), Error::<T>::EmptyTargets);
-			ensure!(targets.len() <= MAX_NOMINATIONS, Error::<T>::TooManyTargets);
+			ensure!(targets.len() <= T::MAX_NOMINATIONS as usize, Error::<T>::TooManyTargets);
 
 			let old = Nominators::<T>::get(stash).map_or_else(Vec::new, |x| x.targets);
 
@@ -1797,7 +1551,6 @@ decl_module! {
 		/// # </weight>
 		#[weight = T::WeightInfo::chill()]
 		fn chill(origin) {
-			ensure!(Self::era_election_status().is_closed(), Error::<T>::CallNotAllowed);
 			let controller = ensure_signed(origin)?;
 			let ledger = Self::ledger(&controller).ok_or(Error::<T>::NotController)?;
 			Self::chill_stash(&ledger.stash);
@@ -2040,8 +1793,7 @@ decl_module! {
 		///   Paying even a dead controller is cheaper weight-wise. We don't do any refunds here.
 		/// # </weight>
 		#[weight = T::WeightInfo::payout_stakers_alive_staked(T::MaxNominatorRewardedPerValidator::get())]
-		fn payout_stakers(origin, validator_stash: T::AccountId, era: EraIndex) -> DispatchResult {
-			ensure!(Self::era_election_status().is_closed(), Error::<T>::CallNotAllowed);
+		fn payout_stakers(origin, validator_stash: T::AccountId, era: EraIndex) -> DispatchResultWithPostInfo {
 			ensure_signed(origin)?;
 			Self::do_payout_stakers(validator_stash, era)
 		}
@@ -2062,7 +1814,6 @@ decl_module! {
 		/// # </weight>
 		#[weight = T::WeightInfo::rebond(MAX_UNLOCKING_CHUNKS as u32)]
 		fn rebond(origin, #[compact] value: BalanceOf<T>) -> DispatchResultWithPostInfo {
-			ensure!(Self::era_election_status().is_closed(), Error::<T>::CallNotAllowed);
 			let controller = ensure_signed(origin)?;
 			let ledger = Self::ledger(&controller).ok_or(Error::<T>::NotController)?;
 			ensure!(!ledger.unlocking.is_empty(), Error::<T>::NoUnlockChunk);
@@ -2141,121 +1892,6 @@ decl_module! {
 			T::Currency::remove_lock(STAKING_ID, &stash);
 		}
 
-		/// Submit an election result to the chain. If the solution:
-		///
-		/// 1. is valid.
-		/// 2. has a better score than a potentially existing solution on chain.
-		///
-		/// then, it will be _put_ on chain.
-		///
-		/// A solution consists of two pieces of data:
-		///
-		/// 1. `winners`: a flat vector of all the winners of the round.
-		/// 2. `assignments`: the compact version of an assignment vector that encodes the edge
-		///    weights.
-		///
-		/// Both of which may be computed using _phragmen_, or any other algorithm.
-		///
-		/// Additionally, the submitter must provide:
-		///
-		/// - The `score` that they claim their solution has.
-		///
-		/// Both validators and nominators will be represented by indices in the solution. The
-		/// indices should respect the corresponding types ([`ValidatorIndex`] and
-		/// [`NominatorIndex`]). Moreover, they should be valid when used to index into
-		/// [`SnapshotValidators`] and [`SnapshotNominators`]. Any invalid index will cause the
-		/// solution to be rejected. These two storage items are set during the election window and
-		/// may be used to determine the indices.
-		///
-		/// A solution is valid if:
-		///
-		/// 0. It is submitted when [`EraElectionStatus`] is `Open`.
-		/// 1. Its claimed score is equal to the score computed on-chain.
-		/// 2. Presents the correct number of winners.
-		/// 3. All indexes must be value according to the snapshot vectors. All edge values must
-		///    also be correct and should not overflow the granularity of the ratio type (i.e. 256
-		///    or billion).
-		/// 4. For each edge, all targets are actually nominated by the voter.
-		/// 5. Has correct self-votes.
-		///
-		/// A solutions score is consisted of 3 parameters:
-		///
-		/// 1. `min { support.total }` for each support of a winner. This value should be maximized.
-		/// 2. `sum { support.total }` for each support of a winner. This value should be minimized.
-		/// 3. `sum { support.total^2 }` for each support of a winner. This value should be
-		///    minimized (to ensure less variance)
-		///
-		/// # <weight>
-		/// The transaction is assumed to be the longest path, a better solution.
-		///   - Initial solution is almost the same.
-		///   - Worse solution is retraced in pre-dispatch-checks which sets its own weight.
-		/// # </weight>
-		#[weight = T::WeightInfo::submit_solution_better(
-			size.validators.into(),
-			size.nominators.into(),
-			compact.voter_count() as u32,
-			winners.len() as u32,
-		)]
-		pub fn submit_election_solution(
-			origin,
-			winners: Vec<ValidatorIndex>,
-			compact: CompactAssignments,
-			score: ElectionScore,
-			era: EraIndex,
-			size: ElectionSize,
-		) -> DispatchResultWithPostInfo {
-			let _who = ensure_signed(origin)?;
-			Self::check_and_replace_solution(
-				winners,
-				compact,
-				ElectionCompute::Signed,
-				score,
-				era,
-				size,
-			)
-		}
-
-		/// Unsigned version of `submit_election_solution`.
-		///
-		/// Note that this must pass the [`ValidateUnsigned`] check which only allows transactions
-		/// from the local node to be included. In other words, only the block author can include a
-		/// transaction in the block.
-		///
-		/// # <weight>
-		/// See [`submit_election_solution`].
-		/// # </weight>
-		#[weight = T::WeightInfo::submit_solution_better(
-			size.validators.into(),
-			size.nominators.into(),
-			compact.voter_count() as u32,
-			winners.len() as u32,
-		)]
-		pub fn submit_election_solution_unsigned(
-			origin,
-			winners: Vec<ValidatorIndex>,
-			compact: CompactAssignments,
-			score: ElectionScore,
-			era: EraIndex,
-			size: ElectionSize,
-		) -> DispatchResultWithPostInfo {
-			ensure_none(origin)?;
-			let adjustments = Self::check_and_replace_solution(
-				winners,
-				compact,
-				ElectionCompute::Unsigned,
-				score,
-				era,
-				size,
-			).expect(
-				"An unsigned solution can only be submitted by validators; A validator should \
-				always produce correct solutions, else this block should not be imported, thus \
-				effectively depriving the validators from their authoring reward. Hence, this panic
-				is expected."
-			);
-
-			Ok(adjustments)
-		}
-
 		/// Remove the given nominations from the calling validator.
 		///
 		/// Effects will be felt at the beginning of the next era.
@@ -2272,7 +1908,6 @@ decl_module! {
 		#[weight = T::WeightInfo::kick(who.len() as u32)]
 		pub fn kick(origin, who: Vec<<T::Lookup as StaticLookup>::Source>) -> DispatchResult {
 			let controller = ensure_signed(origin)?;
-			ensure!(Self::era_election_status().is_closed(), Error::<T>::CallNotAllowed);
 			let ledger = Self::ledger(&controller).ok_or(Error::<T>::NotController)?;
 			let stash = &ledger.stash;
 
@@ -2322,70 +1957,35 @@ impl<T: Config> Module<T> {
 		})
 	}
 
-	/// Dump the list of validators and nominators into vectors and keep them on-chain.
-	///
-	/// This data is used to efficiently evaluate election results. returns `true` if the operation
-	/// is successful.
-	pub fn create_stakers_snapshot() -> (bool, Weight) {
-		let mut consumed_weight = 0;
-		let mut add_db_reads_writes = |reads, writes| {
-			consumed_weight += T::DbWeight::get().reads_writes(reads, writes);
-		};
-		let validators = <Validators<T>>::iter().map(|(v, _)| v).collect::<Vec<_>>();
-		let mut nominators = <Nominators<T>>::iter().map(|(n, _)| n).collect::<Vec<_>>();
-
-		let num_validators = validators.len();
-		let num_nominators = nominators.len();
-		add_db_reads_writes((num_validators + num_nominators) as Weight, 0);
-
-		if
-			num_validators > MAX_VALIDATORS ||
-			num_nominators.saturating_add(num_validators) > MAX_NOMINATORS
-		{
-			log!(
-				warn,
-				"Snapshot size too big [{} <> {}][{} <> {}].",
-				num_validators,
-				MAX_VALIDATORS,
-				num_nominators,
-				MAX_NOMINATORS,
-			);
-			(false, consumed_weight)
-		} else {
-			// all validators nominate themselves;
-			nominators.extend(validators.clone());
-
-			<SnapshotValidators<T>>::put(validators);
-			<SnapshotNominators<T>>::put(nominators);
-			add_db_reads_writes(0, 2);
-			(true, consumed_weight)
-		}
-	}
-
-	/// Clears both snapshots of stakers.
-	fn kill_stakers_snapshot() {
-		<SnapshotValidators<T>>::kill();
-		<SnapshotNominators<T>>::kill();
-	}
-
-	fn do_payout_stakers(validator_stash: T::AccountId, era: EraIndex) -> DispatchResult {
+	fn do_payout_stakers(validator_stash: T::AccountId, era: EraIndex) -> DispatchResultWithPostInfo {
 		// Validate input data
-		let current_era = CurrentEra::get().ok_or(Error::<T>::InvalidEraToReward)?;
-		ensure!(era <= current_era, Error::<T>::InvalidEraToReward);
+		let current_era = CurrentEra::get().ok_or(
+			Error::<T>::InvalidEraToReward.with_weight(T::WeightInfo::payout_stakers_alive_staked(0))
+		)?;
 		let history_depth = Self::history_depth();
-		ensure!(era >= current_era.saturating_sub(history_depth), Error::<T>::InvalidEraToReward);
+		ensure!(
+			era <= current_era && era >= current_era.saturating_sub(history_depth),
+			Error::<T>::InvalidEraToReward.with_weight(T::WeightInfo::payout_stakers_alive_staked(0))
+		);
 
 		// Note: if era has no reward to be claimed, era may be future. better not to update
 		// `ledger.claimed_rewards` in this case.
 		let era_payout = <ErasValidatorReward<T>>::get(&era)
-			.ok_or_else(|| Error::<T>::InvalidEraToReward)?;
-
-		let controller = Self::bonded(&validator_stash).ok_or(Error::<T>::NotStash)?;
+			.ok_or_else(||
+				Error::<T>::InvalidEraToReward
+					.with_weight(T::WeightInfo::payout_stakers_alive_staked(0))
+			)?;
+
+		let controller = Self::bonded(&validator_stash).ok_or(
+			Error::<T>::NotStash.with_weight(T::WeightInfo::payout_stakers_alive_staked(0))
+		)?;
 		let mut ledger = <Ledger<T>>::get(&controller).ok_or_else(|| Error::<T>::NotController)?;
 
 		ledger.claimed_rewards.retain(|&x| x >= current_era.saturating_sub(history_depth));
 		match ledger.claimed_rewards.binary_search(&era) {
-			Ok(_) => Err(Error::<T>::AlreadyClaimed)?,
+			Ok(_) => Err(
+				Error::<T>::AlreadyClaimed.with_weight(T::WeightInfo::payout_stakers_alive_staked(0))
+			)?,
 			Err(pos) => ledger.claimed_rewards.insert(pos, era),
 		}
 
@@ -2409,11 +2009,13 @@ impl<T: Config> Module<T> {
 			.unwrap_or_else(|| Zero::zero());
 
 		// Nothing to do if they have no reward points.
-		if validator_reward_points.is_zero() { return Ok(())}
+		if validator_reward_points.is_zero() {
+			return Ok(Some(T::WeightInfo::payout_stakers_alive_staked(0)).into())
+		}
 
 		// This is the fraction of the total reward that the validator and the
 		// nominators will get.
-		let validator_total_reward_part = Perbill::from_rational_approximation(
+		let validator_total_reward_part = Perbill::from_rational(
 			validator_reward_points,
 			total_reward_points,
 		);
@@ -2428,7 +2030,7 @@ impl<T: Config> Module<T> {
 
 		let validator_leftover_payout = validator_total_payout - validator_commission_payout;
 		// Now let's calculate how this is split to the validator.
-		let validator_exposure_part = Perbill::from_rational_approximation(
+		let validator_exposure_part = Perbill::from_rational(
 			exposure.own,
 			exposure.total,
 		);
@@ -2442,10 +2044,14 @@ impl<T: Config> Module<T> {
 			Self::deposit_event(RawEvent::Reward(ledger.stash, imbalance.peek()));
 		}
 
+		// Track the number of payout ops to nominators. Note: `WeightInfo::payout_stakers_alive_staked`
+		// always assumes at least a validator is paid out, so we do not need to count their payout op.
+		let mut nominator_payout_count: u32 = 0;
+
 		// Lets now calculate how this is split to the nominators.
 		// Reward only the clipped exposures. Note this is not necessarily sorted.
 		for nominator in exposure.others.iter() {
-			let nominator_exposure_part = Perbill::from_rational_approximation(
+			let nominator_exposure_part = Perbill::from_rational(
 				nominator.value,
 				exposure.total,
 			);
@@ -2453,11 +2059,14 @@ impl<T: Config> Module<T> {
 			let nominator_reward: BalanceOf<T> = nominator_exposure_part * validator_leftover_payout;
 			// We can now make nominator payout:
 			if let Some(imbalance) = Self::make_payout(&nominator.who, nominator_reward) {
+				// Note: this logic does not count payouts for `RewardDestination::None`.
+				nominator_payout_count += 1;
 				Self::deposit_event(RawEvent::Reward(nominator.who.clone(), imbalance.peek()));
 			}
 		}
 
-		Ok(())
+		debug_assert!(nominator_payout_count <= T::MaxNominatorRewardedPerValidator::get());
+		Ok(Some(T::WeightInfo::payout_stakers_alive_staked(nominator_payout_count)).into())
 	}
 
 	/// Update the ledger for a controller.
@@ -2524,18 +2133,15 @@ impl<T: Config> Module<T> {
 				.unwrap_or(0); // Must never happen.
 
 			match ForceEra::get() {
+				// Will set to default again, which is `NotForcing`.
 				Forcing::ForceNew => ForceEra::kill(),
+				// Short circuit to `new_era`.
 				Forcing::ForceAlways => (),
+				// Only go to `new_era` if deadline reached.
 				Forcing::NotForcing if era_length >= T::SessionsPerEra::get() => (),
 				_ => {
-					// Either `ForceNone`, or `NotForcing && era_length < T::SessionsPerEra::get()`.
-					if era_length + 1 == T::SessionsPerEra::get() {
-						IsCurrentSessionFinal::put(true);
-					} else if era_length >= T::SessionsPerEra::get() {
-						// Should only happen when we are ready to trigger an era but we have ForceNone,
-						// otherwise previous arm would short circuit.
-						Self::close_election_window();
-					}
+					// either `Forcing::ForceNone`,
+					// or `Forcing::NotForcing if era_length >= T::SessionsPerEra::get()`.
 					return None
 				},
 			}
@@ -2544,219 +2150,11 @@ impl<T: Config> Module<T> {
 			Self::new_era(session_index)
 		} else {
 			// Set initial era
+			log!(debug, "Starting the first era.");
 			Self::new_era(session_index)
 		}
 	}
 
-	/// Basic and cheap checks that we perform in validate unsigned, and in the execution.
-	///
-	/// State reads: ElectionState, CurrentEr, QueuedScore.
-	///
-	/// This function does weight refund in case of errors, which is based upon the fact that it is
-	/// called at the very beginning of the call site's function.
-	pub fn pre_dispatch_checks(score: ElectionScore, era: EraIndex) -> DispatchResultWithPostInfo {
-		// discard solutions that are not in-time
-		// check window open
-		ensure!(
-			Self::era_election_status().is_open(),
-			Error::<T>::OffchainElectionEarlySubmission.with_weight(T::DbWeight::get().reads(1)),
-		);
-
-		// check current era.
-		if let Some(current_era) = Self::current_era() {
-			ensure!(
-				current_era == era,
-				Error::<T>::OffchainElectionEarlySubmission.with_weight(T::DbWeight::get().reads(2)),
-			)
-		}
-
-		// assume the given score is valid. Is it better than what we have on-chain, if we have any?
-		if let Some(queued_score) = Self::queued_score() {
-			ensure!(
-				is_score_better(score, queued_score, T::MinSolutionScoreBump::get()),
-				Error::<T>::OffchainElectionWeakSubmission.with_weight(T::DbWeight::get().reads(3)),
-			)
-		}
-
-		Ok(None.into())
-	}
-
-	/// Checks a given solution and if correct and improved, writes it on chain as the queued result
-	/// of the next round. This may be called by both a signed and an unsigned transaction.
-	pub fn check_and_replace_solution(
-		winners: Vec<ValidatorIndex>,
-		compact_assignments: CompactAssignments,
-		compute: ElectionCompute,
-		claimed_score: ElectionScore,
-		era: EraIndex,
-		election_size: ElectionSize,
-	) -> DispatchResultWithPostInfo {
-		// Do the basic checks. era, claimed score and window open.
-		let _ = Self::pre_dispatch_checks(claimed_score, era)?;
-
-		// before we read any further state, we check that the unique targets in compact is same as
-		// compact. is a all in-memory check and easy to do. Moreover, it ensures that the solution
-		// is not full of bogus edges that can cause lots of reads to SlashingSpans. Thus, we can
-		// assume that the storage access of this function is always O(|winners|), not
-		// O(|compact.edge_count()|).
-		ensure!(
-			compact_assignments.unique_targets().len() == winners.len(),
-			Error::<T>::OffchainElectionBogusWinnerCount,
-		);
-
-		// Check that the number of presented winners is sane. Most often we have more candidates
-		// than we need. Then it should be `Self::validator_count()`. Else it should be all the
-		// candidates.
-		let snapshot_validators_length = <SnapshotValidators<T>>::decode_len()
-			.map(|l| l as u32)
-			.ok_or_else(|| Error::<T>::SnapshotUnavailable)?;
-
-		// size of the solution must be correct.
-		ensure!(
-			snapshot_validators_length == u32::from(election_size.validators),
-			Error::<T>::OffchainElectionBogusElectionSize,
-		);
-
-		// check the winner length only here and when we know the length of the snapshot validators
-		// length.
-		let desired_winners = Self::validator_count().min(snapshot_validators_length);
-		ensure!(winners.len() as u32 == desired_winners, Error::<T>::OffchainElectionBogusWinnerCount);
-
-		let snapshot_nominators_len = <SnapshotNominators<T>>::decode_len()
-			.map(|l| l as u32)
-			.ok_or_else(|| Error::<T>::SnapshotUnavailable)?;
-
-		// rest of the size of the solution must be correct.
-		ensure!(
-			snapshot_nominators_len == election_size.nominators,
-			Error::<T>::OffchainElectionBogusElectionSize,
-		);
-
-		// decode snapshot validators.
-		let snapshot_validators = Self::snapshot_validators()
-			.ok_or(Error::<T>::SnapshotUnavailable)?;
-
-		// check if all winners were legit; this is rather cheap. Replace with accountId.
-		let winners = winners.into_iter().map(|widx| {
-			// NOTE: at the moment, since staking is explicitly blocking any offence until election
-			// is closed, we don't check here if the account id at `snapshot_validators[widx]` is
-			// actually a validator. If this ever changes, this loop needs to also check this.
-			snapshot_validators.get(widx as usize).cloned().ok_or(Error::<T>::OffchainElectionBogusWinner)
-		}).collect::<Result<Vec<T::AccountId>, Error<T>>>()?;
-
-		// decode the rest of the snapshot.
-		let snapshot_nominators = Self::snapshot_nominators()
-			.ok_or(Error::<T>::SnapshotUnavailable)?;
-
-		// helpers
-		let nominator_at = |i: NominatorIndex| -> Option<T::AccountId> {
-			snapshot_nominators.get(i as usize).cloned()
-		};
-		let validator_at = |i: ValidatorIndex| -> Option<T::AccountId> {
-			snapshot_validators.get(i as usize).cloned()
-		};
-
-		// un-compact.
-		let assignments = compact_assignments.into_assignment(
-			nominator_at,
-			validator_at,
-		).map_err(|e| {
-			// log the error since it is not propagated into the runtime error.
-			log!(warn, "un-compacting solution failed due to {:?}", e);
-			Error::<T>::OffchainElectionBogusCompact
-		})?;
-
-		// check all nominators actually including the claimed vote. Also check correct self votes.
-		// Note that we assume all validators and nominators in `assignments` are properly bonded,
-		// because they are coming from the snapshot via a given index.
-		for Assignment { who, distribution } in assignments.iter() {
-			let is_validator = <Validators<T>>::contains_key(&who);
-			let maybe_nomination = Self::nominators(&who);
-
-			if !(maybe_nomination.is_some() ^ is_validator) {
-				// all of the indices must map to either a validator or a nominator. If this is ever
-				// not the case, then the locking system of staking is most likely faulty, or we
-				// have bigger problems.
-				log!(error, "detected an error in the staking locking and snapshot.");
-				// abort.
-				return Err(Error::<T>::OffchainElectionBogusNominator.into());
-			}
-
-			if !is_validator {
-				// a normal vote
-				let nomination = maybe_nomination.expect(
-					"exactly one of `maybe_validator` and `maybe_nomination.is_some` is true. \
-					is_validator is false; maybe_nomination is some; qed"
-				);
-
-				// NOTE: we don't really have to check here if the sum of all edges are the
-				// nominator correct. Un-compacting assures this by definition.
-
-				for (t, _) in distribution {
-					// each target in the provided distribution must be actually nominated by the
-					// nominator after the last non-zero slash.
-					if nomination.targets.iter().find(|&tt| tt == t).is_none() {
-						return Err(Error::<T>::OffchainElectionBogusNomination.into());
-					}
-
-					if <Self as Store>::SlashingSpans::get(&t).map_or(
-						false,
-						|spans| nomination.submitted_in < spans.last_nonzero_slash(),
-					) {
-						return Err(Error::<T>::OffchainElectionSlashedNomination.into());
-					}
-				}
-			} else {
-				// a self vote
-				ensure!(distribution.len() == 1, Error::<T>::OffchainElectionBogusSelfVote);
-				ensure!(distribution[0].0 == *who, Error::<T>::OffchainElectionBogusSelfVote);
-				// defensive only. A compact assignment of length one does NOT encode the weight and
-				// it is always created to be 100%.
-				ensure!(
-					distribution[0].1 == OffchainAccuracy::one(),
-					Error::<T>::OffchainElectionBogusSelfVote,
-				);
-			}
-		}
-
-		// convert into staked assignments.
-		let staked_assignments = sp_npos_elections::assignment_ratio_to_staked(
-			assignments,
-			Self::slashable_balance_of_fn(),
-		);
-
-		// build the support map thereof in order to evaluate.
-		let supports = to_supports(&winners, &staked_assignments)
-			.map_err(|_| Error::<T>::OffchainElectionBogusEdge)?;
-
-		// Check if the score is the same as the claimed one.
-		let submitted_score = (&supports).evaluate();
-		ensure!(submitted_score == claimed_score, Error::<T>::OffchainElectionBogusScore);
-
-		// At last, alles Ok. Exposures and store the result.
-		let exposures = Self::collect_exposures(supports);
-		log!(
-			info,
-			"A better solution (with compute {:?} and score {:?}) has been validated and stored \
-			 on chain.",
-			compute,
-			submitted_score,
-		);
-
-		// write new results.
-		<QueuedElected<T>>::put(ElectionResult {
-			elected_stashes: winners,
-			exposures,
-			compute,
-		});
-		QueuedScore::put(submitted_score);
-
-		// emit event.
-		Self::deposit_event(RawEvent::SolutionStored(compute));
-
-		Ok(None.into())
-	}
-
 	/// Start a session potentially starting an era.
 	fn start_session(start_session: SessionIndex) {
 		let next_active_era = Self::active_era().map(|e| e.index + 1).unwrap_or(0);
@@ -2837,15 +2235,10 @@ impl<T: Config> Module<T> {
 		if let Some(active_era_start) = active_era.start {
 			let now_as_millis_u64 = T::UnixTime::now().as_millis().saturated_into::<u64>();
 
-			let era_duration = now_as_millis_u64 - active_era_start;
-			let (validator_payout, max_payout) = inflation::compute_total_payout(
-				&T::RewardCurve::get(),
-				Self::eras_total_stake(&active_era.index),
-				T::Currency::total_issuance(),
-				// Duration of era; more than u64::MAX is rewarded as u64::MAX.
-				era_duration.saturated_into::<u64>(),
-			);
-			let rest = max_payout.saturating_sub(validator_payout);
+			let era_duration = (now_as_millis_u64 - active_era_start).saturated_into::<u64>();
+			let staked = Self::eras_total_stake(&active_era.index);
+			let issuance = T::Currency::total_issuance();
+			let (validator_payout, rest) = T::EraPayout::era_payout(staked, issuance, era_duration);
 
 			Self::deposit_event(RawEvent::EraPayout(active_era.index, validator_payout, rest));
 
@@ -2870,249 +2263,27 @@ impl<T: Config> Module<T> {
 		}
 
 		// Set staking information for new era.
-		let maybe_new_validators = Self::select_and_update_validators(current_era);
-		// TWO_PHASE_NOTE: use this later on.
-		let _unused_new_validators = Self::enact_election(current_era);
+		let maybe_new_validators = Self::enact_election(current_era);
 
 		maybe_new_validators
 	}
 
-	/// Remove all the storage items associated with the election.
-	fn close_election_window() {
-		// Close window.
-		<EraElectionStatus<T>>::put(ElectionStatus::Closed);
-		// Kill snapshots.
-		Self::kill_stakers_snapshot();
-		// Don't track final session.
-		IsCurrentSessionFinal::put(false);
-	}
-
-	/// Select the new validator set at the end of the era.
-	///
-	/// Runs [`try_do_phragmen`] and updates the following storage items:
-	/// - [`EraElectionStatus`]: with `None`.
-	/// - [`ErasStakers`]: with the new staker set.
-	/// - [`ErasStakersClipped`].
-	/// - [`ErasValidatorPrefs`].
-	/// - [`ErasTotalStake`]: with the new total stake.
-	/// - [`SnapshotValidators`] and [`SnapshotNominators`] are both removed.
-	///
-	/// Internally, [`QueuedElected`], snapshots and [`QueuedScore`] are also consumed.
-	///
-	/// If the election has been successful, It passes the new set upwards.
-	///
-	/// This should only be called at the end of an era.
-	fn select_and_update_validators(current_era: EraIndex) -> Option<Vec<T::AccountId>> {
-		if let Some(ElectionResult::<T::AccountId, BalanceOf<T>> {
-			elected_stashes,
-			exposures,
-			compute,
-		}) = Self::try_do_election() {
-			// Totally close the election round and data.
-			Self::close_election_window();
-
-			// Populate Stakers and write slot stake.
-			let mut total_stake: BalanceOf<T> = Zero::zero();
-			exposures.into_iter().for_each(|(stash, exposure)| {
-				total_stake = total_stake.saturating_add(exposure.total);
-				<ErasStakers<T>>::insert(current_era, &stash, &exposure);
-
-				let mut exposure_clipped = exposure;
-				let clipped_max_len = T::MaxNominatorRewardedPerValidator::get() as usize;
-				if exposure_clipped.others.len() > clipped_max_len {
-					exposure_clipped.others.sort_by(|a, b| a.value.cmp(&b.value).reverse());
-					exposure_clipped.others.truncate(clipped_max_len);
-				}
-				<ErasStakersClipped<T>>::insert(&current_era, &stash, exposure_clipped);
-			});
-
-			// Insert current era staking information
-			<ErasTotalStake<T>>::insert(&current_era, total_stake);
-
-			// collect the pref of all winners
-			for stash in &elected_stashes {
-				let pref = Self::validators(stash);
-				<ErasValidatorPrefs<T>>::insert(&current_era, stash, pref);
-			}
-
-			// emit event
-			Self::deposit_event(RawEvent::StakingElection(compute));
-
-			log!(
-				info,
-				"new validator set of size {:?} has been elected via {:?} for staring era {:?}",
-				elected_stashes.len(),
-				compute,
-				current_era,
-			);
-
-			Some(elected_stashes)
-		} else {
-			None
-		}
-	}
-
-	/// Select a new validator set from the assembled stakers and their role preferences. It tries
-	/// first to peek into [`QueuedElected`]. Otherwise, it runs a new on-chain phragmen election.
-	///
-	/// If [`QueuedElected`] and [`QueuedScore`] exists, they are both removed. No further storage
-	/// is updated.
-	fn try_do_election() -> Option<ElectionResult<T::AccountId, BalanceOf<T>>> {
-		// an election result from either a stored submission or locally executed one.
-		let next_result = <QueuedElected<T>>::take().or_else(||
-			Self::do_on_chain_phragmen()
-		);
-
-		// either way, kill this. We remove it here to make sure it always has the exact same
-		// lifetime as `QueuedElected`.
-		QueuedScore::kill();
-
-		next_result
-	}
-
-	/// Execute election and return the new results. The edge weights are processed into support
-	/// values.
-	///
-	/// This is basically a wrapper around [`Self::do_phragmen`] which translates
-	/// `PrimitiveElectionResult` into `ElectionResult`.
+	/// Enact and process the election using the `ElectionProvider` type.
 	///
-	/// No storage item is updated.
-	pub fn do_on_chain_phragmen() -> Option<ElectionResult<T::AccountId, BalanceOf<T>>> {
-		if let Some(phragmen_result) = Self::do_phragmen::<ChainAccuracy>(0) {
-			let elected_stashes = phragmen_result.winners.iter()
-				.map(|(s, _)| s.clone())
-				.collect::<Vec<T::AccountId>>();
-			let assignments = phragmen_result.assignments;
-
-			let staked_assignments = sp_npos_elections::assignment_ratio_to_staked(
-				assignments,
-				Self::slashable_balance_of_fn(),
-			);
-
-			let supports = to_supports(
-				&elected_stashes,
-				&staked_assignments,
-			)
-			.map_err(|_|
-				log!(
-					error,
-					"on-chain phragmen is failing due to a problem in the result. This must be a bug."
-				)
-			)
-			.ok()?;
-
-			// collect exposures
-			let exposures = Self::collect_exposures(supports);
-
-			// In order to keep the property required by `on_session_ending` that we must return the
-			// new validator set even if it's the same as the old, as long as any underlying
-			// economic conditions have changed, we don't attempt to do any optimization where we
-			// compare against the prior set.
-			Some(ElectionResult::<T::AccountId, BalanceOf<T>> {
-				elected_stashes,
-				exposures,
-				compute: ElectionCompute::OnChain,
+	/// This will also process the election, as noted in [`process_election`].
+	fn enact_election(current_era: EraIndex) -> Option<Vec<T::AccountId>> {
+		T::ElectionProvider::elect()
+			.map_err(|e| {
+				log!(warn, "election provider failed due to {:?}", e)
+			})
+			.and_then(|(res, weight)| {
+				<frame_system::Pallet<T>>::register_extra_weight_unchecked(
+					weight,
+					frame_support::weights::DispatchClass::Mandatory,
+				);
+				Self::process_election(res, current_era)
 			})
-		} else {
-			// There were not enough candidates for even our minimal level of functionality. This is
-			// bad. We should probably disable all functionality except for block production and let
-			// the chain keep producing blocks until we can decide on a sufficiently substantial
-			// set. TODO: #2494
-			None
-		}
-	}
-
-	/// Execute phragmen election and return the new results. No post-processing is applied and the
-	/// raw edge weights are returned.
-	///
-	/// Self votes are added and nominations before the most recent slashing span are ignored.
-	///
-	/// No storage item is updated.
-	pub fn do_phragmen<Accuracy: PerThing128>(
-		iterations: usize,
-	) -> Option<PrimitiveElectionResult<T::AccountId, Accuracy>> {
-		let weight_of = Self::slashable_balance_of_fn();
-		let mut all_nominators: Vec<(T::AccountId, VoteWeight, Vec<T::AccountId>)> = Vec::new();
-		let mut all_validators = Vec::new();
-		for (validator, _) in <Validators<T>>::iter() {
-			// append self vote
-			let self_vote = (validator.clone(), weight_of(&validator), vec![validator.clone()]);
-			all_nominators.push(self_vote);
-			all_validators.push(validator);
-		}
-
-		let nominator_votes = <Nominators<T>>::iter().map(|(nominator, nominations)| {
-			let Nominations { submitted_in, mut targets, suppressed: _ } = nominations;
-
-			// Filter out nomination targets which were nominated before the most recent
-			// slashing span.
-			targets.retain(|stash| {
-				<Self as Store>::SlashingSpans::get(&stash).map_or(
-					true,
-					|spans| submitted_in >= spans.last_nonzero_slash(),
-				)
-			});
-
-			(nominator, targets)
-		});
-		all_nominators.extend(nominator_votes.map(|(n, ns)| {
-			let s = weight_of(&n);
-			(n, s, ns)
-		}));
-
-		if all_validators.len() < Self::minimum_validator_count().max(1) as usize {
-			// If we don't have enough candidates, nothing to do.
-			log!(
-				warn,
-				"chain does not have enough staking candidates to operate. Era {:?}.",
-				Self::current_era()
-			);
-			None
-		} else {
-			seq_phragmen::<_, Accuracy>(
-				Self::validator_count() as usize,
-				all_validators,
-				all_nominators,
-				Some((iterations, 0)), // exactly run `iterations` rounds.
-			)
-			.map_err(|err| log!(error, "Call to seq-phragmen failed due to {:?}", err))
 			.ok()
-		}
-	}
-
-	/// Consume a set of [`Supports`] from [`sp_npos_elections`] and collect them into a
-	/// [`Exposure`].
-	fn collect_exposures(
-		supports: Supports<T::AccountId>,
-	) -> Vec<(T::AccountId, Exposure<T::AccountId, BalanceOf<T>>)> {
-		let total_issuance = T::Currency::total_issuance();
-		let to_currency = |e: ExtendedBalance| T::CurrencyToVote::to_currency(e, total_issuance);
-
-		supports.into_iter().map(|(validator, support)| {
-			// build `struct exposure` from `support`
-			let mut others = Vec::with_capacity(support.voters.len());
-			let mut own: BalanceOf<T> = Zero::zero();
-			let mut total: BalanceOf<T> = Zero::zero();
-			support.voters
-				.into_iter()
-				.map(|(nominator, weight)| (nominator, to_currency(weight)))
-				.for_each(|(nominator, stake)| {
-					if nominator == validator {
-						own = own.saturating_add(stake);
-					} else {
-						others.push(IndividualExposure { who: nominator, value: stake });
-					}
-					total = total.saturating_add(stake);
-				});
-
-			let exposure = Exposure {
-				own,
-				others,
-				total,
-			};
-
-			(validator, exposure)
-		}).collect::<Vec<(T::AccountId, Exposure<_, _>)>>()
 	}
 
 	/// Process the output of the election.
@@ -3122,25 +2293,28 @@ impl<T: Config> Module<T> {
 	///
 	/// Returns `Err(())` if less than [`MinimumValidatorCount`] validators have been elected, `Ok`
 	/// otherwise.
-	// TWO_PHASE_NOTE: remove the dead code.
-	#[allow(dead_code)]
 	pub fn process_election(
-		flat_supports: sp_npos_elections::Supports<T::AccountId>,
+		flat_supports: frame_election_provider_support::Supports<T::AccountId>,
 		current_era: EraIndex,
 	) -> Result<Vec<T::AccountId>, ()> {
 		let exposures = Self::collect_exposures(flat_supports);
 		let elected_stashes = exposures.iter().cloned().map(|(x, _)| x).collect::<Vec<_>>();
 
-		if (elected_stashes.len() as u32) <= Self::minimum_validator_count() {
-			log!(
-				warn,
-				"chain does not have enough staking candidates to operate for era {:?}",
-				current_era,
-			);
+		if (elected_stashes.len() as u32) < Self::minimum_validator_count().max(1) {
+			// Session will panic if we ever return an empty validator set, thus max(1) ^^.
+			if current_era > 0 {
+				log!(
+					warn,
+					"chain does not have enough staking candidates to operate for era {:?} ({} elected, minimum is {})",
+					current_era,
+					elected_stashes.len(),
+					Self::minimum_validator_count(),
+				);
+			}
 			return Err(());
 		}
 
-		// Populate Stakers and write slot stake.
+		// Populate stakers, exposures, and the snapshot of validator prefs.
 		let mut total_stake: BalanceOf<T> = Zero::zero();
 		exposures.into_iter().for_each(|(stash, exposure)| {
 			total_stake = total_stake.saturating_add(exposure.total);
@@ -3165,28 +2339,54 @@ impl<T: Config> Module<T> {
 		}
 
 		// emit event
-		// TWO_PHASE_NOTE: remove the inner value.
-		Self::deposit_event(RawEvent::StakingElection(ElectionCompute::Signed));
-
-		log!(
-			info,
-			"new validator set of size {:?} has been processed for era {:?}",
-			elected_stashes.len(),
-			current_era,
-		);
+		Self::deposit_event(RawEvent::StakingElection);
+
+		if current_era > 0 {
+			log!(
+				info,
+				"new validator set of size {:?} has been processed for era {:?}",
+				elected_stashes.len(),
+				current_era,
+			);
+		}
 
 		Ok(elected_stashes)
 	}
 
-	/// Enact and process the election using the `ElectionProvider` type.
-	///
-	/// This will also process the election, as noted in [`process_election`].
-	fn enact_election(_current_era: EraIndex) -> Option<Vec<T::AccountId>> {
-		let _outcome = T::ElectionProvider::elect().map(|_| ());
-		log!(debug, "Experimental election provider outputted {:?}", _outcome);
-		// TWO_PHASE_NOTE: This code path shall not return anything for now. Later on, redirect the
-		// results to `process_election`.
-		None
+	/// Consume a set of [`Supports`] from [`sp_npos_elections`] and collect them into a
+	/// [`Exposure`].
+	fn collect_exposures(
+		supports: Supports<T::AccountId>,
+	) -> Vec<(T::AccountId, Exposure<T::AccountId, BalanceOf<T>>)> {
+		let total_issuance = T::Currency::total_issuance();
+		let to_currency = |e: frame_election_provider_support::ExtendedBalance| {
+			T::CurrencyToVote::to_currency(e, total_issuance)
+		};
+
+		supports
+			.into_iter()
+			.map(|(validator, support)| {
+				// build `struct exposure` from `support`
+				let mut others = Vec::with_capacity(support.voters.len());
+				let mut own: BalanceOf<T> = Zero::zero();
+				let mut total: BalanceOf<T> = Zero::zero();
+				support
+					.voters
+					.into_iter()
+					.map(|(nominator, weight)| (nominator, to_currency(weight)))
+					.for_each(|(nominator, stake)| {
+						if nominator == validator {
+						own = own.saturating_add(stake);
+						} else {
+							others.push(IndividualExposure { who: nominator, value: stake });
+						}
+						total = total.saturating_add(stake);
+					});
+
+				let exposure = Exposure { own, others, total };
+				(validator, exposure)
+			})
+			.collect::<Vec<(T::AccountId, Exposure<_, _>)>>()
 	}
 
 	/// Remove all associated data of a stash account from the staking system.
@@ -3208,7 +2408,7 @@ impl<T: Config> Module<T> {
 		<Validators<T>>::remove(stash);
 		<Nominators<T>>::remove(stash);
 
-		system::Module::<T>::dec_consumers(stash);
+		system::Pallet::<T>::dec_consumers(stash);
 
 		Ok(())
 	}
@@ -3251,7 +2451,6 @@ impl<T: Config> Module<T> {
 	/// relatively to their points.
 	///
 	/// COMPLEXITY: Complexity is `number_of_validator_to_reward x current_elected_len`.
-	/// If you need to reward lots of validator consider using `reward_by_indices`.
 	pub fn reward_by_ids(
 		validators_points: impl IntoIterator<Item = (T::AccountId, u32)>
 	) {
@@ -3273,13 +2472,6 @@ impl<T: Config> Module<T> {
 		}
 	}
 
-	fn will_era_be_forced() -> bool {
-		match ForceEra::get() {
-			Forcing::ForceAlways | Forcing::ForceNew => true,
-			Forcing::ForceNone | Forcing::NotForcing => false,
-		}
-	}
-
 	#[cfg(feature = "runtime-benchmarks")]
 	pub fn add_era_stakers(
 		current_era: EraIndex,
@@ -3289,11 +2481,6 @@ impl<T: Config> Module<T> {
 		<ErasStakers<T>>::insert(&current_era, &controller, &exposure);
 	}
 
-	#[cfg(feature = "runtime-benchmarks")]
-	pub fn put_election_status(status: ElectionStatus::<T::BlockNumber>) {
-		<EraElectionStatus<T>>::put(status);
-	}
-
 	#[cfg(feature = "runtime-benchmarks")]
 	pub fn set_slash_reward_fraction(fraction: Perbill) {
 		SlashRewardFraction::put(fraction);
@@ -3319,13 +2506,17 @@ impl<T: Config> Module<T> {
 			all_voters.push(self_vote);
 		}
 
+		// collect all slashing spans into a BTreeMap for further queries.
+		let slashing_spans = <SlashingSpans<T>>::iter().collect::<BTreeMap<_, _>>();
+
 		for (nominator, nominations) in <Nominators<T>>::iter() {
 			let Nominations { submitted_in, mut targets, suppressed: _ } = nominations;
 
 			// Filter out nomination targets which were nominated before the most recent
 			// slashing span.
 			targets.retain(|stash| {
-				Self::slashing_spans(&stash)
+				slashing_spans
+					.get(stash)
 					.map_or(true, |spans| submitted_in >= spans.last_nonzero_slash())
 			});
 
@@ -3341,19 +2532,46 @@ impl<T: Config> Module<T> {
 	}
 }
 
-impl<T: Config> sp_election_providers::ElectionDataProvider<T::AccountId, T::BlockNumber>
+impl<T: Config> frame_election_provider_support::ElectionDataProvider<T::AccountId, T::BlockNumber>
 	for Module<T>
 {
-	fn desired_targets() -> u32 {
-		Self::validator_count()
+	const MAXIMUM_VOTES_PER_VOTER: u32 = T::MAX_NOMINATIONS;
+	fn desired_targets() -> data_provider::Result<(u32, Weight)> {
+		Ok((Self::validator_count(), <T as frame_system::Config>::DbWeight::get().reads(1)))
+	}
+
+	fn voters(
+		maybe_max_len: Option<usize>,
+	) -> data_provider::Result<(Vec<(T::AccountId, VoteWeight, Vec<T::AccountId>)>, Weight)> {
+		// NOTE: reading these counts already needs to iterate a lot of storage keys, but they get
+		// cached. This is okay for the case of `Ok(_)`, but bad for `Err(_)`, as the trait does not
+		// report weight in failures.
+		let nominator_count = <Nominators<T>>::iter().count();
+		let validator_count = <Validators<T>>::iter().count();
+		let voter_count = nominator_count.saturating_add(validator_count);
+
+		if maybe_max_len.map_or(false, |max_len| voter_count > max_len) {
+			return Err("Voter snapshot too big");
+		}
+
+		let slashing_span_count = <SlashingSpans<T>>::iter().count();
+		let weight = T::WeightInfo::get_npos_voters(
+			nominator_count as u32,
+			validator_count as u32,
+			slashing_span_count as u32,
+		);
+		Ok((Self::get_npos_voters(), weight))
 	}
 
-	fn voters() -> Vec<(T::AccountId, VoteWeight, Vec<T::AccountId>)> {
-		Self::get_npos_voters()
-	}
+	fn targets(maybe_max_len: Option<usize>) -> data_provider::Result<(Vec<T::AccountId>, Weight)> {
+		let target_count = <Validators<T>>::iter().count();
+
+		if maybe_max_len.map_or(false, |max_len| target_count > max_len) {
+			return Err("Target snapshot too big");
+		}
 
-	fn targets() -> Vec<T::AccountId> {
-		Self::get_npos_targets()
+		let weight = <T as frame_system::Config>::DbWeight::get().reads(target_count as u64);
+		Ok((Self::get_npos_targets(), weight))
 	}
 
 	fn next_election_prediction(now: T::BlockNumber) -> T::BlockNumber {
@@ -3387,15 +2605,45 @@ impl<T: Config> sp_election_providers::ElectionDataProvider<T::AccountId, T::Blo
 	fn put_snapshot(
 		voters: Vec<(T::AccountId, VoteWeight, Vec<T::AccountId>)>,
 		targets: Vec<T::AccountId>,
+		target_stake: Option<VoteWeight>,
 	) {
+		use sp_std::convert::TryFrom;
 		targets.into_iter().for_each(|v| {
+			let stake: BalanceOf<T> = target_stake
+				.and_then(|w| <BalanceOf<T>>::try_from(w).ok())
+				.unwrap_or(T::Currency::minimum_balance() * 100u32.into());
+			<Bonded<T>>::insert(v.clone(), v.clone());
+			<Ledger<T>>::insert(
+				v.clone(),
+				StakingLedger {
+					stash: v.clone(),
+					active: stake,
+					total: stake,
+					unlocking: vec![],
+					claimed_rewards: vec![],
+				},
+			);
 			<Validators<T>>::insert(
 				v,
 				ValidatorPrefs { commission: Perbill::zero(), blocked: false },
 			);
 		});
 
-		voters.into_iter().for_each(|(v, _s, t)| {
+		voters.into_iter().for_each(|(v, s, t)| {
+			let stake = <BalanceOf<T>>::try_from(s).unwrap_or_else(|_| {
+				panic!("cannot convert a VoteWeight into BalanceOf, benchmark needs reconfiguring.")
+			});
+			<Bonded<T>>::insert(v.clone(), v.clone());
+			<Ledger<T>>::insert(
+				v.clone(),
+				StakingLedger {
+					stash: v.clone(),
+					active: stake,
+					total: stake,
+					unlocking: vec![],
+					claimed_rewards: vec![],
+				},
+			);
 			<Nominators<T>>::insert(
 				v,
 				Nominations { targets: t, submitted_in: 0, suppressed: false },
@@ -3411,31 +2659,16 @@ impl<T: Config> sp_election_providers::ElectionDataProvider<T::AccountId, T::Blo
 /// some session can lag in between the newest session planned and the latest session started.
 impl<T: Config> pallet_session::SessionManager<T::AccountId> for Module<T> {
 	fn new_session(new_index: SessionIndex) -> Option<Vec<T::AccountId>> {
-		log!(
-			trace,
-			"[{:?}] planning new_session({})",
-			<frame_system::Module<T>>::block_number(),
-			new_index,
-		);
+		log!(trace, "planning new_session({})", new_index);
 		CurrentPlannedSession::put(new_index);
 		Self::new_session(new_index)
 	}
 	fn start_session(start_index: SessionIndex) {
-		log!(
-			trace,
-			"[{:?}] starting start_session({})",
-			<frame_system::Module<T>>::block_number(),
-			start_index,
-		);
+		log!(trace, "starting start_session({})", start_index);
 		Self::start_session(start_index)
 	}
 	fn end_session(end_index: SessionIndex) {
-		log!(
-			trace,
-			"[{:?}] ending end_session({})",
-			<frame_system::Module<T>>::block_number(),
-			end_index,
-		);
+		log!(trace, "ending end_session({})", end_index);
 		Self::end_session(end_index)
 	}
 }
@@ -3650,8 +2883,8 @@ where
 	}
 
 	fn can_report() -> bool {
-		// TWO_PHASE_NOTE: we can get rid of this API
-		Self::era_election_status().is_closed()
+		// TODO: https://github.com/paritytech/substrate/issues/8343
+		true
 	}
 }
 
@@ -3687,100 +2920,7 @@ where
 	}
 }
 
-#[allow(deprecated)]
-impl<T: Config> frame_support::unsigned::ValidateUnsigned for Module<T> {
-	type Call = Call<T>;
-	fn validate_unsigned(source: TransactionSource, call: &Self::Call) -> TransactionValidity {
-		if let Call::submit_election_solution_unsigned(
-			_,
-			_,
-			score,
-			era,
-			_,
-		) = call {
-			use offchain_election::DEFAULT_LONGEVITY;
-
-			// discard solution not coming from the local OCW.
-			match source {
-				TransactionSource::Local | TransactionSource::InBlock => { /* allowed */ }
-				_ => {
-					log!(debug, "rejecting unsigned transaction because it is not local/in-block.");
-					return InvalidTransaction::Call.into();
-				}
-			}
-
-			if let Err(error_with_post_info) = Self::pre_dispatch_checks(*score, *era) {
-				let invalid = to_invalid(error_with_post_info);
-				log!(
-					debug,
-					"💸 validate unsigned pre dispatch checks failed due to error #{:?}.",
-					invalid,
-				);
-				return invalid.into();
-			}
-
-			log!(debug, "validateUnsigned succeeded for a solution at era {}.", era);
-
-			ValidTransaction::with_tag_prefix("StakingOffchain")
-				// The higher the score[0], the better a solution is.
-				.priority(T::UnsignedPriority::get().saturating_add(score[0].saturated_into()))
-				// Defensive only. A single solution can exist in the pool per era. Each validator
-				// will run OCW at most once per era, hence there should never exist more than one
-				// transaction anyhow.
-				.and_provides(era)
-				// Note: this can be more accurate in the future. We do something like
-				// `era_end_block - current_block` but that is not needed now as we eagerly run
-				// offchain workers now and the above should be same as `T::ElectionLookahead`
-				// without the need to query more storage in the validation phase. If we randomize
-				// offchain worker, then we might re-consider this.
-				.longevity(TryInto::<u64>::try_into(
-						T::ElectionLookahead::get()).unwrap_or(DEFAULT_LONGEVITY)
-				)
-				// We don't propagate this. This can never the validated at a remote node.
-				.propagate(false)
-				.build()
-		} else {
-			InvalidTransaction::Call.into()
-		}
-	}
-
-	fn pre_dispatch(call: &Self::Call) -> Result<(), TransactionValidityError> {
-		if let Call::submit_election_solution_unsigned(
-			_,
-			_,
-			score,
-			era,
-			_,
-		) = call {
-			// IMPORTANT NOTE: These checks are performed in the dispatch call itself, yet we need
-			// to duplicate them here to prevent a block producer from putting a previously
-			// validated, yet no longer valid solution on chain.
-			// OPTIMISATION NOTE: we could skip this in the `submit_election_solution_unsigned`
-			// since we already do it here. The signed version needs it though. Yer for now we keep
-			// this duplicate check here so both signed and unsigned can use a singular
-			// `check_and_replace_solution`.
-			Self::pre_dispatch_checks(*score, *era)
-				.map(|_| ())
-				.map_err(to_invalid)
-				.map_err(Into::into)
-		} else {
-			Err(InvalidTransaction::Call.into())
-		}
-	}
-}
-
 /// Check that list is sorted and has no duplicates.
 fn is_sorted_and_unique(list: &[u32]) -> bool {
 	list.windows(2).all(|w| w[0] < w[1])
 }
-
-/// convert a DispatchErrorWithPostInfo to a custom InvalidTransaction with the inner code being the
-/// error number.
-fn to_invalid(error_with_post_info: DispatchErrorWithPostInfo) -> InvalidTransaction {
-	let error = error_with_post_info.error;
-	let error_number = match error {
-		DispatchError::Module { error, ..} => error,
-		_ => 0,
-	};
-	InvalidTransaction::Custom(error_number)
-}
diff --git a/frame/staking/src/mock.rs b/frame/staking/src/mock.rs
index 0d6701c48b894..1942e5eed0c6f 100644
--- a/frame/staking/src/mock.rs
+++ b/frame/staking/src/mock.rs
@@ -22,14 +22,11 @@ use crate as staking;
 use frame_support::{
 	assert_ok, parameter_types,
 	traits::{Currency, FindAuthor, Get, OnFinalize, OnInitialize, OneSessionHandler},
-	weights::{constants::RocksDbWeight, Weight},
+	weights::constants::RocksDbWeight,
 	IterableStorageMap, StorageDoubleMap, StorageMap, StorageValue,
 };
 use sp_core::H256;
 use sp_io;
-use sp_npos_elections::{
-	to_supports, reduce, ExtendedBalance, StakedAssignment, ElectionScore, EvaluateSupport,
-};
 use sp_runtime::{
 	curve::PiecewiseLinear,
 	testing::{Header, TestXt, UintAuthorityId},
@@ -37,7 +34,7 @@ use sp_runtime::{
 };
 use sp_staking::offence::{OffenceDetails, OnOffenceHandler};
 use std::{cell::RefCell, collections::HashSet};
-use sp_election_providers::onchain;
+use frame_election_provider_support::onchain;
 
 pub const INIT_TIMESTAMP: u64 = 30_000;
 pub const BLOCK_TIME: u64 = 1000;
@@ -98,11 +95,11 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Timestamp: pallet_timestamp::{Module, Call, Storage, Inherent},
-		Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
-		Staking: staking::{Module, Call, Config<T>, Storage, Event<T>, ValidateUnsigned},
-		Session: pallet_session::{Module, Call, Storage, Event, Config<T>},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Timestamp: pallet_timestamp::{Pallet, Call, Storage, Inherent},
+		Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
+		Staking: staking::{Pallet, Call, Config<T>, Storage, Event<T>},
+		Session: pallet_session::{Pallet, Call, Storage, Event, Config<T>},
 	}
 );
 
@@ -126,10 +123,8 @@ parameter_types! {
 	pub static SessionsPerEra: SessionIndex = 3;
 	pub static ExistentialDeposit: Balance = 1;
 	pub static SlashDeferDuration: EraIndex = 0;
-	pub static ElectionLookahead: BlockNumber = 0;
 	pub static Period: BlockNumber = 5;
 	pub static Offset: BlockNumber = 0;
-	pub static MaxIterations: u32 = 0;
 }
 
 impl frame_system::Config for Test {
@@ -220,9 +215,6 @@ parameter_types! {
 	pub const BondingDuration: EraIndex = 3;
 	pub const RewardCurve: &'static PiecewiseLinear<'static> = &I_NPOS;
 	pub const MaxNominatorRewardedPerValidator: u32 = 64;
-	pub const UnsignedPriority: u64 = 1 << 20;
-	pub const MinSolutionScoreBump: Perbill = Perbill::zero();
-	pub OffchainSolutionWeightLimit: Weight = BlockWeights::get().max_block;
 }
 
 thread_local! {
@@ -243,10 +235,12 @@ impl OnUnbalanced<NegativeImbalanceOf<Test>> for RewardRemainderMock {
 impl onchain::Config for Test {
 	type AccountId = AccountId;
 	type BlockNumber = BlockNumber;
+	type BlockWeights = BlockWeights;
 	type Accuracy = Perbill;
 	type DataProvider = Staking;
 }
 impl Config for Test {
+	const MAX_NOMINATIONS: u32 = 16;
 	type Currency = Balances;
 	type UnixTime = Timestamp;
 	type CurrencyToVote = frame_support::traits::SaturatingCurrencyToVote;
@@ -259,15 +253,9 @@ impl Config for Test {
 	type SlashCancelOrigin = frame_system::EnsureRoot<Self::AccountId>;
 	type BondingDuration = BondingDuration;
 	type SessionInterface = Self;
-	type RewardCurve = RewardCurve;
+	type EraPayout = ConvertCurve<RewardCurve>;
 	type NextNewSession = Session;
-	type ElectionLookahead = ElectionLookahead;
-	type Call = Call;
-	type MaxIterations = MaxIterations;
-	type MinSolutionScoreBump = MinSolutionScoreBump;
 	type MaxNominatorRewardedPerValidator = MaxNominatorRewardedPerValidator;
-	type UnsignedPriority = UnsignedPriority;
-	type OffchainSolutionWeightLimit = OffchainSolutionWeightLimit;
 	type ElectionProvider = onchain::OnChainSequentialPhragmen<Self>;
 	type WeightInfo = ();
 }
@@ -281,6 +269,8 @@ where
 }
 
 pub type Extrinsic = TestXt<Call, ()>;
+pub(crate) type StakingCall = crate::Call<Test>;
+pub(crate) type TestRuntimeCall = <Test as frame_system::Config>::Call;
 
 pub struct ExtBuilder {
 	validator_pool: bool,
@@ -351,10 +341,6 @@ impl ExtBuilder {
 		SESSIONS_PER_ERA.with(|v| *v.borrow_mut() = length);
 		self
 	}
-	pub fn election_lookahead(self, look: BlockNumber) -> Self {
-		ELECTION_LOOKAHEAD.with(|v| *v.borrow_mut() = look);
-		self
-	}
 	pub fn period(self, length: BlockNumber) -> Self {
 		PERIOD.with(|v| *v.borrow_mut() = length);
 		self
@@ -363,13 +349,6 @@ impl ExtBuilder {
 		self.has_stakers = has;
 		self
 	}
-	pub fn max_offchain_iterations(self, iterations: u32) -> Self {
-		MAX_ITERATIONS.with(|v| *v.borrow_mut() = iterations);
-		self
-	}
-	pub fn offchain_election_ext(self) -> Self {
-		self.session_per_era(4).period(5).election_lookahead(3)
-	}
 	pub fn initialize_first_session(mut self, init: bool) -> Self {
 		self.initialize_first_session = init;
 		self
@@ -669,25 +648,22 @@ pub(crate) fn start_active_era(era_index: EraIndex) {
 }
 
 pub(crate) fn current_total_payout_for_duration(duration: u64) -> Balance {
-	let reward = inflation::compute_total_payout(
-		<Test as Config>::RewardCurve::get(),
+	let (payout, _rest) = <Test as Config>::EraPayout::era_payout(
 		Staking::eras_total_stake(active_era()),
 		Balances::total_issuance(),
 		duration,
-	)
-	.0;
-	assert!(reward > 0);
-	reward
+	);
+	assert!(payout > 0);
+	payout
 }
 
 pub(crate) fn maximum_payout_for_duration(duration: u64) -> Balance {
-	inflation::compute_total_payout(
-		<Test as Config>::RewardCurve::get(),
-		0,
+	let (payout, rest) = <Test as Config>::EraPayout::era_payout(
+		Staking::eras_total_stake(active_era()),
 		Balances::total_issuance(),
 		duration,
-	)
-	.1
+	);
+	payout + rest
 }
 
 /// Time it takes to finish a session.
@@ -776,198 +752,6 @@ pub(crate) fn add_slash(who: &AccountId) {
 	);
 }
 
-// winners will be chosen by simply their unweighted total backing stake. Nominator stake is
-// distributed evenly.
-pub(crate) fn horrible_npos_solution(
-	do_reduce: bool,
-) -> (CompactAssignments, Vec<ValidatorIndex>, ElectionScore) {
-	let mut backing_stake_of: BTreeMap<AccountId, Balance> = BTreeMap::new();
-
-	// self stake
-	<Validators<Test>>::iter().for_each(|(who, _p)| {
-		*backing_stake_of.entry(who).or_insert(Zero::zero()) += Staking::slashable_balance_of(&who)
-	});
-
-	// add nominator stuff
-	<Nominators<Test>>::iter().for_each(|(who, nomination)| {
-		nomination.targets.iter().for_each(|v| {
-			*backing_stake_of.entry(*v).or_insert(Zero::zero()) +=
-				Staking::slashable_balance_of(&who)
-		})
-	});
-
-	// elect winners
-	let mut sorted: Vec<AccountId> = backing_stake_of.keys().cloned().collect();
-	sorted.sort_by_key(|x| backing_stake_of.get(x).unwrap());
-	let winners: Vec<AccountId> = sorted
-		.iter()
-		.cloned()
-		.take(Staking::validator_count() as usize)
-		.collect();
-
-	// create assignments
-	let mut staked_assignment: Vec<StakedAssignment<AccountId>> = Vec::new();
-	<Nominators<Test>>::iter().for_each(|(who, nomination)| {
-		let mut dist: Vec<(AccountId, ExtendedBalance)> = Vec::new();
-		nomination.targets.iter().for_each(|v| {
-			if winners.iter().find(|w| *w == v).is_some() {
-				dist.push((*v, ExtendedBalance::zero()));
-			}
-		});
-
-		if dist.len() == 0 {
-			return;
-		}
-
-		// assign real stakes. just split the stake.
-		let stake = Staking::slashable_balance_of(&who) as ExtendedBalance;
-		let mut sum: ExtendedBalance = Zero::zero();
-		let dist_len = dist.len();
-		{
-			dist.iter_mut().for_each(|(_, w)| {
-				let partial = stake / (dist_len as ExtendedBalance);
-				*w = partial;
-				sum += partial;
-			});
-		}
-
-		// assign the leftover to last.
-		{
-			let leftover = stake - sum;
-			let last = dist.last_mut().unwrap();
-			last.1 += leftover;
-		}
-
-		staked_assignment.push(StakedAssignment {
-			who,
-			distribution: dist,
-		});
-	});
-
-	// Ensure that this result is worse than seq-phragmen. Otherwise, it should not have been used
-	// for testing.
-	let score = {
-		let (_, _, better_score) = prepare_submission_with(true, true, 0, |_| {});
-
-		let support = to_supports::<AccountId>(&winners, &staked_assignment).unwrap();
-		let score = support.evaluate();
-
-		assert!(sp_npos_elections::is_score_better::<Perbill>(
-			better_score,
-			score,
-			MinSolutionScoreBump::get(),
-		));
-
-		score
-	};
-
-	if do_reduce {
-		reduce(&mut staked_assignment);
-	}
-
-	let snapshot_validators = Staking::snapshot_validators().unwrap();
-	let snapshot_nominators = Staking::snapshot_nominators().unwrap();
-	let nominator_index = |a: &AccountId| -> Option<NominatorIndex> {
-		snapshot_nominators.iter().position(|x| x == a).map(|i| i as NominatorIndex)
-	};
-	let validator_index = |a: &AccountId| -> Option<ValidatorIndex> {
-		snapshot_validators.iter().position(|x| x == a).map(|i| i as ValidatorIndex)
-	};
-
-	// convert back to ratio assignment. This takes less space.
-	let assignments_reduced =
-		sp_npos_elections::assignment_staked_to_ratio::<AccountId, OffchainAccuracy>(staked_assignment);
-
-	let compact =
-		CompactAssignments::from_assignment(assignments_reduced, nominator_index, validator_index)
-			.unwrap();
-
-	// winner ids to index
-	let winners = winners.into_iter().map(|w| validator_index(&w).unwrap()).collect::<Vec<_>>();
-
-	(compact, winners, score)
-}
-
-/// Note: this should always logically reproduce [`offchain_election::prepare_submission`], yet we
-/// cannot do it since we want to have `tweak` injected into the process.
-///
-/// If the input is being tweaked in a way that the score cannot be compute accurately,
-/// `compute_real_score` can be set to true. In this case a `Default` score is returned.
-pub(crate) fn prepare_submission_with(
-	compute_real_score: bool,
-	do_reduce: bool,
-	iterations: usize,
-	tweak: impl FnOnce(&mut Vec<StakedAssignment<AccountId>>),
-) -> (CompactAssignments, Vec<ValidatorIndex>, ElectionScore) {
-	// run election on the default stuff.
-	let sp_npos_elections::ElectionResult {
-		winners,
-		assignments,
-	} = Staking::do_phragmen::<OffchainAccuracy>(iterations).unwrap();
-	let winners = sp_npos_elections::to_without_backing(winners);
-
-	let mut staked = sp_npos_elections::assignment_ratio_to_staked(
-		assignments,
-		Staking::slashable_balance_of_fn(),
-	);
-
-	// apply custom tweaks. awesome for testing.
-	tweak(&mut staked);
-
-	if do_reduce {
-		reduce(&mut staked);
-	}
-
-	// convert back to ratio assignment. This takes less space.
-	let snapshot_validators = Staking::snapshot_validators().expect("snapshot not created.");
-	let snapshot_nominators = Staking::snapshot_nominators().expect("snapshot not created.");
-	let nominator_index = |a: &AccountId| -> Option<NominatorIndex> {
-		snapshot_nominators
-			.iter()
-			.position(|x| x == a)
-			.map_or_else(
-				|| { println!("unable to find nominator index for {:?}", a); None },
-				|i| Some(i as NominatorIndex),
-			)
-	};
-	let validator_index = |a: &AccountId| -> Option<ValidatorIndex> {
-		snapshot_validators
-			.iter()
-			.position(|x| x == a)
-			.map_or_else(
-				|| { println!("unable to find validator index for {:?}", a); None },
-				|i| Some(i as ValidatorIndex),
-			)
-	};
-
-	let assignments_reduced = sp_npos_elections::assignment_staked_to_ratio(staked);
-
-	// re-compute score by converting, yet again, into staked type
-	let score = if compute_real_score {
-		let staked = sp_npos_elections::assignment_ratio_to_staked(
-			assignments_reduced.clone(),
-			Staking::slashable_balance_of_fn(),
-		);
-
-		let support_map = to_supports(
-			winners.as_slice(),
-			staked.as_slice(),
-		).unwrap();
-		support_map.evaluate()
-	} else {
-		Default::default()
-	};
-
-	let compact =
-		CompactAssignments::from_assignment(assignments_reduced, nominator_index, validator_index)
-			.expect("Failed to create compact");
-
-	// winner ids to index
-	let winners = winners.into_iter().map(|w| validator_index(&w).unwrap()).collect::<Vec<_>>();
-
-	(compact, winners, score)
-}
-
 /// Make all validator and nominator request their payment
 pub(crate) fn make_all_reward_payment(era: EraIndex) {
 	let validators_with_reward =
diff --git a/frame/staking/src/offchain_election.rs b/frame/staking/src/offchain_election.rs
deleted file mode 100644
index 8398c2022fc3f..0000000000000
--- a/frame/staking/src/offchain_election.rs
+++ /dev/null
@@ -1,588 +0,0 @@
-// This file is part of Substrate.
-
-// Copyright (C) 2020-2021 Parity Technologies (UK) Ltd.
-// SPDX-License-Identifier: Apache-2.0
-
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// 	http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-//! Helpers for offchain worker election.
-
-use crate::{
-	Call, CompactAssignments, ElectionSize, Module, NominatorIndex, Nominators, OffchainAccuracy,
-	Config, ValidatorIndex, WeightInfo,
-};
-use codec::Decode;
-use frame_support::{traits::Get, weights::Weight, IterableStorageMap};
-use frame_system::offchain::SubmitTransaction;
-use sp_npos_elections::{
-	to_supports, EvaluateSupport, reduce, Assignment, ElectionResult, ElectionScore,
-	ExtendedBalance, CompactSolution,
-};
-use sp_runtime::{
-	offchain::storage::StorageValueRef, traits::TrailingZeroInput, RuntimeDebug,
-};
-use sp_std::{convert::TryInto, prelude::*};
-
-/// Error types related to the offchain election machinery.
-#[derive(RuntimeDebug)]
-pub enum OffchainElectionError {
-	/// election returned None. This means less candidate that minimum number of needed
-	/// validators were present. The chain is in trouble and not much that we can do about it.
-	ElectionFailed,
-	/// Submission to the transaction pool failed.
-	PoolSubmissionFailed,
-	/// The snapshot data is not available.
-	SnapshotUnavailable,
-	/// Error from npos-election crate. This usually relates to compact operation.
-	InternalElectionError(sp_npos_elections::Error),
-	/// One of the computed winners is invalid.
-	InvalidWinner,
-	/// A nominator is not available in the snapshot.
-	NominatorSnapshotCorrupt,
-}
-
-impl From<sp_npos_elections::Error> for OffchainElectionError {
-	fn from(e: sp_npos_elections::Error) -> Self {
-		Self::InternalElectionError(e)
-	}
-}
-
-/// Storage key used to store the persistent offchain worker status.
-pub(crate) const OFFCHAIN_HEAD_DB: &[u8] = b"parity/staking-election/";
-/// The repeat threshold of the offchain worker. This means we won't run the offchain worker twice
-/// within a window of 5 blocks.
-pub(crate) const OFFCHAIN_REPEAT: u32 = 5;
-/// Default number of blocks for which the unsigned transaction should stay in the pool
-pub(crate) const DEFAULT_LONGEVITY: u64 = 25;
-
-/// Checks if an execution of the offchain worker is permitted at the given block number, or not.
-///
-/// This essentially makes sure that we don't run on previous blocks in case of a re-org, and we
-/// don't run twice within a window of length [`OFFCHAIN_REPEAT`].
-///
-/// Returns `Ok(())` if offchain worker should happen, `Err(reason)` otherwise.
-pub(crate) fn set_check_offchain_execution_status<T: Config>(
-	now: T::BlockNumber,
-) -> Result<(), &'static str> {
-	let storage = StorageValueRef::persistent(&OFFCHAIN_HEAD_DB);
-	let threshold = T::BlockNumber::from(OFFCHAIN_REPEAT);
-
-	let mutate_stat =
-		storage.mutate::<_, &'static str, _>(|maybe_head: Option<Option<T::BlockNumber>>| {
-			match maybe_head {
-				Some(Some(head)) if now < head => Err("fork."),
-				Some(Some(head)) if now >= head && now <= head + threshold => {
-					Err("recently executed.")
-				}
-				Some(Some(head)) if now > head + threshold => {
-					// we can run again now. Write the new head.
-					Ok(now)
-				}
-				_ => {
-					// value doesn't exists. Probably this node just booted up. Write, and run
-					Ok(now)
-				}
-			}
-		});
-
-	match mutate_stat {
-		// all good
-		Ok(Ok(_)) => Ok(()),
-		// failed to write.
-		Ok(Err(_)) => Err("failed to write to offchain db."),
-		// fork etc.
-		Err(why) => Err(why),
-	}
-}
-
-/// The internal logic of the offchain worker of this module. This runs the phragmen election,
-/// compacts and reduces the solution, computes the score and submits it back to the chain as an
-/// unsigned transaction, without any signature.
-pub(crate) fn compute_offchain_election<T: Config>() -> Result<(), OffchainElectionError> {
-	let iters = get_balancing_iters::<T>();
-	// compute raw solution. Note that we use `OffchainAccuracy`.
-	let ElectionResult {
-		winners,
-		assignments,
-	} = <Module<T>>::do_phragmen::<OffchainAccuracy>(iters)
-		.ok_or(OffchainElectionError::ElectionFailed)?;
-
-	// process and prepare it for submission.
-	let (winners, compact, score, size) = prepare_submission::<T>(
-		assignments,
-		winners,
-		true,
-		T::OffchainSolutionWeightLimit::get(),
-	)?;
-
-	crate::log!(
-		info,
-		"prepared a seq-phragmen solution with {} balancing iterations and score {:?}",
-		iters,
-		score,
-	);
-
-	// defensive-only: current era can never be none except genesis.
-	let current_era = <Module<T>>::current_era().unwrap_or_default();
-
-	// send it.
-	let call = Call::submit_election_solution_unsigned(
-		winners,
-		compact,
-		score,
-		current_era,
-		size,
-	).into();
-
-	SubmitTransaction::<T, Call<T>>::submit_unsigned_transaction(call)
-		.map_err(|_| OffchainElectionError::PoolSubmissionFailed)
-}
-
-/// Get a random number of iterations to run the balancing.
-///
-/// Uses the offchain seed to generate a random number.
-pub fn get_balancing_iters<T: Config>() -> usize {
-	match T::MaxIterations::get() {
-		0 => 0,
-		max @ _ => {
-			let seed = sp_io::offchain::random_seed();
-			let random = <u32>::decode(&mut TrailingZeroInput::new(seed.as_ref()))
-				.expect("input is padded with zeroes; qed") % max.saturating_add(1);
-			random as usize
-		}
-	}
-}
-
-/// Find the maximum `len` that a compact can have in order to fit into the block weight.
-///
-/// This only returns a value between zero and `size.nominators`.
-pub fn maximum_compact_len<W: crate::WeightInfo>(
-	winners_len: u32,
-	size: ElectionSize,
-	max_weight: Weight,
-) -> u32 {
-	use sp_std::cmp::Ordering;
-
-	if size.nominators < 1 {
-		return size.nominators;
-	}
-
-	let max_voters = size.nominators.max(1);
-	let mut voters = max_voters;
-
-	// helper closures.
-	let weight_with = |voters: u32| -> Weight {
-		W::submit_solution_better(
-			size.validators.into(),
-			size.nominators.into(),
-			voters,
-			winners_len,
-		)
-	};
-
-	let next_voters = |current_weight: Weight, voters: u32, step: u32| -> Result<u32, ()> {
-		match current_weight.cmp(&max_weight) {
-			Ordering::Less => {
-				let next_voters = voters.checked_add(step);
-				match next_voters {
-					Some(voters) if voters < max_voters => Ok(voters),
-					_ => Err(()),
-				}
-			},
-			Ordering::Greater => voters.checked_sub(step).ok_or(()),
-			Ordering::Equal => Ok(voters),
-		}
-	};
-
-	// First binary-search the right amount of voters
-	let mut step = voters / 2;
-	let mut current_weight = weight_with(voters);
-	while step > 0 {
-		match next_voters(current_weight, voters, step) {
-			// proceed with the binary search
-			Ok(next) if next != voters => {
-				voters = next;
-			},
-			// we are out of bounds, break out of the loop.
-			Err(()) => {
-				break;
-			},
-			// we found the right value - early exit the function.
-			Ok(next) => return next
-		}
-		step = step / 2;
-		current_weight = weight_with(voters);
-	}
-
-
-	// Time to finish.
-	// We might have reduced less than expected due to rounding error. Increase one last time if we
-	// have any room left, the reduce until we are sure we are below limit.
-	while voters + 1 <= max_voters && weight_with(voters + 1) < max_weight {
-		voters += 1;
-	}
-	while voters.checked_sub(1).is_some() && weight_with(voters) > max_weight {
-		voters -= 1;
-	}
-
-	debug_assert!(
-		weight_with(voters.min(size.nominators)) <= max_weight,
-		"weight_with({}) <= {}", voters.min(size.nominators), max_weight,
-	);
-	voters.min(size.nominators)
-}
-
-/// Greedily reduce the size of the a solution to fit into the block, w.r.t. weight.
-///
-/// The weight of the solution is foremost a function of the number of voters (i.e.
-/// `compact.len()`). Aside from this, the other components of the weight are invariant. The number
-/// of winners shall not be changed (otherwise the solution is invalid) and the `ElectionSize` is
-/// merely a representation of the total number of stakers.
-///
-/// Thus, we reside to stripping away some voters. This means only changing the `compact` struct.
-///
-/// Note that the solution is already computed, and the winners are elected based on the merit of
-/// teh entire stake in the system. Nonetheless, some of the voters will be removed further down the
-/// line.
-///
-/// Indeed, the score must be computed **after** this step. If this step reduces the score too much,
-/// then the solution will be discarded.
-pub fn trim_to_weight<T: Config, FN>(
-	maximum_allowed_voters: u32,
-	mut compact: CompactAssignments,
-	nominator_index: FN,
-) -> Result<CompactAssignments, OffchainElectionError>
-where
-	for<'r> FN: Fn(&'r T::AccountId) -> Option<NominatorIndex>,
-{
-	match compact.voter_count().checked_sub(maximum_allowed_voters as usize) {
-		Some(to_remove) if to_remove > 0 => {
-			// grab all voters and sort them by least stake.
-			let balance_of = <Module<T>>::slashable_balance_of_fn();
-			let mut voters_sorted = <Nominators<T>>::iter()
-				.map(|(who, _)| (who.clone(), balance_of(&who)))
-				.collect::<Vec<_>>();
-			voters_sorted.sort_by_key(|(_, y)| *y);
-
-			// start removing from the least stake. Iterate until we know enough have been removed.
-			let mut removed = 0;
-			for (maybe_index, _stake) in voters_sorted
-				.iter()
-				.map(|(who, stake)| (nominator_index(&who), stake))
-			{
-				let index = maybe_index.ok_or(OffchainElectionError::NominatorSnapshotCorrupt)?;
-				if compact.remove_voter(index) {
-					crate::log!(
-						trace,
-						"removed a voter at index {} with stake {:?} from compact to reduce the size",
-						index,
-						_stake,
-					);
-					removed += 1
-				}
-
-				if removed >= to_remove {
-					break;
-				}
-			}
-
-			crate::log!(
-				warn,
-				"{} nominators out of {} had to be removed from compact solution due to size \
-				 limits.",
-				removed,
-				compact.voter_count() + removed,
-			);
-			Ok(compact)
-		}
-		_ => {
-			// nada, return as-is
-			crate::log!(info, "Compact solution did not get trimmed due to block weight limits.",);
-			Ok(compact)
-		}
-	}
-}
-
-/// Takes an election result and spits out some data that can be submitted to the chain.
-///
-/// This does a lot of stuff; read the inline comments.
-pub fn prepare_submission<T: Config>(
-	assignments: Vec<Assignment<T::AccountId, OffchainAccuracy>>,
-	winners: Vec<(T::AccountId, ExtendedBalance)>,
-	do_reduce: bool,
-	maximum_weight: Weight,
-) -> Result<
-	(Vec<ValidatorIndex>, CompactAssignments, ElectionScore, ElectionSize),
-	OffchainElectionError,
-> {
-	// make sure that the snapshot is available.
-	let snapshot_validators =
-		<Module<T>>::snapshot_validators().ok_or(OffchainElectionError::SnapshotUnavailable)?;
-	let snapshot_nominators =
-		<Module<T>>::snapshot_nominators().ok_or(OffchainElectionError::SnapshotUnavailable)?;
-
-	// all helper closures that we'd ever need.
-	let nominator_index = |a: &T::AccountId| -> Option<NominatorIndex> {
-		snapshot_nominators
-			.iter()
-			.position(|x| x == a)
-			.and_then(|i| <usize as TryInto<NominatorIndex>>::try_into(i).ok())
-	};
-	let validator_index = |a: &T::AccountId| -> Option<ValidatorIndex> {
-		snapshot_validators
-			.iter()
-			.position(|x| x == a)
-			.and_then(|i| <usize as TryInto<ValidatorIndex>>::try_into(i).ok())
-	};
-	let nominator_at = |i: NominatorIndex| -> Option<T::AccountId> {
-		snapshot_nominators.get(i as usize).cloned()
-	};
-
-	let validator_at = |i: ValidatorIndex| -> Option<T::AccountId> {
-		snapshot_validators.get(i as usize).cloned()
-	};
-
-	// both conversions are safe; snapshots are not created if they exceed.
-	let size = ElectionSize {
-		validators: snapshot_validators.len() as ValidatorIndex,
-		nominators: snapshot_nominators.len() as NominatorIndex,
-	};
-
-	// Clean winners.
-	let winners = sp_npos_elections::to_without_backing(winners);
-
-	// convert into absolute value and to obtain the reduced version.
-	let mut staked = sp_npos_elections::assignment_ratio_to_staked(
-		assignments,
-		<Module<T>>::slashable_balance_of_fn(),
-	);
-
-	// reduce
-	if do_reduce {
-		reduce(&mut staked);
-	}
-
-	// Convert back to ratio assignment. This takes less space.
-	let low_accuracy_assignment = sp_npos_elections::assignment_staked_to_ratio_normalized(staked)
-		.map_err(|e| OffchainElectionError::from(e))?;
-
-	// compact encode the assignment.
-	let compact = CompactAssignments::from_assignment(
-		low_accuracy_assignment,
-		nominator_index,
-		validator_index,
-	)
-	.map_err(|e| OffchainElectionError::from(e))?;
-
-	// potentially reduce the size of the compact to fit weight.
-	let maximum_allowed_voters =
-		maximum_compact_len::<T::WeightInfo>(winners.len() as u32, size, maximum_weight);
-
-	crate::log!(
-		debug,
-		"Maximum weight = {:?} // current weight = {:?} // maximum voters = {:?} // current votes \
-		 = {:?}",
-		maximum_weight,
-		T::WeightInfo::submit_solution_better(
-			size.validators.into(),
-			size.nominators.into(),
-			compact.voter_count() as u32,
-			winners.len() as u32,
-		),
-		maximum_allowed_voters,
-		compact.voter_count(),
-	);
-
-	let compact = trim_to_weight::<T, _>(maximum_allowed_voters, compact, &nominator_index)?;
-
-	// re-compute the score. We re-create what the chain will do. This is a bit verbose and wastes
-	// CPU time, but it is necessary to ensure that the score that we claim is the same as the one
-	// calculated by the chain.
-	let score = {
-		let compact = compact.clone();
-		let assignments = compact.into_assignment(nominator_at, validator_at).unwrap();
-		let staked = sp_npos_elections::assignment_ratio_to_staked(
-			assignments.clone(),
-			<Module<T>>::slashable_balance_of_fn(),
-		);
-
-		let support_map = to_supports::<T::AccountId>(&winners, &staked)
-			.map_err(|_| OffchainElectionError::ElectionFailed)?;
-		support_map.evaluate()
-	};
-
-	// winners to index. Use a simple for loop for a more expressive early exit in case of error.
-	let mut winners_indexed: Vec<ValidatorIndex> = Vec::with_capacity(winners.len());
-	for w in winners {
-		if let Some(idx) = snapshot_validators.iter().position(|v| *v == w) {
-			let compact_index: ValidatorIndex = idx
-				.try_into()
-				.map_err(|_| OffchainElectionError::InvalidWinner)?;
-			winners_indexed.push(compact_index);
-		} else {
-			return Err(OffchainElectionError::InvalidWinner);
-		}
-	}
-
-	Ok((winners_indexed, compact, score, size))
-}
-
-#[cfg(test)]
-mod test {
-	#![allow(unused_variables)]
-	use super::*;
-	use crate::ElectionSize;
-
-	struct Staking;
-
-	impl crate::WeightInfo for Staking {
-		fn bond() -> Weight {
-			unimplemented!()
-		}
-		fn bond_extra() -> Weight {
-			unimplemented!()
-		}
-		fn unbond() -> Weight {
-			unimplemented!()
-		}
-		fn withdraw_unbonded_update(s: u32) -> Weight {
-			unimplemented!()
-		}
-		fn withdraw_unbonded_kill(s: u32) -> Weight {
-			unimplemented!()
-		}
-		fn validate() -> Weight {
-			unimplemented!()
-		}
-		fn nominate(n: u32) -> Weight {
-			unimplemented!()
-		}
-		fn chill() -> Weight {
-			unimplemented!()
-		}
-		fn set_payee() -> Weight {
-			unimplemented!()
-		}
-		fn set_controller() -> Weight {
-			unimplemented!()
-		}
-		fn set_validator_count() -> Weight {
-			unimplemented!()
-		}
-		fn force_no_eras() -> Weight {
-			unimplemented!()
-		}
-		fn force_new_era() -> Weight {
-			unimplemented!()
-		}
-		fn force_new_era_always() -> Weight {
-			unimplemented!()
-		}
-		fn set_invulnerables(v: u32) -> Weight {
-			unimplemented!()
-		}
-		fn force_unstake(s: u32) -> Weight {
-			unimplemented!()
-		}
-		fn cancel_deferred_slash(s: u32) -> Weight {
-			unimplemented!()
-		}
-		fn payout_stakers_dead_controller(n: u32) -> Weight {
-			unimplemented!()
-		}
-		fn payout_stakers_alive_staked(n: u32) -> Weight {
-			unimplemented!()
-		}
-		fn rebond(l: u32) -> Weight {
-			unimplemented!()
-		}
-		fn set_history_depth(e: u32) -> Weight {
-			unimplemented!()
-		}
-		fn reap_stash(s: u32) -> Weight {
-			unimplemented!()
-		}
-		fn new_era(v: u32, n: u32) -> Weight {
-			unimplemented!()
-		}
-		fn submit_solution_better(v: u32, n: u32, a: u32, w: u32) -> Weight {
-			(0 * v + 0 * n + 1000 * a + 0 * w) as Weight
-		}
-		fn kick(w: u32) -> Weight {
-			unimplemented!()
-		}
-	}
-
-	#[test]
-	fn find_max_voter_binary_search_works() {
-		let size = ElectionSize {
-			validators: 0,
-			nominators: 10,
-		};
-
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 0), 0);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 1), 0);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 999), 0);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 1000), 1);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 1001), 1);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 1990), 1);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 1999), 1);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 2000), 2);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 2001), 2);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 2010), 2);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 2990), 2);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 2999), 2);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 3000), 3);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 3333), 3);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 5500), 5);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 7777), 7);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 9999), 9);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 10_000), 10);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 10_999), 10);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 11_000), 10);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 22_000), 10);
-
-		let size = ElectionSize {
-			validators: 0,
-			nominators: 1,
-		};
-
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 0), 0);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 1), 0);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 999), 0);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 1000), 1);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 1001), 1);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 1990), 1);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 1999), 1);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 2000), 1);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 2001), 1);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 2010), 1);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 3333), 1);
-
-		let size = ElectionSize {
-			validators: 0,
-			nominators: 2,
-		};
-
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 0), 0);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 1), 0);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 999), 0);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 1000), 1);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 1001), 1);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 1999), 1);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 2000), 2);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 2001), 2);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 2010), 2);
-		assert_eq!(maximum_compact_len::<Staking>(0, size, 3333), 2);
-	}
-}
diff --git a/frame/staking/src/testing_utils.rs b/frame/staking/src/testing_utils.rs
index f6ee89704d8d2..c4daf88098e75 100644
--- a/frame/staking/src/testing_utils.rs
+++ b/frame/staking/src/testing_utils.rs
@@ -24,7 +24,6 @@ use frame_benchmarking::account;
 use frame_system::RawOrigin;
 use sp_io::hashing::blake2_256;
 use rand_chacha::{rand_core::{RngCore, SeedableRng}, ChaChaRng};
-use sp_npos_elections::*;
 
 const SEED: u32 = 0;
 
@@ -112,10 +111,10 @@ pub fn create_validators<T: Config>(
 /// - `nominators`: number of bonded nominators.
 /// - `edge_per_nominator`: number of edge (vote) per nominator.
 /// - `randomize_stake`: whether to randomize the stakes.
-/// - `to_nominate`: if `Some(n)`, only the first `n` bonded validator are voted upon.
-///    Else, all of them are considered and `edge_per_nominator` random validators are voted for.
+/// - `to_nominate`: if `Some(n)`, only the first `n` bonded validator are voted upon. Else, all of
+///   them are considered and `edge_per_nominator` random validators are voted for.
 ///
-/// Return the validators choosen to be nominated.
+/// Return the validators chosen to be nominated.
 pub fn create_validators_with_nominators_for_era<T: Config>(
 	validators: u32,
 	nominators: u32,
@@ -143,7 +142,7 @@ pub fn create_validators_with_nominators_for_era<T: Config>(
 	}
 
 	let to_nominate = to_nominate.unwrap_or(validators_stash.len() as u32) as usize;
-	let validator_choosen = validators_stash[0..to_nominate].to_vec();
+	let validator_chosen = validators_stash[0..to_nominate].to_vec();
 
 	// Create nominators
 	for j in 0 .. nominators {
@@ -155,7 +154,7 @@ pub fn create_validators_with_nominators_for_era<T: Config>(
 		)?;
 
 		// Have them randomly validate
-		let mut available_validators = validator_choosen.clone();
+		let mut available_validators = validator_chosen.clone();
 		let mut selected_validators: Vec<<T::Lookup as StaticLookup>::Source> =
 			Vec::with_capacity(edge_per_nominator);
 
@@ -169,227 +168,10 @@ pub fn create_validators_with_nominators_for_era<T: Config>(
 
 	ValidatorCount::put(validators);
 
-	Ok(validator_choosen)
+	Ok(validator_chosen)
 }
 
-
-/// Build a _really bad_ but acceptable solution for election. This should always yield a solution
-/// which has a less score than the seq-phragmen.
-pub fn get_weak_solution<T: Config>(
-	do_reduce: bool,
-) -> (Vec<ValidatorIndex>, CompactAssignments, ElectionScore, ElectionSize) {
-	let mut backing_stake_of: BTreeMap<T::AccountId, BalanceOf<T>> = BTreeMap::new();
-
-	// self stake
-	<Validators<T>>::iter().for_each(|(who, _p)| {
-		*backing_stake_of.entry(who.clone()).or_insert_with(|| Zero::zero()) +=
-			<Module<T>>::slashable_balance_of(&who)
-	});
-
-	// elect winners. We chose the.. least backed ones.
-	let mut sorted: Vec<T::AccountId> = backing_stake_of.keys().cloned().collect();
-	sorted.sort_by_key(|x| backing_stake_of.get(x).unwrap());
-	let winners: Vec<T::AccountId> = sorted
-		.iter()
-		.rev()
-		.cloned()
-		.take(<Module<T>>::validator_count() as usize)
-		.collect();
-
-	let mut staked_assignments: Vec<StakedAssignment<T::AccountId>> = Vec::new();
-	// you could at this point start adding some of the nominator's stake, but for now we don't.
-	// This solution must be bad.
-
-	// add self support to winners.
-	winners.iter().for_each(|w| {
-		staked_assignments.push(StakedAssignment {
-			who: w.clone(),
-			distribution: vec![(
-				w.clone(),
-				<Module<T>>::slashable_balance_of_vote_weight(
-					&w,
-					T::Currency::total_issuance(),
-				).into(),
-			)],
-		})
-	});
-
-	if do_reduce {
-		reduce(&mut staked_assignments);
-	}
-
-	// helpers for building the compact
-	let snapshot_validators = <Module<T>>::snapshot_validators().unwrap();
-	let snapshot_nominators = <Module<T>>::snapshot_nominators().unwrap();
-
-	let nominator_index = |a: &T::AccountId| -> Option<NominatorIndex> {
-		snapshot_nominators
-			.iter()
-			.position(|x| x == a)
-			.and_then(|i| <usize as TryInto<NominatorIndex>>::try_into(i).ok())
-	};
-	let validator_index = |a: &T::AccountId| -> Option<ValidatorIndex> {
-		snapshot_validators
-			.iter()
-			.position(|x| x == a)
-			.and_then(|i| <usize as TryInto<ValidatorIndex>>::try_into(i).ok())
-	};
-
-	// convert back to ratio assignment. This takes less space.
-	let low_accuracy_assignment = assignment_staked_to_ratio_normalized(staked_assignments)
-		.expect("Failed to normalize");
-
-	// re-calculate score based on what the chain will decode.
-	let score = {
-		let staked = assignment_ratio_to_staked::<_, OffchainAccuracy, _>(
-			low_accuracy_assignment.clone(),
-			<Module<T>>::slashable_balance_of_fn(),
-		);
-
-		let support_map =
-			to_supports::<T::AccountId>(winners.as_slice(), staked.as_slice()).unwrap();
-		support_map.evaluate()
-	};
-
-	// compact encode the assignment.
-	let compact = CompactAssignments::from_assignment(
-		low_accuracy_assignment,
-		nominator_index,
-		validator_index,
-	)
-	.unwrap();
-
-	// winners to index.
-	let winners = winners
-		.into_iter()
-		.map(|w| {
-			snapshot_validators
-				.iter()
-				.position(|v| *v == w)
-				.unwrap()
-				.try_into()
-				.unwrap()
-		})
-		.collect::<Vec<ValidatorIndex>>();
-
-	let size = ElectionSize {
-		validators: snapshot_validators.len() as ValidatorIndex,
-		nominators: snapshot_nominators.len() as NominatorIndex,
-	};
-
-	(winners, compact, score, size)
-}
-
-/// Create a solution for seq-phragmen. This uses the same internal function as used by the offchain
-/// worker code.
-pub fn get_seq_phragmen_solution<T: Config>(
-	do_reduce: bool,
-) -> (
-	Vec<ValidatorIndex>,
-	CompactAssignments,
-	ElectionScore,
-	ElectionSize,
-) {
-	let iters = offchain_election::get_balancing_iters::<T>();
-
-	let sp_npos_elections::ElectionResult {
-		winners,
-		assignments,
-	} = <Module<T>>::do_phragmen::<OffchainAccuracy>(iters).unwrap();
-
-	offchain_election::prepare_submission::<T>(
-		assignments,
-		winners,
-		do_reduce,
-		T::BlockWeights::get().max_block,
-	)
-	.unwrap()
-}
-
-/// Returns a solution in which only one winner is elected with just a self vote.
-pub fn get_single_winner_solution<T: Config>(
-	winner: T::AccountId,
-) -> Result<
-	(
-		Vec<ValidatorIndex>,
-		CompactAssignments,
-		ElectionScore,
-		ElectionSize,
-	),
-	&'static str,
-> {
-	let snapshot_validators = <Module<T>>::snapshot_validators().unwrap();
-	let snapshot_nominators = <Module<T>>::snapshot_nominators().unwrap();
-
-	let val_index = snapshot_validators
-		.iter()
-		.position(|x| *x == winner)
-		.ok_or("not a validator")?;
-	let nom_index = snapshot_nominators
-		.iter()
-		.position(|x| *x == winner)
-		.ok_or("not a nominator")?;
-
-	let stake = <Staking<T>>::slashable_balance_of(&winner);
-	let stake =
-		<T::CurrencyToVote>::to_vote(stake, T::Currency::total_issuance()) as ExtendedBalance;
-
-	let val_index = val_index as ValidatorIndex;
-	let nom_index = nom_index as NominatorIndex;
-
-	let winners = vec![val_index];
-	let compact = CompactAssignments {
-		votes1: vec![(nom_index, val_index)],
-		..Default::default()
-	};
-	let score = [stake, stake, stake * stake];
-	let size = ElectionSize {
-		validators: snapshot_validators.len() as ValidatorIndex,
-		nominators: snapshot_nominators.len() as NominatorIndex,
-	};
-
-	Ok((winners, compact, score, size))
-}
-
-/// get the active era.
+/// get the current era.
 pub fn current_era<T: Config>() -> EraIndex {
 	<Module<T>>::current_era().unwrap_or(0)
 }
-
-/// initialize the first era.
-pub fn init_active_era() {
-	ActiveEra::put(ActiveEraInfo {
-		index: 1,
-		start: None,
-	})
-}
-
-/// Create random assignments for the given list of winners. Each assignment will have
-/// MAX_NOMINATIONS edges.
-pub fn create_assignments_for_offchain<T: Config>(
-	num_assignments: u32,
-	winners: Vec<<T::Lookup as StaticLookup>::Source>,
-) -> Result<
-	(
-		Vec<(T::AccountId, ExtendedBalance)>,
-		Vec<Assignment<T::AccountId, OffchainAccuracy>>,
-	),
-	&'static str
-> {
-	let ratio = OffchainAccuracy::from_rational_approximation(1, MAX_NOMINATIONS);
-	let assignments: Vec<Assignment<T::AccountId, OffchainAccuracy>> = <Nominators<T>>::iter()
-		.take(num_assignments as usize)
-		.map(|(n, t)| Assignment {
-			who: n,
-			distribution: t.targets.iter().map(|v| (v.clone(), ratio)).collect(),
-		})
-		.collect();
-
-	ensure!(assignments.len() == num_assignments as usize, "must bench for `a` assignments");
-
-	let winners = winners.into_iter().map(|v| {
-		(<T::Lookup as StaticLookup>::lookup(v).unwrap(), 0)
-	}).collect();
-
-	Ok((winners, assignments))
-}
diff --git a/frame/staking/src/tests.rs b/frame/staking/src/tests.rs
index 92e1862e39813..7a3ec19f8af2f 100644
--- a/frame/staking/src/tests.rs
+++ b/frame/staking/src/tests.rs
@@ -20,15 +20,18 @@
 use super::*;
 use mock::*;
 use sp_runtime::{
-	assert_eq_error_rate, traits::BadOrigin,
+	assert_eq_error_rate,
+	traits::{BadOrigin, Dispatchable},
 };
 use sp_staking::offence::OffenceDetails;
 use frame_support::{
 	assert_ok, assert_noop, StorageMap,
-	traits::{Currency, ReservableCurrency, OnInitialize, OnFinalize},
+	traits::{Currency, ReservableCurrency, OnInitialize},
+	weights::{extract_actual_weight, GetDispatchInfo},
 };
 use pallet_balances::Error as BalancesError;
 use substrate_test_utils::assert_eq_uvec;
+use frame_election_provider_support::Support;
 
 #[test]
 fn force_unstake_works() {
@@ -209,10 +212,10 @@ fn rewards_should_work() {
 				individual: vec![(11, 100), (21, 50)].into_iter().collect(),
 			}
 		);
-		let part_for_10 = Perbill::from_rational_approximation::<u32>(1000, 1125);
-		let part_for_20 = Perbill::from_rational_approximation::<u32>(1000, 1375);
-		let part_for_100_from_10 = Perbill::from_rational_approximation::<u32>(125, 1125);
-		let part_for_100_from_20 = Perbill::from_rational_approximation::<u32>(375, 1375);
+		let part_for_10 = Perbill::from_rational::<u32>(1000, 1125);
+		let part_for_20 = Perbill::from_rational::<u32>(1000, 1375);
+		let part_for_100_from_10 = Perbill::from_rational::<u32>(125, 1125);
+		let part_for_100_from_20 = Perbill::from_rational::<u32>(375, 1375);
 
 		start_session(2);
 		start_session(3);
@@ -598,8 +601,8 @@ fn nominators_also_get_slashed_pro_rata() {
 
 		let slash_amount = slash_percent * exposed_stake;
 		let validator_share =
-			Perbill::from_rational_approximation(exposed_validator, exposed_stake) * slash_amount;
-		let nominator_share = Perbill::from_rational_approximation(
+			Perbill::from_rational(exposed_validator, exposed_stake) * slash_amount;
+		let nominator_share = Perbill::from_rational(
 			exposed_nominator,
 			exposed_stake,
 		) * slash_amount;
@@ -1806,7 +1809,7 @@ fn bond_with_little_staked_value_bounded() {
 }
 
 #[test]
-fn bond_with_duplicate_vote_should_be_ignored_by_npos_election() {
+fn bond_with_duplicate_vote_should_be_ignored_by_election_provider() {
 	ExtBuilder::default()
 		.validator_count(2)
 		.nominate(false)
@@ -1817,43 +1820,43 @@ fn bond_with_duplicate_vote_should_be_ignored_by_npos_election() {
 			assert_ok!(Staking::chill(Origin::signed(100)));
 			// make stakes equal.
 			assert_ok!(Staking::bond_extra(Origin::signed(31), 999));
-
+			// ensure all have equal stake.
 			assert_eq!(
 				<Validators<Test>>::iter()
 					.map(|(v, _)| (v, Staking::ledger(v - 1).unwrap().total))
 					.collect::<Vec<_>>(),
 				vec![(31, 1000), (21, 1000), (11, 1000)],
 			);
+			// no nominators shall exist.
 			assert!(<Nominators<Test>>::iter().map(|(n, _)| n).collect::<Vec<_>>().is_empty());
 
-			// give the man some money
+			// give the man some money.
 			let initial_balance = 1000;
-			for i in [1, 2, 3, 4,].iter() {
+			for i in [1, 2, 3, 4].iter() {
 				let _ = Balances::make_free_balance_be(i, initial_balance);
 			}
 
 			assert_ok!(Staking::bond(Origin::signed(1), 2, 1000, RewardDestination::Controller));
-			// 11 should not be elected. All of these count as ONE vote.
-			assert_ok!(Staking::nominate(Origin::signed(2), vec![11, 11, 11, 21, 31,]));
+			assert_ok!(Staking::nominate(Origin::signed(2), vec![11, 11, 11, 21, 31]));
 
 			assert_ok!(Staking::bond(Origin::signed(3), 4, 1000, RewardDestination::Controller));
 			assert_ok!(Staking::nominate(Origin::signed(4), vec![21, 31]));
 
-			// winners should be 21 and 31. Otherwise this election is taking duplicates into account.
-			let sp_npos_elections::ElectionResult {
-				winners,
-				assignments,
-			} = Staking::do_phragmen::<Perbill>(0).unwrap();
-			let winners = sp_npos_elections::to_without_backing(winners);
-
-			assert_eq!(winners, vec![31, 21]);
-			// only distribution to 21 and 31.
-			assert_eq!(assignments.iter().find(|a| a.who == 1).unwrap().distribution.len(), 2);
+			// winners should be 21 and 31. Otherwise this election is taking duplicates into
+			// account.
+			let supports = <Test as Config>::ElectionProvider::elect().unwrap().0;
+			assert_eq!(
+				supports,
+				vec![
+					(21, Support { total: 1800, voters: vec![(21, 1000), (3, 400), (1, 400)] }),
+					(31, Support { total: 2200, voters: vec![(31, 1000), (3, 600), (1, 600)] })
+				],
+			);
 		});
 }
 
 #[test]
-fn bond_with_duplicate_vote_should_be_ignored_by_npos_election_elected() {
+fn bond_with_duplicate_vote_should_be_ignored_by_election_provider_elected() {
 	// same as above but ensures that even when the duple is being elected, everything is sane.
 	ExtBuilder::default()
 		.validator_count(2)
@@ -1863,39 +1866,39 @@ fn bond_with_duplicate_vote_should_be_ignored_by_npos_election_elected() {
 		.execute_with(|| {
 			// disable the nominator
 			assert_ok!(Staking::chill(Origin::signed(100)));
-			// make stakes equal.
+			// 31/30 will have less stake
 			assert_ok!(Staking::bond_extra(Origin::signed(31), 99));
-
+			// ensure all have equal stake.
 			assert_eq!(
 				<Validators<Test>>::iter()
 					.map(|(v, _)| (v, Staking::ledger(v - 1).unwrap().total))
 					.collect::<Vec<_>>(),
 				vec![(31, 100), (21, 1000), (11, 1000)],
 			);
+			// no nominators shall exist.
 			assert!(<Nominators<Test>>::iter().map(|(n, _)| n).collect::<Vec<_>>().is_empty());
 
-			// give the man some money
+			// give the man some money.
 			let initial_balance = 1000;
 			for i in [1, 2, 3, 4,].iter() {
 				let _ = Balances::make_free_balance_be(i, initial_balance);
 			}
 
 			assert_ok!(Staking::bond(Origin::signed(1), 2, 1000, RewardDestination::Controller));
-			assert_ok!(Staking::nominate(Origin::signed(2), vec![11, 11, 11, 21, 31,]));
+			assert_ok!(Staking::nominate(Origin::signed(2), vec![11, 11, 11, 21, 31]));
 
 			assert_ok!(Staking::bond(Origin::signed(3), 4, 1000, RewardDestination::Controller));
 			assert_ok!(Staking::nominate(Origin::signed(4), vec![21, 31]));
 
-			// winners should be 21 and 31. Otherwise this election is taking duplicates into account.
-			let sp_npos_elections::ElectionResult {
-				winners,
-				assignments,
-			} = Staking::do_phragmen::<Perbill>(0).unwrap();
-
-			let winners = sp_npos_elections::to_without_backing(winners);
-			assert_eq!(winners, vec![21, 11]);
-			// only distribution to 21 and 31.
-			assert_eq!(assignments.iter().find(|a| a.who == 1).unwrap().distribution.len(), 2);
+			// winners should be 21 and 11.
+			let supports = <Test as Config>::ElectionProvider::elect().unwrap().0;
+			assert_eq!(
+				supports,
+				vec![
+					(11, Support { total: 1500, voters: vec![(11, 1000), (1, 500)] }),
+					(21, Support { total: 2500, voters: vec![(21, 1000), (3, 1000), (1, 500)] })
+				],
+			);
 		});
 }
 
@@ -2905,1298 +2908,6 @@ fn remove_multi_deferred() {
 	})
 }
 
-mod offchain_election {
-	use crate::*;
-	use codec::Encode;
-	use frame_support::{
-		assert_noop, assert_ok, assert_err_with_weight,
-		dispatch::DispatchResultWithPostInfo,
-	};
-	use sp_runtime::transaction_validity::TransactionSource;
-	use mock::*;
-	use parking_lot::RwLock;
-	use sp_core::offchain::{
-		testing::{PoolState, TestOffchainExt, TestTransactionPoolExt},
-		OffchainWorkerExt, TransactionPoolExt, OffchainDbExt,
-	};
-	use sp_io::TestExternalities;
-	use sp_npos_elections::StakedAssignment;
-	use frame_support::traits::OffchainWorker;
-	use std::sync::Arc;
-	use substrate_test_utils::assert_eq_uvec;
-
-	fn percent(x: u16) -> OffchainAccuracy {
-		OffchainAccuracy::from_percent(x)
-	}
-
-	/// setup a new set of validators and nominator storage items independent of the parent mock
-	/// file. This produces a edge graph that can be reduced.
-	pub fn build_offchain_election_test_ext() {
-		for i in (10..=40).step_by(10) {
-			// Note: we respect the convention of the mock (10, 11 pairs etc.) since these accounts
-			// have corresponding keys in session which makes everything more ergonomic and
-			// realistic.
-			bond_validator(i + 1, i, 100);
-		}
-
-		let mut voter = 1;
-		bond_nominator(voter, 1000 + voter, 100, vec![11]);
-		voter = 2;
-		bond_nominator(voter, 1000 + voter, 100, vec![11, 11]);
-		voter = 3;
-		bond_nominator(voter, 1000 + voter, 100, vec![21, 41]);
-		voter = 4;
-		bond_nominator(voter, 1000 + voter, 100, vec![21, 31, 41]);
-		voter = 5;
-		bond_nominator(voter, 1000 + voter, 100, vec![21, 31, 41]);
-	}
-
-	/// convert an externalities to one that can handle offchain worker tests.
-	fn offchainify(ext: &mut TestExternalities, iterations: u32) -> Arc<RwLock<PoolState>> {
-		let (offchain, offchain_state) = TestOffchainExt::new();
-		let (pool, pool_state) = TestTransactionPoolExt::new();
-
-		let mut seed = [0_u8; 32];
-		seed[0..4].copy_from_slice(&iterations.to_le_bytes());
-		offchain_state.write().seed = seed;
-
-		ext.register_extension(OffchainDbExt::new(offchain.clone()));
-		ext.register_extension(OffchainWorkerExt::new(offchain));
-		ext.register_extension(TransactionPoolExt::new(pool));
-
-		pool_state
-	}
-
-	fn election_size() -> ElectionSize {
-		ElectionSize {
-			validators: Staking::snapshot_validators().unwrap().len() as ValidatorIndex,
-			nominators: Staking::snapshot_nominators().unwrap().len() as NominatorIndex,
-		}
-	}
-
-	fn submit_solution(
-		origin: Origin,
-		winners: Vec<ValidatorIndex>,
-		compact: CompactAssignments,
-		score: ElectionScore,
-	) -> DispatchResultWithPostInfo {
-		Staking::submit_election_solution(
-			origin,
-			winners,
-			compact,
-			score,
-			current_era(),
-			election_size(),
-		)
-	}
-
-	#[test]
-	fn is_current_session_final_works() {
-		ExtBuilder::default()
-			.session_per_era(3)
-			.build()
-			.execute_with(|| {
-				mock::start_active_era(1);
-				assert_eq!(Session::current_index(), 3);
-				assert_eq!(Staking::current_era(), Some(1));
-				assert_eq!(Staking::is_current_session_final(), false);
-
-				start_session(4);
-				assert_eq!(Session::current_index(), 4);
-				assert_eq!(Staking::current_era(), Some(1));
-				assert_eq!(Staking::is_current_session_final(), true);
-
-				start_session(5);
-				assert_eq!(Session::current_index(), 5);
-				// era changed.
-				assert_eq!(Staking::current_era(), Some(2));
-				assert_eq!(Staking::is_current_session_final(), false);
-			})
-	}
-
-	#[test]
-	fn offchain_window_is_triggered() {
-		ExtBuilder::default()
-			.session_per_era(5)
-			.period(10)
-			.election_lookahead(3)
-			.build()
-			.execute_with(|| {
-				run_to_block(7);
-				assert_session_era!(0, 0);
-
-				run_to_block(10);
-				assert_session_era!(1, 0);
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Closed);
-				assert!(Staking::snapshot_nominators().is_none());
-				assert!(Staking::snapshot_validators().is_none());
-
-				run_to_block(36);
-				assert_session_era!(3, 0);
-
-				// fist era has session 0, which has 0 blocks length, so we have in total 40 blocks
-				// in the era.
-				run_to_block(37);
-				assert_session_era!(3, 0);
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Open(37));
-				assert!(Staking::snapshot_nominators().is_some());
-				assert!(Staking::snapshot_validators().is_some());
-
-				run_to_block(38);
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Open(37));
-
-				run_to_block(39);
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Open(37));
-
-				run_to_block(40);
-				assert_session_era!(4, 1);
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Closed);
-				assert!(Staking::snapshot_nominators().is_none());
-				assert!(Staking::snapshot_validators().is_none());
-
-				run_to_block(86);
-				assert_session_era!(8, 1);
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Closed);
-				assert!(Staking::snapshot_nominators().is_none());
-				assert!(Staking::snapshot_validators().is_none());
-
-				// second era onwards has 50 blocks per era.
-				run_to_block(87);
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Open(87));
-				assert!(Staking::snapshot_nominators().is_some());
-				assert!(Staking::snapshot_validators().is_some());
-
-				run_to_block(90);
-				assert_session_era!(9, 2);
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Closed);
-				assert!(Staking::snapshot_nominators().is_none());
-				assert!(Staking::snapshot_validators().is_none());
-			})
-	}
-
-	#[test]
-	fn offchain_window_is_triggered_when_forcing() {
-		ExtBuilder::default()
-			.session_per_era(5)
-			.period(10)
-			.election_lookahead(3)
-			.build()
-			.execute_with(|| {
-				run_to_block(12);
-				ForceEra::put(Forcing::ForceNew);
-				run_to_block(13);
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Closed);
-
-				run_to_block(17); // instead of 47
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Open(17));
-
-				run_to_block(20);
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Closed);
-			})
-	}
-
-	#[test]
-	fn offchain_window_is_triggered_when_force_always() {
-		ExtBuilder::default()
-			.session_per_era(5)
-			.period(10)
-			.election_lookahead(3)
-			.build()
-			.execute_with(|| {
-				ForceEra::put(Forcing::ForceAlways);
-				run_to_block(16);
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Closed);
-
-				run_to_block(17); // instead of 37
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Open(17));
-
-				run_to_block(20);
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Closed);
-
-				run_to_block(26);
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Closed);
-
-				run_to_block(27); // next one again
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Open(27));
-			})
-	}
-
-	#[test]
-	fn offchain_window_closes_when_forcenone() {
-		ExtBuilder::default()
-			.session_per_era(5)
-			.period(10)
-			.election_lookahead(3)
-			.build()
-			.execute_with(|| {
-				ForceEra::put(Forcing::ForceNone);
-
-				run_to_block(36);
-				assert_session_era!(3, 0);
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Closed);
-
-				// opens
-				run_to_block(37);
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Open(37));
-				assert!(Staking::is_current_session_final());
-				assert!(Staking::snapshot_validators().is_some());
-
-				// closes normally
-				run_to_block(40);
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Closed);
-				assert!(!Staking::is_current_session_final());
-				assert!(Staking::snapshot_validators().is_none());
-				assert_session_era!(4, 0);
-
-				run_to_block(47);
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Closed);
-				assert_session_era!(4, 0);
-
-				run_to_block(57);
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Closed);
-				assert_session_era!(5, 0);
-
-				run_to_block(67);
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Closed);
-
-				// Will not open again as scheduled
-				run_to_block(87);
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Closed);
-				assert_session_era!(8, 0);
-
-				run_to_block(90);
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Closed);
-				assert_session_era!(9, 0);
-			})
-	}
-
-	#[test]
-	fn offchain_window_on_chain_fallback_works() {
-		ExtBuilder::default().build_and_execute(|| {
-			start_session(1);
-			start_session(2);
-			assert_eq!(Staking::era_election_status(), ElectionStatus::Closed);
-			// some election must have happened by now.
-			assert_eq!(
-				System::events()
-					.into_iter()
-					.map(|r| r.event)
-					.filter_map(|e| {
-						if let mock::Event::staking(inner) = e {
-							Some(inner)
-						} else {
-							None
-						}
-					})
-					.last()
-					.unwrap(),
-				RawEvent::StakingElection(ElectionCompute::OnChain),
-			);
-		})
-	}
-
-	#[test]
-	#[ignore]
-	fn offchain_wont_work_if_snapshot_fails() {
-		ExtBuilder::default()
-			.offchain_election_ext()
-			.build()
-			.execute_with(|| {
-				run_to_block(12);
-				assert!(Staking::snapshot_validators().is_some());
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Open(12));
-
-				// validate more than the limit
-				let limit: NominatorIndex = ValidatorIndex::max_value() as NominatorIndex + 1;
-				let ctrl = 1_000_000;
-				for i in 0..limit {
-					bond_validator((1000 + i).into(), (1000 + i + ctrl).into(), 100);
-				}
-
-				// window stays closed since no snapshot was taken.
-				run_to_block(27);
-				assert!(Staking::snapshot_validators().is_none());
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Closed);
-			})
-	}
-
-	#[test]
-	fn staking_is_locked_when_election_window_open() {
-		ExtBuilder::default()
-			.offchain_election_ext()
-			.election_lookahead(3)
-			.build()
-			.execute_with(|| {
-				run_to_block(12);
-				assert!(Staking::snapshot_validators().is_some());
-				// given
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Open(12));
-
-				// chill et. al. are now not allowed.
-				assert_noop!(
-					Staking::chill(Origin::signed(10)),
-					Error::<Test>::CallNotAllowed,
-				);
-			})
-	}
-
-	#[test]
-	fn signed_result_can_be_submitted() {
-		// should check that we have a new validator set normally, event says that it comes from
-		// offchain.
-		ExtBuilder::default()
-			.offchain_election_ext()
-			.build()
-			.execute_with(|| {
-				run_to_block(12);
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Open(12));
-				assert!(Staking::snapshot_validators().is_some());
-
-				let (compact, winners, score) = prepare_submission_with(true, true, 2, |_| {});
-				assert_ok!(submit_solution(
-					Origin::signed(10),
-					winners,
-					compact,
-					score,
-				));
-
-				let queued_result = Staking::queued_elected().unwrap();
-				assert_eq!(queued_result.compute, ElectionCompute::Signed);
-				assert_eq!(
-					System::events()
-						.into_iter()
-						.map(|r| r.event)
-						.filter_map(|e| {
-							if let mock::Event::staking(inner) = e {
-								Some(inner)
-							} else {
-								None
-							}
-						})
-						.last()
-						.unwrap(),
-					RawEvent::SolutionStored(ElectionCompute::Signed),
-				);
-
-				run_to_block(15);
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Closed);
-
-				assert_eq!(
-					System::events()
-						.into_iter()
-						.map(|r| r.event)
-						.filter_map(|e| {
-							if let mock::Event::staking(inner) = e {
-								Some(inner)
-							} else {
-								None
-							}
-						})
-						.last()
-						.unwrap(),
-					RawEvent::StakingElection(ElectionCompute::Signed),
-				);
-			})
-	}
-
-	#[test]
-	fn signed_result_can_be_submitted_later() {
-		// same as `signed_result_can_be_submitted` but at a later block.
-		ExtBuilder::default()
-			.offchain_election_ext()
-			.build()
-			.execute_with(|| {
-				run_to_block(14);
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Open(12));
-
-				let (compact, winners, score) = prepare_submission_with(true, true, 2, |_| {});
-				assert_ok!(submit_solution(Origin::signed(10), winners, compact, score));
-
-				let queued_result = Staking::queued_elected().unwrap();
-				assert_eq!(queued_result.compute, ElectionCompute::Signed);
-
-				run_to_block(15);
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Closed);
-
-				assert_eq!(
-					System::events()
-						.into_iter()
-						.map(|r| r.event)
-						.filter_map(|e| {
-							if let mock::Event::staking(inner) = e {
-								Some(inner)
-							} else {
-								None
-							}
-						})
-						.last()
-						.unwrap(),
-					RawEvent::StakingElection(ElectionCompute::Signed),
-				);
-			})
-	}
-
-	#[test]
-	fn early_solution_submission_is_rejected() {
-		// should check that we have a new validator set normally, event says that it comes from
-		// offchain.
-		ExtBuilder::default()
-			.offchain_election_ext()
-			.build()
-			.execute_with(|| {
-				run_to_block(11);
-				// submission is not yet allowed
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Closed);
-
-				// create all the indices just to build the solution.
-				Staking::create_stakers_snapshot();
-				let (compact, winners, score) = prepare_submission_with(true, true, 2, |_| {});
-				Staking::kill_stakers_snapshot();
-
-				assert_err_with_weight!(
-					Staking::submit_election_solution(
-						Origin::signed(10),
-						winners.clone(),
-						compact.clone(),
-						score,
-						current_era(),
-						ElectionSize::default(),
-					),
-					Error::<Test>::OffchainElectionEarlySubmission,
-					Some(<Test as frame_system::Config>::DbWeight::get().reads(1)),
-				);
-			})
-	}
-
-	#[test]
-	fn weak_solution_is_rejected() {
-		// A solution which is weaker than what we currently have on-chain is rejected.
-		ExtBuilder::default()
-			.offchain_election_ext()
-			.has_stakers(false)
-			.validator_count(4)
-			.build()
-			.execute_with(|| {
-				build_offchain_election_test_ext();
-				run_to_block(12);
-
-				// a good solution
-				let (compact, winners, score) = prepare_submission_with(true, true, 2, |_| {});
-				assert_ok!(submit_solution(
-					Origin::signed(10),
-					winners,
-					compact,
-					score,
-				));
-
-				// a bad solution
-				let (compact, winners, score) = horrible_npos_solution(false);
-				assert_err_with_weight!(
-					submit_solution(
-						Origin::signed(10),
-						winners.clone(),
-						compact.clone(),
-						score,
-					),
-					Error::<Test>::OffchainElectionWeakSubmission,
-					Some(<Test as frame_system::Config>::DbWeight::get().reads(3))
-				);
-			})
-	}
-
-	#[test]
-	fn better_solution_is_accepted() {
-		// A solution which is better than what we currently have on-chain is accepted.
-		ExtBuilder::default()
-			.offchain_election_ext()
-			.validator_count(4)
-			.has_stakers(false)
-			.build()
-			.execute_with(|| {
-				build_offchain_election_test_ext();
-				run_to_block(12);
-
-				// a meeeeh solution
-				let (compact, winners, score) = horrible_npos_solution(false);
-				assert_ok!(submit_solution(
-					Origin::signed(10),
-					winners,
-					compact,
-					score,
-				));
-
-				// a better solution
-				let (compact, winners, score) = prepare_submission_with(true, true, 2, |_| {});
-				assert_ok!(submit_solution(
-					Origin::signed(10),
-					winners,
-					compact,
-					score,
-				));
-			})
-	}
-
-	#[test]
-	fn offchain_worker_runs_when_window_open() {
-		// at the end of the first finalized block with ElectionStatus::open(_), it should execute.
-		let mut ext = ExtBuilder::default()
-			.offchain_election_ext()
-			.validator_count(2)
-			.build();
-		let state = offchainify(&mut ext, 0);
-		ext.execute_with(|| {
-			run_to_block(12);
-
-			// local key 11 is in the elected set.
-			assert_eq_uvec!(Session::validators(), vec![11, 21]);
-			assert_eq!(state.read().transactions.len(), 0);
-			Staking::offchain_worker(12);
-			assert_eq!(state.read().transactions.len(), 1);
-
-			let encoded = state.read().transactions[0].clone();
-			let extrinsic: Extrinsic = Decode::decode(&mut &*encoded).unwrap();
-
-			let call = extrinsic.call;
-			let inner = match call {
-				mock::Call::Staking(inner) => inner,
-				_ => unreachable!(),
-			};
-
-			assert_eq!(
-				<Staking as sp_runtime::traits::ValidateUnsigned>::validate_unsigned(
-					TransactionSource::Local,
-					&inner,
-				),
-				TransactionValidity::Ok(ValidTransaction {
-					priority: UnsignedPriority::get() + 1125, // the proposed slot stake.
-					requires: vec![],
-					provides: vec![("StakingOffchain", current_era()).encode()],
-					longevity: 3,
-					propagate: false,
-				})
-			)
-		})
-	}
-
-	#[test]
-	fn offchain_worker_runs_with_balancing() {
-		// Offchain worker balances based on the number provided by randomness. See the difference
-		// in the priority, which comes from the computed score.
-		let mut ext = ExtBuilder::default()
-			.offchain_election_ext()
-			.validator_count(2)
-			.max_offchain_iterations(2)
-			.build();
-		let state = offchainify(&mut ext, 2);
-		ext.execute_with(|| {
-			run_to_block(12);
-
-			// local key 11 is in the elected set.
-			assert_eq_uvec!(Session::validators(), vec![11, 21]);
-			assert_eq!(state.read().transactions.len(), 0);
-			Staking::offchain_worker(12);
-			assert_eq!(state.read().transactions.len(), 1);
-
-			let encoded = state.read().transactions[0].clone();
-			let extrinsic: Extrinsic = Decode::decode(&mut &*encoded).unwrap();
-
-			let call = extrinsic.call;
-			let inner = match call {
-				mock::Call::Staking(inner) => inner,
-				_ => unreachable!(),
-			};
-
-			assert_eq!(
-				<Staking as sp_runtime::traits::ValidateUnsigned>::validate_unsigned(
-					TransactionSource::Local,
-					&inner,
-				),
-				TransactionValidity::Ok(ValidTransaction {
-					// the proposed slot stake, with balance_solution.
-					priority: UnsignedPriority::get() + 1250,
-					requires: vec![],
-					provides: vec![("StakingOffchain", active_era()).encode()],
-					longevity: 3,
-					propagate: false,
-				})
-			)
-		})
-	}
-
-	#[test]
-	fn mediocre_submission_from_authority_is_early_rejected() {
-		let mut ext = ExtBuilder::default()
-			.offchain_election_ext()
-			.validator_count(4)
-			.build();
-		let state = offchainify(&mut ext, 0);
-		ext.execute_with(|| {
-			run_to_block(12);
-			// put a good solution on-chain
-			let (compact, winners, score) = prepare_submission_with(true, true, 2, |_| {});
-			assert_ok!(submit_solution(
-				Origin::signed(10),
-				winners,
-				compact,
-				score,
-			),);
-
-			// now run the offchain worker in the same chain state.
-			Staking::offchain_worker(12);
-			assert_eq!(state.read().transactions.len(), 1);
-
-			let encoded = state.read().transactions[0].clone();
-			let extrinsic: Extrinsic = Decode::decode(&mut &*encoded).unwrap();
-
-			let call = extrinsic.call;
-			let inner = match call {
-				mock::Call::Staking(inner) => inner,
-				_ => unreachable!(),
-			};
-
-			// pass this call to ValidateUnsigned
-			assert_eq!(
-				<Staking as sp_runtime::traits::ValidateUnsigned>::validate_unsigned(
-					TransactionSource::Local,
-					&inner,
-				),
-				TransactionValidity::Err(
-					InvalidTransaction::Custom(<Error<Test>>::OffchainElectionWeakSubmission.as_u8()).into(),
-				),
-			)
-		})
-	}
-
-	#[test]
-	fn invalid_election_correct_number_of_winners() {
-		ExtBuilder::default()
-			.offchain_election_ext()
-			.validator_count(4)
-			.has_stakers(false)
-			.build()
-			.execute_with(|| {
-				build_offchain_election_test_ext();
-				run_to_block(12);
-
-				ValidatorCount::put(3);
-				let (compact, winners, score) = prepare_submission_with(true, true, 2, |_| {});
-				ValidatorCount::put(4);
-
-				assert_eq!(winners.len(), 3);
-
-				assert_noop!(
-					submit_solution(
-						Origin::signed(10),
-						winners,
-						compact,
-						score,
-					),
-					Error::<Test>::OffchainElectionBogusWinnerCount,
-				);
-			})
-	}
-
-	#[test]
-	fn invalid_election_solution_size() {
-		ExtBuilder::default()
-			.offchain_election_ext()
-			.build()
-			.execute_with(|| {
-				run_to_block(12);
-
-				let (compact, winners, score) = prepare_submission_with(true, true, 2, |_| {});
-
-				assert_noop!(
-					Staking::submit_election_solution(
-						Origin::signed(10),
-						winners,
-						compact,
-						score,
-						current_era(),
-						ElectionSize::default(),
-					),
-					Error::<Test>::OffchainElectionBogusElectionSize,
-				);
-			})
-	}
-
-	#[test]
-	fn invalid_election_correct_number_of_winners_1() {
-		// if we have too little validators, then the number of candidates is the bound.
-		ExtBuilder::default()
-			.offchain_election_ext()
-			.validator_count(8) // we simply cannot elect 8
-			.has_stakers(false)
-			.build()
-			.execute_with(|| {
-				build_offchain_election_test_ext();
-				run_to_block(12);
-
-				ValidatorCount::put(3);
-				let (compact, winners, score) = prepare_submission_with(true, true, 2, |_| {});
-				ValidatorCount::put(4);
-
-				assert_eq!(winners.len(), 3);
-
-				assert_noop!(
-					submit_solution(
-						Origin::signed(10),
-						winners,
-						compact,
-						score,
-					),
-					Error::<Test>::OffchainElectionBogusWinnerCount,
-				);
-			})
-	}
-
-	#[test]
-	fn invalid_election_correct_number_of_winners_2() {
-		// if we have too little validators, then the number of candidates is the bound.
-		ExtBuilder::default()
-			.offchain_election_ext()
-			.validator_count(8) // we simply cannot elect 8
-			.has_stakers(false)
-			.build()
-			.execute_with(|| {
-				build_offchain_election_test_ext();
-				run_to_block(12);
-
-				let (compact, winners, score) = prepare_submission_with(true, true, 2, |_| {});
-
-				assert_eq!(winners.len(), 4);
-
-				// all good. We chose 4 and it works.
-				assert_ok!(submit_solution(
-					Origin::signed(10),
-					winners,
-					compact,
-					score,
-				),);
-			})
-	}
-
-	#[test]
-	fn invalid_election_out_of_bound_nominator_index() {
-		// A nominator index which is simply invalid
-		ExtBuilder::default()
-			.offchain_election_ext()
-			.validator_count(4)
-			.has_stakers(false)
-			.build()
-			.execute_with(|| {
-				build_offchain_election_test_ext();
-				run_to_block(12);
-
-				assert_eq!(Staking::snapshot_nominators().unwrap().len(), 5 + 4);
-				assert_eq!(Staking::snapshot_validators().unwrap().len(), 4);
-				let (mut compact, winners, score) = prepare_submission_with(true, true, 2, |_| {});
-
-				// index 9 doesn't exist.
-				compact.votes1.push((9, 2));
-
-				// The error type sadly cannot be more specific now.
-				assert_noop!(
-					submit_solution(
-						Origin::signed(10),
-						winners,
-						compact,
-						score,
-					),
-					Error::<Test>::OffchainElectionBogusCompact,
-				);
-			})
-	}
-
-	#[test]
-	fn invalid_election_out_of_bound_validator_index() {
-		// A validator index which is out of bound
-		ExtBuilder::default()
-			.offchain_election_ext()
-			.validator_count(2)
-			.has_stakers(false)
-			.build()
-			.execute_with(|| {
-				build_offchain_election_test_ext();
-				run_to_block(12);
-
-				assert_eq!(Staking::snapshot_nominators().unwrap().len(), 5 + 4);
-				assert_eq!(Staking::snapshot_validators().unwrap().len(), 4);
-				let (mut compact, winners, score) = prepare_submission_with(true, true, 2, |_| {});
-
-				// index 4 doesn't exist.
-				compact.votes1.iter_mut().for_each(|(_, vidx)| if *vidx == 1 { *vidx = 4 });
-
-				// The error type sadly cannot be more specific now.
-				assert_noop!(
-					submit_solution(
-						Origin::signed(10),
-						winners,
-						compact,
-						score,
-					),
-					Error::<Test>::OffchainElectionBogusCompact,
-				);
-			})
-	}
-
-	#[test]
-	fn invalid_election_out_of_bound_winner_index() {
-		// A winner index which is simply invalid
-		ExtBuilder::default()
-			.offchain_election_ext()
-			.validator_count(4)
-			.has_stakers(false)
-			.build()
-			.execute_with(|| {
-				build_offchain_election_test_ext();
-				run_to_block(12);
-
-				assert_eq!(Staking::snapshot_nominators().unwrap().len(), 5 + 4);
-				assert_eq!(Staking::snapshot_validators().unwrap().len(), 4);
-				let (compact, _, score) = prepare_submission_with(true, true, 2, |_| {});
-
-				// index 4 doesn't exist.
-				let winners = vec![0, 1, 2, 4];
-
-				assert_noop!(
-					submit_solution(
-						Origin::signed(10),
-						winners,
-						compact,
-						score,
-					),
-					Error::<Test>::OffchainElectionBogusWinner,
-				);
-			})
-	}
-
-	#[test]
-	fn invalid_election_non_winner_validator_index() {
-		// An edge that points to a correct validator index who is NOT a winner. This is very
-		// similar to the test that raises `OffchainElectionBogusNomination`.
-		ExtBuilder::default()
-			.offchain_election_ext()
-			.validator_count(2) // we select only 2.
-			.has_stakers(false)
-			.build()
-			.execute_with(|| {
-				build_offchain_election_test_ext();
-				run_to_block(12);
-
-				assert_eq!(Staking::snapshot_nominators().unwrap().len(), 5 + 4);
-				assert_eq!(Staking::snapshot_validators().unwrap().len(), 4);
-				let (compact, winners, score) = prepare_submission_with(false, true, 2, |a| {
-					// swap all 11 and 41s in the distribution with non-winners. Note that it is
-					// important that the count of winners and the count of unique targets remain
-					// valid.
-					a.iter_mut().for_each(| StakedAssignment { who, distribution } |
-						distribution.iter_mut().for_each(|(t, _)| {
-							if *t == 41 { *t = 31 } else { *t = 21 }
-							// if it is self vote, correct that.
-							if *who == 41 { *who = 31 }
-							if *who == 11 { *who = 21 }
-						})
-					);
-				});
-
-				assert_noop!(
-					submit_solution(
-						Origin::signed(10),
-						winners,
-						compact,
-						score,
-					),
-					Error::<Test>::OffchainElectionBogusNomination,
-				);
-			})
-	}
-
-	#[test]
-	fn offchain_election_unique_target_count_is_checked() {
-		// Number of unique targets and and winners.len must match.
-		ExtBuilder::default()
-			.offchain_election_ext()
-			.validator_count(2) // we select only 2.
-			.has_stakers(false)
-			.build()
-			.execute_with(|| {
-				build_offchain_election_test_ext();
-				run_to_block(12);
-
-				assert_eq!(Staking::snapshot_nominators().unwrap().len(), 5 + 4);
-				assert_eq!(Staking::snapshot_validators().unwrap().len(), 4);
-
-				let (compact, winners, score) = prepare_submission_with(false, true, 2, |a| {
-					a.iter_mut()
-						.find(|x| x.who == 5)
-						// just add any new target.
-						.map(|x| {
-							// old value.
-							assert_eq!(x.distribution, vec![(41, 100)]);
-							// new value.
-							x.distribution = vec![(21, 50), (41, 50)]
-						});
-				});
-
-				assert_noop!(
-					submit_solution(
-						Origin::signed(10),
-						winners,
-						compact,
-						score,
-					),
-					Error::<Test>::OffchainElectionBogusWinnerCount,
-				);
-			})
-	}
-
-	#[test]
-	fn invalid_election_wrong_self_vote() {
-		// A self vote for someone else.
-		ExtBuilder::default()
-			.offchain_election_ext()
-			.validator_count(4)
-			.has_stakers(false)
-			.build()
-			.execute_with(|| {
-				build_offchain_election_test_ext();
-				run_to_block(12);
-
-				let (compact, winners, score) = prepare_submission_with(true, true, 2, |a| {
-					// mutate a self vote to target someone else. That someone else is still among the
-					// winners
-					a.iter_mut().find(|x| x.who == 11).map(|x| {
-						x.distribution
-							.iter_mut()
-							.find(|y| y.0 == 11)
-							.map(|y| y.0 = 21)
-					});
-				});
-
-				assert_noop!(
-					submit_solution(
-						Origin::signed(10),
-						winners,
-						compact,
-						score,
-					),
-					Error::<Test>::OffchainElectionBogusSelfVote,
-				);
-			})
-	}
-
-	#[test]
-	fn invalid_election_wrong_self_vote_2() {
-		// A self validator voting for someone else next to self vote.
-		ExtBuilder::default()
-			.offchain_election_ext()
-			.validator_count(4)
-			.has_stakers(false)
-			.build()
-			.execute_with(|| {
-				build_offchain_election_test_ext();
-				run_to_block(12);
-
-				let (compact, winners, score) = prepare_submission_with(true, true, 2, |a| {
-					// Remove the self vote.
-					a.retain(|x| x.who != 11);
-					// add is as a new double vote
-					a.push(StakedAssignment {
-						who: 11,
-						distribution: vec![(11, 50), (21, 50)],
-					});
-				});
-
-				// This raises score issue.
-				assert_noop!(
-					submit_solution(
-						Origin::signed(10),
-						winners,
-						compact,
-						score,
-					),
-					Error::<Test>::OffchainElectionBogusSelfVote,
-				);
-			})
-	}
-
-	#[test]
-	fn invalid_election_over_stake() {
-		// Someone's edge ratios sums to more than 100%.
-		ExtBuilder::default()
-			.offchain_election_ext()
-			.validator_count(4)
-			.has_stakers(false)
-			.build()
-			.execute_with(|| {
-				build_offchain_election_test_ext();
-				run_to_block(12);
-
-				// Note: we don't reduce here to be able to tweak votes3. votes3 will vanish if you
-				// reduce.
-				let (mut compact, winners, score) = prepare_submission_with(true, false, 0, |_| {});
-
-				if let Some(c) = compact.votes3.iter_mut().find(|x| x.0 == 0) {
-					// by default it should have been (0, [(2, 33%), (1, 33%)], 0)
-					// now the sum is above 100%
-					c.1 = [(2, percent(66)), (1, percent(66))];
-				}
-
-				assert_noop!(
-					submit_solution(
-						Origin::signed(10),
-						winners,
-						compact,
-						score,
-					),
-					Error::<Test>::OffchainElectionBogusCompact,
-				);
-			})
-	}
-
-	#[test]
-	fn invalid_election_under_stake() {
-		// at the time of this writing, we cannot under stake someone. The compact assignment works
-		// in a way that some of the stakes are presented by the submitter, and the last one is read
-		// from chain by subtracting the rest from total. Hence, the sum is always correct.
-		// This test is only here as a demonstration.
-	}
-
-	#[test]
-	fn invalid_election_invalid_target_stealing() {
-		// A valid voter who voted for someone who is a candidate, and is a correct winner, but is
-		// actually NOT nominated by this nominator.
-		ExtBuilder::default()
-			.offchain_election_ext()
-			.validator_count(4)
-			.has_stakers(false)
-			.build()
-			.execute_with(|| {
-				build_offchain_election_test_ext();
-				run_to_block(12);
-
-				let (compact, winners, score) = prepare_submission_with(true, false, 0, |a| {
-					// 3 only voted for 20 and 40. We add a fake vote to 30. The stake sum is still
-					// correctly 100.
-					a.iter_mut()
-						.find(|x| x.who == 3)
-						.map(|x| x.distribution = vec![(21, 50), (41, 30), (31, 20)]);
-				});
-
-				assert_noop!(
-					submit_solution(
-						Origin::signed(10),
-						winners,
-						compact,
-						score,
-					),
-					Error::<Test>::OffchainElectionBogusNomination,
-				);
-			})
-	}
-
-	#[test]
-	fn nomination_slash_filter_is_checked() {
-		// If a nominator has voted for someone who has been recently slashed, that particular
-		// nomination should be disabled for the upcoming election. A solution must respect this
-		// rule.
-		ExtBuilder::default()
-			.offchain_election_ext()
-			.validator_count(4)
-			.has_stakers(false)
-			.build()
-			.execute_with(|| {
-				build_offchain_election_test_ext();
-
-				// finalize the round with fallback. This is needed since all nominator submission
-				// are in era zero and we want this one to pass with no problems.
-				run_to_block(15);
-
-				// go to the next session to trigger mock::start_era and bump the active era
-				run_to_block(20);
-
-				// slash 10. This must happen outside of the election window.
-				let offender_expo = Staking::eras_stakers(Staking::active_era().unwrap().index, 11);
-				on_offence_now(
-					&[OffenceDetails {
-						offender: (11, offender_expo.clone()),
-						reporters: vec![],
-					}],
-					&[Perbill::from_percent(50)],
-				);
-
-				// validate 10 again for the next round. But this guy will not have the votes that
-				// it should have had from 1 and 2.
-				assert_ok!(Staking::validate(
-					Origin::signed(10),
-					Default::default()
-				));
-
-				// open the election window and create snapshots.
-				run_to_block(32);
-
-				// a solution that has been prepared after the slash.
-				let (compact, winners, score) = prepare_submission_with(true, false, 0, |a| {
-					// no one is allowed to vote for 10, except for itself.
-					a.into_iter()
-						.filter(|s| s.who != 11)
-						.for_each(|s|
-							assert!(s.distribution.iter().find(|(t, _)| *t == 11).is_none())
-						);
-				});
-
-				// can be submitted.
-				assert_ok!(submit_solution(
-					Origin::signed(10),
-					winners,
-					compact,
-					score,
-				));
-
-				// a wrong solution.
-				let (compact, winners, score) = prepare_submission_with(true, false, 0, |a| {
-					// add back the vote that has been filtered out.
-					a.push(StakedAssignment {
-						who: 1,
-						distribution: vec![(11, 100)]
-					});
-				});
-
-				// is rejected.
-				assert_noop!(
-					submit_solution(
-						Origin::signed(10),
-						winners,
-						compact,
-						score,
-					),
-					Error::<Test>::OffchainElectionSlashedNomination,
-				);
-			})
-	}
-
-	#[test]
-	fn invalid_election_wrong_score() {
-		// A valid voter who's total distributed stake is more than what they bond
-		ExtBuilder::default()
-			.offchain_election_ext()
-			.validator_count(4)
-			.has_stakers(false)
-			.build()
-			.execute_with(|| {
-				build_offchain_election_test_ext();
-				run_to_block(12);
-
-				let (compact, winners, mut score) = prepare_submission_with(true, true, 2, |_| {});
-				score[0] += 1;
-
-				assert_noop!(
-					submit_solution(
-						Origin::signed(10),
-						winners,
-						compact,
-						score,
-					),
-					Error::<Test>::OffchainElectionBogusScore,
-				);
-			})
-	}
-
-	#[test]
-	fn offchain_storage_is_set() {
-		let mut ext = ExtBuilder::default()
-			.offchain_election_ext()
-			.validator_count(4)
-			.build();
-		let state = offchainify(&mut ext, 0);
-
-		ext.execute_with(|| {
-			use offchain_election::OFFCHAIN_HEAD_DB;
-			use sp_runtime::offchain::storage::StorageValueRef;
-
-			run_to_block(12);
-
-			Staking::offchain_worker(12);
-			// it works
-			assert_eq!(state.read().transactions.len(), 1);
-
-			// and it is set
-			let storage = StorageValueRef::persistent(&OFFCHAIN_HEAD_DB);
-			assert_eq!(storage.get::<BlockNumber>().unwrap().unwrap(), 12);
-		})
-	}
-
-	#[test]
-	fn offchain_storage_prevents_duplicate() {
-		let mut ext = ExtBuilder::default()
-			.offchain_election_ext()
-			.validator_count(4)
-			.build();
-		let _ = offchainify(&mut ext, 0);
-
-		ext.execute_with(|| {
-			use offchain_election::OFFCHAIN_HEAD_DB;
-			use sp_runtime::offchain::storage::StorageValueRef;
-			let storage = StorageValueRef::persistent(&OFFCHAIN_HEAD_DB);
-
-			run_to_block(12);
-
-			// first run -- ok
-			assert_eq!(
-				offchain_election::set_check_offchain_execution_status::<Test>(12),
-				Ok(()),
-			);
-			assert_eq!(storage.get::<BlockNumber>().unwrap().unwrap(), 12);
-
-			// re-execute after the next. not allowed.
-			assert_eq!(
-				offchain_election::set_check_offchain_execution_status::<Test>(13),
-				Err("recently executed."),
-			);
-
-			// a fork like situation -- re-execute 10, 11, 12. But it won't go through.
-			assert_eq!(
-				offchain_election::set_check_offchain_execution_status::<Test>(10),
-				Err("fork."),
-			);
-			assert_eq!(
-				offchain_election::set_check_offchain_execution_status::<Test>(11),
-				Err("fork."),
-			);
-			assert_eq!(
-				offchain_election::set_check_offchain_execution_status::<Test>(12),
-				Err("recently executed."),
-			);
-		})
-	}
-
-	#[test]
-	#[should_panic]
-	fn offence_is_blocked_when_window_open() {
-		ExtBuilder::default()
-			.offchain_election_ext()
-			.validator_count(4)
-			.has_stakers(false)
-			.build()
-			.execute_with(|| {
-				run_to_block(12);
-				assert_eq!(Staking::era_election_status(), ElectionStatus::Open(12));
-
-				let offender_expo = Staking::eras_stakers(Staking::active_era().unwrap().index, 10);
-
-				// panic from the impl in mock
-				on_offence_now(
-					&[OffenceDetails {
-						offender: (10, offender_expo.clone()),
-						reporters: vec![],
-					}],
-					&[Perbill::from_percent(10)],
-				);
-			})
-	}
-}
-
 #[test]
 fn slash_kicks_validators_not_nominators_and_disables_nominator_for_kicked_validator() {
 	ExtBuilder::default().build_and_execute(|| {
@@ -4267,11 +2978,14 @@ fn claim_reward_at_the_last_era_and_no_double_claim_and_invalid_claim() {
 	// * an invalid era to claim doesn't update last_reward
 	// * double claim of one era fails
 	ExtBuilder::default().nominate(true).build_and_execute(|| {
+		// Consumed weight for all payout_stakers dispatches that fail
+		let err_weight = weights::SubstrateWeight::<Test>::payout_stakers_alive_staked(0);
+
 		let init_balance_10 = Balances::total_balance(&10);
 		let init_balance_100 = Balances::total_balance(&100);
 
-		let part_for_10 = Perbill::from_rational_approximation::<u32>(1000, 1125);
-		let part_for_100 = Perbill::from_rational_approximation::<u32>(125, 1125);
+		let part_for_10 = Perbill::from_rational::<u32>(1000, 1125);
+		let part_for_100 = Perbill::from_rational::<u32>(125, 1125);
 
 		// Check state
 		Payee::<Test>::insert(11, RewardDestination::Controller);
@@ -4312,19 +3026,19 @@ fn claim_reward_at_the_last_era_and_no_double_claim_and_invalid_claim() {
 		assert_noop!(
 			Staking::payout_stakers(Origin::signed(1337), 11, 0),
 			// Fail: Era out of history
-			Error::<Test>::InvalidEraToReward
+			Error::<Test>::InvalidEraToReward.with_weight(err_weight)
 		);
 		assert_ok!(Staking::payout_stakers(Origin::signed(1337), 11, 1));
 		assert_ok!(Staking::payout_stakers(Origin::signed(1337), 11, 2));
 		assert_noop!(
 			Staking::payout_stakers(Origin::signed(1337), 11, 2),
 			// Fail: Double claim
-			Error::<Test>::AlreadyClaimed
+			Error::<Test>::AlreadyClaimed.with_weight(err_weight)
 		);
 		assert_noop!(
 			Staking::payout_stakers(Origin::signed(1337), 11, active_era),
 			// Fail: Era not finished yet
-			Error::<Test>::InvalidEraToReward
+			Error::<Test>::InvalidEraToReward.with_weight(err_weight)
 		);
 
 		// Era 0 can't be rewarded anymore and current era can't be rewarded yet
@@ -4578,6 +3292,9 @@ fn test_payout_stakers() {
 fn payout_stakers_handles_basic_errors() {
 	// Here we will test payouts handle all errors.
 	ExtBuilder::default().has_stakers(false).build_and_execute(|| {
+		// Consumed weight for all payout_stakers dispatches that fail
+		let err_weight = weights::SubstrateWeight::<Test>::payout_stakers_alive_staked(0);
+
 		// Same setup as the test above
 		let balance = 1000;
 		bond_validator(11, 10, balance); // Default(64)
@@ -4596,9 +3313,15 @@ fn payout_stakers_handles_basic_errors() {
 		mock::start_active_era(2);
 
 		// Wrong Era, too big
-		assert_noop!(Staking::payout_stakers(Origin::signed(1337), 11, 2), Error::<Test>::InvalidEraToReward);
+		assert_noop!(
+			Staking::payout_stakers(Origin::signed(1337), 11, 2),
+			Error::<Test>::InvalidEraToReward.with_weight(err_weight)
+		);
 		// Wrong Staker
-		assert_noop!(Staking::payout_stakers(Origin::signed(1337), 10, 1), Error::<Test>::NotStash);
+		assert_noop!(
+			Staking::payout_stakers(Origin::signed(1337), 10, 1),
+			Error::<Test>::NotStash.with_weight(err_weight)
+		);
 
 		for i in 3..100 {
 			Staking::reward_by_ids(vec![(11, 1)]);
@@ -4608,14 +3331,134 @@ fn payout_stakers_handles_basic_errors() {
 		}
 		// We are at era 99, with history depth of 84
 		// We should be able to payout era 15 through 98 (84 total eras), but not 14 or 99.
-		assert_noop!(Staking::payout_stakers(Origin::signed(1337), 11, 14), Error::<Test>::InvalidEraToReward);
-		assert_noop!(Staking::payout_stakers(Origin::signed(1337), 11, 99), Error::<Test>::InvalidEraToReward);
+		assert_noop!(
+			Staking::payout_stakers(Origin::signed(1337), 11, 14),
+			Error::<Test>::InvalidEraToReward.with_weight(err_weight)
+		);
+		assert_noop!(
+			Staking::payout_stakers(Origin::signed(1337), 11, 99),
+			Error::<Test>::InvalidEraToReward.with_weight(err_weight)
+		);
 		assert_ok!(Staking::payout_stakers(Origin::signed(1337), 11, 15));
 		assert_ok!(Staking::payout_stakers(Origin::signed(1337), 11, 98));
 
 		// Can't claim again
-		assert_noop!(Staking::payout_stakers(Origin::signed(1337), 11, 15), Error::<Test>::AlreadyClaimed);
-		assert_noop!(Staking::payout_stakers(Origin::signed(1337), 11, 98), Error::<Test>::AlreadyClaimed);
+		assert_noop!(
+			Staking::payout_stakers(Origin::signed(1337), 11, 15),
+			Error::<Test>::AlreadyClaimed.with_weight(err_weight)
+		);
+		assert_noop!(
+			Staking::payout_stakers(Origin::signed(1337), 11, 98),
+			Error::<Test>::AlreadyClaimed.with_weight(err_weight)
+		);
+	});
+}
+
+#[test]
+fn payout_stakers_handles_weight_refund() {
+	// Note: this test relies on the assumption that `payout_stakers_alive_staked` is solely used by
+	// `payout_stakers` to calculate the weight of each payout op.
+	ExtBuilder::default().has_stakers(false).build_and_execute(|| {
+		let max_nom_rewarded = <Test as Config>::MaxNominatorRewardedPerValidator::get();
+		// Make sure the configured value is meaningful for our use.
+		assert!(max_nom_rewarded >= 4);
+		let half_max_nom_rewarded = max_nom_rewarded / 2;
+		// Sanity check our max and half max nominator quantities.
+		assert!(half_max_nom_rewarded > 0);
+		assert!(max_nom_rewarded > half_max_nom_rewarded);
+
+		let max_nom_rewarded_weight
+			= <Test as Config>::WeightInfo::payout_stakers_alive_staked(max_nom_rewarded);
+		let half_max_nom_rewarded_weight
+			= <Test as Config>::WeightInfo::payout_stakers_alive_staked(half_max_nom_rewarded);
+		let zero_nom_payouts_weight = <Test as Config>::WeightInfo::payout_stakers_alive_staked(0);
+		assert!(zero_nom_payouts_weight > 0);
+		assert!(half_max_nom_rewarded_weight > zero_nom_payouts_weight);
+		assert!(max_nom_rewarded_weight > half_max_nom_rewarded_weight);
+
+		let balance = 1000;
+		bond_validator(11, 10, balance);
+
+		/* Era 1 */
+		start_active_era(1);
+
+		// Reward just the validator.
+		Staking::reward_by_ids(vec![(11, 1)]);
+
+		// Add some `half_max_nom_rewarded` nominators who will start backing the validator in the
+		// next era.
+		for i in 0..half_max_nom_rewarded {
+			bond_nominator((1000 + i).into(), (100 + i).into(), balance + i as Balance, vec![11]);
+		}
+
+		/* Era 2 */
+		start_active_era(2);
+
+		// Collect payouts when there are no nominators
+		let call = TestRuntimeCall::Staking(StakingCall::payout_stakers(11, 1));
+		let info = call.get_dispatch_info();
+		let result = call.dispatch(Origin::signed(20));
+		assert_ok!(result);
+		assert_eq!(
+			extract_actual_weight(&result, &info),
+			zero_nom_payouts_weight
+		);
+
+		// The validator is not rewarded in this era; so there will be zero payouts to claim for this era.
+
+		/* Era 3 */
+		start_active_era(3);
+
+		// Collect payouts for an era where the validator did not receive any points.
+		let call = TestRuntimeCall::Staking(StakingCall::payout_stakers(11, 2));
+		let info = call.get_dispatch_info();
+		let result = call.dispatch(Origin::signed(20));
+		assert_ok!(result);
+		assert_eq!(extract_actual_weight(&result, &info), zero_nom_payouts_weight);
+
+		// Reward the validator and its nominators.
+		Staking::reward_by_ids(vec![(11, 1)]);
+
+		/* Era 4 */
+		start_active_era(4);
+
+		// Collect payouts when the validator has `half_max_nom_rewarded` nominators.
+		let call = TestRuntimeCall::Staking(StakingCall::payout_stakers(11, 3));
+		let info = call.get_dispatch_info();
+		let result = call.dispatch(Origin::signed(20));
+		assert_ok!(result);
+		assert_eq!(extract_actual_weight(&result, &info), half_max_nom_rewarded_weight);
+
+		// Add enough nominators so that we are at the limit. They will be active nominators
+		// in the next era.
+		for i in half_max_nom_rewarded..max_nom_rewarded {
+			bond_nominator((1000 + i).into(), (100 + i).into(), balance + i as Balance, vec![11]);
+		}
+
+		/* Era 5 */
+		start_active_era(5);
+		// We now have `max_nom_rewarded` nominators actively nominating our validator.
+
+		// Reward the validator so we can collect for everyone in the next era.
+		Staking::reward_by_ids(vec![(11, 1)]);
+
+		/* Era 6 */
+		start_active_era(6);
+
+		// Collect payouts when the validator had `half_max_nom_rewarded` nominators.
+		let call = TestRuntimeCall::Staking(StakingCall::payout_stakers(11, 5));
+		let info = call.get_dispatch_info();
+		let result = call.dispatch(Origin::signed(20));
+		assert_ok!(result);
+		assert_eq!(extract_actual_weight(&result, &info), max_nom_rewarded_weight);
+
+		// Try and collect payouts for an era that has already been collected.
+		let call = TestRuntimeCall::Staking(StakingCall::payout_stakers(11, 5));
+		let info = call.get_dispatch_info();
+		let result = call.dispatch(Origin::signed(20));
+		assert!(result.is_err());
+		// When there is an error the consumed weight == weight when there are 0 nominator payouts.
+		assert_eq!(extract_actual_weight(&result, &info), zero_nom_payouts_weight);
 	});
 }
 
@@ -4704,39 +3547,6 @@ fn offences_weight_calculated_correctly() {
 	});
 }
 
-#[test]
-fn on_initialize_weight_is_correct() {
-	ExtBuilder::default().has_stakers(false).build_and_execute(|| {
-		assert_eq!(Validators::<Test>::iter().count(), 0);
-		assert_eq!(Nominators::<Test>::iter().count(), 0);
-		// When this pallet has nothing, we do 4 reads each block
-		let base_weight = <Test as frame_system::Config>::DbWeight::get().reads(4);
-		assert_eq!(base_weight, Staking::on_initialize(0));
-	});
-
-	ExtBuilder::default()
-	.offchain_election_ext()
-	.validator_count(4)
-	.has_stakers(false)
-	.build()
-	.execute_with(|| {
-		crate::tests::offchain_election::build_offchain_election_test_ext();
-		run_to_block(11);
-		Staking::on_finalize(System::block_number());
-		System::set_block_number((System::block_number() + 1).into());
-		Timestamp::set_timestamp(System::block_number() * 1000 + INIT_TIMESTAMP);
-		Session::on_initialize(System::block_number());
-
-		assert_eq!(Validators::<Test>::iter().count(), 4);
-		assert_eq!(Nominators::<Test>::iter().count(), 5);
-		// With 4 validators and 5 nominator, we should increase weight by:
-		// - (4 + 5) reads
-		// - 3 Writes
-		let final_weight = <Test as frame_system::Config>::DbWeight::get().reads_writes(4 + 9, 3);
-		assert_eq!(final_weight, Staking::on_initialize(System::block_number()));
-	});
-}
-
 #[test]
 fn payout_creates_controller() {
 	ExtBuilder::default().has_stakers(false).build_and_execute(|| {
@@ -5017,14 +3827,57 @@ fn do_not_die_when_active_is_ed() {
 		})
 }
 
+#[test]
+fn on_finalize_weight_is_nonzero() {
+	ExtBuilder::default().build_and_execute(|| {
+		let on_finalize_weight = <Test as frame_system::Config>::DbWeight::get().reads(1);
+		assert!(Staking::on_initialize(1) >= on_finalize_weight);
+	})
+}
+
 mod election_data_provider {
 	use super::*;
-	use sp_election_providers::ElectionDataProvider;
+	use frame_election_provider_support::ElectionDataProvider;
+
+	#[test]
+	fn targets_2sec_block() {
+		let mut validators = 1000;
+		while <Test as Config>::WeightInfo::get_npos_targets(validators)
+			< 2 * frame_support::weights::constants::WEIGHT_PER_SECOND
+		{
+			validators += 1;
+		}
+
+		println!("Can create a snapshot of {} validators in 2sec block", validators);
+	}
+
+	#[test]
+	fn voters_2sec_block() {
+		// we assume a network only wants up to 1000 validators in most cases, thus having 2000
+		// candidates is as high as it gets.
+		let validators = 2000;
+		// we assume the worse case: each validator also has a slashing span.
+		let slashing_spans = validators;
+		let mut nominators = 1000;
+
+		while <Test as Config>::WeightInfo::get_npos_voters(validators, nominators, slashing_spans)
+			< 2 * frame_support::weights::constants::WEIGHT_PER_SECOND
+		{
+			nominators += 1;
+		}
+
+		println!(
+			"Can create a snapshot of {} nominators [{} validators, each 1 slashing] in 2sec block",
+			nominators, validators
+		);
+	}
 
 	#[test]
 	fn voters_include_self_vote() {
 		ExtBuilder::default().nominate(false).build().execute_with(|| {
-			assert!(<Validators<Test>>::iter().map(|(x, _)| x).all(|v| Staking::voters()
+			assert!(<Validators<Test>>::iter().map(|(x, _)| x).all(|v| Staking::voters(None)
+				.unwrap()
+				.0
 				.into_iter()
 				.find(|(w, _, t)| { v == *w && t[0] == *w })
 				.is_some()))
@@ -5036,7 +3889,9 @@ mod election_data_provider {
 		ExtBuilder::default().build().execute_with(|| {
 			assert_eq!(Staking::nominators(101).unwrap().targets, vec![11, 21]);
 			assert_eq!(
-				<Staking as ElectionDataProvider<AccountId, BlockNumber>>::voters()
+				<Staking as ElectionDataProvider<AccountId, BlockNumber>>::voters(None)
+					.unwrap()
+					.0
 					.iter()
 					.find(|x| x.0 == 101)
 					.unwrap()
@@ -5050,7 +3905,9 @@ mod election_data_provider {
 			// 11 is gone.
 			start_active_era(2);
 			assert_eq!(
-				<Staking as ElectionDataProvider<AccountId, BlockNumber>>::voters()
+				<Staking as ElectionDataProvider<AccountId, BlockNumber>>::voters(None)
+					.unwrap()
+					.0
 					.iter()
 					.find(|x| x.0 == 101)
 					.unwrap()
@@ -5061,7 +3918,9 @@ mod election_data_provider {
 			// resubmit and it is back
 			assert_ok!(Staking::nominate(Origin::signed(100), vec![11, 21]));
 			assert_eq!(
-				<Staking as ElectionDataProvider<AccountId, BlockNumber>>::voters()
+				<Staking as ElectionDataProvider<AccountId, BlockNumber>>::voters(None)
+					.unwrap()
+					.0
 					.iter()
 					.find(|x| x.0 == 101)
 					.unwrap()
@@ -5071,6 +3930,14 @@ mod election_data_provider {
 		})
 	}
 
+	#[test]
+	fn respects_len_limits() {
+		ExtBuilder::default().build().execute_with(|| {
+			assert_eq!(Staking::voters(Some(1)).unwrap_err(), "Voter snapshot too big");
+			assert_eq!(Staking::targets(Some(1)).unwrap_err(), "Target snapshot too big");
+		});
+	}
+
 	#[test]
 	fn estimate_next_election_works() {
 		ExtBuilder::default().session_per_era(5).period(5).build().execute_with(|| {
@@ -5086,7 +3953,7 @@ mod election_data_provider {
 			assert_eq!(staking_events().len(), 1);
 			assert_eq!(
 				*staking_events().last().unwrap(),
-				RawEvent::StakingElection(ElectionCompute::OnChain)
+				RawEvent::StakingElection
 			);
 
 			for b in 21..45 {
@@ -5100,7 +3967,7 @@ mod election_data_provider {
 			assert_eq!(staking_events().len(), 3);
 			assert_eq!(
 				*staking_events().last().unwrap(),
-				RawEvent::StakingElection(ElectionCompute::OnChain)
+				RawEvent::StakingElection
 			);
 		})
 	}
diff --git a/frame/staking/src/weights.rs b/frame/staking/src/weights.rs
index 3489a10135427..d3274cad8050e 100644
--- a/frame/staking/src/weights.rs
+++ b/frame/staking/src/weights.rs
@@ -18,7 +18,7 @@
 //! Autogenerated weights for pallet_staking
 //!
 //! THIS FILE WAS AUTO-GENERATED USING THE SUBSTRATE BENCHMARK CLI VERSION 3.0.0
-//! DATE: 2021-02-13, STEPS: `[50, ]`, REPEAT: 20, LOW RANGE: [], HIGH RANGE: []
+//! DATE: 2021-03-25, STEPS: `[50, ]`, REPEAT: 20, LOW RANGE: `[]`, HIGH RANGE: `[]`
 //! EXECUTION: Some(Wasm), WASM-EXECUTION: Compiled, CHAIN: Some("dev"), DB CACHE: 128
 
 // Executed Command:
@@ -68,356 +68,367 @@ pub trait WeightInfo {
 	fn set_history_depth(e: u32, ) -> Weight;
 	fn reap_stash(s: u32, ) -> Weight;
 	fn new_era(v: u32, n: u32, ) -> Weight;
-	fn submit_solution_better(v: u32, n: u32, a: u32, w: u32, ) -> Weight;
+	fn get_npos_voters(v: u32, n: u32, s: u32, ) -> Weight;
+	fn get_npos_targets(v: u32, ) -> Weight;
 }
 
 /// Weights for pallet_staking using the Substrate node and recommended hardware.
 pub struct SubstrateWeight<T>(PhantomData<T>);
 impl<T: frame_system::Config> WeightInfo for SubstrateWeight<T> {
 	fn bond() -> Weight {
-		(81_642_000 as Weight)
+		(79_895_000 as Weight)
 			.saturating_add(T::DbWeight::get().reads(5 as Weight))
 			.saturating_add(T::DbWeight::get().writes(4 as Weight))
 	}
 	fn bond_extra() -> Weight {
-		(66_025_000 as Weight)
-			.saturating_add(T::DbWeight::get().reads(4 as Weight))
+		(60_561_000 as Weight)
+			.saturating_add(T::DbWeight::get().reads(3 as Weight))
 			.saturating_add(T::DbWeight::get().writes(2 as Weight))
 	}
 	fn unbond() -> Weight {
-		(60_810_000 as Weight)
-			.saturating_add(T::DbWeight::get().reads(5 as Weight))
+		(54_996_000 as Weight)
+			.saturating_add(T::DbWeight::get().reads(4 as Weight))
 			.saturating_add(T::DbWeight::get().writes(3 as Weight))
 	}
 	fn withdraw_unbonded_update(s: u32, ) -> Weight {
-		(61_537_000 as Weight)
-			// Standard Error: 1_000
-			.saturating_add((60_000 as Weight).saturating_mul(s as Weight))
-			.saturating_add(T::DbWeight::get().reads(5 as Weight))
+		(56_056_000 as Weight)
+			// Standard Error: 0
+			.saturating_add((67_000 as Weight).saturating_mul(s as Weight))
+			.saturating_add(T::DbWeight::get().reads(4 as Weight))
 			.saturating_add(T::DbWeight::get().writes(3 as Weight))
 	}
 	fn withdraw_unbonded_kill(s: u32, ) -> Weight {
-		(95_741_000 as Weight)
+		(90_267_000 as Weight)
 			// Standard Error: 1_000
-			.saturating_add((2_754_000 as Weight).saturating_mul(s as Weight))
-			.saturating_add(T::DbWeight::get().reads(7 as Weight))
+			.saturating_add((2_787_000 as Weight).saturating_mul(s as Weight))
+			.saturating_add(T::DbWeight::get().reads(6 as Weight))
 			.saturating_add(T::DbWeight::get().writes(8 as Weight))
 			.saturating_add(T::DbWeight::get().writes((1 as Weight).saturating_mul(s as Weight)))
 	}
 	fn validate() -> Weight {
-		(21_009_000 as Weight)
-			.saturating_add(T::DbWeight::get().reads(2 as Weight))
+		(16_345_000 as Weight)
+			.saturating_add(T::DbWeight::get().reads(1 as Weight))
 			.saturating_add(T::DbWeight::get().writes(2 as Weight))
 	}
 	fn kick(k: u32, ) -> Weight {
-		(31_832_000 as Weight)
-			// Standard Error: 15_000
-			.saturating_add((19_418_000 as Weight).saturating_mul(k as Weight))
-			.saturating_add(T::DbWeight::get().reads(2 as Weight))
+		(27_080_000 as Weight)
+			// Standard Error: 14_000
+			.saturating_add((18_739_000 as Weight).saturating_mul(k as Weight))
+			.saturating_add(T::DbWeight::get().reads(1 as Weight))
 			.saturating_add(T::DbWeight::get().reads((1 as Weight).saturating_mul(k as Weight)))
 			.saturating_add(T::DbWeight::get().writes((1 as Weight).saturating_mul(k as Weight)))
 	}
 	fn nominate(n: u32, ) -> Weight {
-		(34_304_000 as Weight)
-			// Standard Error: 20_000
-			.saturating_add((5_643_000 as Weight).saturating_mul(n as Weight))
-			.saturating_add(T::DbWeight::get().reads(4 as Weight))
+		(29_101_000 as Weight)
+			// Standard Error: 23_000
+			.saturating_add((5_670_000 as Weight).saturating_mul(n as Weight))
+			.saturating_add(T::DbWeight::get().reads(3 as Weight))
 			.saturating_add(T::DbWeight::get().reads((1 as Weight).saturating_mul(n as Weight)))
 			.saturating_add(T::DbWeight::get().writes(2 as Weight))
 	}
 	fn chill() -> Weight {
-		(20_103_000 as Weight)
-			.saturating_add(T::DbWeight::get().reads(2 as Weight))
+		(15_771_000 as Weight)
+			.saturating_add(T::DbWeight::get().reads(1 as Weight))
 			.saturating_add(T::DbWeight::get().writes(2 as Weight))
 	}
 	fn set_payee() -> Weight {
-		(13_858_000 as Weight)
+		(13_329_000 as Weight)
 			.saturating_add(T::DbWeight::get().reads(1 as Weight))
 			.saturating_add(T::DbWeight::get().writes(1 as Weight))
 	}
 	fn set_controller() -> Weight {
-		(30_269_000 as Weight)
+		(29_807_000 as Weight)
 			.saturating_add(T::DbWeight::get().reads(3 as Weight))
 			.saturating_add(T::DbWeight::get().writes(3 as Weight))
 	}
 	fn set_validator_count() -> Weight {
-		(2_444_000 as Weight)
+		(2_323_000 as Weight)
 			.saturating_add(T::DbWeight::get().writes(1 as Weight))
 	}
 	fn force_no_eras() -> Weight {
-		(2_766_000 as Weight)
+		(2_528_000 as Weight)
 			.saturating_add(T::DbWeight::get().writes(1 as Weight))
 	}
 	fn force_new_era() -> Weight {
-		(2_724_000 as Weight)
+		(2_529_000 as Weight)
 			.saturating_add(T::DbWeight::get().writes(1 as Weight))
 	}
 	fn force_new_era_always() -> Weight {
-		(2_702_000 as Weight)
+		(2_527_000 as Weight)
 			.saturating_add(T::DbWeight::get().writes(1 as Weight))
 	}
 	fn set_invulnerables(v: u32, ) -> Weight {
-		(2_914_000 as Weight)
+		(2_661_000 as Weight)
 			// Standard Error: 0
 			.saturating_add((35_000 as Weight).saturating_mul(v as Weight))
 			.saturating_add(T::DbWeight::get().writes(1 as Weight))
 	}
 	fn force_unstake(s: u32, ) -> Weight {
-		(64_032_000 as Weight)
-			// Standard Error: 2_000
-			.saturating_add((2_787_000 as Weight).saturating_mul(s as Weight))
+		(64_650_000 as Weight)
+			// Standard Error: 1_000
+			.saturating_add((2_755_000 as Weight).saturating_mul(s as Weight))
 			.saturating_add(T::DbWeight::get().reads(4 as Weight))
 			.saturating_add(T::DbWeight::get().writes(8 as Weight))
 			.saturating_add(T::DbWeight::get().writes((1 as Weight).saturating_mul(s as Weight)))
 	}
 	fn cancel_deferred_slash(s: u32, ) -> Weight {
-		(5_903_394_000 as Weight)
-			// Standard Error: 391_000
-			.saturating_add((34_834_000 as Weight).saturating_mul(s as Weight))
+		(5_904_642_000 as Weight)
+			// Standard Error: 393_000
+			.saturating_add((34_810_000 as Weight).saturating_mul(s as Weight))
 			.saturating_add(T::DbWeight::get().reads(1 as Weight))
 			.saturating_add(T::DbWeight::get().writes(1 as Weight))
 	}
 	fn payout_stakers_dead_controller(n: u32, ) -> Weight {
-		(141_724_000 as Weight)
-			// Standard Error: 24_000
-			.saturating_add((53_018_000 as Weight).saturating_mul(n as Weight))
-			.saturating_add(T::DbWeight::get().reads(11 as Weight))
+		(131_368_000 as Weight)
+			// Standard Error: 17_000
+			.saturating_add((52_611_000 as Weight).saturating_mul(n as Weight))
+			.saturating_add(T::DbWeight::get().reads(10 as Weight))
 			.saturating_add(T::DbWeight::get().reads((3 as Weight).saturating_mul(n as Weight)))
 			.saturating_add(T::DbWeight::get().writes(2 as Weight))
 			.saturating_add(T::DbWeight::get().writes((1 as Weight).saturating_mul(n as Weight)))
 	}
 	fn payout_stakers_alive_staked(n: u32, ) -> Weight {
-		(159_994_000 as Weight)
-			// Standard Error: 28_000
-			.saturating_add((67_746_000 as Weight).saturating_mul(n as Weight))
-			.saturating_add(T::DbWeight::get().reads(12 as Weight))
+		(165_079_000 as Weight)
+			// Standard Error: 27_000
+			.saturating_add((66_740_000 as Weight).saturating_mul(n as Weight))
+			.saturating_add(T::DbWeight::get().reads(11 as Weight))
 			.saturating_add(T::DbWeight::get().reads((5 as Weight).saturating_mul(n as Weight)))
 			.saturating_add(T::DbWeight::get().writes(3 as Weight))
 			.saturating_add(T::DbWeight::get().writes((3 as Weight).saturating_mul(n as Weight)))
 	}
 	fn rebond(l: u32, ) -> Weight {
-		(42_177_000 as Weight)
-			// Standard Error: 1_000
-			.saturating_add((82_000 as Weight).saturating_mul(l as Weight))
-			.saturating_add(T::DbWeight::get().reads(4 as Weight))
+		(37_039_000 as Weight)
+			// Standard Error: 2_000
+			.saturating_add((93_000 as Weight).saturating_mul(l as Weight))
+			.saturating_add(T::DbWeight::get().reads(3 as Weight))
 			.saturating_add(T::DbWeight::get().writes(3 as Weight))
 	}
 	fn set_history_depth(e: u32, ) -> Weight {
 		(0 as Weight)
-			// Standard Error: 65_000
-			.saturating_add((34_151_000 as Weight).saturating_mul(e as Weight))
+			// Standard Error: 71_000
+			.saturating_add((34_403_000 as Weight).saturating_mul(e as Weight))
 			.saturating_add(T::DbWeight::get().reads(2 as Weight))
 			.saturating_add(T::DbWeight::get().writes(4 as Weight))
 			.saturating_add(T::DbWeight::get().writes((7 as Weight).saturating_mul(e as Weight)))
 	}
 	fn reap_stash(s: u32, ) -> Weight {
-		(68_377_000 as Weight)
+		(67_561_000 as Weight)
 			// Standard Error: 0
-			.saturating_add((2_757_000 as Weight).saturating_mul(s as Weight))
+			.saturating_add((2_766_000 as Weight).saturating_mul(s as Weight))
 			.saturating_add(T::DbWeight::get().reads(4 as Weight))
 			.saturating_add(T::DbWeight::get().writes(8 as Weight))
 			.saturating_add(T::DbWeight::get().writes((1 as Weight).saturating_mul(s as Weight)))
 	}
 	fn new_era(v: u32, n: u32, ) -> Weight {
 		(0 as Weight)
-			// Standard Error: 908_000
-			.saturating_add((588_562_000 as Weight).saturating_mul(v as Weight))
-			// Standard Error: 45_000
-			.saturating_add((83_485_000 as Weight).saturating_mul(n as Weight))
-			.saturating_add(T::DbWeight::get().reads(9 as Weight))
-			.saturating_add(T::DbWeight::get().reads((4 as Weight).saturating_mul(v as Weight)))
+			// Standard Error: 1_016_000
+			.saturating_add((389_979_000 as Weight).saturating_mul(v as Weight))
+			// Standard Error: 51_000
+			.saturating_add((63_208_000 as Weight).saturating_mul(n as Weight))
+			.saturating_add(T::DbWeight::get().reads(10 as Weight))
+			.saturating_add(T::DbWeight::get().reads((3 as Weight).saturating_mul(v as Weight)))
 			.saturating_add(T::DbWeight::get().reads((3 as Weight).saturating_mul(n as Weight)))
-			.saturating_add(T::DbWeight::get().writes(13 as Weight))
+			.saturating_add(T::DbWeight::get().writes(9 as Weight))
 			.saturating_add(T::DbWeight::get().writes((3 as Weight).saturating_mul(v as Weight)))
 	}
-	fn submit_solution_better(v: u32, n: u32, a: u32, w: u32, ) -> Weight {
+	fn get_npos_voters(v: u32, n: u32, s: u32, ) -> Weight {
 		(0 as Weight)
-			// Standard Error: 52_000
-			.saturating_add((750_000 as Weight).saturating_mul(v as Weight))
-			// Standard Error: 20_000
-			.saturating_add((556_000 as Weight).saturating_mul(n as Weight))
-			// Standard Error: 52_000
-			.saturating_add((76_201_000 as Weight).saturating_mul(a as Weight))
-			// Standard Error: 108_000
-			.saturating_add((7_271_000 as Weight).saturating_mul(w as Weight))
-			.saturating_add(T::DbWeight::get().reads(6 as Weight))
-			.saturating_add(T::DbWeight::get().reads((4 as Weight).saturating_mul(a as Weight)))
-			.saturating_add(T::DbWeight::get().reads((1 as Weight).saturating_mul(w as Weight)))
-			.saturating_add(T::DbWeight::get().writes(2 as Weight))
+			// Standard Error: 95_000
+			.saturating_add((26_419_000 as Weight).saturating_mul(v as Weight))
+			// Standard Error: 95_000
+			.saturating_add((29_033_000 as Weight).saturating_mul(n as Weight))
+			// Standard Error: 1_305_000
+			.saturating_add((23_680_000 as Weight).saturating_mul(s as Weight))
+			.saturating_add(T::DbWeight::get().reads(3 as Weight))
+			.saturating_add(T::DbWeight::get().reads((3 as Weight).saturating_mul(v as Weight)))
+			.saturating_add(T::DbWeight::get().reads((3 as Weight).saturating_mul(n as Weight)))
+			.saturating_add(T::DbWeight::get().reads((1 as Weight).saturating_mul(s as Weight)))
+	}
+	fn get_npos_targets(v: u32, ) -> Weight {
+		(0 as Weight)
+			// Standard Error: 32_000
+			.saturating_add((11_317_000 as Weight).saturating_mul(v as Weight))
+			.saturating_add(T::DbWeight::get().reads(1 as Weight))
+			.saturating_add(T::DbWeight::get().reads((1 as Weight).saturating_mul(v as Weight)))
 	}
 }
 
 // For backwards compatibility and tests
 impl WeightInfo for () {
 	fn bond() -> Weight {
-		(81_642_000 as Weight)
+		(79_895_000 as Weight)
 			.saturating_add(RocksDbWeight::get().reads(5 as Weight))
 			.saturating_add(RocksDbWeight::get().writes(4 as Weight))
 	}
 	fn bond_extra() -> Weight {
-		(66_025_000 as Weight)
-			.saturating_add(RocksDbWeight::get().reads(4 as Weight))
+		(60_561_000 as Weight)
+			.saturating_add(RocksDbWeight::get().reads(3 as Weight))
 			.saturating_add(RocksDbWeight::get().writes(2 as Weight))
 	}
 	fn unbond() -> Weight {
-		(60_810_000 as Weight)
-			.saturating_add(RocksDbWeight::get().reads(5 as Weight))
+		(54_996_000 as Weight)
+			.saturating_add(RocksDbWeight::get().reads(4 as Weight))
 			.saturating_add(RocksDbWeight::get().writes(3 as Weight))
 	}
 	fn withdraw_unbonded_update(s: u32, ) -> Weight {
-		(61_537_000 as Weight)
-			// Standard Error: 1_000
-			.saturating_add((60_000 as Weight).saturating_mul(s as Weight))
-			.saturating_add(RocksDbWeight::get().reads(5 as Weight))
+		(56_056_000 as Weight)
+			// Standard Error: 0
+			.saturating_add((67_000 as Weight).saturating_mul(s as Weight))
+			.saturating_add(RocksDbWeight::get().reads(4 as Weight))
 			.saturating_add(RocksDbWeight::get().writes(3 as Weight))
 	}
 	fn withdraw_unbonded_kill(s: u32, ) -> Weight {
-		(95_741_000 as Weight)
+		(90_267_000 as Weight)
 			// Standard Error: 1_000
-			.saturating_add((2_754_000 as Weight).saturating_mul(s as Weight))
-			.saturating_add(RocksDbWeight::get().reads(7 as Weight))
+			.saturating_add((2_787_000 as Weight).saturating_mul(s as Weight))
+			.saturating_add(RocksDbWeight::get().reads(6 as Weight))
 			.saturating_add(RocksDbWeight::get().writes(8 as Weight))
 			.saturating_add(RocksDbWeight::get().writes((1 as Weight).saturating_mul(s as Weight)))
 	}
 	fn validate() -> Weight {
-		(21_009_000 as Weight)
-			.saturating_add(RocksDbWeight::get().reads(2 as Weight))
+		(16_345_000 as Weight)
+			.saturating_add(RocksDbWeight::get().reads(1 as Weight))
 			.saturating_add(RocksDbWeight::get().writes(2 as Weight))
 	}
 	fn kick(k: u32, ) -> Weight {
-		(31_832_000 as Weight)
-			// Standard Error: 15_000
-			.saturating_add((19_418_000 as Weight).saturating_mul(k as Weight))
-			.saturating_add(RocksDbWeight::get().reads(2 as Weight))
+		(27_080_000 as Weight)
+			// Standard Error: 14_000
+			.saturating_add((18_739_000 as Weight).saturating_mul(k as Weight))
+			.saturating_add(RocksDbWeight::get().reads(1 as Weight))
 			.saturating_add(RocksDbWeight::get().reads((1 as Weight).saturating_mul(k as Weight)))
 			.saturating_add(RocksDbWeight::get().writes((1 as Weight).saturating_mul(k as Weight)))
 	}
 	fn nominate(n: u32, ) -> Weight {
-		(34_304_000 as Weight)
-			// Standard Error: 20_000
-			.saturating_add((5_643_000 as Weight).saturating_mul(n as Weight))
-			.saturating_add(RocksDbWeight::get().reads(4 as Weight))
+		(29_101_000 as Weight)
+			// Standard Error: 23_000
+			.saturating_add((5_670_000 as Weight).saturating_mul(n as Weight))
+			.saturating_add(RocksDbWeight::get().reads(3 as Weight))
 			.saturating_add(RocksDbWeight::get().reads((1 as Weight).saturating_mul(n as Weight)))
 			.saturating_add(RocksDbWeight::get().writes(2 as Weight))
 	}
 	fn chill() -> Weight {
-		(20_103_000 as Weight)
-			.saturating_add(RocksDbWeight::get().reads(2 as Weight))
+		(15_771_000 as Weight)
+			.saturating_add(RocksDbWeight::get().reads(1 as Weight))
 			.saturating_add(RocksDbWeight::get().writes(2 as Weight))
 	}
 	fn set_payee() -> Weight {
-		(13_858_000 as Weight)
+		(13_329_000 as Weight)
 			.saturating_add(RocksDbWeight::get().reads(1 as Weight))
 			.saturating_add(RocksDbWeight::get().writes(1 as Weight))
 	}
 	fn set_controller() -> Weight {
-		(30_269_000 as Weight)
+		(29_807_000 as Weight)
 			.saturating_add(RocksDbWeight::get().reads(3 as Weight))
 			.saturating_add(RocksDbWeight::get().writes(3 as Weight))
 	}
 	fn set_validator_count() -> Weight {
-		(2_444_000 as Weight)
+		(2_323_000 as Weight)
 			.saturating_add(RocksDbWeight::get().writes(1 as Weight))
 	}
 	fn force_no_eras() -> Weight {
-		(2_766_000 as Weight)
+		(2_528_000 as Weight)
 			.saturating_add(RocksDbWeight::get().writes(1 as Weight))
 	}
 	fn force_new_era() -> Weight {
-		(2_724_000 as Weight)
+		(2_529_000 as Weight)
 			.saturating_add(RocksDbWeight::get().writes(1 as Weight))
 	}
 	fn force_new_era_always() -> Weight {
-		(2_702_000 as Weight)
+		(2_527_000 as Weight)
 			.saturating_add(RocksDbWeight::get().writes(1 as Weight))
 	}
 	fn set_invulnerables(v: u32, ) -> Weight {
-		(2_914_000 as Weight)
+		(2_661_000 as Weight)
 			// Standard Error: 0
 			.saturating_add((35_000 as Weight).saturating_mul(v as Weight))
 			.saturating_add(RocksDbWeight::get().writes(1 as Weight))
 	}
 	fn force_unstake(s: u32, ) -> Weight {
-		(64_032_000 as Weight)
-			// Standard Error: 2_000
-			.saturating_add((2_787_000 as Weight).saturating_mul(s as Weight))
+		(64_650_000 as Weight)
+			// Standard Error: 1_000
+			.saturating_add((2_755_000 as Weight).saturating_mul(s as Weight))
 			.saturating_add(RocksDbWeight::get().reads(4 as Weight))
 			.saturating_add(RocksDbWeight::get().writes(8 as Weight))
 			.saturating_add(RocksDbWeight::get().writes((1 as Weight).saturating_mul(s as Weight)))
 	}
 	fn cancel_deferred_slash(s: u32, ) -> Weight {
-		(5_903_394_000 as Weight)
-			// Standard Error: 391_000
-			.saturating_add((34_834_000 as Weight).saturating_mul(s as Weight))
+		(5_904_642_000 as Weight)
+			// Standard Error: 393_000
+			.saturating_add((34_810_000 as Weight).saturating_mul(s as Weight))
 			.saturating_add(RocksDbWeight::get().reads(1 as Weight))
 			.saturating_add(RocksDbWeight::get().writes(1 as Weight))
 	}
 	fn payout_stakers_dead_controller(n: u32, ) -> Weight {
-		(141_724_000 as Weight)
-			// Standard Error: 24_000
-			.saturating_add((53_018_000 as Weight).saturating_mul(n as Weight))
-			.saturating_add(RocksDbWeight::get().reads(11 as Weight))
+		(131_368_000 as Weight)
+			// Standard Error: 17_000
+			.saturating_add((52_611_000 as Weight).saturating_mul(n as Weight))
+			.saturating_add(RocksDbWeight::get().reads(10 as Weight))
 			.saturating_add(RocksDbWeight::get().reads((3 as Weight).saturating_mul(n as Weight)))
 			.saturating_add(RocksDbWeight::get().writes(2 as Weight))
 			.saturating_add(RocksDbWeight::get().writes((1 as Weight).saturating_mul(n as Weight)))
 	}
 	fn payout_stakers_alive_staked(n: u32, ) -> Weight {
-		(159_994_000 as Weight)
-			// Standard Error: 28_000
-			.saturating_add((67_746_000 as Weight).saturating_mul(n as Weight))
-			.saturating_add(RocksDbWeight::get().reads(12 as Weight))
+		(165_079_000 as Weight)
+			// Standard Error: 27_000
+			.saturating_add((66_740_000 as Weight).saturating_mul(n as Weight))
+			.saturating_add(RocksDbWeight::get().reads(11 as Weight))
 			.saturating_add(RocksDbWeight::get().reads((5 as Weight).saturating_mul(n as Weight)))
 			.saturating_add(RocksDbWeight::get().writes(3 as Weight))
 			.saturating_add(RocksDbWeight::get().writes((3 as Weight).saturating_mul(n as Weight)))
 	}
 	fn rebond(l: u32, ) -> Weight {
-		(42_177_000 as Weight)
-			// Standard Error: 1_000
-			.saturating_add((82_000 as Weight).saturating_mul(l as Weight))
-			.saturating_add(RocksDbWeight::get().reads(4 as Weight))
+		(37_039_000 as Weight)
+			// Standard Error: 2_000
+			.saturating_add((93_000 as Weight).saturating_mul(l as Weight))
+			.saturating_add(RocksDbWeight::get().reads(3 as Weight))
 			.saturating_add(RocksDbWeight::get().writes(3 as Weight))
 	}
 	fn set_history_depth(e: u32, ) -> Weight {
 		(0 as Weight)
-			// Standard Error: 65_000
-			.saturating_add((34_151_000 as Weight).saturating_mul(e as Weight))
+			// Standard Error: 71_000
+			.saturating_add((34_403_000 as Weight).saturating_mul(e as Weight))
 			.saturating_add(RocksDbWeight::get().reads(2 as Weight))
 			.saturating_add(RocksDbWeight::get().writes(4 as Weight))
 			.saturating_add(RocksDbWeight::get().writes((7 as Weight).saturating_mul(e as Weight)))
 	}
 	fn reap_stash(s: u32, ) -> Weight {
-		(68_377_000 as Weight)
+		(67_561_000 as Weight)
 			// Standard Error: 0
-			.saturating_add((2_757_000 as Weight).saturating_mul(s as Weight))
+			.saturating_add((2_766_000 as Weight).saturating_mul(s as Weight))
 			.saturating_add(RocksDbWeight::get().reads(4 as Weight))
 			.saturating_add(RocksDbWeight::get().writes(8 as Weight))
 			.saturating_add(RocksDbWeight::get().writes((1 as Weight).saturating_mul(s as Weight)))
 	}
 	fn new_era(v: u32, n: u32, ) -> Weight {
 		(0 as Weight)
-			// Standard Error: 908_000
-			.saturating_add((588_562_000 as Weight).saturating_mul(v as Weight))
-			// Standard Error: 45_000
-			.saturating_add((83_485_000 as Weight).saturating_mul(n as Weight))
-			.saturating_add(RocksDbWeight::get().reads(9 as Weight))
-			.saturating_add(RocksDbWeight::get().reads((4 as Weight).saturating_mul(v as Weight)))
+			// Standard Error: 1_016_000
+			.saturating_add((389_979_000 as Weight).saturating_mul(v as Weight))
+			// Standard Error: 51_000
+			.saturating_add((63_208_000 as Weight).saturating_mul(n as Weight))
+			.saturating_add(RocksDbWeight::get().reads(10 as Weight))
+			.saturating_add(RocksDbWeight::get().reads((3 as Weight).saturating_mul(v as Weight)))
 			.saturating_add(RocksDbWeight::get().reads((3 as Weight).saturating_mul(n as Weight)))
-			.saturating_add(RocksDbWeight::get().writes(13 as Weight))
+			.saturating_add(RocksDbWeight::get().writes(9 as Weight))
 			.saturating_add(RocksDbWeight::get().writes((3 as Weight).saturating_mul(v as Weight)))
 	}
-	fn submit_solution_better(v: u32, n: u32, a: u32, w: u32, ) -> Weight {
+	fn get_npos_voters(v: u32, n: u32, s: u32, ) -> Weight {
 		(0 as Weight)
-			// Standard Error: 52_000
-			.saturating_add((750_000 as Weight).saturating_mul(v as Weight))
-			// Standard Error: 20_000
-			.saturating_add((556_000 as Weight).saturating_mul(n as Weight))
-			// Standard Error: 52_000
-			.saturating_add((76_201_000 as Weight).saturating_mul(a as Weight))
-			// Standard Error: 108_000
-			.saturating_add((7_271_000 as Weight).saturating_mul(w as Weight))
-			.saturating_add(RocksDbWeight::get().reads(6 as Weight))
-			.saturating_add(RocksDbWeight::get().reads((4 as Weight).saturating_mul(a as Weight)))
-			.saturating_add(RocksDbWeight::get().reads((1 as Weight).saturating_mul(w as Weight)))
-			.saturating_add(RocksDbWeight::get().writes(2 as Weight))
+			// Standard Error: 95_000
+			.saturating_add((26_419_000 as Weight).saturating_mul(v as Weight))
+			// Standard Error: 95_000
+			.saturating_add((29_033_000 as Weight).saturating_mul(n as Weight))
+			// Standard Error: 1_305_000
+			.saturating_add((23_680_000 as Weight).saturating_mul(s as Weight))
+			.saturating_add(RocksDbWeight::get().reads(3 as Weight))
+			.saturating_add(RocksDbWeight::get().reads((3 as Weight).saturating_mul(v as Weight)))
+			.saturating_add(RocksDbWeight::get().reads((3 as Weight).saturating_mul(n as Weight)))
+			.saturating_add(RocksDbWeight::get().reads((1 as Weight).saturating_mul(s as Weight)))
+	}
+	fn get_npos_targets(v: u32, ) -> Weight {
+		(0 as Weight)
+			// Standard Error: 32_000
+			.saturating_add((11_317_000 as Weight).saturating_mul(v as Weight))
+			.saturating_add(RocksDbWeight::get().reads(1 as Weight))
+			.saturating_add(RocksDbWeight::get().reads((1 as Weight).saturating_mul(v as Weight)))
 	}
 }
diff --git a/frame/sudo/src/lib.rs b/frame/sudo/src/lib.rs
index c7cc38a81c134..d840d45a7f430 100644
--- a/frame/sudo/src/lib.rs
+++ b/frame/sudo/src/lib.rs
@@ -15,14 +15,14 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//! # Sudo Module
+//! # Sudo Pallet
 //!
-//! - [`sudo::Config`](./trait.Config.html)
-//! - [`Call`](./enum.Call.html)
+//! - [`Config`]
+//! - [`Call`]
 //!
 //! ## Overview
 //!
-//! The Sudo module allows for a single account (called the "sudo key")
+//! The Sudo pallet allows for a single account (called the "sudo key")
 //! to execute dispatchable functions that require a `Root` call
 //! or designate a new account to replace them as the sudo key.
 //! Only one account can be the sudo key at a time.
@@ -31,7 +31,7 @@
 //!
 //! ### Dispatchable Functions
 //!
-//! Only the sudo key can call the dispatchable functions from the Sudo module.
+//! Only the sudo key can call the dispatchable functions from the Sudo pallet.
 //!
 //! * `sudo` - Make a `Root` call to a dispatchable function.
 //! * `set_key` - Assign a new account to be the sudo key.
@@ -40,8 +40,8 @@
 //!
 //! ### Executing Privileged Functions
 //!
-//! The Sudo module itself is not intended to be used within other modules.
-//! Instead, you can build "privileged functions" (i.e. functions that require `Root` origin) in other modules.
+//! The Sudo pallet itself is not intended to be used within other pallets.
+//! Instead, you can build "privileged functions" (i.e. functions that require `Root` origin) in other pallets.
 //! You can execute these privileged functions by calling `sudo` with the sudo key account.
 //! Privileged functions cannot be directly executed via an extrinsic.
 //!
@@ -49,40 +49,49 @@
 //!
 //! ### Simple Code Snippet
 //!
-//! This is an example of a module that exposes a privileged function:
+//! This is an example of a pallet that exposes a privileged function:
 //!
 //! ```
-//! use frame_support::{decl_module, dispatch};
-//! use frame_system::ensure_root;
 //!
-//! pub trait Config: frame_system::Config {}
+//! #[frame_support::pallet]
+//! pub mod logger {
+//! 	use frame_support::pallet_prelude::*;
+//! 	use frame_system::pallet_prelude::*;
+//! 	use super::*;
 //!
-//! decl_module! {
-//!     pub struct Module<T: Config> for enum Call where origin: T::Origin {
-//! 		#[weight = 0]
-//!         pub fn privileged_function(origin) -> dispatch::DispatchResult {
+//! 	#[pallet::config]
+//! 	pub trait Config: frame_system::Config {}
+//!
+//! 	#[pallet::pallet]
+//! 	pub struct Pallet<T>(PhantomData<T>);
+//!
+//! 	#[pallet::hooks]
+//! 	impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {}
+//!
+//! 	#[pallet::call]
+//! 	impl<T: Config> Pallet<T> {
+//! 		#[pallet::weight(0)]
+//!         pub fn privileged_function(origin: OriginFor<T>) -> DispatchResultWithPostInfo {
 //!             ensure_root(origin)?;
 //!
 //!             // do something...
 //!
-//!             Ok(())
+//!             Ok(().into())
 //!         }
-//!     }
+//! 	}
 //! }
 //! # fn main() {}
 //! ```
 //!
 //! ## Genesis Config
 //!
-//! The Sudo module depends on the [`GenesisConfig`](./struct.GenesisConfig.html).
+//! The Sudo pallet depends on the [`GenesisConfig`].
 //! You need to set an initial superuser account as the sudo `key`.
 //!
-//! ## Related Modules
+//! ## Related Pallets
 //!
 //! * [Democracy](../pallet_democracy/index.html)
 //!
-//! [`Call`]: ./enum.Call.html
-//! [`Config`]: ./trait.Config.html
 //! [`Origin`]: https://docs.substrate.dev/docs/substrate-types
 
 #![cfg_attr(not(feature = "std"), no_std)]
@@ -91,35 +100,41 @@ use sp_std::prelude::*;
 use sp_runtime::{DispatchResult, traits::StaticLookup};
 
 use frame_support::{
-	Parameter, decl_module, decl_event, decl_storage, decl_error, ensure,
+	weights::GetDispatchInfo,
+	traits::UnfilteredDispatchable,
 };
-use frame_support::{
-	weights::{Weight, GetDispatchInfo, Pays},
-	traits::{UnfilteredDispatchable, Get},
-	dispatch::DispatchResultWithPostInfo,
-};
-use frame_system::ensure_signed;
 
 #[cfg(test)]
 mod mock;
 #[cfg(test)]
 mod tests;
 
-pub trait Config: frame_system::Config {
-	/// The overarching event type.
-	type Event: From<Event<Self>> + Into<<Self as frame_system::Config>::Event>;
+pub use pallet::*;
 
-	/// A sudo-able call.
-	type Call: Parameter + UnfilteredDispatchable<Origin=Self::Origin> + GetDispatchInfo;
-}
+#[frame_support::pallet]
+pub mod pallet {
+	use frame_support::pallet_prelude::*;
+	use frame_system::pallet_prelude::*;
+	use super::{*, DispatchResult};
 
-decl_module! {
-	/// Sudo module declaration.
-	pub struct Module<T: Config> for enum Call where origin: T::Origin {
-		type Error = Error<T>;
+	#[pallet::config]
+	pub trait Config: frame_system::Config {
+		/// The overarching event type.
+		type Event: From<Event<Self>> + IsType<<Self as frame_system::Config>::Event>;
 
-		fn deposit_event() = default;
+		/// A sudo-able call.
+		type Call: Parameter + UnfilteredDispatchable<Origin=Self::Origin> + GetDispatchInfo;
+	}
 
+	#[pallet::pallet]
+	#[pallet::generate_store(pub(super) trait Store)]
+	pub struct Pallet<T>(PhantomData<T>);
+
+	#[pallet::hooks]
+	impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {}
+
+	#[pallet::call]
+	impl<T: Config> Pallet<T> {
 		/// Authenticates the sudo key and dispatches a function call with `Root` origin.
 		///
 		/// The dispatch origin for this call must be _Signed_.
@@ -130,17 +145,20 @@ decl_module! {
 		/// - One DB write (event).
 		/// - Weight of derivative `call` execution + 10,000.
 		/// # </weight>
-		#[weight = {
+		#[pallet::weight({
 			let dispatch_info = call.get_dispatch_info();
 			(dispatch_info.weight.saturating_add(10_000), dispatch_info.class)
-		}]
-		fn sudo(origin, call: Box<<T as Config>::Call>) -> DispatchResultWithPostInfo {
+		})]
+		pub(crate) fn sudo(
+			origin: OriginFor<T>,
+			call: Box<<T as Config>::Call>,
+		) -> DispatchResultWithPostInfo {
 			// This is a public call, so we ensure that the origin is some signed account.
 			let sender = ensure_signed(origin)?;
 			ensure!(sender == Self::key(), Error::<T>::RequireSudo);
 
 			let res = call.dispatch_bypass_filter(frame_system::RawOrigin::Root.into());
-			Self::deposit_event(RawEvent::Sudid(res.map(|_| ()).map_err(|e| e.error)));
+			Self::deposit_event(Event::Sudid(res.map(|_| ()).map_err(|e| e.error)));
 			// Sudo user does not pay a fee.
 			Ok(Pays::No.into())
 		}
@@ -155,14 +173,18 @@ decl_module! {
 		/// - O(1).
 		/// - The weight of this call is defined by the caller.
 		/// # </weight>
-		#[weight = (*_weight, call.get_dispatch_info().class)]
-		fn sudo_unchecked_weight(origin, call: Box<<T as Config>::Call>, _weight: Weight) -> DispatchResultWithPostInfo {
+		#[pallet::weight((*_weight, call.get_dispatch_info().class))]
+		pub(crate) fn sudo_unchecked_weight(
+			origin: OriginFor<T>,
+			call: Box<<T as Config>::Call>,
+			_weight: Weight,
+		) -> DispatchResultWithPostInfo {
 			// This is a public call, so we ensure that the origin is some signed account.
 			let sender = ensure_signed(origin)?;
 			ensure!(sender == Self::key(), Error::<T>::RequireSudo);
 
 			let res = call.dispatch_bypass_filter(frame_system::RawOrigin::Root.into());
-			Self::deposit_event(RawEvent::Sudid(res.map(|_| ()).map_err(|e| e.error)));
+			Self::deposit_event(Event::Sudid(res.map(|_| ()).map_err(|e| e.error)));
 			// Sudo user does not pay a fee.
 			Ok(Pays::No.into())
 		}
@@ -176,14 +198,17 @@ decl_module! {
 		/// - Limited storage reads.
 		/// - One DB change.
 		/// # </weight>
-		#[weight = 0]
-		fn set_key(origin, new: <T::Lookup as StaticLookup>::Source) -> DispatchResultWithPostInfo {
+		#[pallet::weight(0)]
+		pub(crate) fn set_key(
+			origin: OriginFor<T>,
+			new: <T::Lookup as StaticLookup>::Source,
+		) -> DispatchResultWithPostInfo {
 			// This is a public call, so we ensure that the origin is some signed account.
 			let sender = ensure_signed(origin)?;
 			ensure!(sender == Self::key(), Error::<T>::RequireSudo);
 			let new = T::Lookup::lookup(new)?;
 
-			Self::deposit_event(RawEvent::KeyChanged(Self::key()));
+			Self::deposit_event(Event::KeyChanged(Self::key()));
 			<Key<T>>::put(new);
 			// Sudo user does not pay a fee.
 			Ok(Pays::No.into())
@@ -200,7 +225,7 @@ decl_module! {
 		/// - One DB write (event).
 		/// - Weight of derivative `call` execution + 10,000.
 		/// # </weight>
-		#[weight = {
+		#[pallet::weight({
 			let dispatch_info = call.get_dispatch_info();
 			(
 				dispatch_info.weight
@@ -209,8 +234,9 @@ decl_module! {
 					.saturating_add(T::DbWeight::get().reads_writes(1, 1)),
 				dispatch_info.class,
 			)
-		}]
-		fn sudo_as(origin,
+		})]
+		pub(crate) fn sudo_as(
+			origin: OriginFor<T>,
 			who: <T::Lookup as StaticLookup>::Source,
 			call: Box<<T as Config>::Call>
 		) -> DispatchResultWithPostInfo {
@@ -222,35 +248,55 @@ decl_module! {
 
 			let res = call.dispatch_bypass_filter(frame_system::RawOrigin::Signed(who).into());
 
-			Self::deposit_event(RawEvent::SudoAsDone(res.map(|_| ()).map_err(|e| e.error)));
+			Self::deposit_event(Event::SudoAsDone(res.map(|_| ()).map_err(|e| e.error)));
 			// Sudo user does not pay a fee.
 			Ok(Pays::No.into())
 		}
 	}
-}
 
-decl_event!(
-	pub enum Event<T> where AccountId = <T as frame_system::Config>::AccountId {
+	#[pallet::event]
+	#[pallet::generate_deposit(pub(super) fn deposit_event)]
+	#[pallet::metadata(T::AccountId = "AccountId")]
+	pub enum Event<T: Config> {
 		/// A sudo just took place. \[result\]
 		Sudid(DispatchResult),
 		/// The \[sudoer\] just switched identity; the old key is supplied.
-		KeyChanged(AccountId),
+		KeyChanged(T::AccountId),
 		/// A sudo just took place. \[result\]
 		SudoAsDone(DispatchResult),
 	}
-);
 
-decl_storage! {
-	trait Store for Module<T: Config> as Sudo {
+	#[pallet::error]
+	/// Error for the Sudo pallet
+	pub enum Error<T> {
+		/// Sender must be the Sudo account
+		RequireSudo,
+	}
+
+	/// The `AccountId` of the sudo key.
+	#[pallet::storage]
+	#[pallet::getter(fn key)]
+	pub(super) type Key<T: Config> = StorageValue<_, T::AccountId, ValueQuery>;
+
+	#[pallet::genesis_config]
+	pub struct GenesisConfig<T: Config> {
 		/// The `AccountId` of the sudo key.
-		Key get(fn key) config(): T::AccountId;
+		pub key: T::AccountId,
 	}
-}
 
-decl_error! {
-	/// Error for the Sudo module
-	pub enum Error for Module<T: Config> {
-		/// Sender must be the Sudo account
-		RequireSudo,
+	#[cfg(feature = "std")]
+	impl<T: Config> Default for GenesisConfig<T> {
+		fn default() -> Self {
+			Self {
+				key: Default::default(),
+			}
+		}
+	}
+
+	#[pallet::genesis_build]
+	impl<T: Config> GenesisBuild<T> for GenesisConfig<T> {
+		fn build(&self) {
+			<Key<T>>::put(&self.key);
+		}
 	}
 }
diff --git a/frame/sudo/src/mock.rs b/frame/sudo/src/mock.rs
index 91cd03ac4756a..9aac0a129907f 100644
--- a/frame/sudo/src/mock.rs
+++ b/frame/sudo/src/mock.rs
@@ -18,7 +18,7 @@
 //! Test utilities
 
 use super::*;
-use frame_support::{parameter_types, weights::Weight};
+use frame_support::{parameter_types, traits::GenesisBuild};
 use sp_core::H256;
 use sp_runtime::{traits::{BlakeTwo256, IdentityLookup}, testing::Header};
 use sp_io;
@@ -27,52 +27,80 @@ use frame_support::traits::Filter;
 use frame_system::limits;
 
 // Logger module to track execution.
+#[frame_support::pallet]
 pub mod logger {
+	use frame_support::pallet_prelude::*;
+	use frame_system::pallet_prelude::*;
 	use super::*;
-	use frame_system::ensure_root;
 
+	#[pallet::config]
 	pub trait Config: frame_system::Config {
-		type Event: From<Event<Self>> + Into<<Self as frame_system::Config>::Event>;
+		type Event: From<Event<Self>> + IsType<<Self as frame_system::Config>::Event>;
 	}
 
-	decl_storage! {
-		trait Store for Module<T: Config> as Logger {
-			AccountLog get(fn account_log): Vec<T::AccountId>;
-			I32Log get(fn i32_log): Vec<i32>;
+	#[pallet::pallet]
+	#[pallet::generate_store(pub(super) trait Store)]
+	pub struct Pallet<T>(PhantomData<T>);
+
+	#[pallet::hooks]
+	impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {}
+
+	#[pallet::call]
+	impl<T: Config> Pallet<T> {
+		#[pallet::weight(*weight)]
+		pub(crate) fn privileged_i32_log(
+			origin: OriginFor<T>,
+			i: i32,
+			weight: Weight
+		) -> DispatchResultWithPostInfo {
+			// Ensure that the `origin` is `Root`.
+			ensure_root(origin)?;
+			<I32Log<T>>::append(i);
+			Self::deposit_event(Event::AppendI32(i, weight));
+			Ok(().into())
 		}
-	}
 
-	decl_event! {
-		pub enum Event<T> where AccountId = <T as frame_system::Config>::AccountId {
-			AppendI32(i32, Weight),
-			AppendI32AndAccount(AccountId, i32, Weight),
+		#[pallet::weight(*weight)]
+		pub(crate) fn non_privileged_log(
+			origin: OriginFor<T>,
+			i: i32,
+			weight: Weight
+		) -> DispatchResultWithPostInfo {
+			// Ensure that the `origin` is some signed account.
+			let sender = ensure_signed(origin)?;
+			<I32Log<T>>::append(i);
+			<AccountLog<T>>::append(sender.clone());
+			Self::deposit_event(Event::AppendI32AndAccount(sender, i, weight));
+			Ok(().into())
 		}
 	}
 
-	decl_module! {
-		pub struct Module<T: Config> for enum Call where origin: <T as frame_system::Config>::Origin {
-			fn deposit_event() = default;
-
-			#[weight = *weight]
-			fn privileged_i32_log(origin, i: i32, weight: Weight){
-				// Ensure that the `origin` is `Root`.
-				ensure_root(origin)?;
-				<I32Log>::append(i);
-				Self::deposit_event(RawEvent::AppendI32(i, weight));
-			}
-
-			#[weight = *weight]
-			fn non_privileged_log(origin, i: i32, weight: Weight){
-				// Ensure that the `origin` is some signed account.
-				let sender = ensure_signed(origin)?;
-				<I32Log>::append(i);
-				<AccountLog<T>>::append(sender.clone());
-				Self::deposit_event(RawEvent::AppendI32AndAccount(sender, i, weight));
-			}
-		}
+	#[pallet::event]
+	#[pallet::generate_deposit(pub(super) fn deposit_event)]
+	#[pallet::metadata(T::AccountId = "AccountId")]
+	pub enum Event<T: Config> {
+		AppendI32(i32, Weight),
+		AppendI32AndAccount(T::AccountId, i32, Weight),
 	}
+
+	#[pallet::storage]
+	#[pallet::getter(fn account_log)]
+	pub(super) type AccountLog<T: Config> = StorageValue<
+		_,
+		Vec<T::AccountId>,
+		ValueQuery
+	>;
+
+	#[pallet::storage]
+	#[pallet::getter(fn i32_log)]
+	pub(super) type I32Log<T> = StorageValue<
+		_,
+		Vec<i32>,
+		ValueQuery
+	>;
 }
 
+
 type UncheckedExtrinsic = frame_system::mocking::MockUncheckedExtrinsic<Test>;
 type Block = frame_system::mocking::MockBlock<Test>;
 
@@ -82,9 +110,9 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Sudo: sudo::{Module, Call, Config<T>, Storage, Event<T>},
-		Logger: logger::{Module, Call, Storage, Event<T>},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Sudo: sudo::{Pallet, Call, Config<T>, Storage, Event<T>},
+		Logger: logger::{Pallet, Call, Storage, Event<T>},
 	}
 );
 
diff --git a/frame/sudo/src/tests.rs b/frame/sudo/src/tests.rs
index 4d2552b7b88b4..780e07676b29c 100644
--- a/frame/sudo/src/tests.rs
+++ b/frame/sudo/src/tests.rs
@@ -58,7 +58,7 @@ fn sudo_emits_events_correctly() {
 		// Should emit event to indicate success when called with the root `key` and `call` is `Ok`.
 		let call = Box::new(Call::Logger(LoggerCall::privileged_i32_log(42, 1)));
 		assert_ok!(Sudo::sudo(Origin::signed(1), call));
-		let expected_event = TestEvent::sudo(RawEvent::Sudid(Ok(())));
+		let expected_event = TestEvent::sudo(Event::Sudid(Ok(())));
 		assert!(System::events().iter().any(|a| a.event == expected_event));
 	})
 }
@@ -97,7 +97,7 @@ fn sudo_unchecked_weight_emits_events_correctly() {
 		// Should emit event to indicate success when called with the root `key` and `call` is `Ok`.
 		let call = Box::new(Call::Logger(LoggerCall::privileged_i32_log(42, 1)));
 		assert_ok!(Sudo::sudo_unchecked_weight(Origin::signed(1), call, 1_000));
-		let expected_event = TestEvent::sudo(RawEvent::Sudid(Ok(())));
+		let expected_event = TestEvent::sudo(Event::Sudid(Ok(())));
 		assert!(System::events().iter().any(|a| a.event == expected_event));
 	})
 }
@@ -124,11 +124,11 @@ fn set_key_emits_events_correctly() {
 
 		// A root `key` can change the root `key`.
 		assert_ok!(Sudo::set_key(Origin::signed(1), 2));
-		let expected_event = TestEvent::sudo(RawEvent::KeyChanged(1));
+		let expected_event = TestEvent::sudo(Event::KeyChanged(1));
 		assert!(System::events().iter().any(|a| a.event == expected_event));
 		// Double check.
 		assert_ok!(Sudo::set_key(Origin::signed(2), 4));
-		let expected_event = TestEvent::sudo(RawEvent::KeyChanged(2));
+		let expected_event = TestEvent::sudo(Event::KeyChanged(2));
 		assert!(System::events().iter().any(|a| a.event == expected_event));
 	});
 }
@@ -164,7 +164,7 @@ fn sudo_as_emits_events_correctly() {
 		// A non-privileged function will work when passed to `sudo_as` with the root `key`.
 		let call = Box::new(Call::Logger(LoggerCall::non_privileged_log(42, 1)));
 		assert_ok!(Sudo::sudo_as(Origin::signed(1), 2, call));
-		let expected_event = TestEvent::sudo(RawEvent::SudoAsDone(Ok(())));
+		let expected_event = TestEvent::sudo(Event::SudoAsDone(Ok(())));
 		assert!(System::events().iter().any(|a| a.event == expected_event));
 	});
 }
diff --git a/frame/support/procedural/src/construct_runtime/mod.rs b/frame/support/procedural/src/construct_runtime/mod.rs
index abd68e4425d89..0951dbdea987d 100644
--- a/frame/support/procedural/src/construct_runtime/mod.rs
+++ b/frame/support/procedural/src/construct_runtime/mod.rs
@@ -19,90 +19,90 @@ mod parse;
 
 use frame_support_procedural_tools::syn_ext as ext;
 use frame_support_procedural_tools::{generate_crate_access, generate_hidden_includes};
-use parse::{ModuleDeclaration, RuntimeDefinition, WhereSection, ModulePart};
+use parse::{PalletDeclaration, RuntimeDefinition, WhereSection, PalletPart};
 use proc_macro::TokenStream;
 use proc_macro2::{TokenStream as TokenStream2};
 use quote::quote;
 use syn::{Ident, Result, TypePath};
 use std::collections::HashMap;
 
-/// The fixed name of the system module.
-const SYSTEM_MODULE_NAME: &str = "System";
+/// The fixed name of the system pallet.
+const SYSTEM_PALLET_NAME: &str = "System";
 
-/// The complete definition of a module with the resulting fixed index.
+/// The complete definition of a pallet with the resulting fixed index.
 #[derive(Debug, Clone)]
-pub struct Module {
+pub struct Pallet {
 	pub name: Ident,
 	pub index: u8,
-	pub module: Ident,
+	pub pallet: Ident,
 	pub instance: Option<Ident>,
-	pub module_parts: Vec<ModulePart>,
+	pub pallet_parts: Vec<PalletPart>,
 }
 
-impl Module {
-	/// Get resolved module parts
-	fn module_parts(&self) -> &[ModulePart] {
-		&self.module_parts
+impl Pallet {
+	/// Get resolved pallet parts
+	fn pallet_parts(&self) -> &[PalletPart] {
+		&self.pallet_parts
 	}
 
 	/// Find matching parts
-	fn find_part(&self, name: &str) -> Option<&ModulePart> {
-		self.module_parts.iter().find(|part| part.name() == name)
+	fn find_part(&self, name: &str) -> Option<&PalletPart> {
+		self.pallet_parts.iter().find(|part| part.name() == name)
 	}
 
-	/// Return whether module contains part
+	/// Return whether pallet contains part
 	fn exists_part(&self, name: &str) -> bool {
 		self.find_part(name).is_some()
 	}
 }
 
-/// Convert from the parsed module to their final information.
-/// Assign index to each modules using same rules as rust for fieldless enum.
+/// Convert from the parsed pallet to their final information.
+/// Assign index to each pallet using same rules as rust for fieldless enum.
 /// I.e. implicit are assigned number incrementedly from last explicit or 0.
-fn complete_modules(decl: impl Iterator<Item = ModuleDeclaration>) -> syn::Result<Vec<Module>> {
+fn complete_pallets(decl: impl Iterator<Item = PalletDeclaration>) -> syn::Result<Vec<Pallet>> {
 	let mut indices = HashMap::new();
 	let mut last_index: Option<u8> = None;
 	let mut names = HashMap::new();
 
 	decl
-		.map(|module| {
-			let final_index = match module.index {
+		.map(|pallet| {
+			let final_index = match pallet.index {
 				Some(i) => i,
 				None => last_index.map_or(Some(0), |i| i.checked_add(1))
 					.ok_or_else(|| {
-						let msg = "Module index doesn't fit into u8, index is 256";
-						syn::Error::new(module.name.span(), msg)
+						let msg = "Pallet index doesn't fit into u8, index is 256";
+						syn::Error::new(pallet.name.span(), msg)
 					})?,
 			};
 
 			last_index = Some(final_index);
 
-			if let Some(used_module) = indices.insert(final_index, module.name.clone()) {
+			if let Some(used_pallet) = indices.insert(final_index, pallet.name.clone()) {
 				let msg = format!(
-					"Module indices are conflicting: Both modules {} and {} are at index {}",
-					used_module,
-					module.name,
+					"Pallet indices are conflicting: Both pallets {} and {} are at index {}",
+					used_pallet,
+					pallet.name,
 					final_index,
 				);
-				let mut err = syn::Error::new(used_module.span(), &msg);
-				err.combine(syn::Error::new(module.name.span(), msg));
+				let mut err = syn::Error::new(used_pallet.span(), &msg);
+				err.combine(syn::Error::new(pallet.name.span(), msg));
 				return Err(err);
 			}
 
-			if let Some(used_module) = names.insert(module.name.clone(), module.name.span()) {
-				let msg = "Two modules with the same name!";
+			if let Some(used_pallet) = names.insert(pallet.name.clone(), pallet.name.span()) {
+				let msg = "Two pallets with the same name!";
 
-				let mut err = syn::Error::new(used_module, &msg);
-				err.combine(syn::Error::new(module.name.span(), &msg));
+				let mut err = syn::Error::new(used_pallet, &msg);
+				err.combine(syn::Error::new(pallet.name.span(), &msg));
 				return Err(err);
 			}
 
-			Ok(Module {
-				name: module.name,
+			Ok(Pallet {
+				name: pallet.name,
 				index: final_index,
-				module: module.module,
-				instance: module.instance,
-				module_parts: module.module_parts,
+				pallet: pallet.pallet,
+				instance: pallet.instance,
+				pallet_parts: pallet.pallet_parts,
 			})
 		})
 		.collect()
@@ -124,55 +124,55 @@ fn construct_runtime_parsed(definition: RuntimeDefinition) -> Result<TokenStream
 			unchecked_extrinsic,
 			..
 		},
-		modules:
+		pallets:
 			ext::Braces {
-				content: ext::Punctuated { inner: modules, .. },
-				token: modules_token,
+				content: ext::Punctuated { inner: pallets, .. },
+				token: pallets_token,
 			},
 		..
 	} = definition;
 
-	let modules = complete_modules(modules.into_iter())?;
+	let pallets = complete_pallets(pallets.into_iter())?;
 
-	let system_module = modules.iter()
-		.find(|decl| decl.name == SYSTEM_MODULE_NAME)
+	let system_pallet = pallets.iter()
+		.find(|decl| decl.name == SYSTEM_PALLET_NAME)
 		.ok_or_else(|| syn::Error::new(
-			modules_token.span,
-			"`System` module declaration is missing. \
-			 Please add this line: `System: frame_system::{Module, Call, Storage, Config, Event<T>},`",
+			pallets_token.span,
+			"`System` pallet declaration is missing. \
+			 Please add this line: `System: frame_system::{Pallet, Call, Storage, Config, Event<T>},`",
 		))?;
 
 	let hidden_crate_name = "construct_runtime";
 	let scrate = generate_crate_access(&hidden_crate_name, "frame-support");
 	let scrate_decl = generate_hidden_includes(&hidden_crate_name, "frame-support");
 
-	let all_but_system_modules = modules.iter().filter(|module| module.name != SYSTEM_MODULE_NAME);
+	let all_but_system_pallets = pallets.iter().filter(|pallet| pallet.name != SYSTEM_PALLET_NAME);
 
 	let outer_event = decl_outer_event(
 		&name,
-		modules.iter(),
+		pallets.iter(),
 		&scrate,
 	)?;
 
 	let outer_origin = decl_outer_origin(
 		&name,
-		all_but_system_modules,
-		&system_module,
+		all_but_system_pallets,
+		&system_pallet,
 		&scrate,
 	)?;
-	let all_modules = decl_all_modules(&name, modules.iter());
-	let module_to_index = decl_pallet_runtime_setup(&modules, &scrate);
+	let all_pallets = decl_all_pallets(&name, pallets.iter());
+	let pallet_to_index = decl_pallet_runtime_setup(&pallets, &scrate);
 
-	let dispatch = decl_outer_dispatch(&name, modules.iter(), &scrate);
-	let metadata = decl_runtime_metadata(&name, modules.iter(), &scrate, &unchecked_extrinsic);
-	let outer_config = decl_outer_config(&name, modules.iter(), &scrate);
+	let dispatch = decl_outer_dispatch(&name, pallets.iter(), &scrate);
+	let metadata = decl_runtime_metadata(&name, pallets.iter(), &scrate, &unchecked_extrinsic);
+	let outer_config = decl_outer_config(&name, pallets.iter(), &scrate);
 	let inherent = decl_outer_inherent(
 		&block,
 		&unchecked_extrinsic,
-		modules.iter(),
+		pallets.iter(),
 		&scrate,
 	);
-	let validate_unsigned = decl_validate_unsigned(&name, modules.iter(), &scrate);
+	let validate_unsigned = decl_validate_unsigned(&name, pallets.iter(), &scrate);
 	let integrity_test = decl_integrity_test(&scrate);
 
 	let res = quote!(
@@ -197,9 +197,9 @@ fn construct_runtime_parsed(definition: RuntimeDefinition) -> Result<TokenStream
 
 		#outer_origin
 
-		#all_modules
+		#all_pallets
 
-		#module_to_index
+		#pallet_to_index
 
 		#dispatch
 
@@ -219,16 +219,16 @@ fn construct_runtime_parsed(definition: RuntimeDefinition) -> Result<TokenStream
 
 fn decl_validate_unsigned<'a>(
 	runtime: &'a Ident,
-	module_declarations: impl Iterator<Item = &'a Module>,
+	pallet_declarations: impl Iterator<Item = &'a Pallet>,
 	scrate: &'a TokenStream2,
 ) -> TokenStream2 {
-	let modules_tokens = module_declarations
-		.filter(|module_declaration| module_declaration.exists_part("ValidateUnsigned"))
-		.map(|module_declaration| &module_declaration.name);
+	let pallets_tokens = pallet_declarations
+		.filter(|pallet_declaration| pallet_declaration.exists_part("ValidateUnsigned"))
+		.map(|pallet_declaration| &pallet_declaration.name);
 	quote!(
 		#scrate::impl_outer_validate_unsigned!(
 			impl ValidateUnsigned for #runtime {
-				#( #modules_tokens )*
+				#( #pallets_tokens )*
 			}
 		);
 	)
@@ -237,13 +237,13 @@ fn decl_validate_unsigned<'a>(
 fn decl_outer_inherent<'a>(
 	block: &'a syn::TypePath,
 	unchecked_extrinsic: &'a syn::TypePath,
-	module_declarations: impl Iterator<Item = &'a Module>,
+	pallet_declarations: impl Iterator<Item = &'a Pallet>,
 	scrate: &'a TokenStream2,
 ) -> TokenStream2 {
-	let modules_tokens = module_declarations.filter_map(|module_declaration| {
-		let maybe_config_part = module_declaration.find_part("Inherent");
+	let pallets_tokens = pallet_declarations.filter_map(|pallet_declaration| {
+		let maybe_config_part = pallet_declaration.find_part("Inherent");
 		maybe_config_part.map(|_| {
-			let name = &module_declaration.name;
+			let name = &pallet_declaration.name;
 			quote!(#name,)
 		})
 	});
@@ -253,7 +253,7 @@ fn decl_outer_inherent<'a>(
 				Block = #block,
 				UncheckedExtrinsic = #unchecked_extrinsic
 			{
-				#(#modules_tokens)*
+				#(#pallets_tokens)*
 			}
 		);
 	)
@@ -261,37 +261,37 @@ fn decl_outer_inherent<'a>(
 
 fn decl_outer_config<'a>(
 	runtime: &'a Ident,
-	module_declarations: impl Iterator<Item = &'a Module>,
+	pallet_declarations: impl Iterator<Item = &'a Pallet>,
 	scrate: &'a TokenStream2,
 ) -> TokenStream2 {
-	let modules_tokens = module_declarations
-		.filter_map(|module_declaration| {
-			module_declaration.find_part("Config").map(|part| {
+	let pallets_tokens = pallet_declarations
+		.filter_map(|pallet_declaration| {
+			pallet_declaration.find_part("Config").map(|part| {
 				let transformed_generics: Vec<_> = part
 					.generics
 					.params
 					.iter()
 					.map(|param| quote!(<#param>))
 					.collect();
-				(module_declaration, transformed_generics)
+				(pallet_declaration, transformed_generics)
 			})
 		})
-		.map(|(module_declaration, generics)| {
-			let module = &module_declaration.module;
+		.map(|(pallet_declaration, generics)| {
+			let pallet = &pallet_declaration.pallet;
 			let name = Ident::new(
-				&format!("{}Config", module_declaration.name),
-				module_declaration.name.span(),
+				&format!("{}Config", pallet_declaration.name),
+				pallet_declaration.name.span(),
 			);
-			let instance = module_declaration.instance.as_ref().into_iter();
+			let instance = pallet_declaration.instance.as_ref().into_iter();
 			quote!(
 				#name =>
-					#module #(#instance)* #(#generics)*,
+					#pallet #(#instance)* #(#generics)*,
 			)
 		});
 	quote!(
 		#scrate::impl_outer_config! {
-			pub struct GenesisConfig for #runtime where AllModulesWithSystem = AllModulesWithSystem {
-				#(#modules_tokens)*
+			pub struct GenesisConfig for #runtime where AllPalletsWithSystem = AllPalletsWithSystem {
+				#(#pallets_tokens)*
 			}
 		}
 	)
@@ -299,63 +299,63 @@ fn decl_outer_config<'a>(
 
 fn decl_runtime_metadata<'a>(
 	runtime: &'a Ident,
-	module_declarations: impl Iterator<Item = &'a Module>,
+	pallet_declarations: impl Iterator<Item = &'a Pallet>,
 	scrate: &'a TokenStream2,
 	extrinsic: &TypePath,
 ) -> TokenStream2 {
-	let modules_tokens = module_declarations
-		.filter_map(|module_declaration| {
-			module_declaration.find_part("Module").map(|_| {
-				let filtered_names: Vec<_> = module_declaration
-					.module_parts()
+	let pallets_tokens = pallet_declarations
+		.filter_map(|pallet_declaration| {
+			pallet_declaration.find_part("Pallet").map(|_| {
+				let filtered_names: Vec<_> = pallet_declaration
+					.pallet_parts()
 					.iter()
-					.filter(|part| part.name() != "Module")
+					.filter(|part| part.name() != "Pallet")
 					.map(|part| part.ident())
 					.collect();
-				(module_declaration, filtered_names)
+				(pallet_declaration, filtered_names)
 			})
 		})
-		.map(|(module_declaration, filtered_names)| {
-			let module = &module_declaration.module;
-			let name = &module_declaration.name;
-			let instance = module_declaration
+		.map(|(pallet_declaration, filtered_names)| {
+			let pallet = &pallet_declaration.pallet;
+			let name = &pallet_declaration.name;
+			let instance = pallet_declaration
 				.instance
 				.as_ref()
 				.map(|name| quote!(<#name>))
 				.into_iter();
 
-			let index = module_declaration.index;
+			let index = pallet_declaration.index;
 
 			quote!(
-				#module::Module #(#instance)* as #name { index #index } with #(#filtered_names)*,
+				#pallet::Pallet #(#instance)* as #name { index #index } with #(#filtered_names)*,
 			)
 		});
 	quote!(
 		#scrate::impl_runtime_metadata!{
-			for #runtime with modules where Extrinsic = #extrinsic
-				#(#modules_tokens)*
+			for #runtime with pallets where Extrinsic = #extrinsic
+				#(#pallets_tokens)*
 		}
 	)
 }
 
 fn decl_outer_dispatch<'a>(
 	runtime: &'a Ident,
-	module_declarations: impl Iterator<Item = &'a Module>,
+	pallet_declarations: impl Iterator<Item = &'a Pallet>,
 	scrate: &'a TokenStream2,
 ) -> TokenStream2 {
-	let modules_tokens = module_declarations
-		.filter(|module_declaration| module_declaration.exists_part("Call"))
-		.map(|module_declaration| {
-			let module = &module_declaration.module;
-			let name = &module_declaration.name;
-			let index = module_declaration.index;
-			quote!(#[codec(index = #index)] #module::#name)
+	let pallets_tokens = pallet_declarations
+		.filter(|pallet_declaration| pallet_declaration.exists_part("Call"))
+		.map(|pallet_declaration| {
+			let pallet = &pallet_declaration.pallet;
+			let name = &pallet_declaration.name;
+			let index = pallet_declaration.index;
+			quote!(#[codec(index = #index)] #pallet::#name)
 		});
 
 	quote!(
 		#scrate::impl_outer_dispatch! {
 			pub enum Call for #runtime where origin: Origin {
-				#(#modules_tokens,)*
+				#(#pallets_tokens,)*
 			}
 		}
 	)
@@ -363,32 +363,32 @@ fn decl_outer_dispatch<'a>(
 
 fn decl_outer_origin<'a>(
 	runtime_name: &'a Ident,
-	modules_except_system: impl Iterator<Item = &'a Module>,
-	system_module: &'a Module,
+	pallets_except_system: impl Iterator<Item = &'a Pallet>,
+	system_pallet: &'a Pallet,
 	scrate: &'a TokenStream2,
 ) -> syn::Result<TokenStream2> {
-	let mut modules_tokens = TokenStream2::new();
-	for module_declaration in modules_except_system {
-		if let Some(module_entry) = module_declaration.find_part("Origin") {
-			let module = &module_declaration.module;
-			let instance = module_declaration.instance.as_ref();
-			let generics = &module_entry.generics;
+	let mut pallets_tokens = TokenStream2::new();
+	for pallet_declaration in pallets_except_system {
+		if let Some(pallet_entry) = pallet_declaration.find_part("Origin") {
+			let pallet = &pallet_declaration.pallet;
+			let instance = pallet_declaration.instance.as_ref();
+			let generics = &pallet_entry.generics;
 			if instance.is_some() && generics.params.is_empty() {
 				let msg = format!(
-					"Instantiable module with no generic `Origin` cannot \
-					 be constructed: module `{}` must have generic `Origin`",
-					module_declaration.name
+					"Instantiable pallet with no generic `Origin` cannot \
+					 be constructed: pallet `{}` must have generic `Origin`",
+					pallet_declaration.name
 				);
-				return Err(syn::Error::new(module_declaration.name.span(), msg));
+				return Err(syn::Error::new(pallet_declaration.name.span(), msg));
 			}
-			let index = module_declaration.index;
-			let tokens = quote!(#[codec(index = #index)] #module #instance #generics,);
-			modules_tokens.extend(tokens);
+			let index = pallet_declaration.index;
+			let tokens = quote!(#[codec(index = #index)] #pallet #instance #generics,);
+			pallets_tokens.extend(tokens);
 		}
 	}
 
-	let system_name = &system_module.module;
-	let system_index = system_module.index;
+	let system_name = &system_pallet.pallet;
+	let system_index = system_pallet.index;
 
 	Ok(quote!(
 		#scrate::impl_outer_origin! {
@@ -396,7 +396,7 @@ fn decl_outer_origin<'a>(
 				system = #system_name,
 				system_index = #system_index
 			{
-				#modules_tokens
+				#pallets_tokens
 			}
 		}
 	))
@@ -404,89 +404,99 @@ fn decl_outer_origin<'a>(
 
 fn decl_outer_event<'a>(
 	runtime_name: &'a Ident,
-	module_declarations: impl Iterator<Item = &'a Module>,
+	pallet_declarations: impl Iterator<Item = &'a Pallet>,
 	scrate: &'a TokenStream2,
 ) -> syn::Result<TokenStream2> {
-	let mut modules_tokens = TokenStream2::new();
-	for module_declaration in module_declarations {
-		if let Some(module_entry) = module_declaration.find_part("Event") {
-			let module = &module_declaration.module;
-			let instance = module_declaration.instance.as_ref();
-			let generics = &module_entry.generics;
+	let mut pallets_tokens = TokenStream2::new();
+	for pallet_declaration in pallet_declarations {
+		if let Some(pallet_entry) = pallet_declaration.find_part("Event") {
+			let pallet = &pallet_declaration.pallet;
+			let instance = pallet_declaration.instance.as_ref();
+			let generics = &pallet_entry.generics;
 			if instance.is_some() && generics.params.is_empty() {
 				let msg = format!(
-					"Instantiable module with no generic `Event` cannot \
-					 be constructed: module `{}` must have generic `Event`",
-					module_declaration.name,
+					"Instantiable pallet with no generic `Event` cannot \
+					 be constructed: pallet `{}` must have generic `Event`",
+					pallet_declaration.name,
 				);
-				return Err(syn::Error::new(module_declaration.name.span(), msg));
+				return Err(syn::Error::new(pallet_declaration.name.span(), msg));
 			}
 
-			let index = module_declaration.index;
-			let tokens = quote!(#[codec(index = #index)] #module #instance #generics,);
-			modules_tokens.extend(tokens);
+			let index = pallet_declaration.index;
+			let tokens = quote!(#[codec(index = #index)] #pallet #instance #generics,);
+			pallets_tokens.extend(tokens);
 		}
 	}
 
 	Ok(quote!(
 		#scrate::impl_outer_event! {
 			pub enum Event for #runtime_name {
-				#modules_tokens
+				#pallets_tokens
 			}
 		}
 	))
 }
 
-fn decl_all_modules<'a>(
+fn decl_all_pallets<'a>(
 	runtime: &'a Ident,
-	module_declarations: impl Iterator<Item = &'a Module>,
+	pallet_declarations: impl Iterator<Item = &'a Pallet>,
 ) -> TokenStream2 {
 	let mut types = TokenStream2::new();
 	let mut names = Vec::new();
-	for module_declaration in module_declarations {
-		let type_name = &module_declaration.name;
-		let module = &module_declaration.module;
+	for pallet_declaration in pallet_declarations {
+		let type_name = &pallet_declaration.name;
+		let pallet = &pallet_declaration.pallet;
 		let mut generics = vec![quote!(#runtime)];
 		generics.extend(
-			module_declaration
+			pallet_declaration
 				.instance
 				.iter()
-				.map(|name| quote!(#module::#name)),
+				.map(|name| quote!(#pallet::#name)),
 		);
 		let type_decl = quote!(
-			pub type #type_name = #module::Module <#(#generics),*>;
+			pub type #type_name = #pallet::Pallet <#(#generics),*>;
 		);
 		types.extend(type_decl);
-		names.push(&module_declaration.name);
+		names.push(&pallet_declaration.name);
 	}
 	// Make nested tuple structure like (((Babe, Consensus), Grandpa), ...)
-	// But ignore the system module.
-	let all_modules = names.iter()
-		.filter(|n| **n != SYSTEM_MODULE_NAME)
+	// But ignore the system pallet.
+	let all_pallets = names.iter()
+		.filter(|n| **n != SYSTEM_PALLET_NAME)
 		.fold(TokenStream2::default(), |combined, name| quote!((#name, #combined)));
 
-	let all_modules_with_system = names.iter()
+	let all_pallets_with_system = names.iter()
 		.fold(TokenStream2::default(), |combined, name| quote!((#name, #combined)));
 
 	quote!(
 		#types
 		/// All pallets included in the runtime as a nested tuple of types.
 		/// Excludes the System pallet.
-		pub type AllModules = ( #all_modules );
+		pub type AllPallets = ( #all_pallets );
 		/// All pallets included in the runtime as a nested tuple of types.
-		pub type AllModulesWithSystem = ( #all_modules_with_system );
+		pub type AllPalletsWithSystem = ( #all_pallets_with_system );
+
+		/// All modules included in the runtime as a nested tuple of types.
+		/// Excludes the System pallet.
+		#[deprecated(note = "use `AllPallets` instead")]
+		#[allow(dead_code)]
+		pub type AllModules = ( #all_pallets );
+		/// All modules included in the runtime as a nested tuple of types.
+		#[deprecated(note = "use `AllPalletsWithSystem` instead")]
+		#[allow(dead_code)]
+		pub type AllModulesWithSystem = ( #all_pallets_with_system );
 	)
 }
 
 fn decl_pallet_runtime_setup(
-	module_declarations: &[Module],
+	pallet_declarations: &[Pallet],
 	scrate: &TokenStream2,
 ) -> TokenStream2 {
-	let names = module_declarations.iter().map(|d| &d.name);
-	let names2 = module_declarations.iter().map(|d| &d.name);
-	let name_strings = module_declarations.iter().map(|d| d.name.to_string());
-	let indices = module_declarations.iter()
-		.map(|module| module.index as usize);
+	let names = pallet_declarations.iter().map(|d| &d.name);
+	let names2 = pallet_declarations.iter().map(|d| &d.name);
+	let name_strings = pallet_declarations.iter().map(|d| d.name.to_string());
+	let indices = pallet_declarations.iter()
+		.map(|pallet| pallet.index as usize);
 
 	quote!(
 		/// Provides an implementation of `PalletInfo` to provide information
@@ -527,7 +537,7 @@ fn decl_integrity_test(scrate: &TokenStream2) -> TokenStream2 {
 
 			#[test]
 			pub fn runtime_integrity_tests() {
-				<AllModules as #scrate::traits::IntegrityTest>::integrity_test();
+				<AllPallets as #scrate::traits::IntegrityTest>::integrity_test();
 			}
 		}
 	)
diff --git a/frame/support/procedural/src/construct_runtime/parse.rs b/frame/support/procedural/src/construct_runtime/parse.rs
index 6d4ba6cdbf743..def207439b536 100644
--- a/frame/support/procedural/src/construct_runtime/parse.rs
+++ b/frame/support/procedural/src/construct_runtime/parse.rs
@@ -28,7 +28,7 @@ mod keyword {
 	syn::custom_keyword!(Block);
 	syn::custom_keyword!(NodeBlock);
 	syn::custom_keyword!(UncheckedExtrinsic);
-	syn::custom_keyword!(Module);
+	syn::custom_keyword!(Pallet);
 	syn::custom_keyword!(Call);
 	syn::custom_keyword!(Storage);
 	syn::custom_keyword!(Event);
@@ -44,7 +44,7 @@ pub struct RuntimeDefinition {
 	pub enum_token: Token![enum],
 	pub name: Ident,
 	pub where_section: WhereSection,
-	pub modules: ext::Braces<ext::Punctuated<ModuleDeclaration, Token![,]>>,
+	pub pallets: ext::Braces<ext::Punctuated<PalletDeclaration, Token![,]>>,
 }
 
 impl Parse for RuntimeDefinition {
@@ -54,7 +54,7 @@ impl Parse for RuntimeDefinition {
 			enum_token: input.parse()?,
 			name: input.parse()?,
 			where_section: input.parse()?,
-			modules: input.parse()?,
+			pallets: input.parse()?,
 		})
 	}
 }
@@ -150,20 +150,20 @@ impl Parse for WhereDefinition {
 }
 
 #[derive(Debug, Clone)]
-pub struct ModuleDeclaration {
+pub struct PalletDeclaration {
 	pub name: Ident,
 	/// Optional fixed index (e.g. `MyPallet ...  = 3,`)
 	pub index: Option<u8>,
-	pub module: Ident,
+	pub pallet: Ident,
 	pub instance: Option<Ident>,
-	pub module_parts: Vec<ModulePart>,
+	pub pallet_parts: Vec<PalletPart>,
 }
 
-impl Parse for ModuleDeclaration {
+impl Parse for PalletDeclaration {
 	fn parse(input: ParseStream) -> Result<Self> {
 		let name = input.parse()?;
 		let _: Token![:] = input.parse()?;
-		let module = input.parse()?;
+		let pallet = input.parse()?;
 		let instance = if input.peek(Token![::]) && input.peek3(Token![<]) {
 			let _: Token![::] = input.parse()?;
 			let _: Token![<] = input.parse()?;
@@ -175,7 +175,7 @@ impl Parse for ModuleDeclaration {
 		};
 
 		let _: Token![::] = input.parse()?;
-		let module_parts = parse_module_parts(input)?;
+		let pallet_parts = parse_pallet_parts(input)?;
 
 		let index = if input.peek(Token![=]) {
 			input.parse::<Token![=]>()?;
@@ -188,9 +188,9 @@ impl Parse for ModuleDeclaration {
 
 		let parsed = Self {
 			name,
-			module,
+			pallet,
 			instance,
-			module_parts,
+			pallet_parts,
 			index,
 		};
 
@@ -198,14 +198,14 @@ impl Parse for ModuleDeclaration {
 	}
 }
 
-/// Parse [`ModulePart`]'s from a braces enclosed list that is split by commas, e.g.
+/// Parse [`PalletPart`]'s from a braces enclosed list that is split by commas, e.g.
 ///
 /// `{ Call, Event }`
-fn parse_module_parts(input: ParseStream) -> Result<Vec<ModulePart>> {
-	let module_parts :ext::Braces<ext::Punctuated<ModulePart, Token![,]>> = input.parse()?;
+fn parse_pallet_parts(input: ParseStream) -> Result<Vec<PalletPart>> {
+	let pallet_parts :ext::Braces<ext::Punctuated<PalletPart, Token![,]>> = input.parse()?;
 
 	let mut resolved = HashSet::new();
-	for part in module_parts.content.inner.iter() {
+	for part in pallet_parts.content.inner.iter() {
 		if !resolved.insert(part.name()) {
 			let msg = format!(
 				"`{}` was already declared before. Please remove the duplicate declaration",
@@ -215,12 +215,12 @@ fn parse_module_parts(input: ParseStream) -> Result<Vec<ModulePart>> {
 		}
 	}
 
-	Ok(module_parts.content.inner.into_iter().collect())
+	Ok(pallet_parts.content.inner.into_iter().collect())
 }
 
 #[derive(Debug, Clone)]
-pub enum ModulePartKeyword {
-	Module(keyword::Module),
+pub enum PalletPartKeyword {
+	Pallet(keyword::Pallet),
 	Call(keyword::Call),
 	Storage(keyword::Storage),
 	Event(keyword::Event),
@@ -230,12 +230,12 @@ pub enum ModulePartKeyword {
 	ValidateUnsigned(keyword::ValidateUnsigned),
 }
 
-impl Parse for ModulePartKeyword {
+impl Parse for PalletPartKeyword {
 	fn parse(input: ParseStream) -> Result<Self> {
 		let lookahead = input.lookahead1();
 
-		if lookahead.peek(keyword::Module) {
-			Ok(Self::Module(input.parse()?))
+		if lookahead.peek(keyword::Pallet) {
+			Ok(Self::Pallet(input.parse()?))
 		} else if lookahead.peek(keyword::Call) {
 			Ok(Self::Call(input.parse()?))
 		} else if lookahead.peek(keyword::Storage) {
@@ -256,11 +256,11 @@ impl Parse for ModulePartKeyword {
 	}
 }
 
-impl ModulePartKeyword {
+impl PalletPartKeyword {
 	/// Returns the name of `Self`.
 	fn name(&self) -> &'static str {
 		match self {
-			Self::Module(_) => "Module",
+			Self::Pallet(_) => "Pallet",
 			Self::Call(_) => "Call",
 			Self::Storage(_) => "Storage",
 			Self::Event(_) => "Event",
@@ -276,21 +276,21 @@ impl ModulePartKeyword {
 		Ident::new(self.name(), self.span())
 	}
 
-	/// Returns `true` if this module part is allowed to have generic arguments.
+	/// Returns `true` if this pallet part is allowed to have generic arguments.
 	fn allows_generic(&self) -> bool {
 		Self::all_generic_arg().iter().any(|n| *n == self.name())
 	}
 
-	/// Returns the names of all module parts that allow to have a generic argument.
+	/// Returns the names of all pallet parts that allow to have a generic argument.
 	fn all_generic_arg() -> &'static [&'static str] {
 		&["Event", "Origin", "Config"]
 	}
 }
 
-impl Spanned for ModulePartKeyword {
+impl Spanned for PalletPartKeyword {
 	fn span(&self) -> Span {
 		match self {
-			Self::Module(inner) => inner.span(),
+			Self::Pallet(inner) => inner.span(),
 			Self::Call(inner) => inner.span(),
 			Self::Storage(inner) => inner.span(),
 			Self::Event(inner) => inner.span(),
@@ -303,21 +303,21 @@ impl Spanned for ModulePartKeyword {
 }
 
 #[derive(Debug, Clone)]
-pub struct ModulePart {
-	pub keyword: ModulePartKeyword,
+pub struct PalletPart {
+	pub keyword: PalletPartKeyword,
 	pub generics: syn::Generics,
 }
 
-impl Parse for ModulePart {
+impl Parse for PalletPart {
 	fn parse(input: ParseStream) -> Result<Self> {
-		let keyword: ModulePartKeyword = input.parse()?;
+		let keyword: PalletPartKeyword = input.parse()?;
 
 		let generics: syn::Generics = input.parse()?;
 		if !generics.params.is_empty() && !keyword.allows_generic() {
-			let valid_generics = ModulePart::format_names(ModulePartKeyword::all_generic_arg());
+			let valid_generics = PalletPart::format_names(PalletPartKeyword::all_generic_arg());
 			let msg = format!(
 				"`{}` is not allowed to have generics. \
-				 Only the following modules are allowed to have generics: {}.",
+				 Only the following pallets are allowed to have generics: {}.",
 				keyword.name(),
 				valid_generics,
 			);
@@ -331,18 +331,18 @@ impl Parse for ModulePart {
 	}
 }
 
-impl ModulePart {
+impl PalletPart {
 	pub fn format_names(names: &[&'static str]) -> String {
 		let res: Vec<_> = names.iter().map(|s| format!("`{}`", s)).collect();
 		res.join(", ")
 	}
 
-	/// The name of this module part.
+	/// The name of this pallet part.
 	pub fn name(&self) -> &'static str {
 		self.keyword.name()
 	}
 
-	/// The name of this module part as `Ident`.
+	/// The name of this pallet part as `Ident`.
 	pub fn ident(&self) -> Ident {
 		self.keyword.ident()
 	}
diff --git a/frame/support/procedural/src/lib.rs b/frame/support/procedural/src/lib.rs
index e64a364d2951e..2aecc5b993928 100644
--- a/frame/support/procedural/src/lib.rs
+++ b/frame/support/procedural/src/lib.rs
@@ -192,7 +192,7 @@ use proc_macro::TokenStream;
 /// construct_runtime!(
 /// 	pub enum Runtime with ... {
 ///         ...,
-///         Example: example::{Module, Storage, ..., Config<T>},
+///         Example: example::{Pallet, Storage, ..., Config<T>},
 ///         ...,
 ///	}
 /// );
@@ -258,13 +258,13 @@ pub fn decl_storage(input: TokenStream) -> TokenStream {
 ///         NodeBlock = runtime::Block,
 ///         UncheckedExtrinsic = UncheckedExtrinsic
 ///     {
-///         System: system::{Module, Call, Event<T>, Config<T>} = 0,
-///         Test: test::{Module, Call} = 1,
-///         Test2: test_with_long_module::{Module, Event<T>},
+///         System: system::{Pallet, Call, Event<T>, Config<T>} = 0,
+///         Test: test::{Pallet, Call} = 1,
+///         Test2: test_with_long_module::{Pallet, Event<T>},
 ///
 ///         // Module with instances
-///         Test3_Instance1: test3::<Instance1>::{Module, Call, Storage, Event<T, I>, Config<T, I>, Origin<T, I>},
-///         Test3_DefaultInstance: test3::{Module, Call, Storage, Event<T>, Config<T>, Origin<T>} = 4,
+///         Test3_Instance1: test3::<Instance1>::{Pallet, Call, Storage, Event<T, I>, Config<T, I>, Origin<T, I>},
+///         Test3_DefaultInstance: test3::{Pallet, Call, Storage, Event<T>, Config<T>, Origin<T>} = 4,
 ///     }
 /// )
 /// ```
@@ -306,7 +306,7 @@ pub fn decl_storage(input: TokenStream) -> TokenStream {
 /// # Type definitions
 ///
 /// * The macro generates a type alias for each pallet to their `Module` (or `Pallet`).
-///   E.g. `type System = frame_system::Module<Runtime>`
+///   E.g. `type System = frame_system::Pallet<Runtime>`
 #[proc_macro]
 pub fn construct_runtime(input: TokenStream) -> TokenStream {
 	construct_runtime::construct_runtime(input)
diff --git a/frame/support/procedural/src/pallet/expand/call.rs b/frame/support/procedural/src/pallet/expand/call.rs
index 137e055405a38..301d3fc5d9fa8 100644
--- a/frame/support/procedural/src/pallet/expand/call.rs
+++ b/frame/support/procedural/src/pallet/expand/call.rs
@@ -108,26 +108,26 @@ pub fn expand_call(def: &mut Def) -> proc_macro2::TokenStream {
 				match *self {
 					#(
 						Self::#fn_name ( #( ref #args_name, )* ) => {
-							let base_weight = #fn_weight;
+							let __pallet_base_weight = #fn_weight;
 
-							let weight = <
+							let __pallet_weight = <
 								dyn #frame_support::dispatch::WeighData<( #( & #args_type, )* )>
-							>::weigh_data(&base_weight, ( #( #args_name, )* ));
+							>::weigh_data(&__pallet_base_weight, ( #( #args_name, )* ));
 
-							let class = <
+							let __pallet_class = <
 								dyn #frame_support::dispatch::ClassifyDispatch<
 									( #( & #args_type, )* )
 								>
-							>::classify_dispatch(&base_weight, ( #( #args_name, )* ));
+							>::classify_dispatch(&__pallet_base_weight, ( #( #args_name, )* ));
 
-							let pays_fee = <
+							let __pallet_pays_fee = <
 								dyn #frame_support::dispatch::PaysFee<( #( & #args_type, )* )>
-							>::pays_fee(&base_weight, ( #( #args_name, )* ));
+							>::pays_fee(&__pallet_base_weight, ( #( #args_name, )* ));
 
 							#frame_support::dispatch::DispatchInfo {
-								weight,
-								class,
-								pays_fee,
+								weight: __pallet_weight,
+								class: __pallet_class,
+								pays_fee: __pallet_pays_fee,
 							}
 						},
 					)*
@@ -162,9 +162,13 @@ pub fn expand_call(def: &mut Def) -> proc_macro2::TokenStream {
 			) -> #frame_support::dispatch::DispatchResultWithPostInfo {
 				match self {
 					#(
-						Self::#fn_name( #( #args_name, )* ) =>
+						Self::#fn_name( #( #args_name, )* ) => {
+							#frame_support::sp_tracing::enter_span!(
+								#frame_support::sp_tracing::trace_span!(stringify!(#fn_name))
+							);
 							<#pallet_ident<#type_use_gen>>::#fn_name(origin, #( #args_name, )* )
-								.map(Into::into).map_err(Into::into),
+								.map(Into::into).map_err(Into::into)
+						},
 					)*
 					Self::__Ignore(_, _) => {
 						let _ = origin; // Use origin for empty Call enum
@@ -182,6 +186,7 @@ pub fn expand_call(def: &mut Def) -> proc_macro2::TokenStream {
 
 		impl<#type_impl_gen> #pallet_ident<#type_use_gen> #where_clause {
 			#[doc(hidden)]
+			#[allow(dead_code)]
 			pub fn call_functions() -> &'static [#frame_support::dispatch::FunctionMetadata] {
 				&[ #(
 					#frame_support::dispatch::FunctionMetadata {
diff --git a/frame/support/procedural/src/pallet/expand/hooks.rs b/frame/support/procedural/src/pallet/expand/hooks.rs
index 3976f2c602dde..2d12d5ecf9d46 100644
--- a/frame/support/procedural/src/pallet/expand/hooks.rs
+++ b/frame/support/procedural/src/pallet/expand/hooks.rs
@@ -55,6 +55,9 @@ pub fn expand_hooks(def: &mut Def) -> proc_macro2::TokenStream {
 			for #pallet_ident<#type_use_gen> #where_clause
 		{
 			fn on_finalize(n: <T as #frame_system::Config>::BlockNumber) {
+				#frame_support::sp_tracing::enter_span!(
+					#frame_support::sp_tracing::trace_span!("on_finalize")
+				);
 				<
 					Self as #frame_support::traits::Hooks<
 						<T as #frame_system::Config>::BlockNumber
@@ -86,6 +89,9 @@ pub fn expand_hooks(def: &mut Def) -> proc_macro2::TokenStream {
 			fn on_initialize(
 				n: <T as #frame_system::Config>::BlockNumber
 			) -> #frame_support::weights::Weight {
+				#frame_support::sp_tracing::enter_span!(
+					#frame_support::sp_tracing::trace_span!("on_initialize")
+				);
 				<
 					Self as #frame_support::traits::Hooks<
 						<T as #frame_system::Config>::BlockNumber
@@ -99,6 +105,10 @@ pub fn expand_hooks(def: &mut Def) -> proc_macro2::TokenStream {
 			for #pallet_ident<#type_use_gen> #where_clause
 		{
 			fn on_runtime_upgrade() -> #frame_support::weights::Weight {
+				#frame_support::sp_tracing::enter_span!(
+					#frame_support::sp_tracing::trace_span!("on_runtime_update")
+				);
+
 				// log info about the upgrade.
 				let new_storage_version = #frame_support::crate_to_pallet_version!();
 				let pallet_name = <
diff --git a/frame/support/procedural/src/pallet/expand/pallet_struct.rs b/frame/support/procedural/src/pallet/expand/pallet_struct.rs
index 47e4344c50d8e..fd3230edd1e74 100644
--- a/frame/support/procedural/src/pallet/expand/pallet_struct.rs
+++ b/frame/support/procedural/src/pallet/expand/pallet_struct.rs
@@ -102,6 +102,8 @@ pub fn expand_pallet_struct(def: &mut Def) -> proc_macro2::TokenStream {
 		/// Type alias to `Pallet`, to be used by `construct_runtime`.
 		///
 		/// Generated by `pallet` attribute macro.
+		#[deprecated(note = "use `Pallet` instead")]
+		#[allow(dead_code)]
 		pub type Module<#type_decl_gen> = #pallet_ident<#type_use_gen>;
 
 		// Implement `GetPalletVersion` for `Pallet`
diff --git a/frame/support/procedural/src/pallet/expand/storage.rs b/frame/support/procedural/src/pallet/expand/storage.rs
index 7948fca2faf06..86fb84b339b24 100644
--- a/frame/support/procedural/src/pallet/expand/storage.rs
+++ b/frame/support/procedural/src/pallet/expand/storage.rs
@@ -78,6 +78,8 @@ pub fn expand_storages(def: &mut Def) -> proc_macro2::TokenStream {
 			let gen = &def.type_use_generics(storage.attr_span);
 			let full_ident = quote::quote_spanned!(storage.attr_span => #ident<#gen> );
 
+			let cfg_attrs = &storage.cfg_attrs;
+
 			let metadata_trait = match &storage.metadata {
 				Metadata::Value { .. } => quote::quote_spanned!(storage.attr_span =>
 					#frame_support::storage::types::StorageValueMetadata
@@ -128,7 +130,7 @@ pub fn expand_storages(def: &mut Def) -> proc_macro2::TokenStream {
 			};
 
 			quote::quote_spanned!(storage.attr_span =>
-				#frame_support::metadata::StorageEntryMetadata {
+				#(#cfg_attrs)* #frame_support::metadata::StorageEntryMetadata {
 					name: #frame_support::metadata::DecodeDifferent::Encode(
 						<#full_ident as #metadata_trait>::NAME
 					),
@@ -159,6 +161,8 @@ pub fn expand_storages(def: &mut Def) -> proc_macro2::TokenStream {
 			let type_use_gen = &def.type_use_generics(storage.attr_span);
 			let full_ident = quote::quote_spanned!(storage.attr_span => #ident<#gen> );
 
+			let cfg_attrs = &storage.cfg_attrs;
+
 			match &storage.metadata {
 				Metadata::Value { value } => {
 					let query = match storage.query_kind.as_ref().expect("Checked by def") {
@@ -168,6 +172,7 @@ pub fn expand_storages(def: &mut Def) -> proc_macro2::TokenStream {
 						QueryKind::ValueQuery => quote::quote!(#value),
 					};
 					quote::quote_spanned!(storage.attr_span =>
+						#(#cfg_attrs)*
 						impl<#type_impl_gen> #pallet_ident<#type_use_gen> #completed_where_clause {
 							#( #docs )*
 							pub fn #getter() -> #query {
@@ -186,6 +191,7 @@ pub fn expand_storages(def: &mut Def) -> proc_macro2::TokenStream {
 						QueryKind::ValueQuery => quote::quote!(#value),
 					};
 					quote::quote_spanned!(storage.attr_span =>
+						#(#cfg_attrs)*
 						impl<#type_impl_gen> #pallet_ident<#type_use_gen> #completed_where_clause {
 							#( #docs )*
 							pub fn #getter<KArg>(k: KArg) -> #query where
@@ -206,6 +212,7 @@ pub fn expand_storages(def: &mut Def) -> proc_macro2::TokenStream {
 						QueryKind::ValueQuery => quote::quote!(#value),
 					};
 					quote::quote_spanned!(storage.attr_span =>
+						#(#cfg_attrs)*
 						impl<#type_impl_gen> #pallet_ident<#type_use_gen> #completed_where_clause {
 							#( #docs )*
 							pub fn #getter<KArg1, KArg2>(k1: KArg1, k2: KArg2) -> #query where
@@ -233,10 +240,14 @@ pub fn expand_storages(def: &mut Def) -> proc_macro2::TokenStream {
 		let prefix_struct_const = storage_def.ident.to_string();
 		let config_where_clause = &def.config.where_clause;
 
+		let cfg_attrs = &storage_def.cfg_attrs;
+
 		quote::quote_spanned!(storage_def.attr_span =>
+			#(#cfg_attrs)*
 			#prefix_struct_vis struct #prefix_struct_ident<#type_use_gen>(
 				core::marker::PhantomData<(#type_use_gen,)>
 			);
+			#(#cfg_attrs)*
 			impl<#type_impl_gen> #frame_support::traits::StorageInstance
 				for #prefix_struct_ident<#type_use_gen>
 				#config_where_clause
diff --git a/frame/support/procedural/src/pallet/expand/store_trait.rs b/frame/support/procedural/src/pallet/expand/store_trait.rs
index cdc7e2837245f..81ed52ac87a68 100644
--- a/frame/support/procedural/src/pallet/expand/store_trait.rs
+++ b/frame/support/procedural/src/pallet/expand/store_trait.rs
@@ -37,10 +37,12 @@ pub fn expand_store_trait(def: &mut Def) -> proc_macro2::TokenStream {
 	let completed_where_clause = super::merge_where_clauses(&where_clauses);
 
 	let storage_names = &def.storages.iter().map(|storage| &storage.ident).collect::<Vec<_>>();
+	let storage_cfg_attrs = &def.storages.iter().map(|storage| &storage.cfg_attrs).collect::<Vec<_>>();
 
 	quote::quote_spanned!(trait_store.span() =>
 		#trait_vis trait #trait_store {
 			#(
+				#(#storage_cfg_attrs)*
 				type #storage_names;
 			)*
 		}
@@ -48,6 +50,7 @@ pub fn expand_store_trait(def: &mut Def) -> proc_macro2::TokenStream {
 			#completed_where_clause
 		{
 			#(
+				#(#storage_cfg_attrs)*
 				type #storage_names = #storage_names<#type_use_gen>;
 			)*
 		}
diff --git a/frame/support/procedural/src/pallet/parse/call.rs b/frame/support/procedural/src/pallet/parse/call.rs
index c3f6751ef70b6..23406aeb23431 100644
--- a/frame/support/procedural/src/pallet/parse/call.rs
+++ b/frame/support/procedural/src/pallet/parse/call.rs
@@ -172,7 +172,7 @@ impl CallDef {
 				}
 
 				let mut call_var_attrs: Vec<FunctionAttr> =
-					helper::take_item_attrs(&mut method.attrs)?;
+					helper::take_item_pallet_attrs(&mut method.attrs)?;
 
 				if call_var_attrs.len() != 1 {
 					let msg = if call_var_attrs.is_empty() {
@@ -193,7 +193,7 @@ impl CallDef {
 					};
 
 					let arg_attrs: Vec<ArgAttrIsCompact> =
-						helper::take_item_attrs(&mut arg.attrs)?;
+						helper::take_item_pallet_attrs(&mut arg.attrs)?;
 
 					if arg_attrs.len() > 1 {
 						let msg = "Invalid pallet::call, argument has too many attributes";
diff --git a/frame/support/procedural/src/pallet/parse/config.rs b/frame/support/procedural/src/pallet/parse/config.rs
index 44525164f03d5..045f2bff50e45 100644
--- a/frame/support/procedural/src/pallet/parse/config.rs
+++ b/frame/support/procedural/src/pallet/parse/config.rs
@@ -309,7 +309,7 @@ impl ConfigDef {
 				|| check_event_type(frame_system, trait_item, has_instance)?;
 
 			// Parse for constant
-			let type_attrs_const: Vec<TypeAttrConst> = helper::take_item_attrs(trait_item)?;
+			let type_attrs_const: Vec<TypeAttrConst> = helper::take_item_pallet_attrs(trait_item)?;
 
 			if type_attrs_const.len() > 1 {
 				let msg = "Invalid attribute in pallet::config, only one attribute is expected";
@@ -339,7 +339,7 @@ impl ConfigDef {
 			}
 		}
 
-		let attr: Option<DisableFrameSystemSupertraitCheck> = helper::take_first_item_attr(
+		let attr: Option<DisableFrameSystemSupertraitCheck> = helper::take_first_item_pallet_attr(
 			&mut item.attrs
 		)?;
 
diff --git a/frame/support/procedural/src/pallet/parse/event.rs b/frame/support/procedural/src/pallet/parse/event.rs
index 7d8b7d075ef23..e5aad2b5b5d2c 100644
--- a/frame/support/procedural/src/pallet/parse/event.rs
+++ b/frame/support/procedural/src/pallet/parse/event.rs
@@ -163,7 +163,7 @@ impl EventDef {
 			return Err(syn::Error::new(item.span(), "Invalid pallet::event, expected item enum"))
 		};
 
-		let event_attrs: Vec<PalletEventAttr> = helper::take_item_attrs(&mut item.attrs)?;
+		let event_attrs: Vec<PalletEventAttr> = helper::take_item_pallet_attrs(&mut item.attrs)?;
 		let attr_info = PalletEventAttrInfo::from_attrs(event_attrs)?;
 		let metadata = attr_info.metadata.unwrap_or_else(Vec::new);
 		let deposit_event = attr_info.deposit_event;
diff --git a/frame/support/procedural/src/pallet/parse/helper.rs b/frame/support/procedural/src/pallet/parse/helper.rs
index b6ee5c614d6f6..3a7729c47e1d7 100644
--- a/frame/support/procedural/src/pallet/parse/helper.rs
+++ b/frame/support/procedural/src/pallet/parse/helper.rs
@@ -47,7 +47,7 @@ pub trait MutItemAttrs {
 }
 
 /// Take the first pallet attribute (e.g. attribute like `#[pallet..]`) and decode it to `Attr`
-pub fn take_first_item_attr<Attr>(item: &mut impl MutItemAttrs) -> syn::Result<Option<Attr>> where
+pub fn take_first_item_pallet_attr<Attr>(item: &mut impl MutItemAttrs) -> syn::Result<Option<Attr>> where
 	Attr: syn::parse::Parse,
 {
 	let attrs = if let Some(attrs) = item.mut_item_attrs() {
@@ -69,18 +69,29 @@ pub fn take_first_item_attr<Attr>(item: &mut impl MutItemAttrs) -> syn::Result<O
 }
 
 /// Take all the pallet attributes (e.g. attribute like `#[pallet..]`) and decode them to `Attr`
-pub fn take_item_attrs<Attr>(item: &mut impl MutItemAttrs) -> syn::Result<Vec<Attr>> where
+pub fn take_item_pallet_attrs<Attr>(item: &mut impl MutItemAttrs) -> syn::Result<Vec<Attr>> where
 	Attr: syn::parse::Parse,
 {
 	let mut pallet_attrs = Vec::new();
 
-	while let Some(attr) = take_first_item_attr(item)? {
+	while let Some(attr) = take_first_item_pallet_attr(item)? {
 		pallet_attrs.push(attr)
 	}
 
 	Ok(pallet_attrs)
 }
 
+/// Get all the cfg attributes (e.g. attribute like `#[cfg..]`) and decode them to `Attr`
+pub fn get_item_cfg_attrs(attrs: &[syn::Attribute]) -> Vec<syn::Attribute> {
+	attrs.iter().filter_map(|attr|  {
+		if attr.path.segments.first().map_or(false, |segment| segment.ident == "cfg") {
+			Some(attr.clone())
+		} else {
+			None
+		}
+	}).collect::<Vec<_>>()
+}
+
 impl MutItemAttrs for syn::Item {
 	fn mut_item_attrs(&mut self) -> Option<&mut Vec<syn::Attribute>> {
 		match self {
diff --git a/frame/support/procedural/src/pallet/parse/mod.rs b/frame/support/procedural/src/pallet/parse/mod.rs
index 4d8f239ded0af..39a40fc148bcd 100644
--- a/frame/support/procedural/src/pallet/parse/mod.rs
+++ b/frame/support/procedural/src/pallet/parse/mod.rs
@@ -89,7 +89,7 @@ impl Def {
 		let mut type_values = vec![];
 
 		for (index, item) in items.iter_mut().enumerate() {
-			let pallet_attr: Option<PalletAttr> = helper::take_first_item_attr(item)?;
+			let pallet_attr: Option<PalletAttr> = helper::take_first_item_pallet_attr(item)?;
 
 			match pallet_attr {
 				Some(PalletAttr::Config(span)) if config.is_none() =>
diff --git a/frame/support/procedural/src/pallet/parse/pallet_struct.rs b/frame/support/procedural/src/pallet/parse/pallet_struct.rs
index 1c979741d9803..6c2c90bd61a5f 100644
--- a/frame/support/procedural/src/pallet/parse/pallet_struct.rs
+++ b/frame/support/procedural/src/pallet/parse/pallet_struct.rs
@@ -78,7 +78,7 @@ impl PalletStructDef {
 			return Err(syn::Error::new(item.span(), msg));
 		};
 
-		let mut event_attrs: Vec<PalletStructAttr> = helper::take_item_attrs(&mut item.attrs)?;
+		let mut event_attrs: Vec<PalletStructAttr> = helper::take_item_pallet_attrs(&mut item.attrs)?;
 		if event_attrs.len() > 1 {
 			let msg = "Invalid pallet::pallet, multiple argument pallet::generate_store found";
 			return Err(syn::Error::new(event_attrs[1].keyword.span(), msg));
diff --git a/frame/support/procedural/src/pallet/parse/storage.rs b/frame/support/procedural/src/pallet/parse/storage.rs
index c0da266cfca2b..41ef337b76615 100644
--- a/frame/support/procedural/src/pallet/parse/storage.rs
+++ b/frame/support/procedural/src/pallet/parse/storage.rs
@@ -91,6 +91,8 @@ pub struct StorageDef {
 	pub where_clause: Option<syn::WhereClause>,
 	/// The span of the pallet::storage attribute.
 	pub attr_span: proc_macro2::Span,
+	/// The `cfg` attributes.
+	pub cfg_attrs: Vec<syn::Attribute>,
 }
 
 /// In `Foo<A, B, C>` retrieve the argument at given position, i.e. A is argument at position 0.
@@ -125,13 +127,15 @@ impl StorageDef {
 			return Err(syn::Error::new(item.span(), "Invalid pallet::storage, expected item type"));
 		};
 
-		let mut attrs: Vec<PalletStorageAttr> = helper::take_item_attrs(&mut item.attrs)?;
+		let mut attrs: Vec<PalletStorageAttr> = helper::take_item_pallet_attrs(&mut item.attrs)?;
 		if attrs.len() > 1 {
 			let msg = "Invalid pallet::storage, multiple argument pallet::getter found";
 			return Err(syn::Error::new(attrs[1].getter.span(), msg));
 		}
 		let getter = attrs.pop().map(|attr| attr.getter);
 
+		let cfg_attrs = helper::get_item_cfg_attrs(&item.attrs);
+
 		let mut instances = vec![];
 		instances.push(helper::check_type_def_gen(&item.generics, item.ident.span())?);
 
@@ -223,6 +227,7 @@ impl StorageDef {
 			getter,
 			query_kind,
 			where_clause,
+			cfg_attrs,
 		})
 	}
 }
diff --git a/frame/support/src/dispatch.rs b/frame/support/src/dispatch.rs
index 64b7b7a8e2180..d6f133a8d20a3 100644
--- a/frame/support/src/dispatch.rs
+++ b/frame/support/src/dispatch.rs
@@ -1375,11 +1375,11 @@ macro_rules! decl_module {
 		impl<$trait_instance: $trait_name$(<I>, $instance: $instantiable)?> $module<$trait_instance $(, $instance)?>
 			where $( $other_where_bounds )*
 		{
-			/// Deposits an event using `frame_system::Module::deposit_event`.
+			/// Deposits an event using `frame_system::Pallet::deposit_event`.
 			$vis fn deposit_event(
 				event: impl Into<< $trait_instance as $trait_name $(<$instance>)? >::Event>
 			) {
-				<$system::Module<$trait_instance>>::deposit_event(event.into())
+				<$system::Pallet<$trait_instance>>::deposit_event(event.into())
 			}
 		}
 	};
@@ -1859,6 +1859,11 @@ macro_rules! decl_module {
 		>($crate::sp_std::marker::PhantomData<($trait_instance, $( $instance)?)>) where
 			$( $other_where_bounds )*;
 
+		/// Type alias to `Module`, to be used by `construct_runtime`.
+		#[allow(dead_code)]
+		pub type Pallet<$trait_instance $(, $instance $( = $module_default_instance)?)?>
+			= $mod_type<$trait_instance $(, $instance)?>;
+
 		$crate::decl_module! {
 			@impl_on_initialize
 			{ $system }
@@ -1962,23 +1967,23 @@ macro_rules! decl_module {
 				match *self {
 					$(
 						$call_type::$fn_name( $( ref $param_name ),* ) => {
-							let base_weight = $weight;
-							let weight = <dyn $crate::dispatch::WeighData<( $( & $param, )* )>>::weigh_data(
-								&base_weight,
+							let __pallet_base_weight = $weight;
+							let __pallet_weight = <dyn $crate::dispatch::WeighData<( $( & $param, )* )>>::weigh_data(
+								&__pallet_base_weight,
 								($( $param_name, )*)
 							);
-							let class = <dyn $crate::dispatch::ClassifyDispatch<( $( & $param, )* )>>::classify_dispatch(
-								&base_weight,
+							let __pallet_class = <dyn $crate::dispatch::ClassifyDispatch<( $( & $param, )* )>>::classify_dispatch(
+								&__pallet_base_weight,
 								($( $param_name, )*)
 							);
-							let pays_fee = <dyn $crate::dispatch::PaysFee<( $( & $param, )* )>>::pays_fee(
-								&base_weight,
+							let __pallet_pays_fee = <dyn $crate::dispatch::PaysFee<( $( & $param, )* )>>::pays_fee(
+								&__pallet_base_weight,
 								($( $param_name, )*)
 							);
 							$crate::dispatch::DispatchInfo {
-								weight,
-								class,
-								pays_fee,
+								weight: __pallet_weight,
+								class: __pallet_class,
+								pays_fee: __pallet_pays_fee,
 							}
 						},
 					)*
diff --git a/frame/support/src/genesis_config.rs b/frame/support/src/genesis_config.rs
index 8f915082e8bb0..3f7f943603e42 100644
--- a/frame/support/src/genesis_config.rs
+++ b/frame/support/src/genesis_config.rs
@@ -56,7 +56,7 @@ macro_rules! __impl_outer_config_types {
 /// specific genesis configuration.
 ///
 /// ```ignore
-/// pub struct GenesisConfig for Runtime where AllModulesWithSystem = AllModulesWithSystem {
+/// pub struct GenesisConfig for Runtime where AllPalletsWithSystem = AllPalletsWithSystem {
 /// 	rust_module_one: Option<ModuleOneConfig>,
 /// 	...
 /// }
@@ -65,7 +65,7 @@ macro_rules! __impl_outer_config_types {
 macro_rules! impl_outer_config {
 	(
 		pub struct $main:ident for $concrete:ident where
-			AllModulesWithSystem = $all_modules_with_system:ident
+			AllPalletsWithSystem = $all_pallets_with_system:ident
 		{
 			$( $config:ident =>
 				$snake:ident $( $instance:ident )? $( <$generic:ident> )*, )*
@@ -103,7 +103,7 @@ macro_rules! impl_outer_config {
 					)*
 
 					$crate::BasicExternalities::execute_with_storage(storage, || {
-						<$all_modules_with_system as $crate::traits::OnGenesis>::on_genesis();
+						<$all_pallets_with_system as $crate::traits::OnGenesis>::on_genesis();
 					});
 
 					Ok(())
diff --git a/frame/support/src/lib.rs b/frame/support/src/lib.rs
index a06fd7a1d9b92..362c4c5a0a73b 100644
--- a/frame/support/src/lib.rs
+++ b/frame/support/src/lib.rs
@@ -87,6 +87,124 @@ pub const LOG_TARGET: &'static str = "runtime::frame-support";
 #[derive(Debug, PartialEq, Eq, Clone)]
 pub enum Never {}
 
+/// Generate a new type alias for [`storage::types::value::StorageValue`],
+/// [`storage::types::value::StorageMap`] and [`storage::types::value::StorageDoubleMap`].
+///
+/// Useful for creating a *storage-like* struct for test and migrations.
+///
+///```
+/// # use frame_support::generate_storage_alias;
+/// use frame_support::codec;
+/// use frame_support::Twox64Concat;
+/// // generate a storage value with type u32.
+/// generate_storage_alias!(Prefix, StorageName => Value<u32>);
+///
+/// // generate a double map from `(u32, u32)` (with hasher `Twox64Concat`) to `Vec<u8>`
+/// generate_storage_alias!(
+///		OtherPrefix, OtherStorageName => DoubleMap<
+/// 		(u32, u32),
+/// 		(u32, u32),
+/// 		Vec<u8>
+///		>
+/// );
+///
+/// // generate a map from `Config::AccountId` (with hasher `Twox64Concat`) to `Vec<u8>`
+/// trait Config { type AccountId: codec::FullCodec; }
+/// generate_storage_alias!(
+///		Prefix, GenericStorage<T: Config> => Map<(Twox64Concat, T::AccountId), Vec<u8>>
+/// );
+/// # fn main() {}
+///```
+#[macro_export]
+macro_rules! generate_storage_alias {
+	// without generic for $name.
+	($pallet:ident, $name:ident => Map<($key:ty, $hasher:ty), $value:ty>) => {
+		$crate::paste::paste! {
+			$crate::generate_storage_alias!(@GENERATE_INSTANCE_STRUCT $pallet, $name);
+			type $name = $crate::storage::types::StorageMap<
+				[<$name Instance>],
+				$hasher,
+				$key,
+				$value,
+			>;
+		}
+	};
+	($pallet:ident, $name:ident => DoubleMap<($key1:ty, $hasher1:ty), ($key2:ty, $hasher2:ty), $value:ty>) => {
+		$crate::paste::paste! {
+			$crate::generate_storage_alias!(@GENERATE_INSTANCE_STRUCT $pallet, $name);
+			type $name = $crate::storage::types::StorageMap<
+				[<$name Instance>],
+				$hasher1,
+				$key1,
+				$hasher2,
+				$key2,
+				$value,
+			>;
+		}
+	};
+	($pallet:ident, $name:ident => Value<$value:ty>) => {
+		$crate::paste::paste! {
+			$crate::generate_storage_alias!(@GENERATE_INSTANCE_STRUCT $pallet, $name);
+			type $name = $crate::storage::types::StorageValue<
+				[<$name Instance>],
+				$value,
+			>;
+		}
+	};
+	// with generic for $name.
+	($pallet:ident, $name:ident<$t:ident : $bounds:tt> => Map<($key:ty, $hasher:ty), $value:ty>) => {
+		$crate::paste::paste! {
+			$crate::generate_storage_alias!(@GENERATE_INSTANCE_STRUCT $pallet, $name);
+			#[allow(type_alias_bounds)]
+			type $name<$t : $bounds> = $crate::storage::types::StorageMap<
+				[<$name Instance>],
+				$key,
+				$hasher,
+				$value,
+			>;
+		}
+	};
+	(
+		$pallet:ident,
+		$name:ident<$t:ident : $bounds:tt>
+		=> DoubleMap<($key1:ty, $hasher1:ty), ($key2:ty, $hasher2:ty), $value:ty>)
+	=> {
+		$crate::paste::paste! {
+			$crate::generate_storage_alias!(@GENERATE_INSTANCE_STRUCT $pallet, $name);
+			#[allow(type_alias_bounds)]
+			type $name<$t : $bounds> = $crate::storage::types::StorageMap<
+				[<$name Instance>],
+				$key1,
+				$hasher1,
+				$key2,
+				$hasher2,
+				$value,
+			>;
+		}
+	};
+	($pallet:ident, $name:ident<$t:ident : $bounds:tt> => Value<$value:ty>) => {
+		$crate::paste::paste! {
+			$crate::generate_storage_alias!(@GENERATE_INSTANCE_STRUCT $pallet, $name);
+			#[allow(type_alias_bounds)]
+			type $name<$t : $bounds> = $crate::storage::types::StorageValue<
+				[<$name Instance>],
+				$value,
+				$crate::storage::types::ValueQuery,
+			>;
+		}
+	};
+	// helper used in all arms.
+	(@GENERATE_INSTANCE_STRUCT $pallet:ident, $name:ident) => {
+		$crate::paste::paste! {
+			struct [<$name Instance>];
+			impl $crate::traits::StorageInstance for [<$name Instance>] {
+				fn pallet_prefix() -> &'static str { stringify!($pallet) }
+				const STORAGE_PREFIX: &'static str = stringify!($name);
+			}
+		}
+	}
+}
+
 /// Create new implementations of the [`Get`](crate::traits::Get) trait.
 ///
 /// The so-called parameter type can be created in four different ways:
@@ -1229,6 +1347,9 @@ pub mod pallet_prelude {
 /// NOTE: OnRuntimeUpgrade is implemented with `Hooks::on_runtime_upgrade` and some additional
 /// logic. E.g. logic to write pallet version into storage.
 ///
+/// NOTE: The macro also adds some tracing logic when implementing the above traits. The following
+///  hooks emit traces: `on_initialize`, `on_finalize` and `on_runtime_upgrade`.
+///
 /// # Call: `#[pallet::call]` mandatory
 ///
 /// Implementation of pallet dispatchables.
@@ -1418,6 +1539,18 @@ pub mod pallet_prelude {
 /// pub(super) type MyStorage<T> = StorageMap<_, Blake2_128Concat, u32, u32>;
 /// ```
 ///
+/// The optional attributes `#[cfg(..)]` allow conditional compilation for the storage.
+///
+/// E.g:
+/// ```ignore
+/// #[cfg(feature = "my-feature")]
+/// #[pallet::storage]
+/// pub(super) type MyStorage<T> = StorageValue<_, u32>;
+/// ```
+///
+/// All the `cfg` attributes are automatically copied to the items generated for the storage, i.e. the
+/// getter, storage prefix, and the metadata element etc.
+///
 /// NOTE: If the `QueryKind` generic parameter is still generic at this stage or is using some type
 /// alias then the generation of the getter might fail. In this case the getter can be implemented
 /// manually.
diff --git a/frame/support/src/metadata.rs b/frame/support/src/metadata.rs
index 2edaba1cb47e9..d0c59a0dfdc1d 100644
--- a/frame/support/src/metadata.rs
+++ b/frame/support/src/metadata.rs
@@ -58,7 +58,7 @@ pub use frame_metadata::{
 ///
 /// struct Runtime;
 /// frame_support::impl_runtime_metadata! {
-///     for Runtime with modules where Extrinsic = UncheckedExtrinsic
+///     for Runtime with pallets where Extrinsic = UncheckedExtrinsic
 ///         module0::Module as Module0 { index 0 } with,
 ///         module1::Module as Module1 { index 1 } with,
 ///         module2::Module as Module2 { index 2 } with Storage,
@@ -69,7 +69,7 @@ pub use frame_metadata::{
 #[macro_export]
 macro_rules! impl_runtime_metadata {
 	(
-		for $runtime:ident with modules where Extrinsic = $ext:ident
+		for $runtime:ident with pallets where Extrinsic = $ext:ident
 			$( $rest:tt )*
 	) => {
 		impl $runtime {
@@ -421,7 +421,7 @@ mod tests {
 	impl crate::traits::PalletInfo for TestRuntime {
 		fn index<P: 'static>() -> Option<usize> {
 			let type_id = sp_std::any::TypeId::of::<P>();
-			if type_id == sp_std::any::TypeId::of::<system::Module<TestRuntime>>() {
+			if type_id == sp_std::any::TypeId::of::<system::Pallet<TestRuntime>>() {
 				return Some(0)
 			}
 			if type_id == sp_std::any::TypeId::of::<EventModule>() {
@@ -435,7 +435,7 @@ mod tests {
 		}
 		fn name<P: 'static>() -> Option<&'static str> {
 			let type_id = sp_std::any::TypeId::of::<P>();
-			if type_id == sp_std::any::TypeId::of::<system::Module<TestRuntime>>() {
+			if type_id == sp_std::any::TypeId::of::<system::Pallet<TestRuntime>>() {
 				return Some("System")
 			}
 			if type_id == sp_std::any::TypeId::of::<EventModule>() {
@@ -492,8 +492,8 @@ mod tests {
 	}
 
 	impl_runtime_metadata!(
-		for TestRuntime with modules where Extrinsic = TestExtrinsic
-			system::Module as System { index 0 } with Event,
+		for TestRuntime with pallets where Extrinsic = TestExtrinsic
+			system::Pallet as System { index 0 } with Event,
 			event_module::Module as Module { index 1 } with Event Call,
 			event_module2::Module as Module2 { index 2 } with Event Storage Call,
 	);
diff --git a/frame/support/src/storage/generator/mod.rs b/frame/support/src/storage/generator/mod.rs
index fc2a21ff72517..86eafe86f43f4 100644
--- a/frame/support/src/storage/generator/mod.rs
+++ b/frame/support/src/storage/generator/mod.rs
@@ -80,7 +80,8 @@ mod tests {
 			let translate_fn = |old: Option<u32>| -> Option<(u64, u64)> {
 				old.map(|o| (o.into(), (o*2).into()))
 			};
-			let _ = Value::translate(translate_fn);
+			let res = Value::translate(translate_fn);
+			debug_assert!(res.is_ok());
 
 			// new storage should be `(1111, 1111 * 2)`
 			assert_eq!(Value::get(), (1111, 2222));
diff --git a/frame/support/src/traits.rs b/frame/support/src/traits.rs
index 286c545d30d90..ba4869d4b8718 100644
--- a/frame/support/src/traits.rs
+++ b/frame/support/src/traits.rs
@@ -15,2331 +15,64 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//! Traits for FRAME.
+//! Traits and associated utilities for use in the FRAME environment.
 //!
 //! NOTE: If you're looking for `parameter_types`, it has moved in to the top-level module.
 
-use sp_std::{prelude::*, result, marker::PhantomData, ops::Div, fmt::Debug};
-use codec::{FullCodec, Codec, Encode, Decode, EncodeLike};
-use sp_core::u32_trait::Value as U32;
-use sp_runtime::{
-	traits::{
-		AtLeast32Bit, AtLeast32BitUnsigned, Block as BlockT, BadOrigin, Convert,
-		MaybeSerializeDeserialize, SaturatedConversion, Saturating, StoredMapError,
-		UniqueSaturatedFrom, UniqueSaturatedInto, Zero,
-	},
-	BoundToRuntimeAppPublic, ConsensusEngineId, DispatchError, DispatchResult, Percent,
-	RuntimeAppPublic, RuntimeDebug,
+pub mod tokens;
+pub use tokens::fungible;
+pub use tokens::fungibles;
+pub use tokens::currency::{
+	Currency, LockIdentifier, LockableCurrency, ReservableCurrency, VestingSchedule,
 };
-use sp_staking::SessionIndex;
-use crate::dispatch::Parameter;
-use crate::storage::StorageMap;
-use crate::weights::Weight;
-use bitflags::bitflags;
-use impl_trait_for_tuples::impl_for_tuples;
+pub use tokens::imbalance::{Imbalance, OnUnbalanced, SignedImbalance};
+pub use tokens::{ExistenceRequirement, WithdrawReasons, BalanceStatus};
 
-/// Re-expected for the macro.
-#[doc(hidden)]
-pub use sp_std::{mem::{swap, take}, cell::RefCell, vec::Vec, boxed::Box};
+mod members;
+pub use members::{Contains, ContainsLengthBound, InitializeMembers, ChangeMembers};
 
-/// A trait for online node inspection in a session.
-///
-/// Something that can give information about the current validator set.
-pub trait ValidatorSet<AccountId> {
-	/// Type for representing validator id in a session.
-	type ValidatorId: Parameter;
-	/// A type for converting `AccountId` to `ValidatorId`.
-	type ValidatorIdOf: Convert<AccountId, Option<Self::ValidatorId>>;
-
-	/// Returns current session index.
-	fn session_index() -> SessionIndex;
-
-	/// Returns the active set of validators.
-	fn validators() -> Vec<Self::ValidatorId>;
-}
-
-/// [`ValidatorSet`] combined with an identification.
-pub trait ValidatorSetWithIdentification<AccountId>: ValidatorSet<AccountId> {
-	/// Full identification of `ValidatorId`.
-	type Identification: Parameter;
-	/// A type for converting `ValidatorId` to `Identification`.
-	type IdentificationOf: Convert<Self::ValidatorId, Option<Self::Identification>>;
-}
-
-/// A session handler for specific key type.
-pub trait OneSessionHandler<ValidatorId>: BoundToRuntimeAppPublic {
-	/// The key type expected.
-	type Key: Decode + Default + RuntimeAppPublic;
-
-	/// The given validator set will be used for the genesis session.
-	/// It is guaranteed that the given validator set will also be used
-	/// for the second session, therefore the first call to `on_new_session`
-	/// should provide the same validator set.
-	fn on_genesis_session<'a, I: 'a>(validators: I)
-		where I: Iterator<Item=(&'a ValidatorId, Self::Key)>, ValidatorId: 'a;
-
-	/// Session set has changed; act appropriately. Note that this can be called
-	/// before initialization of your module.
-	///
-	/// `changed` is true when at least one of the session keys
-	/// or the underlying economic identities/distribution behind one the
-	/// session keys has changed, false otherwise.
-	///
-	/// The `validators` are the validators of the incoming session, and `queued_validators`
-	/// will follow.
-	fn on_new_session<'a, I: 'a>(
-		changed: bool,
-		validators: I,
-		queued_validators: I,
-	) where I: Iterator<Item=(&'a ValidatorId, Self::Key)>, ValidatorId: 'a;
-
-	/// A notification for end of the session.
-	///
-	/// Note it is triggered before any `SessionManager::end_session` handlers,
-	/// so we can still affect the validator set.
-	fn on_before_session_ending() {}
-
-	/// A validator got disabled. Act accordingly until a new session begins.
-	fn on_disabled(_validator_index: usize);
-}
-
-/// Simple trait for providing a filter over a reference to some type.
-pub trait Filter<T> {
-	/// Determine if a given value should be allowed through the filter (returns `true`) or not.
-	fn filter(_: &T) -> bool;
-}
-
-impl<T> Filter<T> for () {
-	fn filter(_: &T) -> bool { true }
-}
-
-/// Trait to add a constraint onto the filter.
-pub trait FilterStack<T>: Filter<T> {
-	/// The type used to archive the stack.
-	type Stack;
-
-	/// Add a new `constraint` onto the filter.
-	fn push(constraint: impl Fn(&T) -> bool + 'static);
-
-	/// Removes the most recently pushed, and not-yet-popped, constraint from the filter.
-	fn pop();
-
-	/// Clear the filter, returning a value that may be used later to `restore` it.
-	fn take() -> Self::Stack;
-
-	/// Restore the filter from a previous `take` operation.
-	fn restore(taken: Self::Stack);
-}
-
-/// Guard type for pushing a constraint to a `FilterStack` and popping when dropped.
-pub struct FilterStackGuard<F: FilterStack<T>, T>(PhantomData<(F, T)>);
-
-/// Guard type for clearing all pushed constraints from a `FilterStack` and reinstating them when
-/// dropped.
-pub struct ClearFilterGuard<F: FilterStack<T>, T>(Option<F::Stack>, PhantomData<T>);
-
-impl<F: FilterStack<T>, T> FilterStackGuard<F, T> {
-	/// Create a new instance, adding a new `constraint` onto the filter `T`, and popping it when
-	/// this instance is dropped.
-	pub fn new(constraint: impl Fn(&T) -> bool + 'static) -> Self {
-		F::push(constraint);
-		Self(PhantomData)
-	}
-}
-
-impl<F: FilterStack<T>, T> Drop for FilterStackGuard<F, T> {
-	fn drop(&mut self) {
-		F::pop();
-	}
-}
-
-impl<F: FilterStack<T>, T> ClearFilterGuard<F, T> {
-	/// Create a new instance, adding a new `constraint` onto the filter `T`, and popping it when
-	/// this instance is dropped.
-	pub fn new() -> Self {
-		Self(Some(F::take()), PhantomData)
-	}
-}
-
-impl<F: FilterStack<T>, T> Drop for ClearFilterGuard<F, T> {
-	fn drop(&mut self) {
-		if let Some(taken) = self.0.take() {
-			F::restore(taken);
-		}
-	}
-}
-
-/// Simple trait for providing a filter over a reference to some type, given an instance of itself.
-pub trait InstanceFilter<T>: Sized + Send + Sync {
-	/// Determine if a given value should be allowed through the filter (returns `true`) or not.
-	fn filter(&self, _: &T) -> bool;
-
-	/// Determines whether `self` matches at least everything that `_o` does.
-	fn is_superset(&self, _o: &Self) -> bool { false }
-}
-
-impl<T> InstanceFilter<T> for () {
-	fn filter(&self, _: &T) -> bool { true }
-	fn is_superset(&self, _o: &Self) -> bool { true }
-}
-
-#[macro_export]
-macro_rules! impl_filter_stack {
-	($target:ty, $base:ty, $call:ty, $module:ident) => {
-		#[cfg(feature = "std")]
-		mod $module {
-			#[allow(unused_imports)]
-			use super::*;
-			use $crate::traits::{swap, take, RefCell, Vec, Box, Filter, FilterStack};
-
-			thread_local! {
-				static FILTER: RefCell<Vec<Box<dyn Fn(&$call) -> bool + 'static>>> = RefCell::new(Vec::new());
-			}
-
-			impl Filter<$call> for $target {
-				fn filter(call: &$call) -> bool {
-					<$base>::filter(call) &&
-						FILTER.with(|filter| filter.borrow().iter().all(|f| f(call)))
-				}
-			}
-
-			impl FilterStack<$call> for $target {
-				type Stack = Vec<Box<dyn Fn(&$call) -> bool + 'static>>;
-				fn push(f: impl Fn(&$call) -> bool + 'static) {
-					FILTER.with(|filter| filter.borrow_mut().push(Box::new(f)));
-				}
-				fn pop() {
-					FILTER.with(|filter| filter.borrow_mut().pop());
-				}
-				fn take() -> Self::Stack {
-					FILTER.with(|filter| take(filter.borrow_mut().as_mut()))
-				}
-				fn restore(mut s: Self::Stack) {
-					FILTER.with(|filter| swap(filter.borrow_mut().as_mut(), &mut s));
-				}
-			}
-		}
-
-		#[cfg(not(feature = "std"))]
-		mod $module {
-			#[allow(unused_imports)]
-			use super::*;
-			use $crate::traits::{swap, take, RefCell, Vec, Box, Filter, FilterStack};
-
-			struct ThisFilter(RefCell<Vec<Box<dyn Fn(&$call) -> bool + 'static>>>);
-			// NOTE: Safe only in wasm (guarded above) because there's only one thread.
-			unsafe impl Send for ThisFilter {}
-			unsafe impl Sync for ThisFilter {}
-
-			static FILTER: ThisFilter = ThisFilter(RefCell::new(Vec::new()));
-
-			impl Filter<$call> for $target {
-				fn filter(call: &$call) -> bool {
-					<$base>::filter(call) && FILTER.0.borrow().iter().all(|f| f(call))
-				}
-			}
-
-			impl FilterStack<$call> for $target {
-				type Stack = Vec<Box<dyn Fn(&$call) -> bool + 'static>>;
-				fn push(f: impl Fn(&$call) -> bool + 'static) {
-					FILTER.0.borrow_mut().push(Box::new(f));
-				}
-				fn pop() {
-					FILTER.0.borrow_mut().pop();
-				}
-				fn take() -> Self::Stack {
-					take(FILTER.0.borrow_mut().as_mut())
-				}
-				fn restore(mut s: Self::Stack) {
-					swap(FILTER.0.borrow_mut().as_mut(), &mut s);
-				}
-			}
-		}
-	}
-}
-
-/// Type that provide some integrity tests.
-///
-/// This implemented for modules by `decl_module`.
-#[impl_for_tuples(30)]
-pub trait IntegrityTest {
-	/// Run integrity test.
-	///
-	/// The test is not executed in a externalities provided environment.
-	fn integrity_test() {}
-}
-
-#[cfg(test)]
-mod test_impl_filter_stack {
-	use super::*;
-
-	pub struct IsCallable;
-	pub struct BaseFilter;
-	impl Filter<u32> for BaseFilter {
-		fn filter(x: &u32) -> bool { x % 2 == 0 }
-	}
-	impl_filter_stack!(
-		crate::traits::test_impl_filter_stack::IsCallable,
-		crate::traits::test_impl_filter_stack::BaseFilter,
-		u32,
-		is_callable
-	);
-
-	#[test]
-	fn impl_filter_stack_should_work() {
-		assert!(IsCallable::filter(&36));
-		assert!(IsCallable::filter(&40));
-		assert!(IsCallable::filter(&42));
-		assert!(!IsCallable::filter(&43));
-
-		IsCallable::push(|x| *x < 42);
-		assert!(IsCallable::filter(&36));
-		assert!(IsCallable::filter(&40));
-		assert!(!IsCallable::filter(&42));
-
-		IsCallable::push(|x| *x % 3 == 0);
-		assert!(IsCallable::filter(&36));
-		assert!(!IsCallable::filter(&40));
-
-		IsCallable::pop();
-		assert!(IsCallable::filter(&36));
-		assert!(IsCallable::filter(&40));
-		assert!(!IsCallable::filter(&42));
-
-		let saved = IsCallable::take();
-		assert!(IsCallable::filter(&36));
-		assert!(IsCallable::filter(&40));
-		assert!(IsCallable::filter(&42));
-		assert!(!IsCallable::filter(&43));
-
-		IsCallable::restore(saved);
-		assert!(IsCallable::filter(&36));
-		assert!(IsCallable::filter(&40));
-		assert!(!IsCallable::filter(&42));
-
-		IsCallable::pop();
-		assert!(IsCallable::filter(&36));
-		assert!(IsCallable::filter(&40));
-		assert!(IsCallable::filter(&42));
-		assert!(!IsCallable::filter(&43));
-	}
-
-	#[test]
-	fn guards_should_work() {
-		assert!(IsCallable::filter(&36));
-		assert!(IsCallable::filter(&40));
-		assert!(IsCallable::filter(&42));
-		assert!(!IsCallable::filter(&43));
-		{
-			let _guard_1 = FilterStackGuard::<IsCallable, u32>::new(|x| *x < 42);
-			assert!(IsCallable::filter(&36));
-			assert!(IsCallable::filter(&40));
-			assert!(!IsCallable::filter(&42));
-			{
-				let _guard_2 = FilterStackGuard::<IsCallable, u32>::new(|x| *x % 3 == 0);
-				assert!(IsCallable::filter(&36));
-				assert!(!IsCallable::filter(&40));
-			}
-			assert!(IsCallable::filter(&36));
-			assert!(IsCallable::filter(&40));
-			assert!(!IsCallable::filter(&42));
-			{
-				let _guard_2 = ClearFilterGuard::<IsCallable, u32>::new();
-				assert!(IsCallable::filter(&36));
-				assert!(IsCallable::filter(&40));
-				assert!(IsCallable::filter(&42));
-				assert!(!IsCallable::filter(&43));
-			}
-			assert!(IsCallable::filter(&36));
-			assert!(IsCallable::filter(&40));
-			assert!(!IsCallable::filter(&42));
-		}
-		assert!(IsCallable::filter(&36));
-		assert!(IsCallable::filter(&40));
-		assert!(IsCallable::filter(&42));
-		assert!(!IsCallable::filter(&43));
-	}
-}
-
-/// An abstraction of a value stored within storage, but possibly as part of a larger composite
-/// item.
-pub trait StoredMap<K, T: Default> {
-	/// Get the item, or its default if it doesn't yet exist; we make no distinction between the
-	/// two.
-	fn get(k: &K) -> T;
-
-	/// Maybe mutate the item only if an `Ok` value is returned from `f`. Do nothing if an `Err` is
-	/// returned. It is removed or reset to default value if it has been mutated to `None`
-	fn try_mutate_exists<R, E: From<StoredMapError>>(
-		k: &K,
-		f: impl FnOnce(&mut Option<T>) -> Result<R, E>,
-	) -> Result<R, E>;
-
-	// Everything past here has a default implementation.
-
-	/// Mutate the item.
-	fn mutate<R>(k: &K, f: impl FnOnce(&mut T) -> R) -> Result<R, StoredMapError> {
-		Self::mutate_exists(k, |maybe_account| match maybe_account {
-			Some(ref mut account) => f(account),
-			x @ None => {
-				let mut account = Default::default();
-				let r = f(&mut account);
-				*x = Some(account);
-				r
-			}
-		})
-	}
-
-	/// Mutate the item, removing or resetting to default value if it has been mutated to `None`.
-	///
-	/// This is infallible as long as the value does not get destroyed.
-	fn mutate_exists<R>(
-		k: &K,
-		f: impl FnOnce(&mut Option<T>) -> R,
-	) -> Result<R, StoredMapError> {
-		Self::try_mutate_exists(k, |x| -> Result<R, StoredMapError> { Ok(f(x)) })
-	}
-
-	/// Set the item to something new.
-	fn insert(k: &K, t: T) -> Result<(), StoredMapError> { Self::mutate(k, |i| *i = t) }
-
-	/// Remove the item or otherwise replace it with its default value; we don't care which.
-	fn remove(k: &K) -> Result<(), StoredMapError> { Self::mutate_exists(k, |x| *x = None) }
-}
-
-/// A simple, generic one-parameter event notifier/handler.
-pub trait HandleLifetime<T> {
-	/// An account was created.
-	fn created(_t: &T) -> Result<(), StoredMapError> { Ok(()) }
-
-	/// An account was killed.
-	fn killed(_t: &T) -> Result<(), StoredMapError> { Ok(()) }
-}
-
-impl<T> HandleLifetime<T> for () {}
-
-/// A shim for placing around a storage item in order to use it as a `StoredValue`. Ideally this
-/// wouldn't be needed as `StorageValue`s should blanket implement `StoredValue`s, however this
-/// would break the ability to have custom impls of `StoredValue`. The other workaround is to
-/// implement it directly in the macro.
-///
-/// This form has the advantage that two additional types are provides, `Created` and `Removed`,
-/// which are both generic events that can be tied to handlers to do something in the case of being
-/// about to create an account where one didn't previously exist (at all; not just where it used to
-/// be the default value), or where the account is being removed or reset back to the default value
-/// where previously it did exist (though may have been in a default state). This works well with
-/// system module's `CallOnCreatedAccount` and `CallKillAccount`.
-pub struct StorageMapShim<S, L, K, T>(sp_std::marker::PhantomData<(S, L, K, T)>);
-impl<
-	S: StorageMap<K, T, Query=T>,
-	L: HandleLifetime<K>,
-	K: FullCodec,
-	T: FullCodec + Default,
-> StoredMap<K, T> for StorageMapShim<S, L, K, T> {
-	fn get(k: &K) -> T { S::get(k) }
-	fn insert(k: &K, t: T) -> Result<(), StoredMapError> {
-		if !S::contains_key(&k) {
-			L::created(k)?;
-		}
-		S::insert(k, t);
-		Ok(())
-	}
-	fn remove(k: &K) -> Result<(), StoredMapError> {
-		if S::contains_key(&k) {
-			L::killed(&k)?;
-			S::remove(k);
-		}
-		Ok(())
-	}
-	fn mutate<R>(k: &K, f: impl FnOnce(&mut T) -> R) -> Result<R, StoredMapError> {
-		if !S::contains_key(&k) {
-			L::created(k)?;
-		}
-		Ok(S::mutate(k, f))
-	}
-	fn mutate_exists<R>(k: &K, f: impl FnOnce(&mut Option<T>) -> R) -> Result<R, StoredMapError> {
-		S::try_mutate_exists(k, |maybe_value| {
-			let existed = maybe_value.is_some();
-			let r = f(maybe_value);
-			let exists = maybe_value.is_some();
-
-			if !existed && exists {
-				L::created(k)?;
-			} else if existed && !exists {
-				L::killed(k)?;
-			}
-			Ok(r)
-		})
-	}
-	fn try_mutate_exists<R, E: From<StoredMapError>>(
-		k: &K,
-		f: impl FnOnce(&mut Option<T>) -> Result<R, E>,
-	) -> Result<R, E> {
-		S::try_mutate_exists(k, |maybe_value| {
-			let existed = maybe_value.is_some();
-			let r = f(maybe_value)?;
-			let exists = maybe_value.is_some();
-
-			if !existed && exists {
-				L::created(k).map_err(E::from)?;
-			} else if existed && !exists {
-				L::killed(k).map_err(E::from)?;
-			}
-			Ok(r)
-		})
-	}
-}
-
-/// Something that can estimate at which block the next session rotation will happen (i.e. a new
-/// session starts).
-///
-/// The accuracy of the estimates is dependent on the specific implementation, but in order to get
-/// the best estimate possible these methods should be called throughout the duration of the session
-/// (rather than calling once and storing the result).
-///
-/// This should be the same logical unit that dictates `ShouldEndSession` to the session module. No
-/// assumptions are made about the scheduling of the sessions.
-pub trait EstimateNextSessionRotation<BlockNumber> {
-	/// Return the average length of a session.
-	///
-	/// This may or may not be accurate.
-	fn average_session_length() -> BlockNumber;
-
-	/// Return an estimate of the current session progress.
-	///
-	/// None should be returned if the estimation fails to come to an answer.
-	fn estimate_current_session_progress(now: BlockNumber) -> (Option<Percent>, Weight);
-
-	/// Return the block number at which the next session rotation is estimated to happen.
-	///
-	/// None should be returned if the estimation fails to come to an answer.
-	fn estimate_next_session_rotation(now: BlockNumber) -> (Option<BlockNumber>, Weight);
-}
-
-impl<BlockNumber: Zero> EstimateNextSessionRotation<BlockNumber> for () {
-	fn average_session_length() -> BlockNumber {
-		Zero::zero()
-	}
-
-	fn estimate_current_session_progress(_: BlockNumber) -> (Option<Percent>, Weight) {
-		(None, Zero::zero())
-	}
-
-	fn estimate_next_session_rotation(_: BlockNumber) -> (Option<BlockNumber>, Weight) {
-		(None, Zero::zero())
-	}
-}
-
-/// Something that can estimate at which block scheduling of the next session will happen (i.e when
-/// we will try to fetch new validators).
-///
-/// This only refers to the point when we fetch the next session details and not when we enact them
-/// (for enactment there's `EstimateNextSessionRotation`). With `pallet-session` this should be
-/// triggered whenever `SessionManager::new_session` is called.
-///
-/// For example, if we are using a staking module this would be the block when the session module
-/// would ask staking what the next validator set will be, as such this must always be implemented
-/// by the session module.
-pub trait EstimateNextNewSession<BlockNumber> {
-	/// Return the average length of a session.
-	///
-	/// This may or may not be accurate.
-	fn average_session_length() -> BlockNumber;
-
-	/// Return the block number at which the next new session is estimated to happen.
-	///
-	/// None should be returned if the estimation fails to come to an answer.
-	fn estimate_next_new_session(_: BlockNumber) -> (Option<BlockNumber>, Weight);
-}
-
-impl<BlockNumber: Zero> EstimateNextNewSession<BlockNumber> for () {
-	fn average_session_length() -> BlockNumber {
-		Zero::zero()
-	}
-
-	fn estimate_next_new_session(_: BlockNumber) -> (Option<BlockNumber>, Weight) {
-		(None, Zero::zero())
-	}
-}
-
-/// Anything that can have a `::len()` method.
-pub trait Len {
-	/// Return the length of data type.
-	fn len(&self) -> usize;
-}
-
-impl<T: IntoIterator + Clone,> Len for T where <T as IntoIterator>::IntoIter: ExactSizeIterator {
-	fn len(&self) -> usize {
-		self.clone().into_iter().len()
-	}
-}
-
-/// A trait for querying a single value from a type.
-///
-/// It is not required that the value is constant.
-pub trait Get<T> {
-	/// Return the current value.
-	fn get() -> T;
-}
-
-impl<T: Default> Get<T> for () {
-	fn get() -> T { T::default() }
-}
-
-/// A trait for querying whether a type can be said to "contain" a value.
-pub trait Contains<T: Ord> {
-	/// Return `true` if this "contains" the given value `t`.
-	fn contains(t: &T) -> bool { Self::sorted_members().binary_search(t).is_ok() }
-
-	/// Get a vector of all members in the set, ordered.
-	fn sorted_members() -> Vec<T>;
-
-	/// Get the number of items in the set.
-	fn count() -> usize { Self::sorted_members().len() }
-
-	/// Add an item that would satisfy `contains`. It does not make sure any other
-	/// state is correctly maintained or generated.
-	///
-	/// **Should be used for benchmarking only!!!**
-	#[cfg(feature = "runtime-benchmarks")]
-	fn add(_t: &T) { unimplemented!() }
-}
-
-/// A trait for querying bound for the length of an implementation of `Contains`
-pub trait ContainsLengthBound {
-	/// Minimum number of elements contained
-	fn min_len() -> usize;
-	/// Maximum number of elements contained
-	fn max_len() -> usize;
-}
-
-/// Handler for when a new account has been created.
-#[impl_for_tuples(30)]
-pub trait OnNewAccount<AccountId> {
-	/// A new account `who` has been registered.
-	fn on_new_account(who: &AccountId);
-}
-
-/// The account with the given id was reaped.
-#[impl_for_tuples(30)]
-pub trait OnKilledAccount<AccountId> {
-	/// The account with the given id was reaped.
-	fn on_killed_account(who: &AccountId);
-}
-
-/// A trait for finding the author of a block header based on the `PreRuntime` digests contained
-/// within it.
-pub trait FindAuthor<Author> {
-	/// Find the author of a block based on the pre-runtime digests.
-	fn find_author<'a, I>(digests: I) -> Option<Author>
-		where I: 'a + IntoIterator<Item=(ConsensusEngineId, &'a [u8])>;
-}
-
-impl<A> FindAuthor<A> for () {
-	fn find_author<'a, I>(_: I) -> Option<A>
-		where I: 'a + IntoIterator<Item=(ConsensusEngineId, &'a [u8])>
-	{
-		None
-	}
-}
-
-/// A trait for verifying the seal of a header and returning the author.
-pub trait VerifySeal<Header, Author> {
-	/// Verify a header and return the author, if any.
-	fn verify_seal(header: &Header) -> Result<Option<Author>, &'static str>;
-}
-
-/// Something which can compute and check proofs of
-/// a historical key owner and return full identification data of that
-/// key owner.
-pub trait KeyOwnerProofSystem<Key> {
-	/// The proof of membership itself.
-	type Proof: Codec;
-	/// The full identification of a key owner and the stash account.
-	type IdentificationTuple: Codec;
-
-	/// Prove membership of a key owner in the current block-state.
-	///
-	/// This should typically only be called off-chain, since it may be
-	/// computationally heavy.
-	///
-	/// Returns `Some` iff the key owner referred to by the given `key` is a
-	/// member of the current set.
-	fn prove(key: Key) -> Option<Self::Proof>;
-
-	/// Check a proof of membership on-chain. Return `Some` iff the proof is
-	/// valid and recent enough to check.
-	fn check_proof(key: Key, proof: Self::Proof) -> Option<Self::IdentificationTuple>;
-}
-
-impl<Key> KeyOwnerProofSystem<Key> for () {
-	// The proof and identification tuples is any bottom type to guarantee that the methods of this
-	// implementation can never be called or return anything other than `None`.
-	type Proof = crate::Void;
-	type IdentificationTuple = crate::Void;
-
-	fn prove(_key: Key) -> Option<Self::Proof> {
-		None
-	}
-
-	fn check_proof(_key: Key, _proof: Self::Proof) -> Option<Self::IdentificationTuple> {
-		None
-	}
-}
-
-/// Handler for when some currency "account" decreased in balance for
-/// some reason.
-///
-/// The only reason at present for an increase would be for validator rewards, but
-/// there may be other reasons in the future or for other chains.
-///
-/// Reasons for decreases include:
-///
-/// - Someone got slashed.
-/// - Someone paid for a transaction to be included.
-pub trait OnUnbalanced<Imbalance: TryDrop> {
-	/// Handler for some imbalances. The different imbalances might have different origins or
-	/// meanings, dependent on the context. Will default to simply calling on_unbalanced for all
-	/// of them. Infallible.
-	fn on_unbalanceds<B>(amounts: impl Iterator<Item=Imbalance>) where Imbalance: crate::traits::Imbalance<B> {
-		Self::on_unbalanced(amounts.fold(Imbalance::zero(), |i, x| x.merge(i)))
-	}
-
-	/// Handler for some imbalance. Infallible.
-	fn on_unbalanced(amount: Imbalance) {
-		amount.try_drop().unwrap_or_else(Self::on_nonzero_unbalanced)
-	}
-
-	/// Actually handle a non-zero imbalance. You probably want to implement this rather than
-	/// `on_unbalanced`.
-	fn on_nonzero_unbalanced(amount: Imbalance) { drop(amount); }
-}
-
-impl<Imbalance: TryDrop> OnUnbalanced<Imbalance> for () {}
-
-/// Simple boolean for whether an account needs to be kept in existence.
-#[derive(Copy, Clone, Eq, PartialEq)]
-pub enum ExistenceRequirement {
-	/// Operation must not result in the account going out of existence.
-	///
-	/// Note this implies that if the account never existed in the first place, then the operation
-	/// may legitimately leave the account unchanged and still non-existent.
-	KeepAlive,
-	/// Operation may result in account going out of existence.
-	AllowDeath,
-}
-
-/// A type for which some values make sense to be able to drop without further consideration.
-pub trait TryDrop: Sized {
-	/// Drop an instance cleanly. Only works if its value represents "no-operation".
-	fn try_drop(self) -> Result<(), Self>;
-}
-
-/// A trait for a not-quite Linear Type that tracks an imbalance.
-///
-/// Functions that alter account balances return an object of this trait to
-/// express how much account balances have been altered in aggregate. If
-/// dropped, the currency system will take some default steps to deal with
-/// the imbalance (`balances` module simply reduces or increases its
-/// total issuance). Your module should generally handle it in some way,
-/// good practice is to do so in a configurable manner using an
-/// `OnUnbalanced` type for each situation in which your module needs to
-/// handle an imbalance.
-///
-/// Imbalances can either be Positive (funds were added somewhere without
-/// being subtracted elsewhere - e.g. a reward) or Negative (funds deducted
-/// somewhere without an equal and opposite addition - e.g. a slash or
-/// system fee payment).
-///
-/// Since they are unsigned, the actual type is always Positive or Negative.
-/// The trait makes no distinction except to define the `Opposite` type.
-///
-/// New instances of zero value can be created (`zero`) and destroyed
-/// (`drop_zero`).
-///
-/// Existing instances can be `split` and merged either consuming `self` with
-/// `merge` or mutating `self` with `subsume`. If the target is an `Option`,
-/// then `maybe_merge` and `maybe_subsume` might work better. Instances can
-/// also be `offset` with an `Opposite` that is less than or equal to in value.
-///
-/// You can always retrieve the raw balance value using `peek`.
-#[must_use]
-pub trait Imbalance<Balance>: Sized + TryDrop {
-	/// The oppositely imbalanced type. They come in pairs.
-	type Opposite: Imbalance<Balance>;
-
-	/// The zero imbalance. Can be destroyed with `drop_zero`.
-	fn zero() -> Self;
-
-	/// Drop an instance cleanly. Only works if its `self.value()` is zero.
-	fn drop_zero(self) -> Result<(), Self>;
-
-	/// Consume `self` and return two independent instances; the first
-	/// is guaranteed to be at most `amount` and the second will be the remainder.
-	fn split(self, amount: Balance) -> (Self, Self);
-
-	/// Consume `self` and return two independent instances; the amounts returned will be in
-	/// approximately the same ratio as `first`:`second`.
-	///
-	/// NOTE: This requires up to `first + second` room for a multiply, and `first + second` should
-	/// fit into a `u32`. Overflow will safely saturate in both cases.
-	fn ration(self, first: u32, second: u32) -> (Self, Self)
-		where Balance: From<u32> + Saturating + Div<Output=Balance>
-	{
-		let total: u32 = first.saturating_add(second);
-		let amount1 = self.peek().saturating_mul(first.into()) / total.into();
-		self.split(amount1)
-	}
-
-	/// Consume self and add its two components, defined by the first component's balance,
-	/// element-wise to two pre-existing Imbalances.
-	///
-	/// A convenient replacement for `split` and `merge`.
-	fn split_merge(self, amount: Balance, others: (Self, Self)) -> (Self, Self) {
-		let (a, b) = self.split(amount);
-		(a.merge(others.0), b.merge(others.1))
-	}
-
-	/// Consume self and add its two components, defined by the ratio `first`:`second`,
-	/// element-wise to two pre-existing Imbalances.
-	///
-	/// A convenient replacement for `split` and `merge`.
-	fn ration_merge(self, first: u32, second: u32, others: (Self, Self)) -> (Self, Self)
-		where Balance: From<u32> + Saturating + Div<Output=Balance>
-	{
-		let (a, b) = self.ration(first, second);
-		(a.merge(others.0), b.merge(others.1))
-	}
-
-	/// Consume self and add its two components, defined by the first component's balance,
-	/// element-wise into two pre-existing Imbalance refs.
-	///
-	/// A convenient replacement for `split` and `subsume`.
-	fn split_merge_into(self, amount: Balance, others: &mut (Self, Self)) {
-		let (a, b) = self.split(amount);
-		others.0.subsume(a);
-		others.1.subsume(b);
-	}
-
-	/// Consume self and add its two components, defined by the ratio `first`:`second`,
-	/// element-wise to two pre-existing Imbalances.
-	///
-	/// A convenient replacement for `split` and `merge`.
-	fn ration_merge_into(self, first: u32, second: u32, others: &mut (Self, Self))
-		where Balance: From<u32> + Saturating + Div<Output=Balance>
-	{
-		let (a, b) = self.ration(first, second);
-		others.0.subsume(a);
-		others.1.subsume(b);
-	}
-
-	/// Consume `self` and an `other` to return a new instance that combines
-	/// both.
-	fn merge(self, other: Self) -> Self;
-
-	/// Consume self to mutate `other` so that it combines both. Just like `subsume`, only with
-	/// reversed arguments.
-	fn merge_into(self, other: &mut Self) {
-		other.subsume(self)
-	}
-
-	/// Consume `self` and maybe an `other` to return a new instance that combines
-	/// both.
-	fn maybe_merge(self, other: Option<Self>) -> Self {
-		if let Some(o) = other {
-			self.merge(o)
-		} else {
-			self
-		}
-	}
-
-	/// Consume an `other` to mutate `self` into a new instance that combines
-	/// both.
-	fn subsume(&mut self, other: Self);
-
-	/// Maybe consume an `other` to mutate `self` into a new instance that combines
-	/// both.
-	fn maybe_subsume(&mut self, other: Option<Self>) {
-		if let Some(o) = other {
-			self.subsume(o)
-		}
-	}
-
-	/// Consume self and along with an opposite counterpart to return
-	/// a combined result.
-	///
-	/// Returns `Ok` along with a new instance of `Self` if this instance has a
-	/// greater value than the `other`. Otherwise returns `Err` with an instance of
-	/// the `Opposite`. In both cases the value represents the combination of `self`
-	/// and `other`.
-	fn offset(self, other: Self::Opposite) -> Result<Self, Self::Opposite>;
-
-	/// The raw value of self.
-	fn peek(&self) -> Balance;
-}
-
-/// Either a positive or a negative imbalance.
-pub enum SignedImbalance<B, P: Imbalance<B>>{
-	/// A positive imbalance (funds have been created but none destroyed).
-	Positive(P),
-	/// A negative imbalance (funds have been destroyed but none created).
-	Negative(P::Opposite),
-}
-
-impl<
-	P: Imbalance<B, Opposite=N>,
-	N: Imbalance<B, Opposite=P>,
-	B: AtLeast32BitUnsigned + FullCodec + Copy + MaybeSerializeDeserialize + Debug + Default,
-> SignedImbalance<B, P> {
-	pub fn zero() -> Self {
-		SignedImbalance::Positive(P::zero())
-	}
-
-	pub fn drop_zero(self) -> Result<(), Self> {
-		match self {
-			SignedImbalance::Positive(x) => x.drop_zero().map_err(SignedImbalance::Positive),
-			SignedImbalance::Negative(x) => x.drop_zero().map_err(SignedImbalance::Negative),
-		}
-	}
-
-	/// Consume `self` and an `other` to return a new instance that combines
-	/// both.
-	pub fn merge(self, other: Self) -> Self {
-		match (self, other) {
-			(SignedImbalance::Positive(one), SignedImbalance::Positive(other)) =>
-				SignedImbalance::Positive(one.merge(other)),
-			(SignedImbalance::Negative(one), SignedImbalance::Negative(other)) =>
-				SignedImbalance::Negative(one.merge(other)),
-			(SignedImbalance::Positive(one), SignedImbalance::Negative(other)) =>
-				if one.peek() > other.peek() {
-					SignedImbalance::Positive(one.offset(other).ok().unwrap_or_else(P::zero))
-				} else {
-					SignedImbalance::Negative(other.offset(one).ok().unwrap_or_else(N::zero))
-				},
-			(one, other) => other.merge(one),
-		}
-	}
-}
-
-/// Split an unbalanced amount two ways between a common divisor.
-pub struct SplitTwoWays<
-	Balance,
-	Imbalance,
-	Part1,
-	Target1,
-	Part2,
-	Target2,
->(PhantomData<(Balance, Imbalance, Part1, Target1, Part2, Target2)>);
-
-impl<
-	Balance: From<u32> + Saturating + Div<Output=Balance>,
-	I: Imbalance<Balance>,
-	Part1: U32,
-	Target1: OnUnbalanced<I>,
-	Part2: U32,
-	Target2: OnUnbalanced<I>,
-> OnUnbalanced<I> for SplitTwoWays<Balance, I, Part1, Target1, Part2, Target2>
-{
-	fn on_nonzero_unbalanced(amount: I) {
-		let total: u32 = Part1::VALUE + Part2::VALUE;
-		let amount1 = amount.peek().saturating_mul(Part1::VALUE.into()) / total.into();
-		let (imb1, imb2) = amount.split(amount1);
-		Target1::on_unbalanced(imb1);
-		Target2::on_unbalanced(imb2);
-	}
-}
-
-/// Abstraction over a fungible assets system.
-pub trait Currency<AccountId> {
-	/// The balance of an account.
-	type Balance: AtLeast32BitUnsigned + FullCodec + Copy + MaybeSerializeDeserialize + Debug +
-		Default;
-
-	/// The opaque token type for an imbalance. This is returned by unbalanced operations
-	/// and must be dealt with. It may be dropped but cannot be cloned.
-	type PositiveImbalance: Imbalance<Self::Balance, Opposite=Self::NegativeImbalance>;
-
-	/// The opaque token type for an imbalance. This is returned by unbalanced operations
-	/// and must be dealt with. It may be dropped but cannot be cloned.
-	type NegativeImbalance: Imbalance<Self::Balance, Opposite=Self::PositiveImbalance>;
-
-	// PUBLIC IMMUTABLES
-
-	/// The combined balance of `who`.
-	fn total_balance(who: &AccountId) -> Self::Balance;
-
-	/// Same result as `slash(who, value)` (but without the side-effects) assuming there are no
-	/// balance changes in the meantime and only the reserved balance is not taken into account.
-	fn can_slash(who: &AccountId, value: Self::Balance) -> bool;
-
-	/// The total amount of issuance in the system.
-	fn total_issuance() -> Self::Balance;
-
-	/// The minimum balance any single account may have. This is equivalent to the `Balances` module's
-	/// `ExistentialDeposit`.
-	fn minimum_balance() -> Self::Balance;
-
-	/// Reduce the total issuance by `amount` and return the according imbalance. The imbalance will
-	/// typically be used to reduce an account by the same amount with e.g. `settle`.
-	///
-	/// This is infallible, but doesn't guarantee that the entire `amount` is burnt, for example
-	/// in the case of underflow.
-	fn burn(amount: Self::Balance) -> Self::PositiveImbalance;
-
-	/// Increase the total issuance by `amount` and return the according imbalance. The imbalance
-	/// will typically be used to increase an account by the same amount with e.g.
-	/// `resolve_into_existing` or `resolve_creating`.
-	///
-	/// This is infallible, but doesn't guarantee that the entire `amount` is issued, for example
-	/// in the case of overflow.
-	fn issue(amount: Self::Balance) -> Self::NegativeImbalance;
-
-	/// Produce a pair of imbalances that cancel each other out exactly.
-	///
-	/// This is just the same as burning and issuing the same amount and has no effect on the
-	/// total issuance.
-	fn pair(amount: Self::Balance) -> (Self::PositiveImbalance, Self::NegativeImbalance) {
-		(Self::burn(amount.clone()), Self::issue(amount))
-	}
-
-	/// The 'free' balance of a given account.
-	///
-	/// This is the only balance that matters in terms of most operations on tokens. It alone
-	/// is used to determine the balance when in the contract execution environment. When this
-	/// balance falls below the value of `ExistentialDeposit`, then the 'current account' is
-	/// deleted: specifically `FreeBalance`.
-	///
-	/// `system::AccountNonce` is also deleted if `ReservedBalance` is also zero (it also gets
-	/// collapsed to zero if it ever becomes less than `ExistentialDeposit`.
-	fn free_balance(who: &AccountId) -> Self::Balance;
-
-	/// Returns `Ok` iff the account is able to make a withdrawal of the given amount
-	/// for the given reason. Basically, it's just a dry-run of `withdraw`.
-	///
-	/// `Err(...)` with the reason why not otherwise.
-	fn ensure_can_withdraw(
-		who: &AccountId,
-		_amount: Self::Balance,
-		reasons: WithdrawReasons,
-		new_balance: Self::Balance,
-	) -> DispatchResult;
-
-	// PUBLIC MUTABLES (DANGEROUS)
-
-	/// Transfer some liquid free balance to another staker.
-	///
-	/// This is a very high-level function. It will ensure all appropriate fees are paid
-	/// and no imbalance in the system remains.
-	fn transfer(
-		source: &AccountId,
-		dest: &AccountId,
-		value: Self::Balance,
-		existence_requirement: ExistenceRequirement,
-	) -> DispatchResult;
-
-	/// Deducts up to `value` from the combined balance of `who`, preferring to deduct from the
-	/// free balance. This function cannot fail.
-	///
-	/// The resulting imbalance is the first item of the tuple returned.
-	///
-	/// As much funds up to `value` will be deducted as possible. If this is less than `value`,
-	/// then a non-zero second item will be returned.
-	fn slash(
-		who: &AccountId,
-		value: Self::Balance
-	) -> (Self::NegativeImbalance, Self::Balance);
-
-	/// Mints `value` to the free balance of `who`.
-	///
-	/// If `who` doesn't exist, nothing is done and an Err returned.
-	fn deposit_into_existing(
-		who: &AccountId,
-		value: Self::Balance
-	) -> result::Result<Self::PositiveImbalance, DispatchError>;
-
-	/// Similar to deposit_creating, only accepts a `NegativeImbalance` and returns nothing on
-	/// success.
-	fn resolve_into_existing(
-		who: &AccountId,
-		value: Self::NegativeImbalance,
-	) -> result::Result<(), Self::NegativeImbalance> {
-		let v = value.peek();
-		match Self::deposit_into_existing(who, v) {
-			Ok(opposite) => Ok(drop(value.offset(opposite))),
-			_ => Err(value),
-		}
-	}
-
-	/// Adds up to `value` to the free balance of `who`. If `who` doesn't exist, it is created.
-	///
-	/// Infallible.
-	fn deposit_creating(
-		who: &AccountId,
-		value: Self::Balance,
-	) -> Self::PositiveImbalance;
-
-	/// Similar to deposit_creating, only accepts a `NegativeImbalance` and returns nothing on
-	/// success.
-	fn resolve_creating(
-		who: &AccountId,
-		value: Self::NegativeImbalance,
-	) {
-		let v = value.peek();
-		drop(value.offset(Self::deposit_creating(who, v)));
-	}
-
-	/// Removes some free balance from `who` account for `reason` if possible. If `liveness` is
-	/// `KeepAlive`, then no less than `ExistentialDeposit` must be left remaining.
-	///
-	/// This checks any locks, vesting, and liquidity requirements. If the removal is not possible,
-	/// then it returns `Err`.
-	///
-	/// If the operation is successful, this will return `Ok` with a `NegativeImbalance` whose value
-	/// is `value`.
-	fn withdraw(
-		who: &AccountId,
-		value: Self::Balance,
-		reasons: WithdrawReasons,
-		liveness: ExistenceRequirement,
-	) -> result::Result<Self::NegativeImbalance, DispatchError>;
-
-	/// Similar to withdraw, only accepts a `PositiveImbalance` and returns nothing on success.
-	fn settle(
-		who: &AccountId,
-		value: Self::PositiveImbalance,
-		reasons: WithdrawReasons,
-		liveness: ExistenceRequirement,
-	) -> result::Result<(), Self::PositiveImbalance> {
-		let v = value.peek();
-		match Self::withdraw(who, v, reasons, liveness) {
-			Ok(opposite) => Ok(drop(value.offset(opposite))),
-			_ => Err(value),
-		}
-	}
-
-	/// Ensure an account's free balance equals some value; this will create the account
-	/// if needed.
-	///
-	/// Returns a signed imbalance and status to indicate if the account was successfully updated or update
-	/// has led to killing of the account.
-	fn make_free_balance_be(
-		who: &AccountId,
-		balance: Self::Balance,
-	) -> SignedImbalance<Self::Balance, Self::PositiveImbalance>;
-}
-
-/// Status of funds.
-#[derive(PartialEq, Eq, Clone, Copy, Encode, Decode, RuntimeDebug)]
-pub enum BalanceStatus {
-	/// Funds are free, as corresponding to `free` item in Balances.
-	Free,
-	/// Funds are reserved, as corresponding to `reserved` item in Balances.
-	Reserved,
-}
-
-/// A currency where funds can be reserved from the user.
-pub trait ReservableCurrency<AccountId>: Currency<AccountId> {
-	/// Same result as `reserve(who, value)` (but without the side-effects) assuming there
-	/// are no balance changes in the meantime.
-	fn can_reserve(who: &AccountId, value: Self::Balance) -> bool;
-
-	/// Deducts up to `value` from reserved balance of `who`. This function cannot fail.
-	///
-	/// As much funds up to `value` will be deducted as possible. If the reserve balance of `who`
-	/// is less than `value`, then a non-zero second item will be returned.
-	fn slash_reserved(
-		who: &AccountId,
-		value: Self::Balance
-	) -> (Self::NegativeImbalance, Self::Balance);
-
-	/// The amount of the balance of a given account that is externally reserved; this can still get
-	/// slashed, but gets slashed last of all.
-	///
-	/// This balance is a 'reserve' balance that other subsystems use in order to set aside tokens
-	/// that are still 'owned' by the account holder, but which are suspendable.
-	///
-	/// When this balance falls below the value of `ExistentialDeposit`, then this 'reserve account'
-	/// is deleted: specifically, `ReservedBalance`.
-	///
-	/// `system::AccountNonce` is also deleted if `FreeBalance` is also zero (it also gets
-	/// collapsed to zero if it ever becomes less than `ExistentialDeposit`.
-	fn reserved_balance(who: &AccountId) -> Self::Balance;
-
-	/// Moves `value` from balance to reserved balance.
-	///
-	/// If the free balance is lower than `value`, then no funds will be moved and an `Err` will
-	/// be returned to notify of this. This is different behavior than `unreserve`.
-	fn reserve(who: &AccountId, value: Self::Balance) -> DispatchResult;
-
-	/// Moves up to `value` from reserved balance to free balance. This function cannot fail.
-	///
-	/// As much funds up to `value` will be moved as possible. If the reserve balance of `who`
-	/// is less than `value`, then the remaining amount will be returned.
-	///
-	/// # NOTES
-	///
-	/// - This is different from `reserve`.
-	/// - If the remaining reserved balance is less than `ExistentialDeposit`, it will
-	/// invoke `on_reserved_too_low` and could reap the account.
-	fn unreserve(who: &AccountId, value: Self::Balance) -> Self::Balance;
-
-	/// Moves up to `value` from reserved balance of account `slashed` to balance of account
-	/// `beneficiary`. `beneficiary` must exist for this to succeed. If it does not, `Err` will be
-	/// returned. Funds will be placed in either the `free` balance or the `reserved` balance,
-	/// depending on the `status`.
-	///
-	/// As much funds up to `value` will be deducted as possible. If this is less than `value`,
-	/// then `Ok(non_zero)` will be returned.
-	fn repatriate_reserved(
-		slashed: &AccountId,
-		beneficiary: &AccountId,
-		value: Self::Balance,
-		status: BalanceStatus,
-	) -> result::Result<Self::Balance, DispatchError>;
-}
-
-/// An identifier for a lock. Used for disambiguating different locks so that
-/// they can be individually replaced or removed.
-pub type LockIdentifier = [u8; 8];
-
-/// A currency whose accounts can have liquidity restrictions.
-pub trait LockableCurrency<AccountId>: Currency<AccountId> {
-	/// The quantity used to denote time; usually just a `BlockNumber`.
-	type Moment;
-
-	/// The maximum number of locks a user should have on their account.
-	type MaxLocks: Get<u32>;
-
-	/// Create a new balance lock on account `who`.
-	///
-	/// If the new lock is valid (i.e. not already expired), it will push the struct to
-	/// the `Locks` vec in storage. Note that you can lock more funds than a user has.
-	///
-	/// If the lock `id` already exists, this will update it.
-	fn set_lock(
-		id: LockIdentifier,
-		who: &AccountId,
-		amount: Self::Balance,
-		reasons: WithdrawReasons,
-	);
-
-	/// Changes a balance lock (selected by `id`) so that it becomes less liquid in all
-	/// parameters or creates a new one if it does not exist.
-	///
-	/// Calling `extend_lock` on an existing lock `id` differs from `set_lock` in that it
-	/// applies the most severe constraints of the two, while `set_lock` replaces the lock
-	/// with the new parameters. As in, `extend_lock` will set:
-	/// - maximum `amount`
-	/// - bitwise mask of all `reasons`
-	fn extend_lock(
-		id: LockIdentifier,
-		who: &AccountId,
-		amount: Self::Balance,
-		reasons: WithdrawReasons,
-	);
-
-	/// Remove an existing lock.
-	fn remove_lock(
-		id: LockIdentifier,
-		who: &AccountId,
-	);
-}
-
-/// A vesting schedule over a currency. This allows a particular currency to have vesting limits
-/// applied to it.
-pub trait VestingSchedule<AccountId> {
-	/// The quantity used to denote time; usually just a `BlockNumber`.
-	type Moment;
-
-	/// The currency that this schedule applies to.
-	type Currency: Currency<AccountId>;
-
-	/// Get the amount that is currently being vested and cannot be transferred out of this account.
-	/// Returns `None` if the account has no vesting schedule.
-	fn vesting_balance(who: &AccountId) -> Option<<Self::Currency as Currency<AccountId>>::Balance>;
-
-	/// Adds a vesting schedule to a given account.
-	///
-	/// If there already exists a vesting schedule for the given account, an `Err` is returned
-	/// and nothing is updated.
-	///
-	/// Is a no-op if the amount to be vested is zero.
-	///
-	/// NOTE: This doesn't alter the free balance of the account.
-	fn add_vesting_schedule(
-		who: &AccountId,
-		locked: <Self::Currency as Currency<AccountId>>::Balance,
-		per_block: <Self::Currency as Currency<AccountId>>::Balance,
-		starting_block: Self::Moment,
-	) -> DispatchResult;
-
-	/// Remove a vesting schedule for a given account.
-	///
-	/// NOTE: This doesn't alter the free balance of the account.
-	fn remove_vesting_schedule(who: &AccountId);
-}
-
-bitflags! {
-	/// Reasons for moving funds out of an account.
-	#[derive(Encode, Decode)]
-	pub struct WithdrawReasons: i8 {
-		/// In order to pay for (system) transaction costs.
-		const TRANSACTION_PAYMENT = 0b00000001;
-		/// In order to transfer ownership.
-		const TRANSFER = 0b00000010;
-		/// In order to reserve some funds for a later return or repatriation.
-		const RESERVE = 0b00000100;
-		/// In order to pay some other (higher-level) fees.
-		const FEE = 0b00001000;
-		/// In order to tip a validator for transaction inclusion.
-		const TIP = 0b00010000;
-	}
-}
-
-impl WithdrawReasons {
-	/// Choose all variants except for `one`.
-	///
-	/// ```rust
-	/// # use frame_support::traits::WithdrawReasons;
-	/// # fn main() {
-	/// assert_eq!(
-	/// 	WithdrawReasons::FEE | WithdrawReasons::TRANSFER | WithdrawReasons::RESERVE | WithdrawReasons::TIP,
-	/// 	WithdrawReasons::except(WithdrawReasons::TRANSACTION_PAYMENT),
-	///	);
-	/// # }
-	/// ```
-	pub fn except(one: WithdrawReasons) -> WithdrawReasons {
-		let mut flags = Self::all();
-		flags.toggle(one);
-		flags
-	}
-}
-
-pub trait Time {
-	type Moment: AtLeast32Bit + Parameter + Default + Copy;
-
-	fn now() -> Self::Moment;
-}
-
-/// Trait to deal with unix time.
-pub trait UnixTime {
-	/// Return duration since `SystemTime::UNIX_EPOCH`.
-	fn now() -> core::time::Duration;
-}
-
-/// Trait for type that can handle incremental changes to a set of account IDs.
-pub trait ChangeMembers<AccountId: Clone + Ord> {
-	/// A number of members `incoming` just joined the set and replaced some `outgoing` ones. The
-	/// new set is given by `new`, and need not be sorted.
-	///
-	/// This resets any previous value of prime.
-	fn change_members(incoming: &[AccountId], outgoing: &[AccountId], mut new: Vec<AccountId>) {
-		new.sort();
-		Self::change_members_sorted(incoming, outgoing, &new[..]);
-	}
-
-	/// A number of members `_incoming` just joined the set and replaced some `_outgoing` ones. The
-	/// new set is thus given by `sorted_new` and **must be sorted**.
-	///
-	/// NOTE: This is the only function that needs to be implemented in `ChangeMembers`.
-	///
-	/// This resets any previous value of prime.
-	fn change_members_sorted(
-		incoming: &[AccountId],
-		outgoing: &[AccountId],
-		sorted_new: &[AccountId],
-	);
-
-	/// Set the new members; they **must already be sorted**. This will compute the diff and use it to
-	/// call `change_members_sorted`.
-	///
-	/// This resets any previous value of prime.
-	fn set_members_sorted(new_members: &[AccountId], old_members: &[AccountId]) {
-		let (incoming, outgoing) = Self::compute_members_diff_sorted(new_members, old_members);
-		Self::change_members_sorted(&incoming[..], &outgoing[..], &new_members);
-	}
-
-	/// Compute diff between new and old members; they **must already be sorted**.
-	///
-	/// Returns incoming and outgoing members.
-	fn compute_members_diff_sorted(
-		new_members: &[AccountId],
-		old_members: &[AccountId],
-	) -> (Vec<AccountId>, Vec<AccountId>) {
-		let mut old_iter = old_members.iter();
-		let mut new_iter = new_members.iter();
-		let mut incoming = Vec::new();
-		let mut outgoing = Vec::new();
-		let mut old_i = old_iter.next();
-		let mut new_i = new_iter.next();
-		loop {
-			match (old_i, new_i) {
-				(None, None) => break,
-				(Some(old), Some(new)) if old == new => {
-					old_i = old_iter.next();
-					new_i = new_iter.next();
-				}
-				(Some(old), Some(new)) if old < new => {
-					outgoing.push(old.clone());
-					old_i = old_iter.next();
-				}
-				(Some(old), None) => {
-					outgoing.push(old.clone());
-					old_i = old_iter.next();
-				}
-				(_, Some(new)) => {
-					incoming.push(new.clone());
-					new_i = new_iter.next();
-				}
-			}
-		}
-		(incoming, outgoing)
-	}
-
-	/// Set the prime member.
-	fn set_prime(_prime: Option<AccountId>) {}
-
-	/// Get the current prime.
-	fn get_prime() -> Option<AccountId> {
-		None
-	}
-}
-
-impl<T: Clone + Ord> ChangeMembers<T> for () {
-	fn change_members(_: &[T], _: &[T], _: Vec<T>) {}
-	fn change_members_sorted(_: &[T], _: &[T], _: &[T]) {}
-	fn set_members_sorted(_: &[T], _: &[T]) {}
-	fn set_prime(_: Option<T>) {}
-}
-
-/// Trait for type that can handle the initialization of account IDs at genesis.
-pub trait InitializeMembers<AccountId> {
-	/// Initialize the members to the given `members`.
-	fn initialize_members(members: &[AccountId]);
-}
-
-impl<T> InitializeMembers<T> for () {
-	fn initialize_members(_: &[T]) {}
-}
-
-/// A trait that is able to provide randomness.
-///
-/// Being a deterministic blockchain, real randomness is difficult to come by, different
-/// implementations of this trait will provide different security guarantees. At best,
-/// this will be randomness which was hard to predict a long time ago, but that has become
-/// easy to predict recently.
-pub trait Randomness<Output, BlockNumber> {
-	/// Get the most recently determined random seed, along with the time in the past
-	/// since when it was determinable by chain observers.
-	///
-	/// `subject` is a context identifier and allows you to get a different result to
-	/// other callers of this function; use it like `random(&b"my context"[..])`.
-	///
-	/// NOTE: The returned seed should only be used to distinguish commitments made before
-	/// the returned block number. If the block number is too early (i.e. commitments were
-	/// made afterwards), then ensure no further commitments may be made and repeatedly
-	/// call this on later blocks until the block number returned is later than the latest
-	/// commitment.
-	fn random(subject: &[u8]) -> (Output, BlockNumber);
-
-	/// Get the basic random seed.
-	///
-	/// In general you won't want to use this, but rather `Self::random` which allows
-	/// you to give a subject for the random result and whose value will be
-	/// independently low-influence random from any other such seeds.
-	///
-	/// NOTE: The returned seed should only be used to distinguish commitments made before
-	/// the returned block number. If the block number is too early (i.e. commitments were
-	/// made afterwards), then ensure no further commitments may be made and repeatedly
-	/// call this on later blocks until the block number returned is later than the latest
-	/// commitment.
-	fn random_seed() -> (Output, BlockNumber) {
-		Self::random(&[][..])
-	}
-}
-
-/// Trait to be used by block producing consensus engine modules to determine
-/// how late the current block is (e.g. in a slot-based proposal mechanism how
-/// many slots were skipped since the previous block).
-pub trait Lateness<N> {
-	/// Returns a generic measure of how late the current block is compared to
-	/// its parent.
-	fn lateness(&self) -> N;
-}
-
-impl<N: Zero> Lateness<N> for () {
-	fn lateness(&self) -> N {
-		Zero::zero()
-	}
-}
-
-/// Implementors of this trait provide information about whether or not some validator has
-/// been registered with them. The [Session module](../../pallet_session/index.html) is an implementor.
-pub trait ValidatorRegistration<ValidatorId> {
-	/// Returns true if the provided validator ID has been registered with the implementing runtime
-	/// module
-	fn is_registered(id: &ValidatorId) -> bool;
-}
-
-/// Provides information about the pallet setup in the runtime.
-///
-/// An implementor should be able to provide information about each pallet that
-/// is configured in `construct_runtime!`.
-pub trait PalletInfo {
-	/// Convert the given pallet `P` into its index as configured in the runtime.
-	fn index<P: 'static>() -> Option<usize>;
-	/// Convert the given pallet `P` into its name as configured in the runtime.
-	fn name<P: 'static>() -> Option<&'static str>;
-}
-
-/// The function and pallet name of the Call.
-#[derive(Clone, Eq, PartialEq, Default, RuntimeDebug)]
-pub struct CallMetadata {
-	/// Name of the function.
-	pub function_name: &'static str,
-	/// Name of the pallet to which the function belongs.
-	pub pallet_name: &'static str,
-}
-
-/// Gets the function name of the Call.
-pub trait GetCallName {
-	/// Return all function names.
-	fn get_call_names() -> &'static [&'static str];
-	/// Return the function name of the Call.
-	fn get_call_name(&self) -> &'static str;
-}
-
-/// Gets the metadata for the Call - function name and pallet name.
-pub trait GetCallMetadata {
-	/// Return all module names.
-	fn get_module_names() -> &'static [&'static str];
-	/// Return all function names for the given `module`.
-	fn get_call_names(module: &str) -> &'static [&'static str];
-	/// Return a [`CallMetadata`], containing function and pallet name of the Call.
-	fn get_call_metadata(&self) -> CallMetadata;
-}
-
-/// The block finalization trait.
-///
-/// Implementing this lets you express what should happen for your pallet when the block is ending.
-#[impl_for_tuples(30)]
-pub trait OnFinalize<BlockNumber> {
-	/// The block is being finalized. Implement to have something happen.
-	///
-	/// NOTE: This function is called AFTER ALL extrinsics in a block are applied,
-	/// including inherent extrinsics.
-	fn on_finalize(_n: BlockNumber) {}
-}
-
-/// The block's on idle trait.
-///
-/// Implementing this lets you express what should happen for your pallet before
-/// block finalization (see `on_finalize` hook) in case any remaining weight is left.
-pub trait OnIdle<BlockNumber> {
-	/// The block is being finalized.
-	/// Implement to have something happen in case there is leftover weight.
-	/// Check the passed `remaining_weight` to make sure it is high enough to allow for
-	/// your pallet's extra computation.
-	///
-	/// NOTE: This function is called AFTER ALL extrinsics - including inherent extrinsics -
-	/// in a block are applied but before `on_finalize` is executed.
-	fn on_idle(
-		_n: BlockNumber,
-		_remaining_weight: crate::weights::Weight
-	) -> crate::weights::Weight {
-		0
-	}
-}
-
-#[impl_for_tuples(30)]
-impl<BlockNumber: Clone> OnIdle<BlockNumber> for Tuple {
-	fn on_idle(n: BlockNumber,  remaining_weight: crate::weights::Weight) -> crate::weights::Weight {
-		let mut weight = 0;
-		for_tuples!( #(
-			let adjusted_remaining_weight = remaining_weight.saturating_sub(weight);
-			weight = weight.saturating_add(Tuple::on_idle(n.clone(),  adjusted_remaining_weight));
-		)* );
-		weight
-	}
-}
-
-/// The block initialization trait.
-///
-/// Implementing this lets you express what should happen for your pallet when the block is
-/// beginning (right before the first extrinsic is executed).
-pub trait OnInitialize<BlockNumber> {
-	/// The block is being initialized. Implement to have something happen.
-	///
-	/// Return the non-negotiable weight consumed in the block.
-	///
-	/// NOTE: This function is called BEFORE ANY extrinsic in a block is applied,
-	/// including inherent extrinsics. Hence for instance, if you runtime includes
-	/// `pallet_timestamp`, the `timestamp` is not yet up to date at this point.
-	fn on_initialize(_n: BlockNumber) -> crate::weights::Weight { 0 }
-}
-
-#[impl_for_tuples(30)]
-impl<BlockNumber: Clone> OnInitialize<BlockNumber> for Tuple {
-	fn on_initialize(n: BlockNumber) -> crate::weights::Weight {
-		let mut weight = 0;
-		for_tuples!( #( weight = weight.saturating_add(Tuple::on_initialize(n.clone())); )* );
-		weight
-	}
-}
-
-/// A trait that will be called at genesis.
-///
-/// Implementing this trait for a pallet let's you express operations that should
-/// happen at genesis. It will be called in an externalities provided environment and
-/// will see the genesis state after all pallets have written their genesis state.
-#[impl_for_tuples(30)]
-pub trait OnGenesis {
-	/// Something that should happen at genesis.
-	fn on_genesis() {}
-}
-
-/// Prefix to be used (optionally) for implementing [`OnRuntimeUpgradeHelpersExt::storage_key`].
-#[cfg(feature = "try-runtime")]
-pub const ON_RUNTIME_UPGRADE_PREFIX: &[u8] = b"__ON_RUNTIME_UPGRADE__";
-
-/// Some helper functions for [`OnRuntimeUpgrade`] during `try-runtime` testing.
-#[cfg(feature = "try-runtime")]
-pub trait OnRuntimeUpgradeHelpersExt {
-	/// Generate a storage key unique to this runtime upgrade.
-	///
-	/// This can be used to communicate data from pre-upgrade to post-upgrade state and check
-	/// them. See [`Self::set_temp_storage`] and [`Self::get_temp_storage`].
-	#[cfg(feature = "try-runtime")]
-	fn storage_key(ident: &str) -> [u8; 32] {
-		let prefix = sp_io::hashing::twox_128(ON_RUNTIME_UPGRADE_PREFIX);
-		let ident = sp_io::hashing::twox_128(ident.as_bytes());
+mod validation;
+pub use validation::{
+	ValidatorSet, ValidatorSetWithIdentification, OneSessionHandler, FindAuthor, VerifySeal,
+	EstimateNextNewSession, EstimateNextSessionRotation, KeyOwnerProofSystem, ValidatorRegistration,
+	Lateness,
+};
 
-		let mut final_key = [0u8; 32];
-		final_key[..16].copy_from_slice(&prefix);
-		final_key[16..].copy_from_slice(&ident);
+mod filter;
+pub use filter::{
+	Filter, FilterStack, FilterStackGuard, ClearFilterGuard, InstanceFilter, IntegrityTest,
+};
 
-		final_key
-	}
+mod misc;
+pub use misc::{
+	Len, Get, GetDefault, HandleLifetime, TryDrop, Time, UnixTime, IsType, IsSubType, ExecuteBlock,
+	SameOrOther, OnNewAccount, OnKilledAccount, OffchainWorker,
+};
 
-	/// Get temporary storage data written by [`Self::set_temp_storage`].
-	///
-	/// Returns `None` if either the data is unavailable or un-decodable.
-	///
-	/// A `at` storage identifier must be provided to indicate where the storage is being read from.
-	#[cfg(feature = "try-runtime")]
-	fn get_temp_storage<T: Decode>(at: &str) -> Option<T> {
-		sp_io::storage::get(&Self::storage_key(at))
-			.and_then(|bytes| Decode::decode(&mut &*bytes).ok())
-	}
+mod stored_map;
+pub use stored_map::{StoredMap, StorageMapShim};
+mod randomness;
+pub use randomness::Randomness;
 
-	/// Write some temporary data to a specific storage that can be read (potentially in
-	/// post-upgrade hook) via [`Self::get_temp_storage`].
-	///
-	/// A `at` storage identifier must be provided to indicate where the storage is being written
-	/// to.
-	#[cfg(feature = "try-runtime")]
-	fn set_temp_storage<T: Encode>(data: T, at: &str) {
-		sp_io::storage::set(&Self::storage_key(at), &data.encode());
-	}
-}
+mod metadata;
+pub use metadata::{
+	CallMetadata, GetCallMetadata, GetCallName, PalletInfo, PalletVersion, GetPalletVersion,
+	PALLET_VERSION_STORAGE_KEY_POSTFIX,
+};
 
+mod hooks;
+pub use hooks::{Hooks, OnGenesis, OnInitialize, OnFinalize, OnIdle, OnRuntimeUpgrade, OnTimestampSet};
 #[cfg(feature = "try-runtime")]
-impl<U: OnRuntimeUpgrade> OnRuntimeUpgradeHelpersExt for U {}
-
-/// The runtime upgrade trait.
-///
-/// Implementing this lets you express what should happen when the runtime upgrades,
-/// and changes may need to occur to your module.
-pub trait OnRuntimeUpgrade {
-	/// Perform a module upgrade.
-	///
-	/// # Warning
-	///
-	/// This function will be called before we initialized any runtime state, aka `on_initialize`
-	/// wasn't called yet. So, information like the block number and any other
-	/// block local data are not accessible.
-	///
-	/// Return the non-negotiable weight consumed for runtime upgrade.
-	fn on_runtime_upgrade() -> crate::weights::Weight {
-		0
-	}
-
-	/// Execute some pre-checks prior to a runtime upgrade.
-	///
-	/// This hook is never meant to be executed on-chain but is meant to be used by testing tools.
-	#[cfg(feature = "try-runtime")]
-	fn pre_upgrade() -> Result<(), &'static str> { Ok(()) }
-
-	/// Execute some post-checks after a runtime upgrade.
-	///
-	/// This hook is never meant to be executed on-chain but is meant to be used by testing tools.
-	#[cfg(feature = "try-runtime")]
-	fn post_upgrade() -> Result<(), &'static str> { Ok(()) }
-}
-
-#[impl_for_tuples(30)]
-impl OnRuntimeUpgrade for Tuple {
-	fn on_runtime_upgrade() -> crate::weights::Weight {
-		let mut weight = 0;
-		for_tuples!( #( weight = weight.saturating_add(Tuple::on_runtime_upgrade()); )* );
-		weight
-	}
-
-	#[cfg(feature = "try-runtime")]
-	fn pre_upgrade() -> Result<(), &'static str> {
-		let mut result = Ok(());
-		for_tuples!( #( result = result.and(Tuple::pre_upgrade()); )* );
-		result
-	}
-
-	#[cfg(feature = "try-runtime")]
-	fn post_upgrade() -> Result<(), &'static str> {
-		let mut result = Ok(());
-		for_tuples!( #( result = result.and(Tuple::post_upgrade()); )* );
-		result
-	}
-}
-
-/// Off-chain computation trait.
-///
-/// Implementing this trait on a module allows you to perform long-running tasks
-/// that make (by default) validators generate transactions that feed results
-/// of those long-running computations back on chain.
-///
-/// NOTE: This function runs off-chain, so it can access the block state,
-/// but cannot preform any alterations. More specifically alterations are
-/// not forbidden, but they are not persisted in any way after the worker
-/// has finished.
-#[impl_for_tuples(30)]
-pub trait OffchainWorker<BlockNumber> {
-	/// This function is being called after every block import (when fully synced).
-	///
-	/// Implement this and use any of the `Offchain` `sp_io` set of APIs
-	/// to perform off-chain computations, calls and submit transactions
-	/// with results to trigger any on-chain changes.
-	/// Any state alterations are lost and are not persisted.
-	fn offchain_worker(_n: BlockNumber) {}
-}
-
-pub mod schedule {
-	use super::*;
-
-	/// Information relating to the period of a scheduled task. First item is the length of the
-	/// period and the second is the number of times it should be executed in total before the task
-	/// is considered finished and removed.
-	pub type Period<BlockNumber> = (BlockNumber, u32);
-
-	/// Priority with which a call is scheduled. It's just a linear amount with lowest values meaning
-	/// higher priority.
-	pub type Priority = u8;
-
-	/// The dispatch time of a scheduled task.
-	#[derive(Encode, Decode, Copy, Clone, PartialEq, Eq, RuntimeDebug)]
-	pub enum DispatchTime<BlockNumber> {
-		/// At specified block.
-		At(BlockNumber),
-		/// After specified number of blocks.
-		After(BlockNumber),
-	}
-
-	/// The highest priority. We invert the value so that normal sorting will place the highest
-	/// priority at the beginning of the list.
-	pub const HIGHEST_PRIORITY: Priority = 0;
-	/// Anything of this value or lower will definitely be scheduled on the block that they ask for, even
-	/// if it breaches the `MaximumWeight` limitation.
-	pub const HARD_DEADLINE: Priority = 63;
-	/// The lowest priority. Most stuff should be around here.
-	pub const LOWEST_PRIORITY: Priority = 255;
-
-	/// A type that can be used as a scheduler.
-	pub trait Anon<BlockNumber, Call, Origin> {
-		/// An address which can be used for removing a scheduled task.
-		type Address: Codec + Clone + Eq + EncodeLike + Debug;
-
-		/// Schedule a dispatch to happen at the beginning of some block in the future.
-		///
-		/// This is not named.
-		fn schedule(
-			when: DispatchTime<BlockNumber>,
-			maybe_periodic: Option<Period<BlockNumber>>,
-			priority: Priority,
-			origin: Origin,
-			call: Call
-		) -> Result<Self::Address, DispatchError>;
-
-		/// Cancel a scheduled task. If periodic, then it will cancel all further instances of that,
-		/// also.
-		///
-		/// Will return an error if the `address` is invalid.
-		///
-		/// NOTE: This guaranteed to work only *before* the point that it is due to be executed.
-		/// If it ends up being delayed beyond the point of execution, then it cannot be cancelled.
-		///
-		/// NOTE2: This will not work to cancel periodic tasks after their initial execution. For
-		/// that, you must name the task explicitly using the `Named` trait.
-		fn cancel(address: Self::Address) -> Result<(), ()>;
-
-		/// Reschedule a task. For one-off tasks, this dispatch is guaranteed to succeed
-		/// only if it is executed *before* the currently scheduled block. For periodic tasks,
-		/// this dispatch is guaranteed to succeed only before the *initial* execution; for
-		/// others, use `reschedule_named`.
-		///
-		/// Will return an error if the `address` is invalid.
-		fn reschedule(
-			address: Self::Address,
-			when: DispatchTime<BlockNumber>,
-		) -> Result<Self::Address, DispatchError>;
-
-		/// Return the next dispatch time for a given task.
-		///
-		/// Will return an error if the `address` is invalid.
-		fn next_dispatch_time(address: Self::Address) -> Result<BlockNumber, ()>;
-	}
-
-	/// A type that can be used as a scheduler.
-	pub trait Named<BlockNumber, Call, Origin> {
-		/// An address which can be used for removing a scheduled task.
-		type Address: Codec + Clone + Eq + EncodeLike + sp_std::fmt::Debug;
-
-		/// Schedule a dispatch to happen at the beginning of some block in the future.
-		///
-		/// - `id`: The identity of the task. This must be unique and will return an error if not.
-		fn schedule_named(
-			id: Vec<u8>,
-			when: DispatchTime<BlockNumber>,
-			maybe_periodic: Option<Period<BlockNumber>>,
-			priority: Priority,
-			origin: Origin,
-			call: Call
-		) -> Result<Self::Address, ()>;
-
-		/// Cancel a scheduled, named task. If periodic, then it will cancel all further instances
-		/// of that, also.
-		///
-		/// Will return an error if the `id` is invalid.
-		///
-		/// NOTE: This guaranteed to work only *before* the point that it is due to be executed.
-		/// If it ends up being delayed beyond the point of execution, then it cannot be cancelled.
-		fn cancel_named(id: Vec<u8>) -> Result<(), ()>;
-
-		/// Reschedule a task. For one-off tasks, this dispatch is guaranteed to succeed
-		/// only if it is executed *before* the currently scheduled block.
-		fn reschedule_named(
-			id: Vec<u8>,
-			when: DispatchTime<BlockNumber>,
-		) -> Result<Self::Address, DispatchError>;
-
-		/// Return the next dispatch time for a given task.
-		///
-		/// Will return an error if the `id` is invalid.
-		fn next_dispatch_time(id: Vec<u8>) -> Result<BlockNumber, ()>;
-	}
-}
-
-/// Some sort of check on the origin is performed by this object.
-pub trait EnsureOrigin<OuterOrigin> {
-	/// A return type.
-	type Success;
-	/// Perform the origin check.
-	fn ensure_origin(o: OuterOrigin) -> result::Result<Self::Success, BadOrigin> {
-		Self::try_origin(o).map_err(|_| BadOrigin)
-	}
-	/// Perform the origin check.
-	fn try_origin(o: OuterOrigin) -> result::Result<Self::Success, OuterOrigin>;
-
-	/// Returns an outer origin capable of passing `try_origin` check.
-	///
-	/// ** Should be used for benchmarking only!!! **
-	#[cfg(feature = "runtime-benchmarks")]
-	fn successful_origin() -> OuterOrigin;
-}
-
-/// Type that can be dispatched with an origin but without checking the origin filter.
-///
-/// Implemented for pallet dispatchable type by `decl_module` and for runtime dispatchable by
-/// `construct_runtime` and `impl_outer_dispatch`.
-pub trait UnfilteredDispatchable {
-	/// The origin type of the runtime, (i.e. `frame_system::Config::Origin`).
-	type Origin;
-
-	/// Dispatch this call but do not check the filter in origin.
-	fn dispatch_bypass_filter(self, origin: Self::Origin) -> crate::dispatch::DispatchResultWithPostInfo;
-}
-
-/// Methods available on `frame_system::Config::Origin`.
-pub trait OriginTrait: Sized {
-	/// Runtime call type, as in `frame_system::Config::Call`
-	type Call;
-
-	/// The caller origin, overarching type of all pallets origins.
-	type PalletsOrigin;
-
-	/// The AccountId used across the system.
-	type AccountId;
-
-	/// Add a filter to the origin.
-	fn add_filter(&mut self, filter: impl Fn(&Self::Call) -> bool + 'static);
-
-	/// Reset origin filters to default one, i.e `frame_system::Config::BaseCallFilter`.
-	fn reset_filter(&mut self);
-
-	/// Replace the caller with caller from the other origin
-	fn set_caller_from(&mut self, other: impl Into<Self>);
-
-	/// Filter the call, if false then call is filtered out.
-	fn filter_call(&self, call: &Self::Call) -> bool;
-
-	/// Get the caller.
-	fn caller(&self) -> &Self::PalletsOrigin;
-
-	/// Create with system none origin and `frame-system::Config::BaseCallFilter`.
-	fn none() -> Self;
-
-	/// Create with system root origin and no filter.
-	fn root() -> Self;
-
-	/// Create with system signed origin and `frame-system::Config::BaseCallFilter`.
-	fn signed(by: Self::AccountId) -> Self;
-}
-
-/// Trait to be used when types are exactly same.
-///
-/// This allow to convert back and forth from type, a reference and a mutable reference.
-pub trait IsType<T>: Into<T> + From<T> {
-	/// Cast reference.
-	fn from_ref(t: &T) -> &Self;
-
-	/// Cast reference.
-	fn into_ref(&self) -> &T;
-
-	/// Cast mutable reference.
-	fn from_mut(t: &mut T) -> &mut Self;
-
-	/// Cast mutable reference.
-	fn into_mut(&mut self) -> &mut T;
-}
-
-impl<T> IsType<T> for T {
-	fn from_ref(t: &T) -> &Self { t }
-	fn into_ref(&self) -> &T { self }
-	fn from_mut(t: &mut T) -> &mut Self { t }
-	fn into_mut(&mut self) -> &mut T { self }
-}
-
-/// An instance of a pallet in the storage.
-///
-/// It is required that these instances are unique, to support multiple instances per pallet in the same runtime!
-///
-/// E.g. for module MyModule default instance will have prefix "MyModule" and other instances
-/// "InstanceNMyModule".
-pub trait Instance: 'static {
-	/// Unique module prefix. E.g. "InstanceNMyModule" or "MyModule"
-	const PREFIX: &'static str;
-}
-
-/// An instance of a storage in a pallet.
-///
-/// Define an instance for an individual storage inside a pallet.
-/// The pallet prefix is used to isolate the storage between pallets, and the storage prefix is
-/// used to isolate storages inside a pallet.
-///
-/// NOTE: These information can be used to define storages in pallet such as a `StorageMap` which
-/// can use keys after `twox_128(pallet_prefix())++twox_128(STORAGE_PREFIX)`
-pub trait StorageInstance {
-	/// Prefix of a pallet to isolate it from other pallets.
-	fn pallet_prefix() -> &'static str;
-
-	/// Prefix given to a storage to isolate from other storages in the pallet.
-	const STORAGE_PREFIX: &'static str;
-}
-
-/// Implement Get by returning Default for any type that implements Default.
-pub struct GetDefault;
-impl<T: Default> crate::traits::Get<T> for GetDefault {
-	fn get() -> T {
-		T::default()
-	}
-}
-
-/// A trait similar to `Convert` to convert values from `B` an abstract balance type
-/// into u64 and back from u128. (This conversion is used in election and other places where complex
-/// calculation over balance type is needed)
-///
-/// Total issuance of the currency is passed in, but an implementation of this trait may or may not
-/// use it.
-///
-/// # WARNING
-///
-/// the total issuance being passed in implies that the implementation must be aware of the fact
-/// that its values can affect the outcome. This implies that if the vote value is dependent on the
-/// total issuance, it should never ber written to storage for later re-use.
-pub trait CurrencyToVote<B> {
-	/// Convert balance to u64.
-	fn to_vote(value: B, issuance: B) -> u64;
-
-	/// Convert u128 to balance.
-	fn to_currency(value: u128, issuance: B) -> B;
-}
-
-/// An implementation of `CurrencyToVote` tailored for chain's that have a balance type of u128.
-///
-/// The factor is the `(total_issuance / u64::max()).max(1)`, represented as u64. Let's look at the
-/// important cases:
-///
-/// If the chain's total issuance is less than u64::max(), this will always be 1, which means that
-/// the factor will not have any effect. In this case, any account's balance is also less. Thus,
-/// both of the conversions are basically an `as`; Any balance can fit in u64.
-///
-/// If the chain's total issuance is more than 2*u64::max(), then a factor might be multiplied and
-/// divided upon conversion.
-pub struct U128CurrencyToVote;
-
-impl U128CurrencyToVote {
-	fn factor(issuance: u128) -> u128 {
-		(issuance / u64::max_value() as u128).max(1)
-	}
-}
-
-impl CurrencyToVote<u128> for U128CurrencyToVote {
-	fn to_vote(value: u128, issuance: u128) -> u64 {
-		(value / Self::factor(issuance)).saturated_into()
-	}
-
-	fn to_currency(value: u128, issuance: u128) -> u128 {
-		value.saturating_mul(Self::factor(issuance))
-	}
-}
-
-
-/// A naive implementation of `CurrencyConvert` that simply saturates all conversions.
-///
-/// # Warning
-///
-/// This is designed to be used mostly for testing. Use with care, and think about the consequences.
-pub struct SaturatingCurrencyToVote;
-
-impl<B: UniqueSaturatedInto<u64> + UniqueSaturatedFrom<u128>> CurrencyToVote<B> for SaturatingCurrencyToVote {
-	fn to_vote(value: B, _: B) -> u64 {
-		value.unique_saturated_into()
-	}
-
-	fn to_currency(value: u128, _: B) -> B {
-		B::unique_saturated_from(value)
-	}
-}
-
-/// Something that can be checked to be a of sub type `T`.
-///
-/// This is useful for enums where each variant encapsulates a different sub type, and
-/// you need access to these sub types.
-///
-/// For example, in FRAME, this trait is implemented for the runtime `Call` enum. Pallets use this
-/// to check if a certain call is an instance of the local pallet's `Call` enum.
-///
-/// # Example
-///
-/// ```
-/// # use frame_support::traits::IsSubType;
-///
-/// enum Test {
-///     String(String),
-///     U32(u32),
-/// }
-///
-/// impl IsSubType<String> for Test {
-///     fn is_sub_type(&self) -> Option<&String> {
-///         match self {
-///             Self::String(ref r) => Some(r),
-///             _ => None,
-///         }
-///     }
-/// }
-///
-/// impl IsSubType<u32> for Test {
-///     fn is_sub_type(&self) -> Option<&u32> {
-///         match self {
-///             Self::U32(ref r) => Some(r),
-///             _ => None,
-///         }
-///     }
-/// }
-///
-/// fn main() {
-///     let data = Test::String("test".into());
-///
-///     assert_eq!("test", IsSubType::<String>::is_sub_type(&data).unwrap().as_str());
-/// }
-/// ```
-pub trait IsSubType<T> {
-	/// Returns `Some(_)` if `self` is an instance of sub type `T`.
-	fn is_sub_type(&self) -> Option<&T>;
-}
-
-/// The pallet hooks trait. Implementing this lets you express some logic to execute.
-pub trait Hooks<BlockNumber> {
-	/// The block is being finalized. Implement to have something happen.
-	fn on_finalize(_n: BlockNumber) {}
-
-	/// This will be run when the block is being finalized (before `on_finalize`).
-	/// Implement to have something happen using the remaining weight.
-	/// Will not fire if the remaining weight is 0.
-	/// Return the weight used, the hook will subtract it from current weight used
-	/// and pass the result to the next `on_idle` hook if it exists.
-	fn on_idle(
-		_n: BlockNumber,
-		_remaining_weight: crate::weights::Weight
-	) -> crate::weights::Weight {
-		0
-	}
-
-	/// The block is being initialized. Implement to have something happen.
-	///
-	/// Return the non-negotiable weight consumed in the block.
-	fn on_initialize(_n: BlockNumber) -> crate::weights::Weight { 0 }
-
-	/// Perform a module upgrade.
-	///
-	/// NOTE: this doesn't include all pallet logic triggered on runtime upgrade. For instance it
-	/// doesn't include the write of the pallet version in storage. The final complete logic
-	/// triggered on runtime upgrade is given by implementation of `OnRuntimeUpgrade` trait by
-	/// `Pallet`.
-	///
-	/// # Warning
-	///
-	/// This function will be called before we initialized any runtime state, aka `on_initialize`
-	/// wasn't called yet. So, information like the block number and any other
-	/// block local data are not accessible.
-	///
-	/// Return the non-negotiable weight consumed for runtime upgrade.
-	fn on_runtime_upgrade() -> crate::weights::Weight { 0 }
-
-	/// Execute some pre-checks prior to a runtime upgrade.
-	///
-	/// This hook is never meant to be executed on-chain but is meant to be used by testing tools.
-	#[cfg(feature = "try-runtime")]
-	fn pre_upgrade() -> Result<(), &'static str> {
-		Ok(())
-	}
-
-	/// Execute some post-checks after a runtime upgrade.
-	///
-	/// This hook is never meant to be executed on-chain but is meant to be used by testing tools.
-	#[cfg(feature = "try-runtime")]
-	fn post_upgrade() -> Result<(), &'static str> {
-		Ok(())
-	}
-
-	/// Implementing this function on a module allows you to perform long-running tasks
-	/// that make (by default) validators generate transactions that feed results
-	/// of those long-running computations back on chain.
-	///
-	/// NOTE: This function runs off-chain, so it can access the block state,
-	/// but cannot preform any alterations. More specifically alterations are
-	/// not forbidden, but they are not persisted in any way after the worker
-	/// has finished.
-	///
-	/// This function is being called after every block import (when fully synced).
-	///
-	/// Implement this and use any of the `Offchain` `sp_io` set of APIs
-	/// to perform off-chain computations, calls and submit transactions
-	/// with results to trigger any on-chain changes.
-	/// Any state alterations are lost and are not persisted.
-	fn offchain_worker(_n: BlockNumber) {}
-
-	/// Run integrity test.
-	///
-	/// The test is not executed in a externalities provided environment.
-	fn integrity_test() {}
-}
-
-/// A trait to define the build function of a genesis config, T and I are placeholder for pallet
-/// trait and pallet instance.
+pub use hooks::{OnRuntimeUpgradeHelpersExt, ON_RUNTIME_UPGRADE_PREFIX};
 #[cfg(feature = "std")]
-pub trait GenesisBuild<T, I=()>: Default + MaybeSerializeDeserialize {
-	/// The build function is called within an externalities allowing storage APIs.
-	/// Thus one can write to storage using regular pallet storages.
-	fn build(&self);
-
-	/// Build the storage using `build` inside default storage.
-	fn build_storage(&self) -> Result<sp_runtime::Storage, String> {
-		let mut storage = Default::default();
-		self.assimilate_storage(&mut storage)?;
-		Ok(storage)
-	}
-
-	/// Assimilate the storage for this module into pre-existing overlays.
-	fn assimilate_storage(&self, storage: &mut sp_runtime::Storage) -> Result<(), String> {
-		sp_state_machine::BasicExternalities::execute_with_storage(storage, || {
-			self.build();
-			Ok(())
-		})
-	}
-}
-
-/// The storage key postfix that is used to store the [`PalletVersion`] per pallet.
-///
-/// The full storage key is built by using:
-/// Twox128([`PalletInfo::name`]) ++ Twox128([`PALLET_VERSION_STORAGE_KEY_POSTFIX`])
-pub const PALLET_VERSION_STORAGE_KEY_POSTFIX: &[u8] = b":__PALLET_VERSION__:";
-
-/// The version of a pallet.
-///
-/// Each pallet version is stored in the state under a fixed key. See
-/// [`PALLET_VERSION_STORAGE_KEY_POSTFIX`] for how this key is built.
-#[derive(RuntimeDebug, Eq, PartialEq, Encode, Decode, Ord, Clone, Copy)]
-pub struct PalletVersion {
-	/// The major version of the pallet.
-	pub major: u16,
-	/// The minor version of the pallet.
-	pub minor: u8,
-	/// The patch version of the pallet.
-	pub patch: u8,
-}
-
-impl PalletVersion {
-	/// Creates a new instance of `Self`.
-	pub fn new(major: u16, minor: u8, patch: u8) -> Self {
-		Self {
-			major,
-			minor,
-			patch,
-		}
-	}
-
-	/// Returns the storage key for a pallet version.
-	///
-	/// See [`PALLET_VERSION_STORAGE_KEY_POSTFIX`] on how this key is built.
-	///
-	/// Returns `None` if the given `PI` returned a `None` as name for the given
-	/// `Pallet`.
-	pub fn storage_key<PI: PalletInfo, Pallet: 'static>() -> Option<[u8; 32]> {
-		let pallet_name = PI::name::<Pallet>()?;
-
-		let pallet_name = sp_io::hashing::twox_128(pallet_name.as_bytes());
-		let postfix = sp_io::hashing::twox_128(PALLET_VERSION_STORAGE_KEY_POSTFIX);
-
-		let mut final_key = [0u8; 32];
-		final_key[..16].copy_from_slice(&pallet_name);
-		final_key[16..].copy_from_slice(&postfix);
-
-		Some(final_key)
-	}
-
-	/// Put this pallet version into the storage.
-	///
-	/// It will use the storage key that is associated with the given `Pallet`.
-	///
-	/// # Panics
-	///
-	/// This function will panic iff `Pallet` can not be found by `PalletInfo`.
-	/// In a runtime that is put together using
-	/// [`construct_runtime!`](crate::construct_runtime) this should never happen.
-	///
-	/// It will also panic if this function isn't executed in an externalities
-	/// provided environment.
-	pub fn put_into_storage<PI: PalletInfo, Pallet: 'static>(&self) {
-		let key = Self::storage_key::<PI, Pallet>()
-			.expect("Every active pallet has a name in the runtime; qed");
-
-		crate::storage::unhashed::put(&key, self);
-	}
-}
-
-impl sp_std::cmp::PartialOrd for PalletVersion {
-	fn partial_cmp(&self, other: &Self) -> Option<sp_std::cmp::Ordering> {
-		let res = self.major
-			.cmp(&other.major)
-			.then_with(||
-				self.minor
-					.cmp(&other.minor)
-					.then_with(|| self.patch.cmp(&other.patch)
-			));
-
-		Some(res)
-	}
-}
-
-/// Provides version information about a pallet.
-///
-/// This trait provides two functions for returning the version of a
-/// pallet. There is a state where both functions can return distinct versions.
-/// See [`GetPalletVersion::storage_version`] for more information about this.
-pub trait GetPalletVersion {
-	/// Returns the current version of the pallet.
-	fn current_version() -> PalletVersion;
-
-	/// Returns the version of the pallet that is stored in storage.
-	///
-	/// Most of the time this will return the exact same version as
-	/// [`GetPalletVersion::current_version`]. Only when being in
-	/// a state after a runtime upgrade happened and the pallet did
-	/// not yet updated its version in storage, this will return a
-	/// different(the previous, seen from the time of calling) version.
-	///
-	/// See [`PalletVersion`] for more information.
-	///
-	/// # Note
-	///
-	/// If there was no previous version of the pallet stored in the state,
-	/// this function returns `None`.
-	fn storage_version() -> Option<PalletVersion>;
-}
-
-/// Something that can execute a given block.
-///
-/// Executing a block means that all extrinsics in a given block will be executed and the resulting
-/// header will be checked against the header of the given block.
-pub trait ExecuteBlock<Block: BlockT> {
-	/// Execute the given `block`.
-	///
-	/// This will execute all extrinsics in the block and check that the resulting header is correct.
-	///
-	/// # Panic
-	///
-	/// Panics when an extrinsics panics or the resulting header doesn't match the expected header.
-	fn execute_block(block: Block);
-}
-
-/// A trait which is called when the timestamp is set in the runtime.
-#[impl_trait_for_tuples::impl_for_tuples(30)]
-pub trait OnTimestampSet<Moment> {
-	/// Called when the timestamp is set.
-	fn on_timestamp_set(moment: Moment);
-}
-
-#[cfg(test)]
-mod tests {
-	use super::*;
-
-	#[test]
-	fn on_initialize_and_on_runtime_upgrade_weight_merge_works() {
-		struct Test;
-		impl OnInitialize<u8> for Test {
-			fn on_initialize(_n: u8) -> crate::weights::Weight {
-				10
-			}
-		}
-		impl OnRuntimeUpgrade for Test {
-			fn on_runtime_upgrade() -> crate::weights::Weight {
-				20
-			}
-		}
+pub use hooks::GenesisBuild;
 
-		assert_eq!(<(Test, Test)>::on_initialize(0), 20);
-		assert_eq!(<(Test, Test)>::on_runtime_upgrade(), 40);
-	}
+pub mod schedule;
+mod storage;
+pub use storage::{Instance, StorageInstance};
 
-	#[test]
-	fn check_pallet_version_ordering() {
-		let version = PalletVersion::new(1, 0, 0);
-		assert!(version > PalletVersion::new(0, 1, 2));
-		assert!(version == PalletVersion::new(1, 0, 0));
-		assert!(version < PalletVersion::new(1, 0, 1));
-		assert!(version < PalletVersion::new(1, 1, 0));
+mod dispatch;
+pub use dispatch::{EnsureOrigin, OriginTrait, UnfilteredDispatchable};
 
-		let version = PalletVersion::new(2, 50, 50);
-		assert!(version < PalletVersion::new(2, 50, 51));
-		assert!(version > PalletVersion::new(2, 49, 51));
-		assert!(version < PalletVersion::new(3, 49, 51));
-	}
-}
+mod voting;
+pub use voting::{CurrencyToVote, SaturatingCurrencyToVote, U128CurrencyToVote};
diff --git a/frame/support/src/traits/dispatch.rs b/frame/support/src/traits/dispatch.rs
new file mode 100644
index 0000000000000..29dbaf105a05a
--- /dev/null
+++ b/frame/support/src/traits/dispatch.rs
@@ -0,0 +1,87 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Traits for dealing with dispatching calls and the origin from which they are dispatched.
+
+use crate::dispatch::DispatchResultWithPostInfo;
+use sp_runtime::traits::BadOrigin;
+
+/// Some sort of check on the origin is performed by this object.
+pub trait EnsureOrigin<OuterOrigin> {
+	/// A return type.
+	type Success;
+	/// Perform the origin check.
+	fn ensure_origin(o: OuterOrigin) -> Result<Self::Success, BadOrigin> {
+		Self::try_origin(o).map_err(|_| BadOrigin)
+	}
+	/// Perform the origin check.
+	fn try_origin(o: OuterOrigin) -> Result<Self::Success, OuterOrigin>;
+
+	/// Returns an outer origin capable of passing `try_origin` check.
+	///
+	/// ** Should be used for benchmarking only!!! **
+	#[cfg(feature = "runtime-benchmarks")]
+	fn successful_origin() -> OuterOrigin;
+}
+
+/// Type that can be dispatched with an origin but without checking the origin filter.
+///
+/// Implemented for pallet dispatchable type by `decl_module` and for runtime dispatchable by
+/// `construct_runtime` and `impl_outer_dispatch`.
+pub trait UnfilteredDispatchable {
+	/// The origin type of the runtime, (i.e. `frame_system::Config::Origin`).
+	type Origin;
+
+	/// Dispatch this call but do not check the filter in origin.
+	fn dispatch_bypass_filter(self, origin: Self::Origin) -> DispatchResultWithPostInfo;
+}
+
+/// Methods available on `frame_system::Config::Origin`.
+pub trait OriginTrait: Sized {
+	/// Runtime call type, as in `frame_system::Config::Call`
+	type Call;
+
+	/// The caller origin, overarching type of all pallets origins.
+	type PalletsOrigin;
+
+	/// The AccountId used across the system.
+	type AccountId;
+
+	/// Add a filter to the origin.
+	fn add_filter(&mut self, filter: impl Fn(&Self::Call) -> bool + 'static);
+
+	/// Reset origin filters to default one, i.e `frame_system::Config::BaseCallFilter`.
+	fn reset_filter(&mut self);
+
+	/// Replace the caller with caller from the other origin
+	fn set_caller_from(&mut self, other: impl Into<Self>);
+
+	/// Filter the call, if false then call is filtered out.
+	fn filter_call(&self, call: &Self::Call) -> bool;
+
+	/// Get the caller.
+	fn caller(&self) -> &Self::PalletsOrigin;
+
+	/// Create with system none origin and `frame-system::Config::BaseCallFilter`.
+	fn none() -> Self;
+
+	/// Create with system root origin and no filter.
+	fn root() -> Self;
+
+	/// Create with system signed origin and `frame-system::Config::BaseCallFilter`.
+	fn signed(by: Self::AccountId) -> Self;
+}
diff --git a/frame/support/src/traits/filter.rs b/frame/support/src/traits/filter.rs
new file mode 100644
index 0000000000000..f884a8ece72e5
--- /dev/null
+++ b/frame/support/src/traits/filter.rs
@@ -0,0 +1,282 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Traits and associated utilities for dealing with abstract constraint filters.
+
+use sp_std::marker::PhantomData;
+
+/// Simple trait for providing a filter over a reference to some type.
+pub trait Filter<T> {
+	/// Determine if a given value should be allowed through the filter (returns `true`) or not.
+	fn filter(_: &T) -> bool;
+}
+
+impl<T> Filter<T> for () {
+	fn filter(_: &T) -> bool { true }
+}
+
+/// Trait to add a constraint onto the filter.
+pub trait FilterStack<T>: Filter<T> {
+	/// The type used to archive the stack.
+	type Stack;
+
+	/// Add a new `constraint` onto the filter.
+	fn push(constraint: impl Fn(&T) -> bool + 'static);
+
+	/// Removes the most recently pushed, and not-yet-popped, constraint from the filter.
+	fn pop();
+
+	/// Clear the filter, returning a value that may be used later to `restore` it.
+	fn take() -> Self::Stack;
+
+	/// Restore the filter from a previous `take` operation.
+	fn restore(taken: Self::Stack);
+}
+
+/// Guard type for pushing a constraint to a `FilterStack` and popping when dropped.
+pub struct FilterStackGuard<F: FilterStack<T>, T>(PhantomData<(F, T)>);
+
+/// Guard type for clearing all pushed constraints from a `FilterStack` and reinstating them when
+/// dropped.
+pub struct ClearFilterGuard<F: FilterStack<T>, T>(Option<F::Stack>, PhantomData<T>);
+
+impl<F: FilterStack<T>, T> FilterStackGuard<F, T> {
+	/// Create a new instance, adding a new `constraint` onto the filter `T`, and popping it when
+	/// this instance is dropped.
+	pub fn new(constraint: impl Fn(&T) -> bool + 'static) -> Self {
+		F::push(constraint);
+		Self(PhantomData)
+	}
+}
+
+impl<F: FilterStack<T>, T> Drop for FilterStackGuard<F, T> {
+	fn drop(&mut self) {
+		F::pop();
+	}
+}
+
+impl<F: FilterStack<T>, T> ClearFilterGuard<F, T> {
+	/// Create a new instance, adding a new `constraint` onto the filter `T`, and popping it when
+	/// this instance is dropped.
+	pub fn new() -> Self {
+		Self(Some(F::take()), PhantomData)
+	}
+}
+
+impl<F: FilterStack<T>, T> Drop for ClearFilterGuard<F, T> {
+	fn drop(&mut self) {
+		if let Some(taken) = self.0.take() {
+			F::restore(taken);
+		}
+	}
+}
+
+/// Simple trait for providing a filter over a reference to some type, given an instance of itself.
+pub trait InstanceFilter<T>: Sized + Send + Sync {
+	/// Determine if a given value should be allowed through the filter (returns `true`) or not.
+	fn filter(&self, _: &T) -> bool;
+
+	/// Determines whether `self` matches at least everything that `_o` does.
+	fn is_superset(&self, _o: &Self) -> bool { false }
+}
+
+impl<T> InstanceFilter<T> for () {
+	fn filter(&self, _: &T) -> bool { true }
+	fn is_superset(&self, _o: &Self) -> bool { true }
+}
+
+/// Re-expected for the macro.
+#[doc(hidden)]
+pub use sp_std::{mem::{swap, take}, cell::RefCell, vec::Vec, boxed::Box};
+
+#[macro_export]
+macro_rules! impl_filter_stack {
+	($target:ty, $base:ty, $call:ty, $module:ident) => {
+		#[cfg(feature = "std")]
+		mod $module {
+			#[allow(unused_imports)]
+			use super::*;
+			use $crate::traits::filter::{swap, take, RefCell, Vec, Box, Filter, FilterStack};
+
+			thread_local! {
+				static FILTER: RefCell<Vec<Box<dyn Fn(&$call) -> bool + 'static>>> = RefCell::new(Vec::new());
+			}
+
+			impl Filter<$call> for $target {
+				fn filter(call: &$call) -> bool {
+					<$base>::filter(call) &&
+						FILTER.with(|filter| filter.borrow().iter().all(|f| f(call)))
+				}
+			}
+
+			impl FilterStack<$call> for $target {
+				type Stack = Vec<Box<dyn Fn(&$call) -> bool + 'static>>;
+				fn push(f: impl Fn(&$call) -> bool + 'static) {
+					FILTER.with(|filter| filter.borrow_mut().push(Box::new(f)));
+				}
+				fn pop() {
+					FILTER.with(|filter| filter.borrow_mut().pop());
+				}
+				fn take() -> Self::Stack {
+					FILTER.with(|filter| take(filter.borrow_mut().as_mut()))
+				}
+				fn restore(mut s: Self::Stack) {
+					FILTER.with(|filter| swap(filter.borrow_mut().as_mut(), &mut s));
+				}
+			}
+		}
+
+		#[cfg(not(feature = "std"))]
+		mod $module {
+			#[allow(unused_imports)]
+			use super::*;
+			use $crate::traits::{swap, take, RefCell, Vec, Box, Filter, FilterStack};
+
+			struct ThisFilter(RefCell<Vec<Box<dyn Fn(&$call) -> bool + 'static>>>);
+			// NOTE: Safe only in wasm (guarded above) because there's only one thread.
+			unsafe impl Send for ThisFilter {}
+			unsafe impl Sync for ThisFilter {}
+
+			static FILTER: ThisFilter = ThisFilter(RefCell::new(Vec::new()));
+
+			impl Filter<$call> for $target {
+				fn filter(call: &$call) -> bool {
+					<$base>::filter(call) && FILTER.0.borrow().iter().all(|f| f(call))
+				}
+			}
+
+			impl FilterStack<$call> for $target {
+				type Stack = Vec<Box<dyn Fn(&$call) -> bool + 'static>>;
+				fn push(f: impl Fn(&$call) -> bool + 'static) {
+					FILTER.0.borrow_mut().push(Box::new(f));
+				}
+				fn pop() {
+					FILTER.0.borrow_mut().pop();
+				}
+				fn take() -> Self::Stack {
+					take(FILTER.0.borrow_mut().as_mut())
+				}
+				fn restore(mut s: Self::Stack) {
+					swap(FILTER.0.borrow_mut().as_mut(), &mut s);
+				}
+			}
+		}
+	}
+}
+
+/// Type that provide some integrity tests.
+///
+/// This implemented for modules by `decl_module`.
+#[impl_trait_for_tuples::impl_for_tuples(30)]
+pub trait IntegrityTest {
+	/// Run integrity test.
+	///
+	/// The test is not executed in a externalities provided environment.
+	fn integrity_test() {}
+}
+
+#[cfg(test)]
+pub mod test_impl_filter_stack {
+	use super::*;
+
+	pub struct IsCallable;
+	pub struct BaseFilter;
+	impl Filter<u32> for BaseFilter {
+		fn filter(x: &u32) -> bool { x % 2 == 0 }
+	}
+	impl_filter_stack!(
+		crate::traits::filter::test_impl_filter_stack::IsCallable,
+		crate::traits::filter::test_impl_filter_stack::BaseFilter,
+		u32,
+		is_callable
+	);
+
+	#[test]
+	fn impl_filter_stack_should_work() {
+		assert!(IsCallable::filter(&36));
+		assert!(IsCallable::filter(&40));
+		assert!(IsCallable::filter(&42));
+		assert!(!IsCallable::filter(&43));
+
+		IsCallable::push(|x| *x < 42);
+		assert!(IsCallable::filter(&36));
+		assert!(IsCallable::filter(&40));
+		assert!(!IsCallable::filter(&42));
+
+		IsCallable::push(|x| *x % 3 == 0);
+		assert!(IsCallable::filter(&36));
+		assert!(!IsCallable::filter(&40));
+
+		IsCallable::pop();
+		assert!(IsCallable::filter(&36));
+		assert!(IsCallable::filter(&40));
+		assert!(!IsCallable::filter(&42));
+
+		let saved = IsCallable::take();
+		assert!(IsCallable::filter(&36));
+		assert!(IsCallable::filter(&40));
+		assert!(IsCallable::filter(&42));
+		assert!(!IsCallable::filter(&43));
+
+		IsCallable::restore(saved);
+		assert!(IsCallable::filter(&36));
+		assert!(IsCallable::filter(&40));
+		assert!(!IsCallable::filter(&42));
+
+		IsCallable::pop();
+		assert!(IsCallable::filter(&36));
+		assert!(IsCallable::filter(&40));
+		assert!(IsCallable::filter(&42));
+		assert!(!IsCallable::filter(&43));
+	}
+
+	#[test]
+	fn guards_should_work() {
+		assert!(IsCallable::filter(&36));
+		assert!(IsCallable::filter(&40));
+		assert!(IsCallable::filter(&42));
+		assert!(!IsCallable::filter(&43));
+		{
+			let _guard_1 = FilterStackGuard::<IsCallable, u32>::new(|x| *x < 42);
+			assert!(IsCallable::filter(&36));
+			assert!(IsCallable::filter(&40));
+			assert!(!IsCallable::filter(&42));
+			{
+				let _guard_2 = FilterStackGuard::<IsCallable, u32>::new(|x| *x % 3 == 0);
+				assert!(IsCallable::filter(&36));
+				assert!(!IsCallable::filter(&40));
+			}
+			assert!(IsCallable::filter(&36));
+			assert!(IsCallable::filter(&40));
+			assert!(!IsCallable::filter(&42));
+			{
+				let _guard_2 = ClearFilterGuard::<IsCallable, u32>::new();
+				assert!(IsCallable::filter(&36));
+				assert!(IsCallable::filter(&40));
+				assert!(IsCallable::filter(&42));
+				assert!(!IsCallable::filter(&43));
+			}
+			assert!(IsCallable::filter(&36));
+			assert!(IsCallable::filter(&40));
+			assert!(!IsCallable::filter(&42));
+		}
+		assert!(IsCallable::filter(&36));
+		assert!(IsCallable::filter(&40));
+		assert!(IsCallable::filter(&42));
+		assert!(!IsCallable::filter(&43));
+	}
+}
diff --git a/frame/support/src/traits/hooks.rs b/frame/support/src/traits/hooks.rs
new file mode 100644
index 0000000000000..5f7b35a9ad25c
--- /dev/null
+++ b/frame/support/src/traits/hooks.rs
@@ -0,0 +1,349 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Traits for hooking tasks to events in a blockchain's lifecycle.
+
+use sp_arithmetic::traits::Saturating;
+use sp_runtime::traits::MaybeSerializeDeserialize;
+use impl_trait_for_tuples::impl_for_tuples;
+
+/// The block initialization trait.
+///
+/// Implementing this lets you express what should happen for your pallet when the block is
+/// beginning (right before the first extrinsic is executed).
+pub trait OnInitialize<BlockNumber> {
+	/// The block is being initialized. Implement to have something happen.
+	///
+	/// Return the non-negotiable weight consumed in the block.
+	///
+	/// NOTE: This function is called BEFORE ANY extrinsic in a block is applied,
+	/// including inherent extrinsics. Hence for instance, if you runtime includes
+	/// `pallet_timestamp`, the `timestamp` is not yet up to date at this point.
+	fn on_initialize(_n: BlockNumber) -> crate::weights::Weight { 0 }
+}
+
+#[impl_for_tuples(30)]
+impl<BlockNumber: Clone> OnInitialize<BlockNumber> for Tuple {
+	fn on_initialize(n: BlockNumber) -> crate::weights::Weight {
+		let mut weight = 0;
+		for_tuples!( #( weight = weight.saturating_add(Tuple::on_initialize(n.clone())); )* );
+		weight
+	}
+}
+
+/// The block finalization trait.
+///
+/// Implementing this lets you express what should happen for your pallet when the block is ending.
+#[impl_for_tuples(30)]
+pub trait OnFinalize<BlockNumber> {
+	/// The block is being finalized. Implement to have something happen.
+	///
+	/// NOTE: This function is called AFTER ALL extrinsics in a block are applied,
+	/// including inherent extrinsics.
+	fn on_finalize(_n: BlockNumber) {}
+}
+
+/// The block's on idle trait.
+///
+/// Implementing this lets you express what should happen for your pallet before
+/// block finalization (see `on_finalize` hook) in case any remaining weight is left.
+pub trait OnIdle<BlockNumber> {
+	/// The block is being finalized.
+	/// Implement to have something happen in case there is leftover weight.
+	/// Check the passed `remaining_weight` to make sure it is high enough to allow for
+	/// your pallet's extra computation.
+	///
+	/// NOTE: This function is called AFTER ALL extrinsics - including inherent extrinsics -
+	/// in a block are applied but before `on_finalize` is executed.
+	fn on_idle(
+		_n: BlockNumber,
+		_remaining_weight: crate::weights::Weight
+	) -> crate::weights::Weight {
+		0
+	}
+}
+
+#[impl_for_tuples(30)]
+impl<BlockNumber: Clone> OnIdle<BlockNumber> for Tuple {
+	fn on_idle(n: BlockNumber,  remaining_weight: crate::weights::Weight) -> crate::weights::Weight {
+		let mut weight = 0;
+		for_tuples!( #(
+			let adjusted_remaining_weight = remaining_weight.saturating_sub(weight);
+			weight = weight.saturating_add(Tuple::on_idle(n.clone(),  adjusted_remaining_weight));
+		)* );
+		weight
+	}
+}
+
+/// A trait that will be called at genesis.
+///
+/// Implementing this trait for a pallet let's you express operations that should
+/// happen at genesis. It will be called in an externalities provided environment and
+/// will see the genesis state after all pallets have written their genesis state.
+#[impl_for_tuples(30)]
+pub trait OnGenesis {
+	/// Something that should happen at genesis.
+	fn on_genesis() {}
+}
+
+/// Prefix to be used (optionally) for implementing [`OnRuntimeUpgradeHelpersExt::storage_key`].
+#[cfg(feature = "try-runtime")]
+pub const ON_RUNTIME_UPGRADE_PREFIX: &[u8] = b"__ON_RUNTIME_UPGRADE__";
+
+/// Some helper functions for [`OnRuntimeUpgrade`] during `try-runtime` testing.
+#[cfg(feature = "try-runtime")]
+pub trait OnRuntimeUpgradeHelpersExt {
+	/// Generate a storage key unique to this runtime upgrade.
+	///
+	/// This can be used to communicate data from pre-upgrade to post-upgrade state and check
+	/// them. See [`Self::set_temp_storage`] and [`Self::get_temp_storage`].
+	#[cfg(feature = "try-runtime")]
+	fn storage_key(ident: &str) -> [u8; 32] {
+		let prefix = sp_io::hashing::twox_128(ON_RUNTIME_UPGRADE_PREFIX);
+		let ident = sp_io::hashing::twox_128(ident.as_bytes());
+
+		let mut final_key = [0u8; 32];
+		final_key[..16].copy_from_slice(&prefix);
+		final_key[16..].copy_from_slice(&ident);
+
+		final_key
+	}
+
+	/// Get temporary storage data written by [`Self::set_temp_storage`].
+	///
+	/// Returns `None` if either the data is unavailable or un-decodable.
+	///
+	/// A `at` storage identifier must be provided to indicate where the storage is being read from.
+	#[cfg(feature = "try-runtime")]
+	fn get_temp_storage<T: codec::Decode>(at: &str) -> Option<T> {
+		sp_io::storage::get(&Self::storage_key(at))
+			.and_then(|bytes| codec::Decode::decode(&mut &*bytes).ok())
+	}
+
+	/// Write some temporary data to a specific storage that can be read (potentially in
+	/// post-upgrade hook) via [`Self::get_temp_storage`].
+	///
+	/// A `at` storage identifier must be provided to indicate where the storage is being written
+	/// to.
+	#[cfg(feature = "try-runtime")]
+	fn set_temp_storage<T: codec::Encode>(data: T, at: &str) {
+		sp_io::storage::set(&Self::storage_key(at), &data.encode());
+	}
+}
+
+#[cfg(feature = "try-runtime")]
+impl<U: OnRuntimeUpgrade> OnRuntimeUpgradeHelpersExt for U {}
+
+/// The runtime upgrade trait.
+///
+/// Implementing this lets you express what should happen when the runtime upgrades,
+/// and changes may need to occur to your module.
+pub trait OnRuntimeUpgrade {
+	/// Perform a module upgrade.
+	///
+	/// # Warning
+	///
+	/// This function will be called before we initialized any runtime state, aka `on_initialize`
+	/// wasn't called yet. So, information like the block number and any other
+	/// block local data are not accessible.
+	///
+	/// Return the non-negotiable weight consumed for runtime upgrade.
+	fn on_runtime_upgrade() -> crate::weights::Weight {
+		0
+	}
+
+	/// Execute some pre-checks prior to a runtime upgrade.
+	///
+	/// This hook is never meant to be executed on-chain but is meant to be used by testing tools.
+	#[cfg(feature = "try-runtime")]
+	fn pre_upgrade() -> Result<(), &'static str> { Ok(()) }
+
+	/// Execute some post-checks after a runtime upgrade.
+	///
+	/// This hook is never meant to be executed on-chain but is meant to be used by testing tools.
+	#[cfg(feature = "try-runtime")]
+	fn post_upgrade() -> Result<(), &'static str> { Ok(()) }
+}
+
+#[impl_for_tuples(30)]
+impl OnRuntimeUpgrade for Tuple {
+	fn on_runtime_upgrade() -> crate::weights::Weight {
+		let mut weight = 0;
+		for_tuples!( #( weight = weight.saturating_add(Tuple::on_runtime_upgrade()); )* );
+		weight
+	}
+
+	#[cfg(feature = "try-runtime")]
+	fn pre_upgrade() -> Result<(), &'static str> {
+		let mut result = Ok(());
+		for_tuples!( #( result = result.and(Tuple::pre_upgrade()); )* );
+		result
+	}
+
+	#[cfg(feature = "try-runtime")]
+	fn post_upgrade() -> Result<(), &'static str> {
+		let mut result = Ok(());
+		for_tuples!( #( result = result.and(Tuple::post_upgrade()); )* );
+		result
+	}
+}
+
+/// The pallet hooks trait. Implementing this lets you express some logic to execute.
+pub trait Hooks<BlockNumber> {
+	/// The block is being finalized. Implement to have something happen.
+	fn on_finalize(_n: BlockNumber) {}
+
+	/// This will be run when the block is being finalized (before `on_finalize`).
+	/// Implement to have something happen using the remaining weight.
+	/// Will not fire if the remaining weight is 0.
+	/// Return the weight used, the hook will subtract it from current weight used
+	/// and pass the result to the next `on_idle` hook if it exists.
+	fn on_idle(
+		_n: BlockNumber,
+		_remaining_weight: crate::weights::Weight
+	) -> crate::weights::Weight {
+		0
+	}
+
+	/// The block is being initialized. Implement to have something happen.
+	///
+	/// Return the non-negotiable weight consumed in the block.
+	fn on_initialize(_n: BlockNumber) -> crate::weights::Weight { 0 }
+
+	/// Perform a module upgrade.
+	///
+	/// NOTE: this doesn't include all pallet logic triggered on runtime upgrade. For instance it
+	/// doesn't include the write of the pallet version in storage. The final complete logic
+	/// triggered on runtime upgrade is given by implementation of `OnRuntimeUpgrade` trait by
+	/// `Pallet`.
+	///
+	/// # Warning
+	///
+	/// This function will be called before we initialized any runtime state, aka `on_initialize`
+	/// wasn't called yet. So, information like the block number and any other
+	/// block local data are not accessible.
+	///
+	/// Return the non-negotiable weight consumed for runtime upgrade.
+	fn on_runtime_upgrade() -> crate::weights::Weight { 0 }
+
+	/// Execute some pre-checks prior to a runtime upgrade.
+	///
+	/// This hook is never meant to be executed on-chain but is meant to be used by testing tools.
+	#[cfg(feature = "try-runtime")]
+	fn pre_upgrade() -> Result<(), &'static str> {
+		Ok(())
+	}
+
+	/// Execute some post-checks after a runtime upgrade.
+	///
+	/// This hook is never meant to be executed on-chain but is meant to be used by testing tools.
+	#[cfg(feature = "try-runtime")]
+	fn post_upgrade() -> Result<(), &'static str> {
+		Ok(())
+	}
+
+	/// Implementing this function on a module allows you to perform long-running tasks
+	/// that make (by default) validators generate transactions that feed results
+	/// of those long-running computations back on chain.
+	///
+	/// NOTE: This function runs off-chain, so it can access the block state,
+	/// but cannot preform any alterations. More specifically alterations are
+	/// not forbidden, but they are not persisted in any way after the worker
+	/// has finished.
+	///
+	/// This function is being called after every block import (when fully synced).
+	///
+	/// Implement this and use any of the `Offchain` `sp_io` set of APIs
+	/// to perform off-chain computations, calls and submit transactions
+	/// with results to trigger any on-chain changes.
+	/// Any state alterations are lost and are not persisted.
+	fn offchain_worker(_n: BlockNumber) {}
+
+	/// Run integrity test.
+	///
+	/// The test is not executed in a externalities provided environment.
+	fn integrity_test() {}
+}
+
+/// A trait to define the build function of a genesis config, T and I are placeholder for pallet
+/// trait and pallet instance.
+#[cfg(feature = "std")]
+pub trait GenesisBuild<T, I=()>: Default + MaybeSerializeDeserialize {
+	/// The build function is called within an externalities allowing storage APIs.
+	/// Thus one can write to storage using regular pallet storages.
+	fn build(&self);
+
+	/// Build the storage using `build` inside default storage.
+	fn build_storage(&self) -> Result<sp_runtime::Storage, String> {
+		let mut storage = Default::default();
+		self.assimilate_storage(&mut storage)?;
+		Ok(storage)
+	}
+
+	/// Assimilate the storage for this module into pre-existing overlays.
+	fn assimilate_storage(&self, storage: &mut sp_runtime::Storage) -> Result<(), String> {
+		sp_state_machine::BasicExternalities::execute_with_storage(storage, || {
+			self.build();
+			Ok(())
+		})
+	}
+}
+
+/// A trait which is called when the timestamp is set in the runtime.
+#[impl_for_tuples(30)]
+pub trait OnTimestampSet<Moment> {
+	/// Called when the timestamp is set.
+	fn on_timestamp_set(moment: Moment);
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+	use crate::traits::metadata::PalletVersion;
+
+	#[test]
+	fn on_initialize_and_on_runtime_upgrade_weight_merge_works() {
+		struct Test;
+		impl OnInitialize<u8> for Test {
+			fn on_initialize(_n: u8) -> crate::weights::Weight {
+				10
+			}
+		}
+		impl OnRuntimeUpgrade for Test {
+			fn on_runtime_upgrade() -> crate::weights::Weight {
+				20
+			}
+		}
+
+		assert_eq!(<(Test, Test)>::on_initialize(0), 20);
+		assert_eq!(<(Test, Test)>::on_runtime_upgrade(), 40);
+	}
+
+	#[test]
+	fn check_pallet_version_ordering() {
+		let version = PalletVersion::new(1, 0, 0);
+		assert!(version > PalletVersion::new(0, 1, 2));
+		assert!(version == PalletVersion::new(1, 0, 0));
+		assert!(version < PalletVersion::new(1, 0, 1));
+		assert!(version < PalletVersion::new(1, 1, 0));
+
+		let version = PalletVersion::new(2, 50, 50);
+		assert!(version < PalletVersion::new(2, 50, 51));
+		assert!(version > PalletVersion::new(2, 49, 51));
+		assert!(version < PalletVersion::new(3, 49, 51));
+	}
+}
diff --git a/frame/support/src/traits/members.rs b/frame/support/src/traits/members.rs
new file mode 100644
index 0000000000000..d3ce6786af8c1
--- /dev/null
+++ b/frame/support/src/traits/members.rs
@@ -0,0 +1,142 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Traits for dealing with the idea of membership.
+
+use sp_std::prelude::*;
+
+/// A trait for querying whether a type can be said to "contain" a value.
+pub trait Contains<T: Ord> {
+	/// Return `true` if this "contains" the given value `t`.
+	fn contains(t: &T) -> bool { Self::sorted_members().binary_search(t).is_ok() }
+
+	/// Get a vector of all members in the set, ordered.
+	fn sorted_members() -> Vec<T>;
+
+	/// Get the number of items in the set.
+	fn count() -> usize { Self::sorted_members().len() }
+
+	/// Add an item that would satisfy `contains`. It does not make sure any other
+	/// state is correctly maintained or generated.
+	///
+	/// **Should be used for benchmarking only!!!**
+	#[cfg(feature = "runtime-benchmarks")]
+	fn add(_t: &T) { unimplemented!() }
+}
+
+/// A trait for querying bound for the length of an implementation of `Contains`
+pub trait ContainsLengthBound {
+	/// Minimum number of elements contained
+	fn min_len() -> usize;
+	/// Maximum number of elements contained
+	fn max_len() -> usize;
+}
+
+/// Trait for type that can handle the initialization of account IDs at genesis.
+pub trait InitializeMembers<AccountId> {
+	/// Initialize the members to the given `members`.
+	fn initialize_members(members: &[AccountId]);
+}
+
+impl<T> InitializeMembers<T> for () {
+	fn initialize_members(_: &[T]) {}
+}
+
+/// Trait for type that can handle incremental changes to a set of account IDs.
+pub trait ChangeMembers<AccountId: Clone + Ord> {
+	/// A number of members `incoming` just joined the set and replaced some `outgoing` ones. The
+	/// new set is given by `new`, and need not be sorted.
+	///
+	/// This resets any previous value of prime.
+	fn change_members(incoming: &[AccountId], outgoing: &[AccountId], mut new: Vec<AccountId>) {
+		new.sort();
+		Self::change_members_sorted(incoming, outgoing, &new[..]);
+	}
+
+	/// A number of members `_incoming` just joined the set and replaced some `_outgoing` ones. The
+	/// new set is thus given by `sorted_new` and **must be sorted**.
+	///
+	/// NOTE: This is the only function that needs to be implemented in `ChangeMembers`.
+	///
+	/// This resets any previous value of prime.
+	fn change_members_sorted(
+		incoming: &[AccountId],
+		outgoing: &[AccountId],
+		sorted_new: &[AccountId],
+	);
+
+	/// Set the new members; they **must already be sorted**. This will compute the diff and use it to
+	/// call `change_members_sorted`.
+	///
+	/// This resets any previous value of prime.
+	fn set_members_sorted(new_members: &[AccountId], old_members: &[AccountId]) {
+		let (incoming, outgoing) = Self::compute_members_diff_sorted(new_members, old_members);
+		Self::change_members_sorted(&incoming[..], &outgoing[..], &new_members);
+	}
+
+	/// Compute diff between new and old members; they **must already be sorted**.
+	///
+	/// Returns incoming and outgoing members.
+	fn compute_members_diff_sorted(
+		new_members: &[AccountId],
+		old_members: &[AccountId],
+	) -> (Vec<AccountId>, Vec<AccountId>) {
+		let mut old_iter = old_members.iter();
+		let mut new_iter = new_members.iter();
+		let mut incoming = Vec::new();
+		let mut outgoing = Vec::new();
+		let mut old_i = old_iter.next();
+		let mut new_i = new_iter.next();
+		loop {
+			match (old_i, new_i) {
+				(None, None) => break,
+				(Some(old), Some(new)) if old == new => {
+					old_i = old_iter.next();
+					new_i = new_iter.next();
+				}
+				(Some(old), Some(new)) if old < new => {
+					outgoing.push(old.clone());
+					old_i = old_iter.next();
+				}
+				(Some(old), None) => {
+					outgoing.push(old.clone());
+					old_i = old_iter.next();
+				}
+				(_, Some(new)) => {
+					incoming.push(new.clone());
+					new_i = new_iter.next();
+				}
+			}
+		}
+		(incoming, outgoing)
+	}
+
+	/// Set the prime member.
+	fn set_prime(_prime: Option<AccountId>) {}
+
+	/// Get the current prime.
+	fn get_prime() -> Option<AccountId> {
+		None
+	}
+}
+
+impl<T: Clone + Ord> ChangeMembers<T> for () {
+	fn change_members(_: &[T], _: &[T], _: Vec<T>) {}
+	fn change_members_sorted(_: &[T], _: &[T], _: &[T]) {}
+	fn set_members_sorted(_: &[T], _: &[T]) {}
+	fn set_prime(_: Option<T>) {}
+}
diff --git a/frame/support/src/traits/metadata.rs b/frame/support/src/traits/metadata.rs
new file mode 100644
index 0000000000000..ff4507dce9c98
--- /dev/null
+++ b/frame/support/src/traits/metadata.rs
@@ -0,0 +1,168 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Traits for managing information attached to pallets and their constituents.
+
+use codec::{Encode, Decode};
+use sp_runtime::RuntimeDebug;
+
+/// Provides information about the pallet setup in the runtime.
+///
+/// An implementor should be able to provide information about each pallet that
+/// is configured in `construct_runtime!`.
+pub trait PalletInfo {
+	/// Convert the given pallet `P` into its index as configured in the runtime.
+	fn index<P: 'static>() -> Option<usize>;
+	/// Convert the given pallet `P` into its name as configured in the runtime.
+	fn name<P: 'static>() -> Option<&'static str>;
+}
+
+/// The function and pallet name of the Call.
+#[derive(Clone, Eq, PartialEq, Default, RuntimeDebug)]
+pub struct CallMetadata {
+	/// Name of the function.
+	pub function_name: &'static str,
+	/// Name of the pallet to which the function belongs.
+	pub pallet_name: &'static str,
+}
+
+/// Gets the function name of the Call.
+pub trait GetCallName {
+	/// Return all function names.
+	fn get_call_names() -> &'static [&'static str];
+	/// Return the function name of the Call.
+	fn get_call_name(&self) -> &'static str;
+}
+
+/// Gets the metadata for the Call - function name and pallet name.
+pub trait GetCallMetadata {
+	/// Return all module names.
+	fn get_module_names() -> &'static [&'static str];
+	/// Return all function names for the given `module`.
+	fn get_call_names(module: &str) -> &'static [&'static str];
+	/// Return a [`CallMetadata`], containing function and pallet name of the Call.
+	fn get_call_metadata(&self) -> CallMetadata;
+}
+
+/// The storage key postfix that is used to store the [`PalletVersion`] per pallet.
+///
+/// The full storage key is built by using:
+/// Twox128([`PalletInfo::name`]) ++ Twox128([`PALLET_VERSION_STORAGE_KEY_POSTFIX`])
+pub const PALLET_VERSION_STORAGE_KEY_POSTFIX: &[u8] = b":__PALLET_VERSION__:";
+
+/// The version of a pallet.
+///
+/// Each pallet version is stored in the state under a fixed key. See
+/// [`PALLET_VERSION_STORAGE_KEY_POSTFIX`] for how this key is built.
+#[derive(RuntimeDebug, Eq, PartialEq, Encode, Decode, Ord, Clone, Copy)]
+pub struct PalletVersion {
+	/// The major version of the pallet.
+	pub major: u16,
+	/// The minor version of the pallet.
+	pub minor: u8,
+	/// The patch version of the pallet.
+	pub patch: u8,
+}
+
+impl PalletVersion {
+	/// Creates a new instance of `Self`.
+	pub fn new(major: u16, minor: u8, patch: u8) -> Self {
+		Self {
+			major,
+			minor,
+			patch,
+		}
+	}
+
+	/// Returns the storage key for a pallet version.
+	///
+	/// See [`PALLET_VERSION_STORAGE_KEY_POSTFIX`] on how this key is built.
+	///
+	/// Returns `None` if the given `PI` returned a `None` as name for the given
+	/// `Pallet`.
+	pub fn storage_key<PI: PalletInfo, Pallet: 'static>() -> Option<[u8; 32]> {
+		let pallet_name = PI::name::<Pallet>()?;
+
+		let pallet_name = sp_io::hashing::twox_128(pallet_name.as_bytes());
+		let postfix = sp_io::hashing::twox_128(PALLET_VERSION_STORAGE_KEY_POSTFIX);
+
+		let mut final_key = [0u8; 32];
+		final_key[..16].copy_from_slice(&pallet_name);
+		final_key[16..].copy_from_slice(&postfix);
+
+		Some(final_key)
+	}
+
+	/// Put this pallet version into the storage.
+	///
+	/// It will use the storage key that is associated with the given `Pallet`.
+	///
+	/// # Panics
+	///
+	/// This function will panic iff `Pallet` can not be found by `PalletInfo`.
+	/// In a runtime that is put together using
+	/// [`construct_runtime!`](crate::construct_runtime) this should never happen.
+	///
+	/// It will also panic if this function isn't executed in an externalities
+	/// provided environment.
+	pub fn put_into_storage<PI: PalletInfo, Pallet: 'static>(&self) {
+		let key = Self::storage_key::<PI, Pallet>()
+			.expect("Every active pallet has a name in the runtime; qed");
+
+		crate::storage::unhashed::put(&key, self);
+	}
+}
+
+impl sp_std::cmp::PartialOrd for PalletVersion {
+	fn partial_cmp(&self, other: &Self) -> Option<sp_std::cmp::Ordering> {
+		let res = self.major
+			.cmp(&other.major)
+			.then_with(||
+				self.minor
+					.cmp(&other.minor)
+					.then_with(|| self.patch.cmp(&other.patch)
+					));
+
+		Some(res)
+	}
+}
+
+/// Provides version information about a pallet.
+///
+/// This trait provides two functions for returning the version of a
+/// pallet. There is a state where both functions can return distinct versions.
+/// See [`GetPalletVersion::storage_version`] for more information about this.
+pub trait GetPalletVersion {
+	/// Returns the current version of the pallet.
+	fn current_version() -> PalletVersion;
+
+	/// Returns the version of the pallet that is stored in storage.
+	///
+	/// Most of the time this will return the exact same version as
+	/// [`GetPalletVersion::current_version`]. Only when being in
+	/// a state after a runtime upgrade happened and the pallet did
+	/// not yet updated its version in storage, this will return a
+	/// different(the previous, seen from the time of calling) version.
+	///
+	/// See [`PalletVersion`] for more information.
+	///
+	/// # Note
+	///
+	/// If there was no previous version of the pallet stored in the state,
+	/// this function returns `None`.
+	fn storage_version() -> Option<PalletVersion>;
+}
diff --git a/frame/support/src/traits/misc.rs b/frame/support/src/traits/misc.rs
new file mode 100644
index 0000000000000..2f219942907d8
--- /dev/null
+++ b/frame/support/src/traits/misc.rs
@@ -0,0 +1,271 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Smaller traits used in FRAME which don't need their own file.
+
+use sp_runtime::traits::{StoredMapError, Block as BlockT};
+use sp_arithmetic::traits::AtLeast32Bit;
+use crate::dispatch::Parameter;
+
+/// Anything that can have a `::len()` method.
+pub trait Len {
+	/// Return the length of data type.
+	fn len(&self) -> usize;
+}
+
+impl<T: IntoIterator + Clone,> Len for T where <T as IntoIterator>::IntoIter: ExactSizeIterator {
+	fn len(&self) -> usize {
+		self.clone().into_iter().len()
+	}
+}
+
+/// A trait for querying a single value from a type.
+///
+/// It is not required that the value is constant.
+pub trait Get<T> {
+	/// Return the current value.
+	fn get() -> T;
+}
+
+impl<T: Default> Get<T> for () {
+	fn get() -> T { T::default() }
+}
+
+/// Implement Get by returning Default for any type that implements Default.
+pub struct GetDefault;
+impl<T: Default> Get<T> for GetDefault {
+	fn get() -> T {
+		T::default()
+	}
+}
+
+/// A type for which some values make sense to be able to drop without further consideration.
+pub trait TryDrop: Sized {
+	/// Drop an instance cleanly. Only works if its value represents "no-operation".
+	fn try_drop(self) -> Result<(), Self>;
+}
+
+/// Return type used when we need to return one of two items, each of the opposite direction or
+/// sign, with one (`Same`) being of the same type as the `self` or primary argument of the function
+/// that returned it.
+pub enum SameOrOther<A, B> {
+	/// No item.
+	None,
+	/// An item of the same type as the `Self` on which the return function was called.
+	Same(A),
+	/// An item of the opposite type to the `Self` on which the return function was called.
+	Other(B),
+}
+
+impl<A, B> TryDrop for SameOrOther<A, B> {
+	fn try_drop(self) -> Result<(), Self> {
+		if let SameOrOther::None = self {
+			Ok(())
+		} else {
+			Err(self)
+		}
+	}
+}
+
+impl<A, B> SameOrOther<A, B> {
+	/// Returns `Ok` with the inner value of `Same` if `self` is that, otherwise returns `Err` with
+	/// `self`.
+	pub fn try_same(self) -> Result<A, Self> {
+		match self {
+			SameOrOther::Same(a) => Ok(a),
+			x => Err(x),
+		}
+	}
+
+	/// Returns `Ok` with the inner value of `Other` if `self` is that, otherwise returns `Err` with
+	/// `self`.
+	pub fn try_other(self) -> Result<B, Self> {
+		match self {
+			SameOrOther::Other(b) => Ok(b),
+			x => Err(x),
+		}
+	}
+
+	/// Returns `Ok` if `self` is `None`, otherwise returns `Err` with `self`.
+	pub fn try_none(self) -> Result<(), Self> {
+		match self {
+			SameOrOther::None => Ok(()),
+			x => Err(x),
+		}
+	}
+
+	pub fn same(self) -> Result<A, B> where A: Default {
+		match self {
+			SameOrOther::Same(a) => Ok(a),
+			SameOrOther::None => Ok(A::default()),
+			SameOrOther::Other(b) => Err(b),
+		}
+	}
+
+	pub fn other(self) -> Result<B, A> where B: Default {
+		match self {
+			SameOrOther::Same(a) => Err(a),
+			SameOrOther::None => Ok(B::default()),
+			SameOrOther::Other(b) => Ok(b),
+		}
+	}
+}
+
+/// Handler for when a new account has been created.
+#[impl_trait_for_tuples::impl_for_tuples(30)]
+pub trait OnNewAccount<AccountId> {
+	/// A new account `who` has been registered.
+	fn on_new_account(who: &AccountId);
+}
+
+/// The account with the given id was reaped.
+#[impl_trait_for_tuples::impl_for_tuples(30)]
+pub trait OnKilledAccount<AccountId> {
+	/// The account with the given id was reaped.
+	fn on_killed_account(who: &AccountId);
+}
+
+/// A simple, generic one-parameter event notifier/handler.
+pub trait HandleLifetime<T> {
+	/// An account was created.
+	fn created(_t: &T) -> Result<(), StoredMapError> { Ok(()) }
+
+	/// An account was killed.
+	fn killed(_t: &T) -> Result<(), StoredMapError> { Ok(()) }
+}
+
+impl<T> HandleLifetime<T> for () {}
+
+pub trait Time {
+	type Moment: AtLeast32Bit + Parameter + Default + Copy;
+
+	fn now() -> Self::Moment;
+}
+
+/// Trait to deal with unix time.
+pub trait UnixTime {
+	/// Return duration since `SystemTime::UNIX_EPOCH`.
+	fn now() -> core::time::Duration;
+}
+
+/// Trait to be used when types are exactly same.
+///
+/// This allow to convert back and forth from type, a reference and a mutable reference.
+pub trait IsType<T>: Into<T> + From<T> {
+	/// Cast reference.
+	fn from_ref(t: &T) -> &Self;
+
+	/// Cast reference.
+	fn into_ref(&self) -> &T;
+
+	/// Cast mutable reference.
+	fn from_mut(t: &mut T) -> &mut Self;
+
+	/// Cast mutable reference.
+	fn into_mut(&mut self) -> &mut T;
+}
+
+impl<T> IsType<T> for T {
+	fn from_ref(t: &T) -> &Self { t }
+	fn into_ref(&self) -> &T { self }
+	fn from_mut(t: &mut T) -> &mut Self { t }
+	fn into_mut(&mut self) -> &mut T { self }
+}
+
+/// Something that can be checked to be a of sub type `T`.
+///
+/// This is useful for enums where each variant encapsulates a different sub type, and
+/// you need access to these sub types.
+///
+/// For example, in FRAME, this trait is implemented for the runtime `Call` enum. Pallets use this
+/// to check if a certain call is an instance of the local pallet's `Call` enum.
+///
+/// # Example
+///
+/// ```
+/// # use frame_support::traits::IsSubType;
+///
+/// enum Test {
+///     String(String),
+///     U32(u32),
+/// }
+///
+/// impl IsSubType<String> for Test {
+///     fn is_sub_type(&self) -> Option<&String> {
+///         match self {
+///             Self::String(ref r) => Some(r),
+///             _ => None,
+///         }
+///     }
+/// }
+///
+/// impl IsSubType<u32> for Test {
+///     fn is_sub_type(&self) -> Option<&u32> {
+///         match self {
+///             Self::U32(ref r) => Some(r),
+///             _ => None,
+///         }
+///     }
+/// }
+///
+/// fn main() {
+///     let data = Test::String("test".into());
+///
+///     assert_eq!("test", IsSubType::<String>::is_sub_type(&data).unwrap().as_str());
+/// }
+/// ```
+pub trait IsSubType<T> {
+	/// Returns `Some(_)` if `self` is an instance of sub type `T`.
+	fn is_sub_type(&self) -> Option<&T>;
+}
+
+/// Something that can execute a given block.
+///
+/// Executing a block means that all extrinsics in a given block will be executed and the resulting
+/// header will be checked against the header of the given block.
+pub trait ExecuteBlock<Block: BlockT> {
+	/// Execute the given `block`.
+	///
+	/// This will execute all extrinsics in the block and check that the resulting header is correct.
+	///
+	/// # Panic
+	///
+	/// Panics when an extrinsics panics or the resulting header doesn't match the expected header.
+	fn execute_block(block: Block);
+}
+
+/// Off-chain computation trait.
+///
+/// Implementing this trait on a module allows you to perform long-running tasks
+/// that make (by default) validators generate transactions that feed results
+/// of those long-running computations back on chain.
+///
+/// NOTE: This function runs off-chain, so it can access the block state,
+/// but cannot preform any alterations. More specifically alterations are
+/// not forbidden, but they are not persisted in any way after the worker
+/// has finished.
+#[impl_trait_for_tuples::impl_for_tuples(30)]
+pub trait OffchainWorker<BlockNumber> {
+	/// This function is being called after every block import (when fully synced).
+	///
+	/// Implement this and use any of the `Offchain` `sp_io` set of APIs
+	/// to perform off-chain computations, calls and submit transactions
+	/// with results to trigger any on-chain changes.
+	/// Any state alterations are lost and are not persisted.
+	fn offchain_worker(_n: BlockNumber) {}
+}
+
diff --git a/frame/support/src/traits/randomness.rs b/frame/support/src/traits/randomness.rs
new file mode 100644
index 0000000000000..865893f99b393
--- /dev/null
+++ b/frame/support/src/traits/randomness.rs
@@ -0,0 +1,54 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Traits for dealing with on-chain randomness.
+
+/// A trait that is able to provide randomness.
+///
+/// Being a deterministic blockchain, real randomness is difficult to come by, different
+/// implementations of this trait will provide different security guarantees. At best,
+/// this will be randomness which was hard to predict a long time ago, but that has become
+/// easy to predict recently.
+pub trait Randomness<Output, BlockNumber> {
+	/// Get the most recently determined random seed, along with the time in the past
+	/// since when it was determinable by chain observers.
+	///
+	/// `subject` is a context identifier and allows you to get a different result to
+	/// other callers of this function; use it like `random(&b"my context"[..])`.
+	///
+	/// NOTE: The returned seed should only be used to distinguish commitments made before
+	/// the returned block number. If the block number is too early (i.e. commitments were
+	/// made afterwards), then ensure no further commitments may be made and repeatedly
+	/// call this on later blocks until the block number returned is later than the latest
+	/// commitment.
+	fn random(subject: &[u8]) -> (Output, BlockNumber);
+
+	/// Get the basic random seed.
+	///
+	/// In general you won't want to use this, but rather `Self::random` which allows
+	/// you to give a subject for the random result and whose value will be
+	/// independently low-influence random from any other such seeds.
+	///
+	/// NOTE: The returned seed should only be used to distinguish commitments made before
+	/// the returned block number. If the block number is too early (i.e. commitments were
+	/// made afterwards), then ensure no further commitments may be made and repeatedly
+	/// call this on later blocks until the block number returned is later than the latest
+	/// commitment.
+	fn random_seed() -> (Output, BlockNumber) {
+		Self::random(&[][..])
+	}
+}
diff --git a/frame/support/src/traits/schedule.rs b/frame/support/src/traits/schedule.rs
new file mode 100644
index 0000000000000..58e4c419f2813
--- /dev/null
+++ b/frame/support/src/traits/schedule.rs
@@ -0,0 +1,133 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Traits and associated utilities for scheduling dispatchables in FRAME.
+
+use sp_std::{prelude::*, fmt::Debug};
+use codec::{Encode, Decode, Codec, EncodeLike};
+use sp_runtime::{RuntimeDebug, DispatchError};
+
+/// Information relating to the period of a scheduled task. First item is the length of the
+/// period and the second is the number of times it should be executed in total before the task
+/// is considered finished and removed.
+pub type Period<BlockNumber> = (BlockNumber, u32);
+
+/// Priority with which a call is scheduled. It's just a linear amount with lowest values meaning
+/// higher priority.
+pub type Priority = u8;
+
+/// The dispatch time of a scheduled task.
+#[derive(Encode, Decode, Copy, Clone, PartialEq, Eq, RuntimeDebug)]
+pub enum DispatchTime<BlockNumber> {
+	/// At specified block.
+	At(BlockNumber),
+	/// After specified number of blocks.
+	After(BlockNumber),
+}
+
+/// The highest priority. We invert the value so that normal sorting will place the highest
+/// priority at the beginning of the list.
+pub const HIGHEST_PRIORITY: Priority = 0;
+/// Anything of this value or lower will definitely be scheduled on the block that they ask for, even
+/// if it breaches the `MaximumWeight` limitation.
+pub const HARD_DEADLINE: Priority = 63;
+/// The lowest priority. Most stuff should be around here.
+pub const LOWEST_PRIORITY: Priority = 255;
+
+/// A type that can be used as a scheduler.
+pub trait Anon<BlockNumber, Call, Origin> {
+	/// An address which can be used for removing a scheduled task.
+	type Address: Codec + Clone + Eq + EncodeLike + Debug;
+
+	/// Schedule a dispatch to happen at the beginning of some block in the future.
+	///
+	/// This is not named.
+	fn schedule(
+		when: DispatchTime<BlockNumber>,
+		maybe_periodic: Option<Period<BlockNumber>>,
+		priority: Priority,
+		origin: Origin,
+		call: Call
+	) -> Result<Self::Address, DispatchError>;
+
+	/// Cancel a scheduled task. If periodic, then it will cancel all further instances of that,
+	/// also.
+	///
+	/// Will return an error if the `address` is invalid.
+	///
+	/// NOTE: This guaranteed to work only *before* the point that it is due to be executed.
+	/// If it ends up being delayed beyond the point of execution, then it cannot be cancelled.
+	///
+	/// NOTE2: This will not work to cancel periodic tasks after their initial execution. For
+	/// that, you must name the task explicitly using the `Named` trait.
+	fn cancel(address: Self::Address) -> Result<(), ()>;
+
+	/// Reschedule a task. For one-off tasks, this dispatch is guaranteed to succeed
+	/// only if it is executed *before* the currently scheduled block. For periodic tasks,
+	/// this dispatch is guaranteed to succeed only before the *initial* execution; for
+	/// others, use `reschedule_named`.
+	///
+	/// Will return an error if the `address` is invalid.
+	fn reschedule(
+		address: Self::Address,
+		when: DispatchTime<BlockNumber>,
+	) -> Result<Self::Address, DispatchError>;
+
+	/// Return the next dispatch time for a given task.
+	///
+	/// Will return an error if the `address` is invalid.
+	fn next_dispatch_time(address: Self::Address) -> Result<BlockNumber, ()>;
+}
+
+/// A type that can be used as a scheduler.
+pub trait Named<BlockNumber, Call, Origin> {
+	/// An address which can be used for removing a scheduled task.
+	type Address: Codec + Clone + Eq + EncodeLike + sp_std::fmt::Debug;
+
+	/// Schedule a dispatch to happen at the beginning of some block in the future.
+	///
+	/// - `id`: The identity of the task. This must be unique and will return an error if not.
+	fn schedule_named(
+		id: Vec<u8>,
+		when: DispatchTime<BlockNumber>,
+		maybe_periodic: Option<Period<BlockNumber>>,
+		priority: Priority,
+		origin: Origin,
+		call: Call
+	) -> Result<Self::Address, ()>;
+
+	/// Cancel a scheduled, named task. If periodic, then it will cancel all further instances
+	/// of that, also.
+	///
+	/// Will return an error if the `id` is invalid.
+	///
+	/// NOTE: This guaranteed to work only *before* the point that it is due to be executed.
+	/// If it ends up being delayed beyond the point of execution, then it cannot be cancelled.
+	fn cancel_named(id: Vec<u8>) -> Result<(), ()>;
+
+	/// Reschedule a task. For one-off tasks, this dispatch is guaranteed to succeed
+	/// only if it is executed *before* the currently scheduled block.
+	fn reschedule_named(
+		id: Vec<u8>,
+		when: DispatchTime<BlockNumber>,
+	) -> Result<Self::Address, DispatchError>;
+
+	/// Return the next dispatch time for a given task.
+	///
+	/// Will return an error if the `id` is invalid.
+	fn next_dispatch_time(id: Vec<u8>) -> Result<BlockNumber, ()>;
+}
diff --git a/frame/support/src/traits/storage.rs b/frame/support/src/traits/storage.rs
new file mode 100644
index 0000000000000..82e9c1e7a60f6
--- /dev/null
+++ b/frame/support/src/traits/storage.rs
@@ -0,0 +1,45 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Traits for encoding data related to pallet's storage items.
+
+/// An instance of a pallet in the storage.
+///
+/// It is required that these instances are unique, to support multiple instances per pallet in the same runtime!
+///
+/// E.g. for module MyModule default instance will have prefix "MyModule" and other instances
+/// "InstanceNMyModule".
+pub trait Instance: 'static {
+	/// Unique module prefix. E.g. "InstanceNMyModule" or "MyModule"
+	const PREFIX: &'static str;
+}
+
+/// An instance of a storage in a pallet.
+///
+/// Define an instance for an individual storage inside a pallet.
+/// The pallet prefix is used to isolate the storage between pallets, and the storage prefix is
+/// used to isolate storages inside a pallet.
+///
+/// NOTE: These information can be used to define storages in pallet such as a `StorageMap` which
+/// can use keys after `twox_128(pallet_prefix())++twox_128(STORAGE_PREFIX)`
+pub trait StorageInstance {
+	/// Prefix of a pallet to isolate it from other pallets.
+	fn pallet_prefix() -> &'static str;
+
+	/// Prefix given to a storage to isolate from other storages in the pallet.
+	const STORAGE_PREFIX: &'static str;
+}
diff --git a/frame/support/src/traits/stored_map.rs b/frame/support/src/traits/stored_map.rs
new file mode 100644
index 0000000000000..10964541ab32b
--- /dev/null
+++ b/frame/support/src/traits/stored_map.rs
@@ -0,0 +1,141 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Traits and associated datatypes for managing abstract stored values.
+
+use codec::FullCodec;
+use sp_runtime::traits::StoredMapError;
+use crate::storage::StorageMap;
+use crate::traits::misc::HandleLifetime;
+
+/// An abstraction of a value stored within storage, but possibly as part of a larger composite
+/// item.
+pub trait StoredMap<K, T: Default> {
+	/// Get the item, or its default if it doesn't yet exist; we make no distinction between the
+	/// two.
+	fn get(k: &K) -> T;
+
+	/// Maybe mutate the item only if an `Ok` value is returned from `f`. Do nothing if an `Err` is
+	/// returned. It is removed or reset to default value if it has been mutated to `None`
+	fn try_mutate_exists<R, E: From<StoredMapError>>(
+		k: &K,
+		f: impl FnOnce(&mut Option<T>) -> Result<R, E>,
+	) -> Result<R, E>;
+
+	// Everything past here has a default implementation.
+
+	/// Mutate the item.
+	fn mutate<R>(k: &K, f: impl FnOnce(&mut T) -> R) -> Result<R, StoredMapError> {
+		Self::mutate_exists(k, |maybe_account| match maybe_account {
+			Some(ref mut account) => f(account),
+			x @ None => {
+				let mut account = Default::default();
+				let r = f(&mut account);
+				*x = Some(account);
+				r
+			}
+		})
+	}
+
+	/// Mutate the item, removing or resetting to default value if it has been mutated to `None`.
+	///
+	/// This is infallible as long as the value does not get destroyed.
+	fn mutate_exists<R>(
+		k: &K,
+		f: impl FnOnce(&mut Option<T>) -> R,
+	) -> Result<R, StoredMapError> {
+		Self::try_mutate_exists(k, |x| -> Result<R, StoredMapError> { Ok(f(x)) })
+	}
+
+	/// Set the item to something new.
+	fn insert(k: &K, t: T) -> Result<(), StoredMapError> { Self::mutate(k, |i| *i = t) }
+
+	/// Remove the item or otherwise replace it with its default value; we don't care which.
+	fn remove(k: &K) -> Result<(), StoredMapError> { Self::mutate_exists(k, |x| *x = None) }
+}
+
+/// A shim for placing around a storage item in order to use it as a `StoredValue`. Ideally this
+/// wouldn't be needed as `StorageValue`s should blanket implement `StoredValue`s, however this
+/// would break the ability to have custom impls of `StoredValue`. The other workaround is to
+/// implement it directly in the macro.
+///
+/// This form has the advantage that two additional types are provides, `Created` and `Removed`,
+/// which are both generic events that can be tied to handlers to do something in the case of being
+/// about to create an account where one didn't previously exist (at all; not just where it used to
+/// be the default value), or where the account is being removed or reset back to the default value
+/// where previously it did exist (though may have been in a default state). This works well with
+/// system module's `CallOnCreatedAccount` and `CallKillAccount`.
+pub struct StorageMapShim<S, L, K, T>(sp_std::marker::PhantomData<(S, L, K, T)>);
+impl<
+	S: StorageMap<K, T, Query=T>,
+	L: HandleLifetime<K>,
+	K: FullCodec,
+	T: FullCodec + Default,
+> StoredMap<K, T> for StorageMapShim<S, L, K, T> {
+	fn get(k: &K) -> T { S::get(k) }
+	fn insert(k: &K, t: T) -> Result<(), StoredMapError> {
+		if !S::contains_key(&k) {
+			L::created(k)?;
+		}
+		S::insert(k, t);
+		Ok(())
+	}
+	fn remove(k: &K) -> Result<(), StoredMapError> {
+		if S::contains_key(&k) {
+			L::killed(&k)?;
+			S::remove(k);
+		}
+		Ok(())
+	}
+	fn mutate<R>(k: &K, f: impl FnOnce(&mut T) -> R) -> Result<R, StoredMapError> {
+		if !S::contains_key(&k) {
+			L::created(k)?;
+		}
+		Ok(S::mutate(k, f))
+	}
+	fn mutate_exists<R>(k: &K, f: impl FnOnce(&mut Option<T>) -> R) -> Result<R, StoredMapError> {
+		S::try_mutate_exists(k, |maybe_value| {
+			let existed = maybe_value.is_some();
+			let r = f(maybe_value);
+			let exists = maybe_value.is_some();
+
+			if !existed && exists {
+				L::created(k)?;
+			} else if existed && !exists {
+				L::killed(k)?;
+			}
+			Ok(r)
+		})
+	}
+	fn try_mutate_exists<R, E: From<StoredMapError>>(
+		k: &K,
+		f: impl FnOnce(&mut Option<T>) -> Result<R, E>,
+	) -> Result<R, E> {
+		S::try_mutate_exists(k, |maybe_value| {
+			let existed = maybe_value.is_some();
+			let r = f(maybe_value)?;
+			let exists = maybe_value.is_some();
+
+			if !existed && exists {
+				L::created(k).map_err(E::from)?;
+			} else if existed && !exists {
+				L::killed(k).map_err(E::from)?;
+			}
+			Ok(r)
+		})
+	}
+}
diff --git a/frame/support/src/traits/tokens.rs b/frame/support/src/traits/tokens.rs
new file mode 100644
index 0000000000000..82af5dbade8f7
--- /dev/null
+++ b/frame/support/src/traits/tokens.rs
@@ -0,0 +1,28 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Traits for working with tokens and their associated datastructures.
+
+pub mod fungible;
+pub mod fungibles;
+pub mod currency;
+pub mod imbalance;
+mod misc;
+pub use misc::{
+	WithdrawConsequence, DepositConsequence, ExistenceRequirement, BalanceStatus, WithdrawReasons,
+};
+pub use imbalance::Imbalance;
diff --git a/frame/support/src/traits/tokens/currency.rs b/frame/support/src/traits/tokens/currency.rs
new file mode 100644
index 0000000000000..567ca44aa78c7
--- /dev/null
+++ b/frame/support/src/traits/tokens/currency.rs
@@ -0,0 +1,208 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! The Currency trait and associated types.
+
+use sp_std::fmt::Debug;
+use sp_runtime::traits::MaybeSerializeDeserialize;
+use crate::dispatch::{DispatchResult, DispatchError};
+use super::misc::{Balance, WithdrawReasons, ExistenceRequirement};
+use super::imbalance::{Imbalance, SignedImbalance};
+
+
+mod reservable;
+pub use reservable::ReservableCurrency;
+mod lockable;
+pub use lockable::{LockableCurrency, VestingSchedule, LockIdentifier};
+
+/// Abstraction over a fungible assets system.
+pub trait Currency<AccountId> {
+	/// The balance of an account.
+	type Balance: Balance + MaybeSerializeDeserialize + Debug;
+
+	/// The opaque token type for an imbalance. This is returned by unbalanced operations
+	/// and must be dealt with. It may be dropped but cannot be cloned.
+	type PositiveImbalance: Imbalance<Self::Balance, Opposite=Self::NegativeImbalance>;
+
+	/// The opaque token type for an imbalance. This is returned by unbalanced operations
+	/// and must be dealt with. It may be dropped but cannot be cloned.
+	type NegativeImbalance: Imbalance<Self::Balance, Opposite=Self::PositiveImbalance>;
+
+	// PUBLIC IMMUTABLES
+
+	/// The combined balance of `who`.
+	fn total_balance(who: &AccountId) -> Self::Balance;
+
+	/// Same result as `slash(who, value)` (but without the side-effects) assuming there are no
+	/// balance changes in the meantime and only the reserved balance is not taken into account.
+	fn can_slash(who: &AccountId, value: Self::Balance) -> bool;
+
+	/// The total amount of issuance in the system.
+	fn total_issuance() -> Self::Balance;
+
+	/// The minimum balance any single account may have. This is equivalent to the `Balances` module's
+	/// `ExistentialDeposit`.
+	fn minimum_balance() -> Self::Balance;
+
+	/// Reduce the total issuance by `amount` and return the according imbalance. The imbalance will
+	/// typically be used to reduce an account by the same amount with e.g. `settle`.
+	///
+	/// This is infallible, but doesn't guarantee that the entire `amount` is burnt, for example
+	/// in the case of underflow.
+	fn burn(amount: Self::Balance) -> Self::PositiveImbalance;
+
+	/// Increase the total issuance by `amount` and return the according imbalance. The imbalance
+	/// will typically be used to increase an account by the same amount with e.g.
+	/// `resolve_into_existing` or `resolve_creating`.
+	///
+	/// This is infallible, but doesn't guarantee that the entire `amount` is issued, for example
+	/// in the case of overflow.
+	fn issue(amount: Self::Balance) -> Self::NegativeImbalance;
+
+	/// Produce a pair of imbalances that cancel each other out exactly.
+	///
+	/// This is just the same as burning and issuing the same amount and has no effect on the
+	/// total issuance.
+	fn pair(amount: Self::Balance) -> (Self::PositiveImbalance, Self::NegativeImbalance) {
+		(Self::burn(amount.clone()), Self::issue(amount))
+	}
+
+	/// The 'free' balance of a given account.
+	///
+	/// This is the only balance that matters in terms of most operations on tokens. It alone
+	/// is used to determine the balance when in the contract execution environment. When this
+	/// balance falls below the value of `ExistentialDeposit`, then the 'current account' is
+	/// deleted: specifically `FreeBalance`.
+	///
+	/// `system::AccountNonce` is also deleted if `ReservedBalance` is also zero (it also gets
+	/// collapsed to zero if it ever becomes less than `ExistentialDeposit`.
+	fn free_balance(who: &AccountId) -> Self::Balance;
+
+	/// Returns `Ok` iff the account is able to make a withdrawal of the given amount
+	/// for the given reason. Basically, it's just a dry-run of `withdraw`.
+	///
+	/// `Err(...)` with the reason why not otherwise.
+	fn ensure_can_withdraw(
+		who: &AccountId,
+		_amount: Self::Balance,
+		reasons: WithdrawReasons,
+		new_balance: Self::Balance,
+	) -> DispatchResult;
+
+	// PUBLIC MUTABLES (DANGEROUS)
+
+	/// Transfer some liquid free balance to another staker.
+	///
+	/// This is a very high-level function. It will ensure all appropriate fees are paid
+	/// and no imbalance in the system remains.
+	fn transfer(
+		source: &AccountId,
+		dest: &AccountId,
+		value: Self::Balance,
+		existence_requirement: ExistenceRequirement,
+	) -> DispatchResult;
+
+	/// Deducts up to `value` from the combined balance of `who`, preferring to deduct from the
+	/// free balance. This function cannot fail.
+	///
+	/// The resulting imbalance is the first item of the tuple returned.
+	///
+	/// As much funds up to `value` will be deducted as possible. If this is less than `value`,
+	/// then a non-zero second item will be returned.
+	fn slash(
+		who: &AccountId,
+		value: Self::Balance
+	) -> (Self::NegativeImbalance, Self::Balance);
+
+	/// Mints `value` to the free balance of `who`.
+	///
+	/// If `who` doesn't exist, nothing is done and an Err returned.
+	fn deposit_into_existing(
+		who: &AccountId,
+		value: Self::Balance
+	) -> Result<Self::PositiveImbalance, DispatchError>;
+
+	/// Similar to deposit_creating, only accepts a `NegativeImbalance` and returns nothing on
+	/// success.
+	fn resolve_into_existing(
+		who: &AccountId,
+		value: Self::NegativeImbalance,
+	) -> Result<(), Self::NegativeImbalance> {
+		let v = value.peek();
+		match Self::deposit_into_existing(who, v) {
+			Ok(opposite) => Ok(drop(value.offset(opposite))),
+			_ => Err(value),
+		}
+	}
+
+	/// Adds up to `value` to the free balance of `who`. If `who` doesn't exist, it is created.
+	///
+	/// Infallible.
+	fn deposit_creating(
+		who: &AccountId,
+		value: Self::Balance,
+	) -> Self::PositiveImbalance;
+
+	/// Similar to deposit_creating, only accepts a `NegativeImbalance` and returns nothing on
+	/// success.
+	fn resolve_creating(
+		who: &AccountId,
+		value: Self::NegativeImbalance,
+	) {
+		let v = value.peek();
+		drop(value.offset(Self::deposit_creating(who, v)));
+	}
+
+	/// Removes some free balance from `who` account for `reason` if possible. If `liveness` is
+	/// `KeepAlive`, then no less than `ExistentialDeposit` must be left remaining.
+	///
+	/// This checks any locks, vesting, and liquidity requirements. If the removal is not possible,
+	/// then it returns `Err`.
+	///
+	/// If the operation is successful, this will return `Ok` with a `NegativeImbalance` whose value
+	/// is `value`.
+	fn withdraw(
+		who: &AccountId,
+		value: Self::Balance,
+		reasons: WithdrawReasons,
+		liveness: ExistenceRequirement,
+	) -> Result<Self::NegativeImbalance, DispatchError>;
+
+	/// Similar to withdraw, only accepts a `PositiveImbalance` and returns nothing on success.
+	fn settle(
+		who: &AccountId,
+		value: Self::PositiveImbalance,
+		reasons: WithdrawReasons,
+		liveness: ExistenceRequirement,
+	) -> Result<(), Self::PositiveImbalance> {
+		let v = value.peek();
+		match Self::withdraw(who, v, reasons, liveness) {
+			Ok(opposite) => Ok(drop(value.offset(opposite))),
+			_ => Err(value),
+		}
+	}
+
+	/// Ensure an account's free balance equals some value; this will create the account
+	/// if needed.
+	///
+	/// Returns a signed imbalance and status to indicate if the account was successfully updated or update
+	/// has led to killing of the account.
+	fn make_free_balance_be(
+		who: &AccountId,
+		balance: Self::Balance,
+	) -> SignedImbalance<Self::Balance, Self::PositiveImbalance>;
+}
diff --git a/frame/support/src/traits/tokens/currency/lockable.rs b/frame/support/src/traits/tokens/currency/lockable.rs
new file mode 100644
index 0000000000000..ed3d1cf46362b
--- /dev/null
+++ b/frame/support/src/traits/tokens/currency/lockable.rs
@@ -0,0 +1,104 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! The lockable currency trait and some associated types.
+
+use crate::dispatch::DispatchResult;
+use crate::traits::misc::Get;
+use super::Currency;
+use super::super::misc::WithdrawReasons;
+
+/// An identifier for a lock. Used for disambiguating different locks so that
+/// they can be individually replaced or removed.
+pub type LockIdentifier = [u8; 8];
+
+/// A currency whose accounts can have liquidity restrictions.
+pub trait LockableCurrency<AccountId>: Currency<AccountId> {
+	/// The quantity used to denote time; usually just a `BlockNumber`.
+	type Moment;
+
+	/// The maximum number of locks a user should have on their account.
+	type MaxLocks: Get<u32>;
+
+	/// Create a new balance lock on account `who`.
+	///
+	/// If the new lock is valid (i.e. not already expired), it will push the struct to
+	/// the `Locks` vec in storage. Note that you can lock more funds than a user has.
+	///
+	/// If the lock `id` already exists, this will update it.
+	fn set_lock(
+		id: LockIdentifier,
+		who: &AccountId,
+		amount: Self::Balance,
+		reasons: WithdrawReasons,
+	);
+
+	/// Changes a balance lock (selected by `id`) so that it becomes less liquid in all
+	/// parameters or creates a new one if it does not exist.
+	///
+	/// Calling `extend_lock` on an existing lock `id` differs from `set_lock` in that it
+	/// applies the most severe constraints of the two, while `set_lock` replaces the lock
+	/// with the new parameters. As in, `extend_lock` will set:
+	/// - maximum `amount`
+	/// - bitwise mask of all `reasons`
+	fn extend_lock(
+		id: LockIdentifier,
+		who: &AccountId,
+		amount: Self::Balance,
+		reasons: WithdrawReasons,
+	);
+
+	/// Remove an existing lock.
+	fn remove_lock(
+		id: LockIdentifier,
+		who: &AccountId,
+	);
+}
+
+/// A vesting schedule over a currency. This allows a particular currency to have vesting limits
+/// applied to it.
+pub trait VestingSchedule<AccountId> {
+	/// The quantity used to denote time; usually just a `BlockNumber`.
+	type Moment;
+
+	/// The currency that this schedule applies to.
+	type Currency: Currency<AccountId>;
+
+	/// Get the amount that is currently being vested and cannot be transferred out of this account.
+	/// Returns `None` if the account has no vesting schedule.
+	fn vesting_balance(who: &AccountId) -> Option<<Self::Currency as Currency<AccountId>>::Balance>;
+
+	/// Adds a vesting schedule to a given account.
+	///
+	/// If there already exists a vesting schedule for the given account, an `Err` is returned
+	/// and nothing is updated.
+	///
+	/// Is a no-op if the amount to be vested is zero.
+	///
+	/// NOTE: This doesn't alter the free balance of the account.
+	fn add_vesting_schedule(
+		who: &AccountId,
+		locked: <Self::Currency as Currency<AccountId>>::Balance,
+		per_block: <Self::Currency as Currency<AccountId>>::Balance,
+		starting_block: Self::Moment,
+	) -> DispatchResult;
+
+	/// Remove a vesting schedule for a given account.
+	///
+	/// NOTE: This doesn't alter the free balance of the account.
+	fn remove_vesting_schedule(who: &AccountId);
+}
diff --git a/frame/support/src/traits/tokens/currency/reservable.rs b/frame/support/src/traits/tokens/currency/reservable.rs
new file mode 100644
index 0000000000000..14ea1d3a16fb6
--- /dev/null
+++ b/frame/support/src/traits/tokens/currency/reservable.rs
@@ -0,0 +1,83 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! The reservable currency trait.
+
+use super::Currency;
+use super::super::misc::BalanceStatus;
+use crate::dispatch::{DispatchResult, DispatchError};
+
+/// A currency where funds can be reserved from the user.
+pub trait ReservableCurrency<AccountId>: Currency<AccountId> {
+	/// Same result as `reserve(who, value)` (but without the side-effects) assuming there
+	/// are no balance changes in the meantime.
+	fn can_reserve(who: &AccountId, value: Self::Balance) -> bool;
+
+	/// Deducts up to `value` from reserved balance of `who`. This function cannot fail.
+	///
+	/// As much funds up to `value` will be deducted as possible. If the reserve balance of `who`
+	/// is less than `value`, then a non-zero second item will be returned.
+	fn slash_reserved(
+		who: &AccountId,
+		value: Self::Balance
+	) -> (Self::NegativeImbalance, Self::Balance);
+
+	/// The amount of the balance of a given account that is externally reserved; this can still get
+	/// slashed, but gets slashed last of all.
+	///
+	/// This balance is a 'reserve' balance that other subsystems use in order to set aside tokens
+	/// that are still 'owned' by the account holder, but which are suspendable.
+	///
+	/// When this balance falls below the value of `ExistentialDeposit`, then this 'reserve account'
+	/// is deleted: specifically, `ReservedBalance`.
+	///
+	/// `system::AccountNonce` is also deleted if `FreeBalance` is also zero (it also gets
+	/// collapsed to zero if it ever becomes less than `ExistentialDeposit`.
+	fn reserved_balance(who: &AccountId) -> Self::Balance;
+
+	/// Moves `value` from balance to reserved balance.
+	///
+	/// If the free balance is lower than `value`, then no funds will be moved and an `Err` will
+	/// be returned to notify of this. This is different behavior than `unreserve`.
+	fn reserve(who: &AccountId, value: Self::Balance) -> DispatchResult;
+
+	/// Moves up to `value` from reserved balance to free balance. This function cannot fail.
+	///
+	/// As much funds up to `value` will be moved as possible. If the reserve balance of `who`
+	/// is less than `value`, then the remaining amount will be returned.
+	///
+	/// # NOTES
+	///
+	/// - This is different from `reserve`.
+	/// - If the remaining reserved balance is less than `ExistentialDeposit`, it will
+	/// invoke `on_reserved_too_low` and could reap the account.
+	fn unreserve(who: &AccountId, value: Self::Balance) -> Self::Balance;
+
+	/// Moves up to `value` from reserved balance of account `slashed` to balance of account
+	/// `beneficiary`. `beneficiary` must exist for this to succeed. If it does not, `Err` will be
+	/// returned. Funds will be placed in either the `free` balance or the `reserved` balance,
+	/// depending on the `status`.
+	///
+	/// As much funds up to `value` will be deducted as possible. If this is less than `value`,
+	/// then `Ok(non_zero)` will be returned.
+	fn repatriate_reserved(
+		slashed: &AccountId,
+		beneficiary: &AccountId,
+		value: Self::Balance,
+		status: BalanceStatus,
+	) -> Result<Self::Balance, DispatchError>;
+}
diff --git a/frame/support/src/traits/tokens/fungible.rs b/frame/support/src/traits/tokens/fungible.rs
new file mode 100644
index 0000000000000..5472212aaa65e
--- /dev/null
+++ b/frame/support/src/traits/tokens/fungible.rs
@@ -0,0 +1,310 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! The traits for dealing with a single fungible token class and any associated types.
+
+use super::*;
+use sp_runtime::traits::Saturating;
+use crate::traits::misc::Get;
+use crate::dispatch::{DispatchResult, DispatchError};
+use super::misc::{DepositConsequence, WithdrawConsequence, Balance};
+
+mod balanced;
+mod imbalance;
+pub use balanced::{Balanced, Unbalanced};
+pub use imbalance::{Imbalance, HandleImbalanceDrop, DebtOf, CreditOf};
+
+/// Trait for providing balance-inspection access to a fungible asset.
+pub trait Inspect<AccountId> {
+	/// Scalar type for representing balance of an account.
+	type Balance: Balance;
+
+	/// The total amount of issuance in the system.
+	fn total_issuance() -> Self::Balance;
+
+	/// The minimum balance any single account may have.
+	fn minimum_balance() -> Self::Balance;
+
+	/// Get the balance of `who`.
+	fn balance(who: &AccountId) -> Self::Balance;
+
+	/// Get the maximum amount that `who` can withdraw/transfer successfully.
+	fn reducible_balance(who: &AccountId, keep_alive: bool) -> Self::Balance;
+
+	/// Returns `true` if the balance of `who` may be increased by `amount`.
+	fn can_deposit(who: &AccountId, amount: Self::Balance) -> DepositConsequence;
+
+	/// Returns `Failed` if the balance of `who` may not be decreased by `amount`, otherwise
+	/// the consequence.
+	fn can_withdraw(who: &AccountId, amount: Self::Balance) -> WithdrawConsequence<Self::Balance>;
+}
+
+/// Trait for providing an ERC-20 style fungible asset.
+pub trait Mutate<AccountId>: Inspect<AccountId> {
+	/// Increase the balance of `who` by exactly `amount`, minting new tokens. If that isn't
+	/// possible then an `Err` is returned and nothing is changed.
+	fn mint_into(who: &AccountId, amount: Self::Balance) -> DispatchResult;
+
+	/// Decrease the balance of `who` by at least `amount`, possibly slightly more in the case of
+	/// minimum_balance requirements, burning the tokens. If that isn't possible then an `Err` is
+	/// returned and nothing is changed. If successful, the amount of tokens reduced is returned.
+	fn burn_from(who: &AccountId, amount: Self::Balance) -> Result<Self::Balance, DispatchError>;
+
+	/// Attempt to reduce the balance of `who` by as much as possible up to `amount`, and possibly
+	/// slightly more due to minimum_balance requirements. If no decrease is possible then an `Err`
+	/// is returned and nothing is changed. If successful, the amount of tokens reduced is returned.
+	///
+	/// The default implementation just uses `withdraw` along with `reducible_balance` to ensure
+	/// that is doesn't fail.
+	fn slash(who: &AccountId, amount: Self::Balance) -> Result<Self::Balance, DispatchError> {
+		Self::burn_from(who, Self::reducible_balance(who, false).min(amount))
+	}
+
+	/// Transfer funds from one account into another. The default implementation uses `mint_into`
+	/// and `burn_from` and may generate unwanted events.
+	fn teleport(
+		source: &AccountId,
+		dest: &AccountId,
+		amount: Self::Balance,
+	) -> Result<Self::Balance, DispatchError> {
+		let extra = Self::can_withdraw(&source, amount).into_result()?;
+		Self::can_deposit(&dest, amount.saturating_add(extra)).into_result()?;
+		let actual = Self::burn_from(source, amount)?;
+		debug_assert!(actual == amount.saturating_add(extra), "can_withdraw must agree with withdraw; qed");
+		match Self::mint_into(dest, actual) {
+			Ok(_) => Ok(actual),
+			Err(err) => {
+				debug_assert!(false, "can_deposit returned true previously; qed");
+				// attempt to return the funds back to source
+				let revert = Self::mint_into(source, actual);
+				debug_assert!(revert.is_ok(), "withdrew funds previously; qed");
+				Err(err)
+			}
+		}
+	}
+}
+
+/// Trait for providing a fungible asset which can only be transferred.
+pub trait Transfer<AccountId>: Inspect<AccountId> {
+	/// Transfer funds from one account into another.
+	fn transfer(
+		source: &AccountId,
+		dest: &AccountId,
+		amount: Self::Balance,
+		keep_alive: bool,
+	) -> Result<Self::Balance, DispatchError>;
+}
+
+/// Trait for inspecting a fungible asset which can be reserved.
+pub trait InspectHold<AccountId>: Inspect<AccountId> {
+	/// Amount of funds held in reserve by `who`.
+	fn balance_on_hold(who: &AccountId) -> Self::Balance;
+
+	/// Check to see if some `amount` of funds of `who` may be placed on hold.
+	fn can_hold(who: &AccountId, amount: Self::Balance) -> bool;
+}
+
+/// Trait for mutating a fungible asset which can be reserved.
+pub trait MutateHold<AccountId>: InspectHold<AccountId> + Transfer<AccountId> {
+	/// Hold some funds in an account.
+	fn hold(who: &AccountId, amount: Self::Balance) -> DispatchResult;
+
+	/// Release up to `amount` held funds in an account.
+	///
+	/// The actual amount released is returned with `Ok`.
+	///
+	/// If `best_effort` is `true`, then the amount actually unreserved and returned as the inner
+	/// value of `Ok` may be smaller than the `amount` passed.
+	fn release(who: &AccountId, amount: Self::Balance, best_effort: bool)
+		-> Result<Self::Balance, DispatchError>;
+
+	/// Transfer held funds into a destination account.
+	///
+	/// If `on_hold` is `true`, then the destination account must already exist and the assets
+	/// transferred will still be on hold in the destination account. If not, then the destination
+	/// account need not already exist, but must be creatable.
+	///
+	/// If `best_effort` is `true`, then an amount less than `amount` may be transferred without
+	/// error.
+	///
+	/// The actual amount transferred is returned, or `Err` in the case of error and nothing is
+	/// changed.
+	fn transfer_held(
+		source: &AccountId,
+		dest: &AccountId,
+		amount: Self::Balance,
+		best_effort: bool,
+		on_held: bool,
+	) -> Result<Self::Balance, DispatchError>;
+}
+
+/// Trait for slashing a fungible asset which can be reserved.
+pub trait BalancedHold<AccountId>: Balanced<AccountId> + MutateHold<AccountId> {
+	/// Reduce the balance of some funds on hold in an account.
+	///
+	/// The resulting imbalance is the first item of the tuple returned.
+	///
+	/// As much funds that are on hold up to `amount` will be deducted as possible. If this is less
+	/// than `amount`, then a non-zero second item will be returned.
+	fn slash_held(who: &AccountId, amount: Self::Balance)
+		-> (CreditOf<AccountId, Self>, Self::Balance);
+}
+
+impl<
+	AccountId,
+	T: Balanced<AccountId> + MutateHold<AccountId>,
+> BalancedHold<AccountId> for T {
+	fn slash_held(who: &AccountId, amount: Self::Balance)
+		-> (CreditOf<AccountId, Self>, Self::Balance)
+	{
+		let actual = match Self::release(who, amount, true) {
+			Ok(x) => x,
+			Err(_) => return (Imbalance::default(), amount),
+		};
+		<Self as fungible::Balanced<AccountId>>::slash(who, actual)
+	}
+}
+
+/// Convert a `fungibles` trait implementation into a `fungible` trait implementation by identifying
+/// a single item.
+pub struct ItemOf<
+	F: fungibles::Inspect<AccountId>,
+	A: Get<<F as fungibles::Inspect<AccountId>>::AssetId>,
+	AccountId,
+>(
+	sp_std::marker::PhantomData<(F, A, AccountId)>
+);
+
+impl<
+	F: fungibles::Inspect<AccountId>,
+	A: Get<<F as fungibles::Inspect<AccountId>>::AssetId>,
+	AccountId,
+> Inspect<AccountId> for ItemOf<F, A, AccountId> {
+	type Balance = <F as fungibles::Inspect<AccountId>>::Balance;
+	fn total_issuance() -> Self::Balance {
+		<F as fungibles::Inspect<AccountId>>::total_issuance(A::get())
+	}
+	fn minimum_balance() -> Self::Balance {
+		<F as fungibles::Inspect<AccountId>>::minimum_balance(A::get())
+	}
+	fn balance(who: &AccountId) -> Self::Balance {
+		<F as fungibles::Inspect<AccountId>>::balance(A::get(), who)
+	}
+	fn reducible_balance(who: &AccountId, keep_alive: bool) -> Self::Balance {
+		<F as fungibles::Inspect<AccountId>>::reducible_balance(A::get(), who, keep_alive)
+	}
+	fn can_deposit(who: &AccountId, amount: Self::Balance) -> DepositConsequence {
+		<F as fungibles::Inspect<AccountId>>::can_deposit(A::get(), who, amount)
+	}
+	fn can_withdraw(who: &AccountId, amount: Self::Balance) -> WithdrawConsequence<Self::Balance> {
+		<F as fungibles::Inspect<AccountId>>::can_withdraw(A::get(), who, amount)
+	}
+}
+
+impl<
+	F: fungibles::Mutate<AccountId>,
+	A: Get<<F as fungibles::Inspect<AccountId>>::AssetId>,
+	AccountId,
+> Mutate<AccountId> for ItemOf<F, A, AccountId> {
+	fn mint_into(who: &AccountId, amount: Self::Balance) -> DispatchResult {
+		<F as fungibles::Mutate<AccountId>>::mint_into(A::get(), who, amount)
+	}
+	fn burn_from(who: &AccountId, amount: Self::Balance) -> Result<Self::Balance, DispatchError> {
+		<F as fungibles::Mutate<AccountId>>::burn_from(A::get(), who, amount)
+	}
+}
+
+impl<
+	F: fungibles::Transfer<AccountId>,
+	A: Get<<F as fungibles::Inspect<AccountId>>::AssetId>,
+	AccountId,
+> Transfer<AccountId> for ItemOf<F, A, AccountId> {
+	fn transfer(source: &AccountId, dest: &AccountId, amount: Self::Balance, keep_alive: bool)
+		-> Result<Self::Balance, DispatchError>
+	{
+		<F as fungibles::Transfer<AccountId>>::transfer(A::get(), source, dest, amount, keep_alive)
+	}
+}
+
+impl<
+	F: fungibles::InspectHold<AccountId>,
+	A: Get<<F as fungibles::Inspect<AccountId>>::AssetId>,
+	AccountId,
+> InspectHold<AccountId> for ItemOf<F, A, AccountId> {
+	fn balance_on_hold(who: &AccountId) -> Self::Balance {
+		<F as fungibles::InspectHold<AccountId>>::balance_on_hold(A::get(), who)
+	}
+	fn can_hold(who: &AccountId, amount: Self::Balance) -> bool {
+		<F as fungibles::InspectHold<AccountId>>::can_hold(A::get(), who, amount)
+	}
+}
+
+impl<
+	F: fungibles::MutateHold<AccountId>,
+	A: Get<<F as fungibles::Inspect<AccountId>>::AssetId>,
+	AccountId,
+> MutateHold<AccountId> for ItemOf<F, A, AccountId> {
+	fn hold(who: &AccountId, amount: Self::Balance) -> DispatchResult {
+		<F as fungibles::MutateHold<AccountId>>::hold(A::get(), who, amount)
+	}
+	fn release(who: &AccountId, amount: Self::Balance, best_effort: bool)
+		-> Result<Self::Balance, DispatchError>
+	{
+		<F as fungibles::MutateHold<AccountId>>::release(A::get(), who, amount, best_effort)
+	}
+	fn transfer_held(
+		source: &AccountId,
+		dest: &AccountId,
+		amount: Self::Balance,
+		best_effort: bool,
+		on_hold: bool,
+	) -> Result<Self::Balance, DispatchError> {
+		<F as fungibles::MutateHold<AccountId>>::transfer_held(
+			A::get(),
+			source,
+			dest,
+			amount,
+			best_effort,
+			on_hold,
+		)
+	}
+}
+
+impl<
+	F: fungibles::Unbalanced<AccountId>,
+	A: Get<<F as fungibles::Inspect<AccountId>>::AssetId>,
+	AccountId,
+> Unbalanced<AccountId> for ItemOf<F, A, AccountId> {
+	fn set_balance(who: &AccountId, amount: Self::Balance) -> DispatchResult {
+		<F as fungibles::Unbalanced<AccountId>>::set_balance(A::get(), who, amount)
+	}
+	fn set_total_issuance(amount: Self::Balance) -> () {
+		<F as fungibles::Unbalanced<AccountId>>::set_total_issuance(A::get(), amount)
+	}
+	fn decrease_balance(who: &AccountId, amount: Self::Balance) -> Result<Self::Balance, DispatchError> {
+		<F as fungibles::Unbalanced<AccountId>>::decrease_balance(A::get(), who, amount)
+	}
+	fn decrease_balance_at_most(who: &AccountId, amount: Self::Balance) -> Self::Balance {
+		<F as fungibles::Unbalanced<AccountId>>::decrease_balance_at_most(A::get(), who, amount)
+	}
+	fn increase_balance(who: &AccountId, amount: Self::Balance) -> Result<Self::Balance, DispatchError> {
+		<F as fungibles::Unbalanced<AccountId>>::increase_balance(A::get(), who, amount)
+	}
+	fn increase_balance_at_most(who: &AccountId, amount: Self::Balance) -> Self::Balance {
+		<F as fungibles::Unbalanced<AccountId>>::increase_balance_at_most(A::get(), who, amount)
+	}
+}
diff --git a/frame/support/src/traits/tokens/fungible/balanced.rs b/frame/support/src/traits/tokens/fungible/balanced.rs
new file mode 100644
index 0000000000000..19bdb4f245ee8
--- /dev/null
+++ b/frame/support/src/traits/tokens/fungible/balanced.rs
@@ -0,0 +1,360 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! The trait and associated types for sets of fungible tokens that manage total issuance without
+//! requiring atomic balanced operations.
+
+use super::*;
+use sp_std::marker::PhantomData;
+use sp_runtime::{TokenError, traits::{CheckedAdd, Zero}};
+use super::super::Imbalance as ImbalanceT;
+use crate::traits::misc::{SameOrOther, TryDrop};
+use crate::dispatch::{DispatchResult, DispatchError};
+
+/// A fungible token class where any creation and deletion of tokens is semi-explicit and where the
+/// total supply is maintained automatically.
+///
+/// This is auto-implemented when a token class has `Unbalanced` implemented.
+pub trait Balanced<AccountId>: Inspect<AccountId> {
+	/// The type for managing what happens when an instance of `Debt` is dropped without being used.
+	type OnDropDebt: HandleImbalanceDrop<Self::Balance>;
+	/// The type for managing what happens when an instance of `Credit` is dropped without being
+	/// used.
+	type OnDropCredit: HandleImbalanceDrop<Self::Balance>;
+
+	/// Reduce the total issuance by `amount` and return the according imbalance. The imbalance will
+	/// typically be used to reduce an account by the same amount with e.g. `settle`.
+	///
+	/// This is infallible, but doesn't guarantee that the entire `amount` is burnt, for example
+	/// in the case of underflow.
+	fn rescind(amount: Self::Balance) -> DebtOf<AccountId, Self>;
+
+	/// Increase the total issuance by `amount` and return the according imbalance. The imbalance
+	/// will typically be used to increase an account by the same amount with e.g.
+	/// `resolve_into_existing` or `resolve_creating`.
+	///
+	/// This is infallible, but doesn't guarantee that the entire `amount` is issued, for example
+	/// in the case of overflow.
+	fn issue(amount: Self::Balance) -> CreditOf<AccountId, Self>;
+
+	/// Produce a pair of imbalances that cancel each other out exactly.
+	///
+	/// This is just the same as burning and issuing the same amount and has no effect on the
+	/// total issuance.
+	fn pair(amount: Self::Balance) -> (DebtOf<AccountId, Self>, CreditOf<AccountId, Self>) {
+		(Self::rescind(amount), Self::issue(amount))
+	}
+
+	/// Deducts up to `value` from the combined balance of `who`. This function cannot fail.
+	///
+	/// The resulting imbalance is the first item of the tuple returned.
+	///
+	/// As much funds up to `value` will be deducted as possible. If this is less than `value`,
+	/// then a non-zero second item will be returned.
+	fn slash(
+		who: &AccountId,
+		amount: Self::Balance,
+	) -> (CreditOf<AccountId, Self>, Self::Balance);
+
+	/// Mints exactly `value` into the account of `who`.
+	///
+	/// If `who` doesn't exist, nothing is done and an `Err` returned. This could happen because it
+	/// the account doesn't yet exist and it isn't possible to create it under the current
+	/// circumstances and with `value` in it.
+	fn deposit(
+		who: &AccountId,
+		value: Self::Balance,
+	) -> Result<DebtOf<AccountId, Self>, DispatchError>;
+
+	/// Removes `value` balance from `who` account if possible.
+	///
+	/// If the removal is not possible, then it returns `Err` and nothing is changed.
+	///
+	/// If the operation is successful, this will return `Ok` with a `NegativeImbalance` whose value
+	/// is no less than `value`. It may be more in the case that removing it reduced it below
+	/// `Self::minimum_balance()`.
+	fn withdraw(
+		who: &AccountId,
+		value: Self::Balance,
+		//TODO: liveness: ExistenceRequirement,
+	) -> Result<CreditOf<AccountId, Self>, DispatchError>;
+
+	/// The balance of `who` is increased in order to counter `credit`. If the whole of `credit`
+	/// cannot be countered, then nothing is changed and the original `credit` is returned in an
+	/// `Err`.
+	///
+	/// Please note: If `credit.peek()` is less than `Self::minimum_balance()`, then `who` must
+	/// already exist for this to succeed.
+	fn resolve(
+		who: &AccountId,
+		credit: CreditOf<AccountId, Self>,
+	) -> Result<(), CreditOf<AccountId, Self>> {
+		let v = credit.peek();
+		let debt = match Self::deposit(who, v) {
+			Err(_) => return Err(credit),
+			Ok(d) => d,
+		};
+		let result = credit.offset(debt).try_drop();
+		debug_assert!(result.is_ok(), "ok deposit return must be equal to credit value; qed");
+		Ok(())
+	}
+
+	/// The balance of `who` is decreased in order to counter `debt`. If the whole of `debt`
+	/// cannot be countered, then nothing is changed and the original `debt` is returned in an
+	/// `Err`.
+	fn settle(
+		who: &AccountId,
+		debt: DebtOf<AccountId, Self>,
+		//TODO: liveness: ExistenceRequirement,
+	) -> Result<CreditOf<AccountId, Self>, DebtOf<AccountId, Self>> {
+		let amount = debt.peek();
+		let credit = match Self::withdraw(who, amount) {
+			Err(_) => return Err(debt),
+			Ok(d) => d,
+		};
+		match credit.offset(debt) {
+			SameOrOther::None => Ok(CreditOf::<AccountId, Self>::zero()),
+			SameOrOther::Same(dust) => Ok(dust),
+			SameOrOther::Other(rest) => {
+				debug_assert!(false, "ok withdraw return must be at least debt value; qed");
+				Err(rest)
+			}
+		}
+	}
+}
+
+/// A fungible token class where the balance can be set arbitrarily.
+///
+/// **WARNING**
+/// Do not use this directly unless you want trouble, since it allows you to alter account balances
+/// without keeping the issuance up to date. It has no safeguards against accidentally creating
+/// token imbalances in your system leading to accidental imflation or deflation. It's really just
+/// for the underlying datatype to implement so the user gets the much safer `Balanced` trait to
+/// use.
+pub trait Unbalanced<AccountId>: Inspect<AccountId> {
+	/// Set the balance of `who` to `amount`. If this cannot be done for some reason (e.g.
+	/// because the account cannot be created or an overflow) then an `Err` is returned.
+	fn set_balance(who: &AccountId, amount: Self::Balance) -> DispatchResult;
+
+	/// Set the total issuance to `amount`.
+	fn set_total_issuance(amount: Self::Balance);
+
+	/// Reduce the balance of `who` by `amount`. If it cannot be reduced by that amount for
+	/// some reason, return `Err` and don't reduce it at all. If Ok, return the imbalance.
+	///
+	/// Minimum balance will be respected and the returned imbalance may be up to
+	/// `Self::minimum_balance() - 1` greater than `amount`.
+	fn decrease_balance(who: &AccountId, amount: Self::Balance)
+		-> Result<Self::Balance, DispatchError>
+	{
+		let old_balance = Self::balance(who);
+		let (mut new_balance, mut amount) = if old_balance < amount {
+			Err(TokenError::NoFunds)?
+		} else {
+			(old_balance - amount, amount)
+		};
+		if new_balance < Self::minimum_balance() {
+			amount = amount.saturating_add(new_balance);
+			new_balance = Zero::zero();
+		}
+		// Defensive only - this should not fail now.
+		Self::set_balance(who, new_balance)?;
+		Ok(amount)
+	}
+
+	/// Reduce the balance of `who` by the most that is possible, up to `amount`.
+	///
+	/// Minimum balance will be respected and the returned imbalance may be up to
+	/// `Self::minimum_balance() - 1` greater than `amount`.
+	///
+	/// Return the imbalance by which the account was reduced.
+	fn decrease_balance_at_most(who: &AccountId, amount: Self::Balance)
+		-> Self::Balance
+	{
+		let old_balance = Self::balance(who);
+		let (mut new_balance, mut amount) = if old_balance < amount {
+			(Zero::zero(), old_balance)
+		} else {
+			(old_balance - amount, amount)
+		};
+		let minimum_balance = Self::minimum_balance();
+		if new_balance < minimum_balance {
+			amount = amount.saturating_add(new_balance);
+			new_balance = Zero::zero();
+		}
+		let mut r = Self::set_balance(who, new_balance);
+		if r.is_err() {
+			// Some error, probably because we tried to destroy an account which cannot be destroyed.
+			if new_balance.is_zero() && amount >= minimum_balance {
+				new_balance = minimum_balance;
+				amount -= minimum_balance;
+				r = Self::set_balance(who, new_balance);
+			}
+			if r.is_err() {
+				// Still an error. Apparently it's not possible to reduce at all.
+				amount = Zero::zero();
+			}
+		}
+		amount
+	}
+
+	/// Increase the balance of `who` by `amount`. If it cannot be increased by that amount
+	/// for some reason, return `Err` and don't increase it at all. If Ok, return the imbalance.
+	///
+	/// Minimum balance will be respected and an error will be returned if
+	/// `amount < Self::minimum_balance()` when the account of `who` is zero.
+	fn increase_balance(who: &AccountId, amount: Self::Balance)
+		-> Result<Self::Balance, DispatchError>
+	{
+		let old_balance = Self::balance(who);
+		let new_balance = old_balance.checked_add(&amount).ok_or(TokenError::Overflow)?;
+		if new_balance < Self::minimum_balance() {
+			Err(TokenError::BelowMinimum)?
+		}
+		if old_balance != new_balance {
+			Self::set_balance(who, new_balance)?;
+		}
+		Ok(amount)
+	}
+
+	/// Increase the balance of `who` by the most that is possible, up to `amount`.
+	///
+	/// Minimum balance will be respected and the returned imbalance will be zero in the case that
+	/// `amount < Self::minimum_balance()`.
+	///
+	/// Return the imbalance by which the account was increased.
+	fn increase_balance_at_most(who: &AccountId, amount: Self::Balance)
+		-> Self::Balance
+	{
+		let old_balance = Self::balance(who);
+		let mut new_balance = old_balance.saturating_add(amount);
+		let mut amount = new_balance - old_balance;
+		if new_balance < Self::minimum_balance() {
+			new_balance = Zero::zero();
+			amount = Zero::zero();
+		}
+		if old_balance == new_balance || Self::set_balance(who, new_balance).is_ok() {
+			amount
+		} else {
+			Zero::zero()
+		}
+	}
+}
+
+/// Simple handler for an imbalance drop which increases the total issuance of the system by the
+/// imbalance amount. Used for leftover debt.
+pub struct IncreaseIssuance<AccountId, U>(PhantomData<(AccountId, U)>);
+impl<AccountId, U: Unbalanced<AccountId>> HandleImbalanceDrop<U::Balance>
+	for IncreaseIssuance<AccountId, U>
+{
+	fn handle(amount: U::Balance) {
+		U::set_total_issuance(U::total_issuance().saturating_add(amount))
+	}
+}
+
+/// Simple handler for an imbalance drop which decreases the total issuance of the system by the
+/// imbalance amount. Used for leftover credit.
+pub struct DecreaseIssuance<AccountId, U>(PhantomData<(AccountId, U)>);
+impl<AccountId, U: Unbalanced<AccountId>> HandleImbalanceDrop<U::Balance>
+	for DecreaseIssuance<AccountId, U>
+{
+	fn handle(amount: U::Balance) {
+		U::set_total_issuance(U::total_issuance().saturating_sub(amount))
+	}
+}
+
+/// An imbalance type which uses `DecreaseIssuance` to deal with anything `Drop`ed.
+///
+/// Basically means that funds in someone's account have been removed and not yet placed anywhere
+/// else. If it gets dropped, then those funds will be assumed to be "burned" and the total supply
+/// will be accordingly decreased to ensure it equals the sum of the balances of all accounts.
+type Credit<AccountId, U> = Imbalance<
+	<U as Inspect<AccountId>>::Balance,
+	DecreaseIssuance<AccountId, U>,
+	IncreaseIssuance<AccountId, U>,
+>;
+
+/// An imbalance type which uses `IncreaseIssuance` to deal with anything `Drop`ed.
+///
+/// Basically means that there are funds in someone's account whose origin is as yet unaccounted
+/// for. If it gets dropped, then those funds will be assumed to be "minted" and the total supply
+/// will be accordingly increased to ensure it equals the sum of the balances of all accounts.
+type Debt<AccountId, U> = Imbalance<
+	<U as Inspect<AccountId>>::Balance,
+	IncreaseIssuance<AccountId, U>,
+	DecreaseIssuance<AccountId, U>,
+>;
+
+/// Create some `Credit` item. Only for internal use.
+fn credit<AccountId, U: Unbalanced<AccountId>>(
+	amount: U::Balance,
+) -> Credit<AccountId, U> {
+	Imbalance::new(amount)
+}
+
+/// Create some `Debt` item. Only for internal use.
+fn debt<AccountId, U: Unbalanced<AccountId>>(
+	amount: U::Balance,
+) -> Debt<AccountId, U> {
+	Imbalance::new(amount)
+}
+
+impl<AccountId, U: Unbalanced<AccountId>> Balanced<AccountId> for U {
+	type OnDropCredit = DecreaseIssuance<AccountId, U>;
+	type OnDropDebt = IncreaseIssuance<AccountId, U>;
+	fn rescind(amount: Self::Balance) -> Debt<AccountId, Self> {
+		let old = U::total_issuance();
+		let new = old.saturating_sub(amount);
+		U::set_total_issuance(new);
+		debt(old - new)
+	}
+	fn issue(amount: Self::Balance) -> Credit<AccountId, Self> {
+		let old = U::total_issuance();
+		let new = old.saturating_add(amount);
+		U::set_total_issuance(new);
+		credit(new - old)
+	}
+	fn slash(
+		who: &AccountId,
+		amount: Self::Balance,
+	) -> (Credit<AccountId, Self>, Self::Balance) {
+		let slashed = U::decrease_balance_at_most(who, amount);
+		// `slashed` could be less than, greater than or equal to `amount`.
+		// If slashed == amount, it means the account had at least amount in it and it could all be
+		//   removed without a problem.
+		// If slashed > amount, it means the account had more than amount in it, but not enough more
+		//   to push it over minimum_balance.
+		// If slashed < amount, it means the account didn't have enough in it to be reduced by
+		//   `amount` without being destroyed.
+		(credit(slashed), amount.saturating_sub(slashed))
+	}
+	fn deposit(
+		who: &AccountId,
+		amount: Self::Balance
+	) -> Result<Debt<AccountId, Self>, DispatchError> {
+		let increase = U::increase_balance(who, amount)?;
+		Ok(debt(increase))
+	}
+	fn withdraw(
+		who: &AccountId,
+		amount: Self::Balance,
+		//TODO: liveness: ExistenceRequirement,
+	) -> Result<Credit<AccountId, Self>, DispatchError> {
+		let decrease = U::decrease_balance(who, amount)?;
+		Ok(credit(decrease))
+	}
+}
diff --git a/frame/support/src/traits/tokens/fungible/imbalance.rs b/frame/support/src/traits/tokens/fungible/imbalance.rs
new file mode 100644
index 0000000000000..c084fa97fbec0
--- /dev/null
+++ b/frame/support/src/traits/tokens/fungible/imbalance.rs
@@ -0,0 +1,162 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! The imbalance type and its associates, which handles keeps everything adding up properly with
+//! unbalanced operations.
+
+use super::*;
+use sp_std::marker::PhantomData;
+use sp_runtime::traits::Zero;
+use super::misc::Balance;
+use super::balanced::Balanced;
+use crate::traits::misc::{TryDrop, SameOrOther};
+use super::super::Imbalance as ImbalanceT;
+
+/// Handler for when an imbalance gets dropped. This could handle either a credit (negative) or
+/// debt (positive) imbalance.
+pub trait HandleImbalanceDrop<Balance> {
+	/// Some something with the imbalance's value which is being dropped.
+	fn handle(amount: Balance);
+}
+
+/// An imbalance in the system, representing a divergence of recorded token supply from the sum of
+/// the balances of all accounts. This is `must_use` in order to ensure it gets handled (placing
+/// into an account, settling from an account or altering the supply).
+///
+/// Importantly, it has a special `Drop` impl, and cannot be created outside of this module.
+#[must_use]
+pub struct Imbalance<
+	B: Balance,
+	OnDrop: HandleImbalanceDrop<B>,
+	OppositeOnDrop: HandleImbalanceDrop<B>,
+> {
+	amount: B,
+	_phantom: PhantomData<(OnDrop, OppositeOnDrop)>,
+}
+
+impl<
+	B: Balance,
+	OnDrop: HandleImbalanceDrop<B>,
+	OppositeOnDrop: HandleImbalanceDrop<B>
+> Drop for Imbalance<B, OnDrop, OppositeOnDrop> {
+	fn drop(&mut self) {
+		if !self.amount.is_zero() {
+			OnDrop::handle(self.amount)
+		}
+	}
+}
+
+impl<
+	B: Balance,
+	OnDrop: HandleImbalanceDrop<B>,
+	OppositeOnDrop: HandleImbalanceDrop<B>,
+> TryDrop for Imbalance<B, OnDrop, OppositeOnDrop> {
+	/// Drop an instance cleanly. Only works if its value represents "no-operation".
+	fn try_drop(self) -> Result<(), Self> {
+		self.drop_zero()
+	}
+}
+
+impl<
+	B: Balance,
+	OnDrop: HandleImbalanceDrop<B>,
+	OppositeOnDrop: HandleImbalanceDrop<B>,
+> Default for Imbalance<B, OnDrop, OppositeOnDrop> {
+	fn default() -> Self {
+		Self::zero()
+	}
+}
+
+impl<
+	B: Balance,
+	OnDrop: HandleImbalanceDrop<B>,
+	OppositeOnDrop: HandleImbalanceDrop<B>,
+> Imbalance<B, OnDrop, OppositeOnDrop> {
+	pub(crate) fn new(amount: B) -> Self {
+		Self { amount, _phantom: PhantomData }
+	}
+}
+
+impl<
+	B: Balance,
+	OnDrop: HandleImbalanceDrop<B>,
+	OppositeOnDrop: HandleImbalanceDrop<B>,
+> ImbalanceT<B> for Imbalance<B, OnDrop, OppositeOnDrop> {
+	type Opposite = Imbalance<B, OppositeOnDrop, OnDrop>;
+
+	fn zero() -> Self {
+		Self { amount: Zero::zero(), _phantom: PhantomData }
+	}
+
+	fn drop_zero(self) -> Result<(), Self> {
+		if self.amount.is_zero() {
+			sp_std::mem::forget(self);
+			Ok(())
+		} else {
+			Err(self)
+		}
+	}
+
+	fn split(self, amount: B) -> (Self, Self) {
+		let first = self.amount.min(amount);
+		let second = self.amount - first;
+		sp_std::mem::forget(self);
+		(Imbalance::new(first), Imbalance::new(second))
+	}
+	fn merge(mut self, other: Self) -> Self {
+		self.amount = self.amount.saturating_add(other.amount);
+		sp_std::mem::forget(other);
+		self
+	}
+	fn subsume(&mut self, other: Self) {
+		self.amount = self.amount.saturating_add(other.amount);
+		sp_std::mem::forget(other);
+	}
+	fn offset(self, other: Imbalance<B, OppositeOnDrop, OnDrop>)
+		-> SameOrOther<Self, Imbalance<B, OppositeOnDrop, OnDrop>>
+	{
+		let (a, b) = (self.amount, other.amount);
+		sp_std::mem::forget((self, other));
+
+		if a == b {
+			SameOrOther::None
+		} else if a > b {
+			SameOrOther::Same(Imbalance::new(a - b))
+		} else {
+			SameOrOther::Other(Imbalance::<B, OppositeOnDrop, OnDrop>::new(b - a))
+		}
+	}
+	fn peek(&self) -> B {
+		self.amount
+	}
+}
+
+/// Imbalance implying that the total_issuance value is less than the sum of all account balances.
+pub type DebtOf<AccountId, B> = Imbalance<
+	<B as Inspect<AccountId>>::Balance,
+	// This will generally be implemented by increasing the total_issuance value.
+	<B as Balanced<AccountId>>::OnDropDebt,
+	<B as Balanced<AccountId>>::OnDropCredit,
+>;
+
+/// Imbalance implying that the total_issuance value is greater than the sum of all account balances.
+pub type CreditOf<AccountId, B> = Imbalance<
+	<B as Inspect<AccountId>>::Balance,
+	// This will generally be implemented by decreasing the total_issuance value.
+	<B as Balanced<AccountId>>::OnDropCredit,
+	<B as Balanced<AccountId>>::OnDropDebt,
+>;
diff --git a/frame/support/src/traits/tokens/fungibles.rs b/frame/support/src/traits/tokens/fungibles.rs
new file mode 100644
index 0000000000000..490f28dfb453a
--- /dev/null
+++ b/frame/support/src/traits/tokens/fungibles.rs
@@ -0,0 +1,210 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! The traits for sets of fungible tokens and any associated types.
+
+use super::*;
+use crate::dispatch::{DispatchError, DispatchResult};
+use super::misc::{AssetId, Balance};
+use sp_runtime::traits::Saturating;
+
+mod balanced;
+pub use balanced::{Balanced, Unbalanced};
+mod imbalance;
+pub use imbalance::{Imbalance, HandleImbalanceDrop, DebtOf, CreditOf};
+
+/// Trait for providing balance-inspection access to a set of named fungible assets.
+pub trait Inspect<AccountId> {
+	/// Means of identifying one asset class from another.
+	type AssetId: AssetId;
+
+	/// Scalar type for representing balance of an account.
+	type Balance: Balance;
+
+	/// The total amount of issuance in the system.
+	fn total_issuance(asset: Self::AssetId) -> Self::Balance;
+
+	/// The minimum balance any single account may have.
+	fn minimum_balance(asset: Self::AssetId) -> Self::Balance;
+
+	/// Get the `asset` balance of `who`.
+	fn balance(asset: Self::AssetId, who: &AccountId) -> Self::Balance;
+
+	/// Get the maximum amount of `asset` that `who` can withdraw/transfer successfully.
+	fn reducible_balance(asset: Self::AssetId, who: &AccountId, keep_alive: bool) -> Self::Balance;
+
+	/// Returns `true` if the `asset` balance of `who` may be increased by `amount`.
+	fn can_deposit(asset: Self::AssetId, who: &AccountId, amount: Self::Balance)
+		-> DepositConsequence;
+
+	/// Returns `Failed` if the `asset` balance of `who` may not be decreased by `amount`, otherwise
+	/// the consequence.
+	fn can_withdraw(
+		asset: Self::AssetId,
+		who: &AccountId,
+		amount: Self::Balance,
+	) -> WithdrawConsequence<Self::Balance>;
+}
+
+/// Trait for providing a set of named fungible assets which can be created and destroyed.
+pub trait Mutate<AccountId>: Inspect<AccountId> {
+	/// Attempt to increase the `asset` balance of `who` by `amount`.
+	///
+	/// If not possible then don't do anything. Possible reasons for failure include:
+	/// - Minimum balance not met.
+	/// - Account cannot be created (e.g. because there is no provider reference and/or the asset
+	///   isn't considered worth anything).
+	///
+	/// Since this is an operation which should be possible to take alone, if successful it will
+	/// increase the overall supply of the underlying token.
+	fn mint_into(asset: Self::AssetId, who: &AccountId, amount: Self::Balance) -> DispatchResult;
+
+	/// Attempt to reduce the `asset` balance of `who` by `amount`.
+	///
+	/// If not possible then don't do anything. Possible reasons for failure include:
+	/// - Less funds in the account than `amount`
+	/// - Liquidity requirements (locks, reservations) prevent the funds from being removed
+	/// - Operation would require destroying the account and it is required to stay alive (e.g.
+	///   because it's providing a needed provider reference).
+	///
+	/// Since this is an operation which should be possible to take alone, if successful it will
+	/// reduce the overall supply of the underlying token.
+	///
+	/// Due to minimum balance requirements, it's possible that the amount withdrawn could be up to
+	/// `Self::minimum_balance() - 1` more than the `amount`. The total amount withdrawn is returned
+	/// in an `Ok` result. This may be safely ignored if you don't mind the overall supply reducing.
+	fn burn_from(asset: Self::AssetId, who: &AccountId, amount: Self::Balance)
+		-> Result<Self::Balance, DispatchError>;
+
+	/// Attempt to reduce the `asset` balance of `who` by as much as possible up to `amount`, and
+	/// possibly slightly more due to minimum_balance requirements. If no decrease is possible then
+	/// an `Err` is returned and nothing is changed. If successful, the amount of tokens reduced is
+	/// returned.
+	///
+	/// The default implementation just uses `withdraw` along with `reducible_balance` to ensure
+	/// that is doesn't fail.
+	fn slash(asset: Self::AssetId, who: &AccountId, amount: Self::Balance)
+		-> Result<Self::Balance, DispatchError>
+	{
+		Self::burn_from(asset, who, Self::reducible_balance(asset, who, false).min(amount))
+	}
+
+	/// Transfer funds from one account into another. The default implementation uses `mint_into`
+	/// and `burn_from` and may generate unwanted events.
+	fn teleport(
+		asset: Self::AssetId,
+		source: &AccountId,
+		dest: &AccountId,
+		amount: Self::Balance,
+	) -> Result<Self::Balance, DispatchError> {
+		let extra = Self::can_withdraw(asset, &source, amount).into_result()?;
+		Self::can_deposit(asset, &dest, amount.saturating_add(extra)).into_result()?;
+		let actual = Self::burn_from(asset, source, amount)?;
+		debug_assert!(actual == amount.saturating_add(extra), "can_withdraw must agree with withdraw; qed");
+		match Self::mint_into(asset, dest, actual) {
+			Ok(_) => Ok(actual),
+			Err(err) => {
+				debug_assert!(false, "can_deposit returned true previously; qed");
+				// attempt to return the funds back to source
+				let revert = Self::mint_into(asset, source, actual);
+				debug_assert!(revert.is_ok(), "withdrew funds previously; qed");
+				Err(err)
+			}
+		}
+	}
+}
+
+/// Trait for providing a set of named fungible assets which can only be transferred.
+pub trait Transfer<AccountId>: Inspect<AccountId> {
+	/// Transfer funds from one account into another.
+	fn transfer(
+		asset: Self::AssetId,
+		source: &AccountId,
+		dest: &AccountId,
+		amount: Self::Balance,
+		keep_alive: bool,
+	) -> Result<Self::Balance, DispatchError>;
+}
+
+/// Trait for inspecting a set of named fungible assets which can be placed on hold.
+pub trait InspectHold<AccountId>: Inspect<AccountId> {
+	/// Amount of funds held in hold.
+	fn balance_on_hold(asset: Self::AssetId, who: &AccountId) -> Self::Balance;
+
+	/// Check to see if some `amount` of `asset` may be held on the account of `who`.
+	fn can_hold(asset: Self::AssetId, who: &AccountId, amount: Self::Balance) -> bool;
+}
+
+/// Trait for mutating a set of named fungible assets which can be placed on hold.
+pub trait MutateHold<AccountId>: InspectHold<AccountId> + Transfer<AccountId> {
+	/// Hold some funds in an account.
+	fn hold(asset: Self::AssetId, who: &AccountId, amount: Self::Balance) -> DispatchResult;
+
+	/// Release some funds in an account from being on hold.
+	///
+	/// If `best_effort` is `true`, then the amount actually released and returned as the inner
+	/// value of `Ok` may be smaller than the `amount` passed.
+	fn release(asset: Self::AssetId, who: &AccountId, amount: Self::Balance, best_effort: bool)
+		-> Result<Self::Balance, DispatchError>;
+
+	/// Transfer held funds into a destination account.
+	///
+	/// If `on_hold` is `true`, then the destination account must already exist and the assets
+	/// transferred will still be on hold in the destination account. If not, then the destination
+	/// account need not already exist, but must be creatable.
+	///
+	/// If `best_effort` is `true`, then an amount less than `amount` may be transferred without
+	/// error.
+	///
+	/// The actual amount transferred is returned, or `Err` in the case of error and nothing is
+	/// changed.
+	fn transfer_held(
+		asset: Self::AssetId,
+		source: &AccountId,
+		dest: &AccountId,
+		amount: Self::Balance,
+		best_effort: bool,
+		on_hold: bool,
+	) -> Result<Self::Balance, DispatchError>;
+}
+
+/// Trait for mutating one of several types of fungible assets which can be held.
+pub trait BalancedHold<AccountId>: Balanced<AccountId> + MutateHold<AccountId> {
+	/// Release and slash some funds in an account.
+	///
+	/// The resulting imbalance is the first item of the tuple returned.
+	///
+	/// As much funds up to `amount` will be deducted as possible. If this is less than `amount`,
+	/// then a non-zero second item will be returned.
+	fn slash_held(asset: Self::AssetId, who: &AccountId, amount: Self::Balance)
+		-> (CreditOf<AccountId, Self>, Self::Balance);
+}
+
+impl<
+	AccountId,
+	T: Balanced<AccountId> + MutateHold<AccountId>,
+> BalancedHold<AccountId> for T {
+	fn slash_held(asset: Self::AssetId, who: &AccountId, amount: Self::Balance)
+		-> (CreditOf<AccountId, Self>, Self::Balance)
+	{
+		let actual = match Self::release(asset, who, amount, true) {
+			Ok(x) => x,
+			Err(_) => return (Imbalance::zero(asset), amount),
+		};
+		<Self as fungibles::Balanced<AccountId>>::slash(asset, who, actual)
+	}
+}
diff --git a/frame/support/src/traits/tokens/fungibles/balanced.rs b/frame/support/src/traits/tokens/fungibles/balanced.rs
new file mode 100644
index 0000000000000..efb21300bcaa8
--- /dev/null
+++ b/frame/support/src/traits/tokens/fungibles/balanced.rs
@@ -0,0 +1,378 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! The trait and associated types for sets of fungible tokens that manage total issuance without
+//! requiring atomic balanced operations.
+
+use super::*;
+use sp_std::marker::PhantomData;
+use sp_runtime::{TokenError, traits::{Zero, CheckedAdd}};
+use sp_arithmetic::traits::Saturating;
+use crate::dispatch::{DispatchError, DispatchResult};
+use crate::traits::misc::{SameOrOther, TryDrop};
+
+/// A fungible token class where any creation and deletion of tokens is semi-explicit and where the
+/// total supply is maintained automatically.
+///
+/// This is auto-implemented when a token class has `Unbalanced` implemented.
+pub trait Balanced<AccountId>: Inspect<AccountId> {
+	/// The type for managing what happens when an instance of `Debt` is dropped without being used.
+	type OnDropDebt: HandleImbalanceDrop<Self::AssetId, Self::Balance>;
+	/// The type for managing what happens when an instance of `Credit` is dropped without being
+	/// used.
+	type OnDropCredit: HandleImbalanceDrop<Self::AssetId, Self::Balance>;
+
+	/// Reduce the total issuance by `amount` and return the according imbalance. The imbalance will
+	/// typically be used to reduce an account by the same amount with e.g. `settle`.
+	///
+	/// This is infallible, but doesn't guarantee that the entire `amount` is burnt, for example
+	/// in the case of underflow.
+	fn rescind(asset: Self::AssetId, amount: Self::Balance) -> DebtOf<AccountId, Self>;
+
+	/// Increase the total issuance by `amount` and return the according imbalance. The imbalance
+	/// will typically be used to increase an account by the same amount with e.g.
+	/// `resolve_into_existing` or `resolve_creating`.
+	///
+	/// This is infallible, but doesn't guarantee that the entire `amount` is issued, for example
+	/// in the case of overflow.
+	fn issue(asset: Self::AssetId, amount: Self::Balance) -> CreditOf<AccountId, Self>;
+
+	/// Produce a pair of imbalances that cancel each other out exactly.
+	///
+	/// This is just the same as burning and issuing the same amount and has no effect on the
+	/// total issuance.
+	fn pair(asset: Self::AssetId, amount: Self::Balance)
+			-> (DebtOf<AccountId, Self>, CreditOf<AccountId, Self>)
+	{
+		(Self::rescind(asset, amount), Self::issue(asset, amount))
+	}
+
+	/// Deducts up to `value` from the combined balance of `who`, preferring to deduct from the
+	/// free balance. This function cannot fail.
+	///
+	/// The resulting imbalance is the first item of the tuple returned.
+	///
+	/// As much funds up to `value` will be deducted as possible. If this is less than `value`,
+	/// then a non-zero second item will be returned.
+	fn slash(
+		asset: Self::AssetId,
+		who: &AccountId,
+		amount: Self::Balance,
+	) -> (CreditOf<AccountId, Self>, Self::Balance);
+
+	/// Mints exactly `value` into the `asset` account of `who`.
+	///
+	/// If `who` doesn't exist, nothing is done and an `Err` returned. This could happen because it
+	/// the account doesn't yet exist and it isn't possible to create it under the current
+	/// circumstances and with `value` in it.
+	fn deposit(
+		asset: Self::AssetId,
+		who: &AccountId,
+		value: Self::Balance,
+	) -> Result<DebtOf<AccountId, Self>, DispatchError>;
+
+	/// Removes `value` free `asset` balance from `who` account if possible.
+	///
+	/// If the removal is not possible, then it returns `Err` and nothing is changed.
+	///
+	/// If the operation is successful, this will return `Ok` with a `NegativeImbalance` whose value
+	/// is no less than `value`. It may be more in the case that removing it reduced it below
+	/// `Self::minimum_balance()`.
+	fn withdraw(
+		asset: Self::AssetId,
+		who: &AccountId,
+		value: Self::Balance,
+		//TODO: liveness: ExistenceRequirement,
+	) -> Result<CreditOf<AccountId, Self>, DispatchError>;
+
+	/// The balance of `who` is increased in order to counter `credit`. If the whole of `credit`
+	/// cannot be countered, then nothing is changed and the original `credit` is returned in an
+	/// `Err`.
+	///
+	/// Please note: If `credit.peek()` is less than `Self::minimum_balance()`, then `who` must
+	/// already exist for this to succeed.
+	fn resolve(
+		who: &AccountId,
+		credit: CreditOf<AccountId, Self>,
+	) -> Result<(), CreditOf<AccountId, Self>> {
+		let v = credit.peek();
+		let debt = match Self::deposit(credit.asset(), who, v) {
+			Err(_) => return Err(credit),
+			Ok(d) => d,
+		};
+		if let Ok(result) = credit.offset(debt) {
+			let result = result.try_drop();
+			debug_assert!(result.is_ok(), "ok deposit return must be equal to credit value; qed");
+		} else {
+			debug_assert!(false, "debt.asset is credit.asset; qed");
+		}
+		Ok(())
+	}
+
+	/// The balance of `who` is decreased in order to counter `debt`. If the whole of `debt`
+	/// cannot be countered, then nothing is changed and the original `debt` is returned in an
+	/// `Err`.
+	fn settle(
+		who: &AccountId,
+		debt: DebtOf<AccountId, Self>,
+		//TODO: liveness: ExistenceRequirement,
+	) -> Result<CreditOf<AccountId, Self>, DebtOf<AccountId, Self>> {
+		let amount = debt.peek();
+		let asset = debt.asset();
+		let credit = match Self::withdraw(asset, who, amount) {
+			Err(_) => return Err(debt),
+			Ok(d) => d,
+		};
+		match credit.offset(debt) {
+			Ok(SameOrOther::None) => Ok(CreditOf::<AccountId, Self>::zero(asset)),
+			Ok(SameOrOther::Same(dust)) => Ok(dust),
+			Ok(SameOrOther::Other(rest)) => {
+				debug_assert!(false, "ok withdraw return must be at least debt value; qed");
+				Err(rest)
+			}
+			Err(_) => {
+				debug_assert!(false, "debt.asset is credit.asset; qed");
+				Ok(CreditOf::<AccountId, Self>::zero(asset))
+			}
+		}
+	}
+}
+
+/// A fungible token class where the balance can be set arbitrarily.
+///
+/// **WARNING**
+/// Do not use this directly unless you want trouble, since it allows you to alter account balances
+/// without keeping the issuance up to date. It has no safeguards against accidentally creating
+/// token imbalances in your system leading to accidental imflation or deflation. It's really just
+/// for the underlying datatype to implement so the user gets the much safer `Balanced` trait to
+/// use.
+pub trait Unbalanced<AccountId>: Inspect<AccountId> {
+	/// Set the `asset` balance of `who` to `amount`. If this cannot be done for some reason (e.g.
+	/// because the account cannot be created or an overflow) then an `Err` is returned.
+	fn set_balance(asset: Self::AssetId, who: &AccountId, amount: Self::Balance) -> DispatchResult;
+
+	/// Set the total issuance of `asset` to `amount`.
+	fn set_total_issuance(asset: Self::AssetId, amount: Self::Balance);
+
+	/// Reduce the `asset` balance of `who` by `amount`. If it cannot be reduced by that amount for
+	/// some reason, return `Err` and don't reduce it at all. If Ok, return the imbalance.
+	///
+	/// Minimum balance will be respected and the returned imbalance may be up to
+	/// `Self::minimum_balance() - 1` greater than `amount`.
+	fn decrease_balance(asset: Self::AssetId, who: &AccountId, amount: Self::Balance)
+		-> Result<Self::Balance, DispatchError>
+	{
+		let old_balance = Self::balance(asset, who);
+		let (mut new_balance, mut amount) = if old_balance < amount {
+			Err(TokenError::NoFunds)?
+		} else {
+			(old_balance - amount, amount)
+		};
+		if new_balance < Self::minimum_balance(asset) {
+			amount = amount.saturating_add(new_balance);
+			new_balance = Zero::zero();
+		}
+		// Defensive only - this should not fail now.
+		Self::set_balance(asset, who, new_balance)?;
+		Ok(amount)
+	}
+
+	/// Reduce the `asset` balance of `who` by the most that is possible, up to `amount`.
+	///
+	/// Minimum balance will be respected and the returned imbalance may be up to
+	/// `Self::minimum_balance() - 1` greater than `amount`.
+	///
+	/// Return the imbalance by which the account was reduced.
+	fn decrease_balance_at_most(asset: Self::AssetId, who: &AccountId, amount: Self::Balance)
+		-> Self::Balance
+	{
+		let old_balance = Self::balance(asset, who);
+		let (mut new_balance, mut amount) = if old_balance < amount {
+			(Zero::zero(), old_balance)
+		} else {
+			(old_balance - amount, amount)
+		};
+		let minimum_balance = Self::minimum_balance(asset);
+		if new_balance < minimum_balance {
+			amount = amount.saturating_add(new_balance);
+			new_balance = Zero::zero();
+		}
+		let mut r = Self::set_balance(asset, who, new_balance);
+		if r.is_err() {
+			// Some error, probably because we tried to destroy an account which cannot be destroyed.
+			if new_balance.is_zero() && amount >= minimum_balance {
+				new_balance = minimum_balance;
+				amount -= minimum_balance;
+				r = Self::set_balance(asset, who, new_balance);
+			}
+			if r.is_err() {
+				// Still an error. Apparently it's not possible to reduce at all.
+				amount = Zero::zero();
+			}
+		}
+		amount
+	}
+
+	/// Increase the `asset` balance of `who` by `amount`. If it cannot be increased by that amount
+	/// for some reason, return `Err` and don't increase it at all. If Ok, return the imbalance.
+	///
+	/// Minimum balance will be respected and an error will be returned if
+	/// `amount < Self::minimum_balance()` when the account of `who` is zero.
+	fn increase_balance(asset: Self::AssetId, who: &AccountId, amount: Self::Balance)
+		-> Result<Self::Balance, DispatchError>
+	{
+		let old_balance = Self::balance(asset, who);
+		let new_balance = old_balance.checked_add(&amount).ok_or(TokenError::Overflow)?;
+		if new_balance < Self::minimum_balance(asset) {
+			Err(TokenError::BelowMinimum)?
+		}
+		if old_balance != new_balance {
+			Self::set_balance(asset, who, new_balance)?;
+		}
+		Ok(amount)
+	}
+
+	/// Increase the `asset` balance of `who` by the most that is possible, up to `amount`.
+	///
+	/// Minimum balance will be respected and the returned imbalance will be zero in the case that
+	/// `amount < Self::minimum_balance()`.
+	///
+	/// Return the imbalance by which the account was increased.
+	fn increase_balance_at_most(asset: Self::AssetId, who: &AccountId, amount: Self::Balance)
+		-> Self::Balance
+	{
+		let old_balance = Self::balance(asset, who);
+		let mut new_balance = old_balance.saturating_add(amount);
+		let mut amount = new_balance - old_balance;
+		if new_balance < Self::minimum_balance(asset) {
+			new_balance = Zero::zero();
+			amount = Zero::zero();
+		}
+		if old_balance == new_balance || Self::set_balance(asset, who, new_balance).is_ok() {
+			amount
+		} else {
+			Zero::zero()
+		}
+	}
+}
+
+/// Simple handler for an imbalance drop which increases the total issuance of the system by the
+/// imbalance amount. Used for leftover debt.
+pub struct IncreaseIssuance<AccountId, U>(PhantomData<(AccountId, U)>);
+impl<AccountId, U: Unbalanced<AccountId>> HandleImbalanceDrop<U::AssetId, U::Balance>
+	for IncreaseIssuance<AccountId, U>
+{
+	fn handle(asset: U::AssetId, amount: U::Balance) {
+		U::set_total_issuance(asset, U::total_issuance(asset).saturating_add(amount))
+	}
+}
+
+/// Simple handler for an imbalance drop which decreases the total issuance of the system by the
+/// imbalance amount. Used for leftover credit.
+pub struct DecreaseIssuance<AccountId, U>(PhantomData<(AccountId, U)>);
+impl<AccountId, U: Unbalanced<AccountId>> HandleImbalanceDrop<U::AssetId, U::Balance>
+	for DecreaseIssuance<AccountId, U>
+{
+	fn handle(asset: U::AssetId, amount: U::Balance) {
+		U::set_total_issuance(asset, U::total_issuance(asset).saturating_sub(amount))
+	}
+}
+
+/// An imbalance type which uses `DecreaseIssuance` to deal with anything `Drop`ed.
+///
+/// Basically means that funds in someone's account have been removed and not yet placed anywhere
+/// else. If it gets dropped, then those funds will be assumed to be "burned" and the total supply
+/// will be accordingly decreased to ensure it equals the sum of the balances of all accounts.
+type Credit<AccountId, U> = Imbalance<
+	<U as Inspect<AccountId>>::AssetId,
+	<U as Inspect<AccountId>>::Balance,
+	DecreaseIssuance<AccountId, U>,
+	IncreaseIssuance<AccountId, U>,
+>;
+
+/// An imbalance type which uses `IncreaseIssuance` to deal with anything `Drop`ed.
+///
+/// Basically means that there are funds in someone's account whose origin is as yet unaccounted
+/// for. If it gets dropped, then those funds will be assumed to be "minted" and the total supply
+/// will be accordingly increased to ensure it equals the sum of the balances of all accounts.
+type Debt<AccountId, U> = Imbalance<
+	<U as Inspect<AccountId>>::AssetId,
+	<U as Inspect<AccountId>>::Balance,
+	IncreaseIssuance<AccountId, U>,
+	DecreaseIssuance<AccountId, U>,
+>;
+
+/// Create some `Credit` item. Only for internal use.
+fn credit<AccountId, U: Unbalanced<AccountId>>(
+	asset: U::AssetId,
+	amount: U::Balance,
+) -> Credit<AccountId, U> {
+	Imbalance::new(asset, amount)
+}
+
+/// Create some `Debt` item. Only for internal use.
+fn debt<AccountId, U: Unbalanced<AccountId>>(
+	asset: U::AssetId,
+	amount: U::Balance,
+) -> Debt<AccountId, U> {
+	Imbalance::new(asset, amount)
+}
+
+impl<AccountId, U: Unbalanced<AccountId>> Balanced<AccountId> for U {
+	type OnDropCredit = DecreaseIssuance<AccountId, U>;
+	type OnDropDebt = IncreaseIssuance<AccountId, U>;
+	fn rescind(asset: Self::AssetId, amount: Self::Balance) -> Debt<AccountId, Self> {
+		U::set_total_issuance(asset, U::total_issuance(asset).saturating_sub(amount));
+		debt(asset, amount)
+	}
+	fn issue(asset: Self::AssetId, amount: Self::Balance) -> Credit<AccountId, Self> {
+		U::set_total_issuance(asset, U::total_issuance(asset).saturating_add(amount));
+		credit(asset, amount)
+	}
+	fn slash(
+		asset: Self::AssetId,
+		who: &AccountId,
+		amount: Self::Balance,
+	) -> (Credit<AccountId, Self>, Self::Balance) {
+		let slashed = U::decrease_balance_at_most(asset, who, amount);
+		// `slashed` could be less than, greater than or equal to `amount`.
+		// If slashed == amount, it means the account had at least amount in it and it could all be
+		//   removed without a problem.
+		// If slashed > amount, it means the account had more than amount in it, but not enough more
+		//   to push it over minimum_balance.
+		// If slashed < amount, it means the account didn't have enough in it to be reduced by
+		//   `amount` without being destroyed.
+		(credit(asset, slashed), amount.saturating_sub(slashed))
+	}
+	fn deposit(
+		asset: Self::AssetId,
+		who: &AccountId,
+		amount: Self::Balance
+	) -> Result<Debt<AccountId, Self>, DispatchError> {
+		let increase = U::increase_balance(asset, who, amount)?;
+		Ok(debt(asset, increase))
+	}
+	fn withdraw(
+		asset: Self::AssetId,
+		who: &AccountId,
+		amount: Self::Balance,
+		//TODO: liveness: ExistenceRequirement,
+	) -> Result<Credit<AccountId, Self>, DispatchError> {
+		let decrease = U::decrease_balance(asset, who, amount)?;
+		Ok(credit(asset, decrease))
+	}
+}
diff --git a/frame/support/src/traits/tokens/fungibles/imbalance.rs b/frame/support/src/traits/tokens/fungibles/imbalance.rs
new file mode 100644
index 0000000000000..ecc415cb568bd
--- /dev/null
+++ b/frame/support/src/traits/tokens/fungibles/imbalance.rs
@@ -0,0 +1,169 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! The imbalance type and its associates, which handles keeps everything adding up properly with
+//! unbalanced operations.
+
+use super::*;
+use sp_std::marker::PhantomData;
+use sp_runtime::traits::Zero;
+use super::fungibles::{AssetId, Balance};
+use super::balanced::Balanced;
+use crate::traits::misc::{TryDrop, SameOrOther};
+
+/// Handler for when an imbalance gets dropped. This could handle either a credit (negative) or
+/// debt (positive) imbalance.
+pub trait HandleImbalanceDrop<AssetId, Balance> {
+	fn handle(asset: AssetId, amount: Balance);
+}
+
+/// An imbalance in the system, representing a divergence of recorded token supply from the sum of
+/// the balances of all accounts. This is `must_use` in order to ensure it gets handled (placing
+/// into an account, settling from an account or altering the supply).
+///
+/// Importantly, it has a special `Drop` impl, and cannot be created outside of this module.
+#[must_use]
+pub struct Imbalance<
+	A: AssetId,
+	B: Balance,
+	OnDrop: HandleImbalanceDrop<A, B>,
+	OppositeOnDrop: HandleImbalanceDrop<A, B>,
+> {
+	asset: A,
+	amount: B,
+	_phantom: PhantomData<(OnDrop, OppositeOnDrop)>,
+}
+
+impl<
+	A: AssetId,
+	B: Balance,
+	OnDrop: HandleImbalanceDrop<A, B>,
+	OppositeOnDrop: HandleImbalanceDrop<A, B>
+> Drop for Imbalance<A, B, OnDrop, OppositeOnDrop> {
+	fn drop(&mut self) {
+		if !self.amount.is_zero() {
+			OnDrop::handle(self.asset, self.amount)
+		}
+	}
+}
+
+impl<
+	A: AssetId,
+	B: Balance,
+	OnDrop: HandleImbalanceDrop<A, B>,
+	OppositeOnDrop: HandleImbalanceDrop<A, B>,
+> TryDrop for Imbalance<A, B, OnDrop, OppositeOnDrop> {
+	/// Drop an instance cleanly. Only works if its value represents "no-operation".
+	fn try_drop(self) -> Result<(), Self> {
+		self.drop_zero()
+	}
+}
+
+impl<
+	A: AssetId,
+	B: Balance,
+	OnDrop: HandleImbalanceDrop<A, B>,
+	OppositeOnDrop: HandleImbalanceDrop<A, B>,
+> Imbalance<A, B, OnDrop, OppositeOnDrop> {
+	pub fn zero(asset: A) -> Self {
+		Self { asset, amount: Zero::zero(), _phantom: PhantomData }
+	}
+
+	pub(crate) fn new(asset: A, amount: B) -> Self {
+		Self { asset, amount, _phantom: PhantomData }
+	}
+
+	pub fn drop_zero(self) -> Result<(), Self> {
+		if self.amount.is_zero() {
+			sp_std::mem::forget(self);
+			Ok(())
+		} else {
+			Err(self)
+		}
+	}
+
+	pub fn split(self, amount: B) -> (Self, Self) {
+		let first = self.amount.min(amount);
+		let second = self.amount - first;
+		let asset = self.asset;
+		sp_std::mem::forget(self);
+		(Imbalance::new(asset, first), Imbalance::new(asset, second))
+	}
+	pub fn merge(mut self, other: Self) -> Result<Self, (Self, Self)> {
+		if self.asset == other.asset {
+			self.amount = self.amount.saturating_add(other.amount);
+			sp_std::mem::forget(other);
+			Ok(self)
+		} else {
+			Err((self, other))
+		}
+	}
+	pub fn subsume(&mut self, other: Self) -> Result<(), Self> {
+		if self.asset == other.asset {
+			self.amount = self.amount.saturating_add(other.amount);
+			sp_std::mem::forget(other);
+			Ok(())
+		} else {
+			Err(other)
+		}
+	}
+	pub fn offset(self, other: Imbalance<A, B, OppositeOnDrop, OnDrop>) -> Result<
+		SameOrOther<Self, Imbalance<A, B, OppositeOnDrop, OnDrop>>,
+		(Self, Imbalance<A, B, OppositeOnDrop, OnDrop>),
+	> {
+		if self.asset == other.asset {
+			let (a, b) = (self.amount, other.amount);
+			let asset = self.asset;
+			sp_std::mem::forget((self, other));
+
+			if a == b {
+				Ok(SameOrOther::None)
+			} else if a > b {
+				Ok(SameOrOther::Same(Imbalance::new(asset, a - b)))
+			} else {
+				Ok(SameOrOther::Other(Imbalance::<A, B, OppositeOnDrop, OnDrop>::new(asset, b - a)))
+			}
+		} else {
+			Err((self, other))
+		}
+	}
+	pub fn peek(&self) -> B {
+		self.amount
+	}
+
+	pub fn asset(&self) -> A {
+		self.asset
+	}
+}
+
+/// Imbalance implying that the total_issuance value is less than the sum of all account balances.
+pub type DebtOf<AccountId, B> = Imbalance<
+	<B as Inspect<AccountId>>::AssetId,
+	<B as Inspect<AccountId>>::Balance,
+	// This will generally be implemented by increasing the total_issuance value.
+	<B as Balanced<AccountId>>::OnDropDebt,
+	<B as Balanced<AccountId>>::OnDropCredit,
+>;
+
+/// Imbalance implying that the total_issuance value is greater than the sum of all account balances.
+pub type CreditOf<AccountId, B> = Imbalance<
+	<B as Inspect<AccountId>>::AssetId,
+	<B as Inspect<AccountId>>::Balance,
+	// This will generally be implemented by decreasing the total_issuance value.
+	<B as Balanced<AccountId>>::OnDropCredit,
+	<B as Balanced<AccountId>>::OnDropDebt,
+>;
diff --git a/frame/support/src/traits/tokens/imbalance.rs b/frame/support/src/traits/tokens/imbalance.rs
new file mode 100644
index 0000000000000..9652b9a0275a1
--- /dev/null
+++ b/frame/support/src/traits/tokens/imbalance.rs
@@ -0,0 +1,174 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! The imbalance trait type and its associates, which handles keeps everything adding up properly
+//! with unbalanced operations.
+
+use sp_std::ops::Div;
+use sp_runtime::traits::Saturating;
+use crate::traits::misc::{TryDrop, SameOrOther};
+
+mod split_two_ways;
+mod signed_imbalance;
+mod on_unbalanced;
+pub use split_two_ways::SplitTwoWays;
+pub use signed_imbalance::SignedImbalance;
+pub use on_unbalanced::OnUnbalanced;
+
+/// A trait for a not-quite Linear Type that tracks an imbalance.
+///
+/// Functions that alter account balances return an object of this trait to
+/// express how much account balances have been altered in aggregate. If
+/// dropped, the currency system will take some default steps to deal with
+/// the imbalance (`balances` module simply reduces or increases its
+/// total issuance). Your module should generally handle it in some way,
+/// good practice is to do so in a configurable manner using an
+/// `OnUnbalanced` type for each situation in which your module needs to
+/// handle an imbalance.
+///
+/// Imbalances can either be Positive (funds were added somewhere without
+/// being subtracted elsewhere - e.g. a reward) or Negative (funds deducted
+/// somewhere without an equal and opposite addition - e.g. a slash or
+/// system fee payment).
+///
+/// Since they are unsigned, the actual type is always Positive or Negative.
+/// The trait makes no distinction except to define the `Opposite` type.
+///
+/// New instances of zero value can be created (`zero`) and destroyed
+/// (`drop_zero`).
+///
+/// Existing instances can be `split` and merged either consuming `self` with
+/// `merge` or mutating `self` with `subsume`. If the target is an `Option`,
+/// then `maybe_merge` and `maybe_subsume` might work better. Instances can
+/// also be `offset` with an `Opposite` that is less than or equal to in value.
+///
+/// You can always retrieve the raw balance value using `peek`.
+#[must_use]
+pub trait Imbalance<Balance>: Sized + TryDrop + Default {
+	/// The oppositely imbalanced type. They come in pairs.
+	type Opposite: Imbalance<Balance>;
+
+	/// The zero imbalance. Can be destroyed with `drop_zero`.
+	fn zero() -> Self;
+
+	/// Drop an instance cleanly. Only works if its `self.value()` is zero.
+	fn drop_zero(self) -> Result<(), Self>;
+
+	/// Consume `self` and return two independent instances; the first
+	/// is guaranteed to be at most `amount` and the second will be the remainder.
+	fn split(self, amount: Balance) -> (Self, Self);
+
+	/// Consume `self` and return two independent instances; the amounts returned will be in
+	/// approximately the same ratio as `first`:`second`.
+	///
+	/// NOTE: This requires up to `first + second` room for a multiply, and `first + second` should
+	/// fit into a `u32`. Overflow will safely saturate in both cases.
+	fn ration(self, first: u32, second: u32) -> (Self, Self)
+		where Balance: From<u32> + Saturating + Div<Output=Balance>
+	{
+		let total: u32 = first.saturating_add(second);
+		if total == 0 { return (Self::zero(), Self::zero()) }
+		let amount1 = self.peek().saturating_mul(first.into()) / total.into();
+		self.split(amount1)
+	}
+
+	/// Consume self and add its two components, defined by the first component's balance,
+	/// element-wise to two pre-existing Imbalances.
+	///
+	/// A convenient replacement for `split` and `merge`.
+	fn split_merge(self, amount: Balance, others: (Self, Self)) -> (Self, Self) {
+		let (a, b) = self.split(amount);
+		(a.merge(others.0), b.merge(others.1))
+	}
+
+	/// Consume self and add its two components, defined by the ratio `first`:`second`,
+	/// element-wise to two pre-existing Imbalances.
+	///
+	/// A convenient replacement for `split` and `merge`.
+	fn ration_merge(self, first: u32, second: u32, others: (Self, Self)) -> (Self, Self)
+		where Balance: From<u32> + Saturating + Div<Output=Balance>
+	{
+		let (a, b) = self.ration(first, second);
+		(a.merge(others.0), b.merge(others.1))
+	}
+
+	/// Consume self and add its two components, defined by the first component's balance,
+	/// element-wise into two pre-existing Imbalance refs.
+	///
+	/// A convenient replacement for `split` and `subsume`.
+	fn split_merge_into(self, amount: Balance, others: &mut (Self, Self)) {
+		let (a, b) = self.split(amount);
+		others.0.subsume(a);
+		others.1.subsume(b);
+	}
+
+	/// Consume self and add its two components, defined by the ratio `first`:`second`,
+	/// element-wise to two pre-existing Imbalances.
+	///
+	/// A convenient replacement for `split` and `merge`.
+	fn ration_merge_into(self, first: u32, second: u32, others: &mut (Self, Self))
+		where Balance: From<u32> + Saturating + Div<Output=Balance>
+	{
+		let (a, b) = self.ration(first, second);
+		others.0.subsume(a);
+		others.1.subsume(b);
+	}
+
+	/// Consume `self` and an `other` to return a new instance that combines
+	/// both.
+	fn merge(self, other: Self) -> Self;
+
+	/// Consume self to mutate `other` so that it combines both. Just like `subsume`, only with
+	/// reversed arguments.
+	fn merge_into(self, other: &mut Self) {
+		other.subsume(self)
+	}
+
+	/// Consume `self` and maybe an `other` to return a new instance that combines
+	/// both.
+	fn maybe_merge(self, other: Option<Self>) -> Self {
+		if let Some(o) = other {
+			self.merge(o)
+		} else {
+			self
+		}
+	}
+
+	/// Consume an `other` to mutate `self` into a new instance that combines
+	/// both.
+	fn subsume(&mut self, other: Self);
+
+	/// Maybe consume an `other` to mutate `self` into a new instance that combines
+	/// both.
+	fn maybe_subsume(&mut self, other: Option<Self>) {
+		if let Some(o) = other {
+			self.subsume(o)
+		}
+	}
+
+	/// Consume self and along with an opposite counterpart to return
+	/// a combined result.
+	///
+	/// Returns `Ok` along with a new instance of `Self` if this instance has a
+	/// greater value than the `other`. Otherwise returns `Err` with an instance of
+	/// the `Opposite`. In both cases the value represents the combination of `self`
+	/// and `other`.
+	fn offset(self, other: Self::Opposite)-> SameOrOther<Self, Self::Opposite>;
+
+	/// The raw value of self.
+	fn peek(&self) -> Balance;
+}
diff --git a/frame/support/src/traits/tokens/imbalance/on_unbalanced.rs b/frame/support/src/traits/tokens/imbalance/on_unbalanced.rs
new file mode 100644
index 0000000000000..f3ecc14308e74
--- /dev/null
+++ b/frame/support/src/traits/tokens/imbalance/on_unbalanced.rs
@@ -0,0 +1,50 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Trait for handling imbalances.
+
+use crate::traits::misc::TryDrop;
+
+/// Handler for when some currency "account" decreased in balance for
+/// some reason.
+///
+/// The only reason at present for an increase would be for validator rewards, but
+/// there may be other reasons in the future or for other chains.
+///
+/// Reasons for decreases include:
+///
+/// - Someone got slashed.
+/// - Someone paid for a transaction to be included.
+pub trait OnUnbalanced<Imbalance: TryDrop> {
+	/// Handler for some imbalances. The different imbalances might have different origins or
+	/// meanings, dependent on the context. Will default to simply calling on_unbalanced for all
+	/// of them. Infallible.
+	fn on_unbalanceds<B>(amounts: impl Iterator<Item=Imbalance>) where Imbalance: crate::traits::Imbalance<B> {
+		Self::on_unbalanced(amounts.fold(Imbalance::zero(), |i, x| x.merge(i)))
+	}
+
+	/// Handler for some imbalance. Infallible.
+	fn on_unbalanced(amount: Imbalance) {
+		amount.try_drop().unwrap_or_else(Self::on_nonzero_unbalanced)
+	}
+
+	/// Actually handle a non-zero imbalance. You probably want to implement this rather than
+	/// `on_unbalanced`.
+	fn on_nonzero_unbalanced(amount: Imbalance) { drop(amount); }
+}
+
+impl<Imbalance: TryDrop> OnUnbalanced<Imbalance> for () {}
diff --git a/frame/support/src/traits/tokens/imbalance/signed_imbalance.rs b/frame/support/src/traits/tokens/imbalance/signed_imbalance.rs
new file mode 100644
index 0000000000000..e3523f86804fd
--- /dev/null
+++ b/frame/support/src/traits/tokens/imbalance/signed_imbalance.rs
@@ -0,0 +1,69 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Convenience type for managing an imbalance whose sign is unknown.
+
+use codec::FullCodec;
+use sp_std::fmt::Debug;
+use sp_runtime::traits::{AtLeast32BitUnsigned, MaybeSerializeDeserialize};
+use crate::traits::misc::SameOrOther;
+use super::super::imbalance::Imbalance;
+
+/// Either a positive or a negative imbalance.
+pub enum SignedImbalance<B, PositiveImbalance: Imbalance<B>>{
+	/// A positive imbalance (funds have been created but none destroyed).
+	Positive(PositiveImbalance),
+	/// A negative imbalance (funds have been destroyed but none created).
+	Negative(PositiveImbalance::Opposite),
+}
+
+impl<
+	P: Imbalance<B, Opposite=N>,
+	N: Imbalance<B, Opposite=P>,
+	B: AtLeast32BitUnsigned + FullCodec + Copy + MaybeSerializeDeserialize + Debug + Default,
+> SignedImbalance<B, P> {
+	/// Create a `Positive` instance of `Self` whose value is zero.
+	pub fn zero() -> Self {
+		SignedImbalance::Positive(P::zero())
+	}
+
+	/// Drop `Self` if and only if it is equal to zero. Return `Err` with `Self` if not.
+	pub fn drop_zero(self) -> Result<(), Self> {
+		match self {
+			SignedImbalance::Positive(x) => x.drop_zero().map_err(SignedImbalance::Positive),
+			SignedImbalance::Negative(x) => x.drop_zero().map_err(SignedImbalance::Negative),
+		}
+	}
+
+	/// Consume `self` and an `other` to return a new instance that combines
+	/// both.
+	pub fn merge(self, other: Self) -> Self {
+		match (self, other) {
+			(SignedImbalance::Positive(one), SignedImbalance::Positive(other)) =>
+				SignedImbalance::Positive(one.merge(other)),
+			(SignedImbalance::Negative(one), SignedImbalance::Negative(other)) =>
+				SignedImbalance::Negative(one.merge(other)),
+			(SignedImbalance::Positive(one), SignedImbalance::Negative(other)) =>
+				match one.offset(other) {
+					SameOrOther::Same(positive) => SignedImbalance::Positive(positive),
+					SameOrOther::Other(negative) => SignedImbalance::Negative(negative),
+					SameOrOther::None => SignedImbalance::Positive(P::zero()),
+				},
+			(one, other) => other.merge(one),
+		}
+	}
+}
diff --git a/frame/support/src/traits/tokens/imbalance/split_two_ways.rs b/frame/support/src/traits/tokens/imbalance/split_two_ways.rs
new file mode 100644
index 0000000000000..f3f9870b62cd2
--- /dev/null
+++ b/frame/support/src/traits/tokens/imbalance/split_two_ways.rs
@@ -0,0 +1,51 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Means for splitting an imbalance into two and hanlding them differently.
+
+use sp_std::{ops::Div, marker::PhantomData};
+use sp_core::u32_trait::Value as U32;
+use sp_runtime::traits::Saturating;
+use super::super::imbalance::{Imbalance, OnUnbalanced};
+
+/// Split an unbalanced amount two ways between a common divisor.
+pub struct SplitTwoWays<
+	Balance,
+	Imbalance,
+	Part1,
+	Target1,
+	Part2,
+	Target2,
+>(PhantomData<(Balance, Imbalance, Part1, Target1, Part2, Target2)>);
+
+impl<
+	Balance: From<u32> + Saturating + Div<Output=Balance>,
+	I: Imbalance<Balance>,
+	Part1: U32,
+	Target1: OnUnbalanced<I>,
+	Part2: U32,
+	Target2: OnUnbalanced<I>,
+> OnUnbalanced<I> for SplitTwoWays<Balance, I, Part1, Target1, Part2, Target2>
+{
+	fn on_nonzero_unbalanced(amount: I) {
+		let total: u32 = Part1::VALUE + Part2::VALUE;
+		let amount1 = amount.peek().saturating_mul(Part1::VALUE.into()) / total.into();
+		let (imb1, imb2) = amount.split(amount1);
+		Target1::on_unbalanced(imb1);
+		Target2::on_unbalanced(imb2);
+	}
+}
diff --git a/frame/support/src/traits/tokens/misc.rs b/frame/support/src/traits/tokens/misc.rs
new file mode 100644
index 0000000000000..02f7ba384bd00
--- /dev/null
+++ b/frame/support/src/traits/tokens/misc.rs
@@ -0,0 +1,168 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Miscellaneous types.
+
+use codec::{Encode, Decode, FullCodec};
+use sp_core::RuntimeDebug;
+use sp_arithmetic::traits::{Zero, AtLeast32BitUnsigned};
+use sp_runtime::TokenError;
+
+/// One of a number of consequences of withdrawing a fungible from an account.
+#[derive(Copy, Clone, Eq, PartialEq)]
+pub enum WithdrawConsequence<Balance> {
+	/// Withdraw could not happen since the amount to be withdrawn is less than the total funds in
+	/// the account.
+	NoFunds,
+	/// The withdraw would mean the account dying when it needs to exist (usually because it is a
+	/// provider and there are consumer references on it).
+	WouldDie,
+	/// The asset is unknown. Usually because an `AssetId` has been presented which doesn't exist
+	/// on the system.
+	UnknownAsset,
+	/// There has been an underflow in the system. This is indicative of a corrupt state and
+	/// likely unrecoverable.
+	Underflow,
+	/// There has been an overflow in the system. This is indicative of a corrupt state and
+	/// likely unrecoverable.
+	Overflow,
+	/// Not enough of the funds in the account are unavailable for withdrawal.
+	Frozen,
+	/// Account balance would reduce to zero, potentially destroying it. The parameter is the
+	/// amount of balance which is destroyed.
+	ReducedToZero(Balance),
+	/// Account continued in existence.
+	Success,
+}
+
+impl<Balance: Zero> WithdrawConsequence<Balance> {
+	/// Convert the type into a `Result` with `TokenError` as the error or the additional `Balance`
+	/// by which the account will be reduced.
+	pub fn into_result(self) -> Result<Balance, TokenError> {
+		use WithdrawConsequence::*;
+		match self {
+			NoFunds => Err(TokenError::NoFunds),
+			WouldDie => Err(TokenError::WouldDie),
+			UnknownAsset => Err(TokenError::UnknownAsset),
+			Underflow => Err(TokenError::Underflow),
+			Overflow => Err(TokenError::Overflow),
+			Frozen => Err(TokenError::Frozen),
+			ReducedToZero(result) => Ok(result),
+			Success => Ok(Zero::zero()),
+		}
+	}
+}
+
+/// One of a number of consequences of withdrawing a fungible from an account.
+#[derive(Copy, Clone, Eq, PartialEq)]
+pub enum DepositConsequence {
+	/// Deposit couldn't happen due to the amount being too low. This is usually because the
+	/// account doesn't yet exist and the deposit wouldn't bring it to at least the minimum needed
+	/// for existance.
+	BelowMinimum,
+	/// Deposit cannot happen since the account cannot be created (usually because it's a consumer
+	/// and there exists no provider reference).
+	CannotCreate,
+	/// The asset is unknown. Usually because an `AssetId` has been presented which doesn't exist
+	/// on the system.
+	UnknownAsset,
+	/// An overflow would occur. This is practically unexpected, but could happen in test systems
+	/// with extremely small balance types or balances that approach the max value of the balance
+	/// type.
+	Overflow,
+	/// Account continued in existence.
+	Success,
+}
+
+impl DepositConsequence {
+	/// Convert the type into a `Result` with `TokenError` as the error.
+	pub fn into_result(self) -> Result<(), TokenError> {
+		use DepositConsequence::*;
+		Err(match self {
+			BelowMinimum => TokenError::BelowMinimum,
+			CannotCreate => TokenError::CannotCreate,
+			UnknownAsset => TokenError::UnknownAsset,
+			Overflow => TokenError::Overflow,
+			Success => return Ok(()),
+		})
+	}
+}
+
+/// Simple boolean for whether an account needs to be kept in existence.
+#[derive(Copy, Clone, Eq, PartialEq)]
+pub enum ExistenceRequirement {
+	/// Operation must not result in the account going out of existence.
+	///
+	/// Note this implies that if the account never existed in the first place, then the operation
+	/// may legitimately leave the account unchanged and still non-existent.
+	KeepAlive,
+	/// Operation may result in account going out of existence.
+	AllowDeath,
+}
+
+/// Status of funds.
+#[derive(PartialEq, Eq, Clone, Copy, Encode, Decode, RuntimeDebug)]
+pub enum BalanceStatus {
+	/// Funds are free, as corresponding to `free` item in Balances.
+	Free,
+	/// Funds are reserved, as corresponding to `reserved` item in Balances.
+	Reserved,
+}
+
+bitflags::bitflags! {
+	/// Reasons for moving funds out of an account.
+	#[derive(Encode, Decode)]
+	pub struct WithdrawReasons: i8 {
+		/// In order to pay for (system) transaction costs.
+		const TRANSACTION_PAYMENT = 0b00000001;
+		/// In order to transfer ownership.
+		const TRANSFER = 0b00000010;
+		/// In order to reserve some funds for a later return or repatriation.
+		const RESERVE = 0b00000100;
+		/// In order to pay some other (higher-level) fees.
+		const FEE = 0b00001000;
+		/// In order to tip a validator for transaction inclusion.
+		const TIP = 0b00010000;
+	}
+}
+
+impl WithdrawReasons {
+	/// Choose all variants except for `one`.
+	///
+	/// ```rust
+	/// # use frame_support::traits::WithdrawReasons;
+	/// # fn main() {
+	/// assert_eq!(
+	/// 	WithdrawReasons::FEE | WithdrawReasons::TRANSFER | WithdrawReasons::RESERVE | WithdrawReasons::TIP,
+	/// 	WithdrawReasons::except(WithdrawReasons::TRANSACTION_PAYMENT),
+	///	);
+	/// # }
+	/// ```
+	pub fn except(one: WithdrawReasons) -> WithdrawReasons {
+		let mut flags = Self::all();
+		flags.toggle(one);
+		flags
+	}
+}
+
+/// Simple amalgamation trait to collect together properties for an AssetId under one roof.
+pub trait AssetId: FullCodec + Copy + Default + Eq + PartialEq {}
+impl<T: FullCodec + Copy + Default + Eq + PartialEq> AssetId for T {}
+
+/// Simple amalgamation trait to collect together properties for a Balance under one roof.
+pub trait Balance: AtLeast32BitUnsigned + FullCodec + Copy + Default {}
+impl<T: AtLeast32BitUnsigned + FullCodec + Copy + Default> Balance for T {}
diff --git a/frame/support/src/traits/validation.rs b/frame/support/src/traits/validation.rs
new file mode 100644
index 0000000000000..900be7bb8e7e2
--- /dev/null
+++ b/frame/support/src/traits/validation.rs
@@ -0,0 +1,242 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Traits for dealing with validation and validators.
+
+use sp_std::prelude::*;
+use codec::{Codec, Decode};
+use sp_runtime::traits::{Convert, Zero};
+use sp_runtime::{BoundToRuntimeAppPublic, ConsensusEngineId, Percent, RuntimeAppPublic};
+use sp_staking::SessionIndex;
+use crate::dispatch::Parameter;
+use crate::weights::Weight;
+
+/// A trait for online node inspection in a session.
+///
+/// Something that can give information about the current validator set.
+pub trait ValidatorSet<AccountId> {
+	/// Type for representing validator id in a session.
+	type ValidatorId: Parameter;
+	/// A type for converting `AccountId` to `ValidatorId`.
+	type ValidatorIdOf: Convert<AccountId, Option<Self::ValidatorId>>;
+
+	/// Returns current session index.
+	fn session_index() -> SessionIndex;
+
+	/// Returns the active set of validators.
+	fn validators() -> Vec<Self::ValidatorId>;
+}
+
+/// [`ValidatorSet`] combined with an identification.
+pub trait ValidatorSetWithIdentification<AccountId>: ValidatorSet<AccountId> {
+	/// Full identification of `ValidatorId`.
+	type Identification: Parameter;
+	/// A type for converting `ValidatorId` to `Identification`.
+	type IdentificationOf: Convert<Self::ValidatorId, Option<Self::Identification>>;
+}
+
+/// A trait for finding the author of a block header based on the `PreRuntime` digests contained
+/// within it.
+pub trait FindAuthor<Author> {
+	/// Find the author of a block based on the pre-runtime digests.
+	fn find_author<'a, I>(digests: I) -> Option<Author>
+		where I: 'a + IntoIterator<Item=(ConsensusEngineId, &'a [u8])>;
+}
+
+impl<A> FindAuthor<A> for () {
+	fn find_author<'a, I>(_: I) -> Option<A>
+		where I: 'a + IntoIterator<Item=(ConsensusEngineId, &'a [u8])>
+	{
+		None
+	}
+}
+
+/// A trait for verifying the seal of a header and returning the author.
+pub trait VerifySeal<Header, Author> {
+	/// Verify a header and return the author, if any.
+	fn verify_seal(header: &Header) -> Result<Option<Author>, &'static str>;
+}
+
+/// A session handler for specific key type.
+pub trait OneSessionHandler<ValidatorId>: BoundToRuntimeAppPublic {
+	/// The key type expected.
+	type Key: Decode + Default + RuntimeAppPublic;
+
+	/// The given validator set will be used for the genesis session.
+	/// It is guaranteed that the given validator set will also be used
+	/// for the second session, therefore the first call to `on_new_session`
+	/// should provide the same validator set.
+	fn on_genesis_session<'a, I: 'a>(validators: I)
+		where I: Iterator<Item=(&'a ValidatorId, Self::Key)>, ValidatorId: 'a;
+
+	/// Session set has changed; act appropriately. Note that this can be called
+	/// before initialization of your module.
+	///
+	/// `changed` is true when at least one of the session keys
+	/// or the underlying economic identities/distribution behind one the
+	/// session keys has changed, false otherwise.
+	///
+	/// The `validators` are the validators of the incoming session, and `queued_validators`
+	/// will follow.
+	fn on_new_session<'a, I: 'a>(
+		changed: bool,
+		validators: I,
+		queued_validators: I,
+	) where I: Iterator<Item=(&'a ValidatorId, Self::Key)>, ValidatorId: 'a;
+
+	/// A notification for end of the session.
+	///
+	/// Note it is triggered before any `SessionManager::end_session` handlers,
+	/// so we can still affect the validator set.
+	fn on_before_session_ending() {}
+
+	/// A validator got disabled. Act accordingly until a new session begins.
+	fn on_disabled(_validator_index: usize);
+}
+
+/// Something that can estimate at which block the next session rotation will happen (i.e. a new
+/// session starts).
+///
+/// The accuracy of the estimates is dependent on the specific implementation, but in order to get
+/// the best estimate possible these methods should be called throughout the duration of the session
+/// (rather than calling once and storing the result).
+///
+/// This should be the same logical unit that dictates `ShouldEndSession` to the session module. No
+/// assumptions are made about the scheduling of the sessions.
+pub trait EstimateNextSessionRotation<BlockNumber> {
+	/// Return the average length of a session.
+	///
+	/// This may or may not be accurate.
+	fn average_session_length() -> BlockNumber;
+
+	/// Return an estimate of the current session progress.
+	///
+	/// None should be returned if the estimation fails to come to an answer.
+	fn estimate_current_session_progress(now: BlockNumber) -> (Option<Percent>, Weight);
+
+	/// Return the block number at which the next session rotation is estimated to happen.
+	///
+	/// None should be returned if the estimation fails to come to an answer.
+	fn estimate_next_session_rotation(now: BlockNumber) -> (Option<BlockNumber>, Weight);
+}
+
+impl<BlockNumber: Zero> EstimateNextSessionRotation<BlockNumber> for () {
+	fn average_session_length() -> BlockNumber {
+		Zero::zero()
+	}
+
+	fn estimate_current_session_progress(_: BlockNumber) -> (Option<Percent>, Weight) {
+		(None, Zero::zero())
+	}
+
+	fn estimate_next_session_rotation(_: BlockNumber) -> (Option<BlockNumber>, Weight) {
+		(None, Zero::zero())
+	}
+}
+
+/// Something that can estimate at which block scheduling of the next session will happen (i.e when
+/// we will try to fetch new validators).
+///
+/// This only refers to the point when we fetch the next session details and not when we enact them
+/// (for enactment there's `EstimateNextSessionRotation`). With `pallet-session` this should be
+/// triggered whenever `SessionManager::new_session` is called.
+///
+/// For example, if we are using a staking module this would be the block when the session module
+/// would ask staking what the next validator set will be, as such this must always be implemented
+/// by the session module.
+pub trait EstimateNextNewSession<BlockNumber> {
+	/// Return the average length of a session.
+	///
+	/// This may or may not be accurate.
+	fn average_session_length() -> BlockNumber;
+
+	/// Return the block number at which the next new session is estimated to happen.
+	///
+	/// None should be returned if the estimation fails to come to an answer.
+	fn estimate_next_new_session(_: BlockNumber) -> (Option<BlockNumber>, Weight);
+}
+
+impl<BlockNumber: Zero> EstimateNextNewSession<BlockNumber> for () {
+	fn average_session_length() -> BlockNumber {
+		Zero::zero()
+	}
+
+	fn estimate_next_new_session(_: BlockNumber) -> (Option<BlockNumber>, Weight) {
+		(None, Zero::zero())
+	}
+}
+
+/// Something which can compute and check proofs of
+/// a historical key owner and return full identification data of that
+/// key owner.
+pub trait KeyOwnerProofSystem<Key> {
+	/// The proof of membership itself.
+	type Proof: Codec;
+	/// The full identification of a key owner and the stash account.
+	type IdentificationTuple: Codec;
+
+	/// Prove membership of a key owner in the current block-state.
+	///
+	/// This should typically only be called off-chain, since it may be
+	/// computationally heavy.
+	///
+	/// Returns `Some` iff the key owner referred to by the given `key` is a
+	/// member of the current set.
+	fn prove(key: Key) -> Option<Self::Proof>;
+
+	/// Check a proof of membership on-chain. Return `Some` iff the proof is
+	/// valid and recent enough to check.
+	fn check_proof(key: Key, proof: Self::Proof) -> Option<Self::IdentificationTuple>;
+}
+
+impl<Key> KeyOwnerProofSystem<Key> for () {
+	// The proof and identification tuples is any bottom type to guarantee that the methods of this
+	// implementation can never be called or return anything other than `None`.
+	type Proof = crate::Void;
+	type IdentificationTuple = crate::Void;
+
+	fn prove(_key: Key) -> Option<Self::Proof> {
+		None
+	}
+
+	fn check_proof(_key: Key, _proof: Self::Proof) -> Option<Self::IdentificationTuple> {
+		None
+	}
+}
+
+/// Trait to be used by block producing consensus engine modules to determine
+/// how late the current block is (e.g. in a slot-based proposal mechanism how
+/// many slots were skipped since the previous block).
+pub trait Lateness<N> {
+	/// Returns a generic measure of how late the current block is compared to
+	/// its parent.
+	fn lateness(&self) -> N;
+}
+
+impl<N: Zero> Lateness<N> for () {
+	fn lateness(&self) -> N {
+		Zero::zero()
+	}
+}
+
+/// Implementors of this trait provide information about whether or not some validator has
+/// been registered with them. The [Session module](../../pallet_session/index.html) is an implementor.
+pub trait ValidatorRegistration<ValidatorId> {
+	/// Returns true if the provided validator ID has been registered with the implementing runtime
+	/// module
+	fn is_registered(id: &ValidatorId) -> bool;
+}
diff --git a/frame/support/src/traits/voting.rs b/frame/support/src/traits/voting.rs
new file mode 100644
index 0000000000000..b6913a182d30b
--- /dev/null
+++ b/frame/support/src/traits/voting.rs
@@ -0,0 +1,88 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Traits and associated data structures concerned with voting, and moving between tokens and
+//! votes.
+
+use sp_arithmetic::traits::{UniqueSaturatedInto, UniqueSaturatedFrom, SaturatedConversion};
+
+/// A trait similar to `Convert` to convert values from `B` an abstract balance type
+/// into u64 and back from u128. (This conversion is used in election and other places where complex
+/// calculation over balance type is needed)
+///
+/// Total issuance of the currency is passed in, but an implementation of this trait may or may not
+/// use it.
+///
+/// # WARNING
+///
+/// the total issuance being passed in implies that the implementation must be aware of the fact
+/// that its values can affect the outcome. This implies that if the vote value is dependent on the
+/// total issuance, it should never ber written to storage for later re-use.
+pub trait CurrencyToVote<B> {
+	/// Convert balance to u64.
+	fn to_vote(value: B, issuance: B) -> u64;
+
+	/// Convert u128 to balance.
+	fn to_currency(value: u128, issuance: B) -> B;
+}
+
+/// An implementation of `CurrencyToVote` tailored for chain's that have a balance type of u128.
+///
+/// The factor is the `(total_issuance / u64::max()).max(1)`, represented as u64. Let's look at the
+/// important cases:
+///
+/// If the chain's total issuance is less than u64::max(), this will always be 1, which means that
+/// the factor will not have any effect. In this case, any account's balance is also less. Thus,
+/// both of the conversions are basically an `as`; Any balance can fit in u64.
+///
+/// If the chain's total issuance is more than 2*u64::max(), then a factor might be multiplied and
+/// divided upon conversion.
+pub struct U128CurrencyToVote;
+
+impl U128CurrencyToVote {
+	fn factor(issuance: u128) -> u128 {
+		(issuance / u64::max_value() as u128).max(1)
+	}
+}
+
+impl CurrencyToVote<u128> for U128CurrencyToVote {
+	fn to_vote(value: u128, issuance: u128) -> u64 {
+		(value / Self::factor(issuance)).saturated_into()
+	}
+
+	fn to_currency(value: u128, issuance: u128) -> u128 {
+		value.saturating_mul(Self::factor(issuance))
+	}
+}
+
+
+/// A naive implementation of `CurrencyConvert` that simply saturates all conversions.
+///
+/// # Warning
+///
+/// This is designed to be used mostly for testing. Use with care, and think about the consequences.
+pub struct SaturatingCurrencyToVote;
+
+impl<B: UniqueSaturatedInto<u64> + UniqueSaturatedFrom<u128>> CurrencyToVote<B> for SaturatingCurrencyToVote {
+	fn to_vote(value: B, _: B) -> u64 {
+		value.unique_saturated_into()
+	}
+
+	fn to_currency(value: u128, _: B) -> B {
+		B::unique_saturated_from(value)
+	}
+}
diff --git a/frame/support/src/weights.rs b/frame/support/src/weights.rs
index abd54994bc9e8..840b1c3c01ac9 100644
--- a/frame/support/src/weights.rs
+++ b/frame/support/src/weights.rs
@@ -130,11 +130,8 @@
 #[cfg(feature = "std")]
 use serde::{Serialize, Deserialize};
 use codec::{Encode, Decode};
-use sp_runtime::{
-	RuntimeDebug,
-	traits::SignedExtension,
-	generic::{CheckedExtrinsic, UncheckedExtrinsic},
-};
+use sp_runtime::{RuntimeDebug, traits::SignedExtension};
+use sp_runtime::generic::{CheckedExtrinsic, UncheckedExtrinsic};
 use crate::dispatch::{DispatchErrorWithPostInfo, DispatchResultWithPostInfo, DispatchError};
 use sp_runtime::traits::SaturatedConversion;
 use sp_arithmetic::{Perbill, traits::{BaseArithmetic, Saturating, Unsigned}};
@@ -964,13 +961,13 @@ mod tests {
 			smallvec![
 				WeightToFeeCoefficient {
 					coeff_integer: 0,
-					coeff_frac: Perbill::from_fraction(0.5),
+					coeff_frac: Perbill::from_float(0.5),
 					negative: false,
 					degree: 3
 				},
 				WeightToFeeCoefficient {
 					coeff_integer: 2,
-					coeff_frac: Perbill::from_rational_approximation(1u32, 3u32),
+					coeff_frac: Perbill::from_rational(1u32, 3u32),
 					negative: false,
 					degree: 2
 				},
diff --git a/frame/support/test/Cargo.toml b/frame/support/test/Cargo.toml
index 17aeea970c057..7d2f0ec463a38 100644
--- a/frame/support/test/Cargo.toml
+++ b/frame/support/test/Cargo.toml
@@ -42,3 +42,4 @@ std = [
 	"sp-state-machine",
 ]
 try-runtime = ["frame-support/try-runtime"]
+conditional-storage = []
diff --git a/frame/support/test/src/lib.rs b/frame/support/test/src/lib.rs
index ae3efdf57aa22..d40031c149d90 100644
--- a/frame/support/test/src/lib.rs
+++ b/frame/support/test/src/lib.rs
@@ -67,7 +67,7 @@ where
 
 		(
 			Output::decode(&mut TrailingZeroInput::new(subject)).unwrap_or_default(),
-			frame_system::Module::<T>::block_number(),
+			frame_system::Pallet::<T>::block_number(),
 		)
 	}
 }
diff --git a/frame/support/test/tests/construct_runtime.rs b/frame/support/test/tests/construct_runtime.rs
index 8dc44c2024adc..a1ec744e42733 100644
--- a/frame/support/test/tests/construct_runtime.rs
+++ b/frame/support/test/tests/construct_runtime.rs
@@ -138,17 +138,17 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic
 	{
-		System: system::{Module, Call, Event<T>, Origin<T>} = 30,
-		Module1_1: module1::<Instance1>::{Module, Call, Storage, Event<T>, Origin<T>},
-		Module2: module2::{Module, Call, Storage, Event, Origin},
-		Module1_2: module1::<Instance2>::{Module, Call, Storage, Event<T>, Origin<T>},
-		Module1_3: module1::<Instance3>::{Module, Storage} = 6,
-		Module1_4: module1::<Instance4>::{Module, Call} = 3,
-		Module1_5: module1::<Instance5>::{Module, Event<T>},
-		Module1_6: module1::<Instance6>::{Module, Call, Storage, Event<T>, Origin<T>} = 1,
-		Module1_7: module1::<Instance7>::{Module, Call, Storage, Event<T>, Origin<T>},
-		Module1_8: module1::<Instance8>::{Module, Call, Storage, Event<T>, Origin<T>} = 12,
-		Module1_9: module1::<Instance9>::{Module, Call, Storage, Event<T>, Origin<T>},
+		System: system::{Pallet, Call, Event<T>, Origin<T>} = 30,
+		Module1_1: module1::<Instance1>::{Pallet, Call, Storage, Event<T>, Origin<T>},
+		Module2: module2::{Pallet, Call, Storage, Event, Origin},
+		Module1_2: module1::<Instance2>::{Pallet, Call, Storage, Event<T>, Origin<T>},
+		Module1_3: module1::<Instance3>::{Pallet, Storage} = 6,
+		Module1_4: module1::<Instance4>::{Pallet, Call} = 3,
+		Module1_5: module1::<Instance5>::{Pallet, Event<T>},
+		Module1_6: module1::<Instance6>::{Pallet, Call, Storage, Event<T>, Origin<T>} = 1,
+		Module1_7: module1::<Instance7>::{Pallet, Call, Storage, Event<T>, Origin<T>},
+		Module1_8: module1::<Instance8>::{Pallet, Call, Storage, Event<T>, Origin<T>} = 12,
+		Module1_9: module1::<Instance9>::{Pallet, Call, Storage, Event<T>, Origin<T>},
 	}
 );
 
diff --git a/frame/support/test/tests/construct_runtime_ui/conflicting_index.stderr b/frame/support/test/tests/construct_runtime_ui/conflicting_index.stderr
index 65368666c88fe..2e2028fd1b862 100644
--- a/frame/support/test/tests/construct_runtime_ui/conflicting_index.stderr
+++ b/frame/support/test/tests/construct_runtime_ui/conflicting_index.stderr
@@ -1,10 +1,10 @@
-error: Module indices are conflicting: Both modules System and Pallet1 are at index 0
+error: Pallet indices are conflicting: Both pallets System and Pallet1 are at index 0
  --> $DIR/conflicting_index.rs:9:3
   |
 9 |         System: system::{},
   |         ^^^^^^
 
-error: Module indices are conflicting: Both modules System and Pallet1 are at index 0
+error: Pallet indices are conflicting: Both pallets System and Pallet1 are at index 0
   --> $DIR/conflicting_index.rs:10:3
    |
 10 |         Pallet1: pallet1::{} = 0,
diff --git a/frame/support/test/tests/construct_runtime_ui/conflicting_index_2.stderr b/frame/support/test/tests/construct_runtime_ui/conflicting_index_2.stderr
index b792ff5d2a541..bfa3706a456a4 100644
--- a/frame/support/test/tests/construct_runtime_ui/conflicting_index_2.stderr
+++ b/frame/support/test/tests/construct_runtime_ui/conflicting_index_2.stderr
@@ -1,10 +1,10 @@
-error: Module indices are conflicting: Both modules System and Pallet3 are at index 5
+error: Pallet indices are conflicting: Both pallets System and Pallet3 are at index 5
  --> $DIR/conflicting_index_2.rs:9:3
   |
 9 |         System: system::{} = 5,
   |         ^^^^^^
 
-error: Module indices are conflicting: Both modules System and Pallet3 are at index 5
+error: Pallet indices are conflicting: Both pallets System and Pallet3 are at index 5
   --> $DIR/conflicting_index_2.rs:12:3
    |
 12 |         Pallet3: pallet3::{},
diff --git a/frame/support/test/tests/construct_runtime_ui/conflicting_module_name.rs b/frame/support/test/tests/construct_runtime_ui/conflicting_module_name.rs
index bc242a57a41e5..7cc6cbd6bd6e2 100644
--- a/frame/support/test/tests/construct_runtime_ui/conflicting_module_name.rs
+++ b/frame/support/test/tests/construct_runtime_ui/conflicting_module_name.rs
@@ -6,9 +6,9 @@ construct_runtime! {
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic
 	{
-		System: system::{Module},
-		Balance: balances::{Module},
-		Balance: balances::{Module},
+		System: system::{Pallet},
+		Balance: balances::{Pallet},
+		Balance: balances::{Pallet},
 	}
 }
 
diff --git a/frame/support/test/tests/construct_runtime_ui/conflicting_module_name.stderr b/frame/support/test/tests/construct_runtime_ui/conflicting_module_name.stderr
index f5b999db66a41..27c5644e0d736 100644
--- a/frame/support/test/tests/construct_runtime_ui/conflicting_module_name.stderr
+++ b/frame/support/test/tests/construct_runtime_ui/conflicting_module_name.stderr
@@ -1,11 +1,11 @@
-error: Two modules with the same name!
+error: Two pallets with the same name!
   --> $DIR/conflicting_module_name.rs:10:3
    |
-10 |         Balance: balances::{Module},
+10 |         Balance: balances::{Pallet},
    |         ^^^^^^^
 
-error: Two modules with the same name!
+error: Two pallets with the same name!
   --> $DIR/conflicting_module_name.rs:11:3
    |
-11 |         Balance: balances::{Module},
+11 |         Balance: balances::{Pallet},
    |         ^^^^^^^
diff --git a/frame/support/test/tests/construct_runtime_ui/double_module_parts.rs b/frame/support/test/tests/construct_runtime_ui/double_module_parts.rs
index ec37456e58e79..836af597851d8 100644
--- a/frame/support/test/tests/construct_runtime_ui/double_module_parts.rs
+++ b/frame/support/test/tests/construct_runtime_ui/double_module_parts.rs
@@ -6,7 +6,7 @@ construct_runtime! {
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic
 	{
-		System: system::{Module},
+		System: system::{Pallet},
 		Balance: balances::{Config, Call, Config<T>, Origin<T>},
 	}
 }
diff --git a/frame/support/test/tests/construct_runtime_ui/generics_in_invalid_module.rs b/frame/support/test/tests/construct_runtime_ui/generics_in_invalid_module.rs
index b79d73ff5c022..b3f0d340d671f 100644
--- a/frame/support/test/tests/construct_runtime_ui/generics_in_invalid_module.rs
+++ b/frame/support/test/tests/construct_runtime_ui/generics_in_invalid_module.rs
@@ -6,7 +6,7 @@ construct_runtime! {
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic
 	{
-		System: system::{Module},
+		System: system::{Pallet},
 		Balance: balances::<Instance1>::{Call<T>, Origin<T>},
 	}
 }
diff --git a/frame/support/test/tests/construct_runtime_ui/generics_in_invalid_module.stderr b/frame/support/test/tests/construct_runtime_ui/generics_in_invalid_module.stderr
index fe880549211bc..06caa036b91ff 100644
--- a/frame/support/test/tests/construct_runtime_ui/generics_in_invalid_module.stderr
+++ b/frame/support/test/tests/construct_runtime_ui/generics_in_invalid_module.stderr
@@ -1,4 +1,4 @@
-error: `Call` is not allowed to have generics. Only the following modules are allowed to have generics: `Event`, `Origin`, `Config`.
+error: `Call` is not allowed to have generics. Only the following pallets are allowed to have generics: `Event`, `Origin`, `Config`.
   --> $DIR/generics_in_invalid_module.rs:10:36
    |
 10 |         Balance: balances::<Instance1>::{Call<T>, Origin<T>},
diff --git a/frame/support/test/tests/construct_runtime_ui/invalid_module_details_keyword.stderr b/frame/support/test/tests/construct_runtime_ui/invalid_module_details_keyword.stderr
index 66c9fc95cb546..29df6e4bd8cb5 100644
--- a/frame/support/test/tests/construct_runtime_ui/invalid_module_details_keyword.stderr
+++ b/frame/support/test/tests/construct_runtime_ui/invalid_module_details_keyword.stderr
@@ -1,4 +1,4 @@
-error: expected one of: `Module`, `Call`, `Storage`, `Event`, `Config`, `Origin`, `Inherent`, `ValidateUnsigned`
+error: expected one of: `Pallet`, `Call`, `Storage`, `Event`, `Config`, `Origin`, `Inherent`, `ValidateUnsigned`
  --> $DIR/invalid_module_details_keyword.rs:9:20
   |
 9 |         system: System::{enum},
diff --git a/frame/support/test/tests/construct_runtime_ui/invalid_module_entry.rs b/frame/support/test/tests/construct_runtime_ui/invalid_module_entry.rs
index 3754d41d6e81c..e7d32559a6cc6 100644
--- a/frame/support/test/tests/construct_runtime_ui/invalid_module_entry.rs
+++ b/frame/support/test/tests/construct_runtime_ui/invalid_module_entry.rs
@@ -6,7 +6,7 @@ construct_runtime! {
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic
 	{
-		System: system::{Module},
+		System: system::{Pallet},
 		Balance: balances::{Error},
 	}
 }
diff --git a/frame/support/test/tests/construct_runtime_ui/invalid_module_entry.stderr b/frame/support/test/tests/construct_runtime_ui/invalid_module_entry.stderr
index 7442c6be3a9a3..bd3e672dc8b40 100644
--- a/frame/support/test/tests/construct_runtime_ui/invalid_module_entry.stderr
+++ b/frame/support/test/tests/construct_runtime_ui/invalid_module_entry.stderr
@@ -1,4 +1,4 @@
-error: expected one of: `Module`, `Call`, `Storage`, `Event`, `Config`, `Origin`, `Inherent`, `ValidateUnsigned`
+error: expected one of: `Pallet`, `Call`, `Storage`, `Event`, `Config`, `Origin`, `Inherent`, `ValidateUnsigned`
   --> $DIR/invalid_module_entry.rs:10:23
    |
 10 |         Balance: balances::{Error},
diff --git a/frame/support/test/tests/construct_runtime_ui/missing_event_generic_on_module_with_instance.rs b/frame/support/test/tests/construct_runtime_ui/missing_event_generic_on_module_with_instance.rs
index 5eb7df5d18c20..f748e643aa18a 100644
--- a/frame/support/test/tests/construct_runtime_ui/missing_event_generic_on_module_with_instance.rs
+++ b/frame/support/test/tests/construct_runtime_ui/missing_event_generic_on_module_with_instance.rs
@@ -6,7 +6,7 @@ construct_runtime! {
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic
 	{
-		System: system::{Module},
+		System: system::{Pallet},
 		Balance: balances::<Instance1>::{Event},
 	}
 }
diff --git a/frame/support/test/tests/construct_runtime_ui/missing_event_generic_on_module_with_instance.stderr b/frame/support/test/tests/construct_runtime_ui/missing_event_generic_on_module_with_instance.stderr
index f80b4bd66abdd..b1aa9b86cd0d6 100644
--- a/frame/support/test/tests/construct_runtime_ui/missing_event_generic_on_module_with_instance.stderr
+++ b/frame/support/test/tests/construct_runtime_ui/missing_event_generic_on_module_with_instance.stderr
@@ -1,4 +1,4 @@
-error: Instantiable module with no generic `Event` cannot be constructed: module `Balance` must have generic `Event`
+error: Instantiable pallet with no generic `Event` cannot be constructed: pallet `Balance` must have generic `Event`
   --> $DIR/missing_event_generic_on_module_with_instance.rs:10:3
    |
 10 |         Balance: balances::<Instance1>::{Event},
diff --git a/frame/support/test/tests/construct_runtime_ui/missing_origin_generic_on_module_with_instance.rs b/frame/support/test/tests/construct_runtime_ui/missing_origin_generic_on_module_with_instance.rs
index 5e44ae84d87c6..7053acc185900 100644
--- a/frame/support/test/tests/construct_runtime_ui/missing_origin_generic_on_module_with_instance.rs
+++ b/frame/support/test/tests/construct_runtime_ui/missing_origin_generic_on_module_with_instance.rs
@@ -6,7 +6,7 @@ construct_runtime! {
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic
 	{
-		System: system::{Module},
+		System: system::{Pallet},
 		Balance: balances::<Instance1>::{Origin},
 	}
 }
diff --git a/frame/support/test/tests/construct_runtime_ui/missing_origin_generic_on_module_with_instance.stderr b/frame/support/test/tests/construct_runtime_ui/missing_origin_generic_on_module_with_instance.stderr
index 0f7d36aafb863..63bb7442a8576 100644
--- a/frame/support/test/tests/construct_runtime_ui/missing_origin_generic_on_module_with_instance.stderr
+++ b/frame/support/test/tests/construct_runtime_ui/missing_origin_generic_on_module_with_instance.stderr
@@ -1,4 +1,4 @@
-error: Instantiable module with no generic `Origin` cannot be constructed: module `Balance` must have generic `Origin`
+error: Instantiable pallet with no generic `Origin` cannot be constructed: pallet `Balance` must have generic `Origin`
   --> $DIR/missing_origin_generic_on_module_with_instance.rs:10:3
    |
 10 |         Balance: balances::<Instance1>::{Origin},
diff --git a/frame/support/test/tests/construct_runtime_ui/missing_system_module.stderr b/frame/support/test/tests/construct_runtime_ui/missing_system_module.stderr
index 2ebe0721eb381..7648f5c1bfb33 100644
--- a/frame/support/test/tests/construct_runtime_ui/missing_system_module.stderr
+++ b/frame/support/test/tests/construct_runtime_ui/missing_system_module.stderr
@@ -1,7 +1,6 @@
-error: `System` module declaration is missing. Please add this line: `System: frame_system::{Module, Call, Storage, Config, Event<T>},`
+error: `System` pallet declaration is missing. Please add this line: `System: frame_system::{Pallet, Call, Storage, Config, Event<T>},`
  --> $DIR/missing_system_module.rs:8:2
   |
-8 |       {
-  |  _____^
+8 | /     {
 9 | |     }
   | |_____^
diff --git a/frame/support/test/tests/construct_runtime_ui/more_than_256_modules.stderr b/frame/support/test/tests/construct_runtime_ui/more_than_256_modules.stderr
index c0ef5c8e60b9e..2e055f5d3726a 100644
--- a/frame/support/test/tests/construct_runtime_ui/more_than_256_modules.stderr
+++ b/frame/support/test/tests/construct_runtime_ui/more_than_256_modules.stderr
@@ -1,4 +1,4 @@
-error: Module index doesn't fit into u8, index is 256
+error: Pallet index doesn't fit into u8, index is 256
   --> $DIR/more_than_256_modules.rs:10:3
    |
 10 |         Pallet256: pallet256::{},
diff --git a/frame/support/test/tests/derive_no_bound_ui/eq.stderr b/frame/support/test/tests/derive_no_bound_ui/eq.stderr
index bbd907adecb33..36384178d469b 100644
--- a/frame/support/test/tests/derive_no_bound_ui/eq.stderr
+++ b/frame/support/test/tests/derive_no_bound_ui/eq.stderr
@@ -4,4 +4,9 @@ error[E0277]: can't compare `Foo<T>` with `Foo<T>`
 6   | struct Foo<T: Config> {
     |        ^^^ no implementation for `Foo<T> == Foo<T>`
     |
+   ::: $RUST/core/src/cmp.rs
+    |
+    | pub trait Eq: PartialEq<Self> {
+    |               --------------- required by this bound in `Eq`
+    |
     = help: the trait `PartialEq` is not implemented for `Foo<T>`
diff --git a/frame/support/test/tests/instance.rs b/frame/support/test/tests/instance.rs
index 42cc2af19c655..e0dd1d1891d26 100644
--- a/frame/support/test/tests/instance.rs
+++ b/frame/support/test/tests/instance.rs
@@ -264,24 +264,24 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic
 	{
-		System: system::{Module, Call, Event<T>},
+		System: system::{Pallet, Call, Event<T>},
 		Module1_1: module1::<Instance1>::{
-			Module, Call, Storage, Event<T>, Config<T>, Origin<T>, Inherent
+			Pallet, Call, Storage, Event<T>, Config<T>, Origin<T>, Inherent
 		},
 		Module1_2: module1::<Instance2>::{
-			Module, Call, Storage, Event<T>, Config<T>, Origin<T>, Inherent
+			Pallet, Call, Storage, Event<T>, Config<T>, Origin<T>, Inherent
 		},
-		Module2: module2::{Module, Call, Storage, Event<T>, Config<T>, Origin<T>, Inherent},
+		Module2: module2::{Pallet, Call, Storage, Event<T>, Config<T>, Origin<T>, Inherent},
 		Module2_1: module2::<Instance1>::{
-			Module, Call, Storage, Event<T>, Config<T>, Origin<T>, Inherent
+			Pallet, Call, Storage, Event<T>, Config<T>, Origin<T>, Inherent
 		},
 		Module2_2: module2::<Instance2>::{
-			Module, Call, Storage, Event<T>, Config<T>, Origin<T>, Inherent
+			Pallet, Call, Storage, Event<T>, Config<T>, Origin<T>, Inherent
 		},
 		Module2_3: module2::<Instance3>::{
-			Module, Call, Storage, Event<T>, Config<T>, Origin<T>, Inherent
+			Pallet, Call, Storage, Event<T>, Config<T>, Origin<T>, Inherent
 		},
-		Module3: module3::{Module, Call},
+		Module3: module3::{Pallet, Call},
 	}
 );
 
diff --git a/frame/support/test/tests/issue2219.rs b/frame/support/test/tests/issue2219.rs
index 9ad9b8be7f415..4525e8c1a1fe2 100644
--- a/frame/support/test/tests/issue2219.rs
+++ b/frame/support/test/tests/issue2219.rs
@@ -177,8 +177,8 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic
 	{
-		System: system::{Module, Call, Event<T>},
-		Module: module::{Module, Call, Storage, Config},
+		System: system::{Pallet, Call, Event<T>},
+		Module: module::{Pallet, Call, Storage, Config},
 	}
 );
 
diff --git a/frame/support/test/tests/pallet.rs b/frame/support/test/tests/pallet.rs
index a31ce9d91ae2d..5387312819c87 100644
--- a/frame/support/test/tests/pallet.rs
+++ b/frame/support/test/tests/pallet.rs
@@ -217,6 +217,28 @@ pub mod pallet {
 	#[pallet::storage]
 	pub type DoubleMap2<T> = StorageDoubleMap<_, Twox64Concat, u16, Blake2_128Concat, u32, u64>;
 
+	#[pallet::storage]
+	#[pallet::getter(fn conditional_value)]
+	#[cfg(feature = "conditional-storage")]
+	pub type ConditionalValue<T> = StorageValue<_, u32>;
+
+	#[cfg(feature = "conditional-storage")]
+	#[pallet::storage]
+	#[pallet::getter(fn conditional_map)]
+	pub type ConditionalMap<T> = StorageMap<_, Twox64Concat, u16, u32>;
+
+	#[cfg(feature = "conditional-storage")]
+	#[pallet::storage]
+	#[pallet::getter(fn conditional_double_map)]
+	pub type ConditionalDoubleMap<T> = StorageDoubleMap<
+		_,
+		Blake2_128Concat,
+		u8,
+		Twox64Concat,
+		u16,
+		u32,
+	>;
+
 	#[pallet::genesis_config]
 	#[derive(Default)]
 	pub struct GenesisConfig {
@@ -396,9 +418,9 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic
 	{
-		System: frame_system::{Module, Call, Event<T>},
-		Example: pallet::{Module, Call, Event<T>, Config, Storage, Inherent, Origin<T>, ValidateUnsigned},
-		Example2: pallet2::{Module, Call, Event, Config<T>, Storage},
+		System: frame_system::{Pallet, Call, Event<T>},
+		Example: pallet::{Pallet, Call, Event<T>, Config, Storage, Inherent, Origin<T>, ValidateUnsigned},
+		Example2: pallet2::{Pallet, Call, Event, Config<T>, Storage},
 	}
 );
 
@@ -522,6 +544,13 @@ fn storage_expand() {
 		k.extend(2u32.using_encoded(blake2_128_concat));
 		assert_eq!(unhashed::get::<u64>(&k), Some(3u64));
 		assert_eq!(&k[..32], &<pallet::DoubleMap2<Runtime>>::final_prefix());
+
+		#[cfg(feature = "conditional-storage")]
+		{
+			pallet::ConditionalValue::<Runtime>::put(1);
+			pallet::ConditionalMap::<Runtime>::insert(1, 2);
+			pallet::ConditionalDoubleMap::<Runtime>::insert(1, 2, 3);
+		}
 	})
 }
 
@@ -530,11 +559,11 @@ fn pallet_hooks_expand() {
 	TestExternalities::default().execute_with(|| {
 		frame_system::Pallet::<Runtime>::set_block_number(1);
 
-		assert_eq!(AllModules::on_initialize(1), 10);
-		AllModules::on_finalize(1);
+		assert_eq!(AllPallets::on_initialize(1), 10);
+		AllPallets::on_finalize(1);
 
 		assert_eq!(pallet::Pallet::<Runtime>::storage_version(), None);
-		assert_eq!(AllModules::on_runtime_upgrade(), 30);
+		assert_eq!(AllPallets::on_runtime_upgrade(), 30);
 		assert_eq!(
 			pallet::Pallet::<Runtime>::storage_version(),
 			Some(pallet::Pallet::<Runtime>::current_version()),
@@ -646,6 +675,38 @@ fn metadata() {
 					default: DecodeDifferent::Decoded(vec![0]),
 					documentation: DecodeDifferent::Decoded(vec![]),
 				},
+				#[cfg(feature = "conditional-storage")] StorageEntryMetadata {
+					name: DecodeDifferent::Decoded("ConditionalValue".to_string()),
+					modifier: StorageEntryModifier::Optional,
+					ty: StorageEntryType::Plain(DecodeDifferent::Decoded("u32".to_string())),
+					default: DecodeDifferent::Decoded(vec![0]),
+					documentation: DecodeDifferent::Decoded(vec![]),
+				},
+				#[cfg(feature = "conditional-storage")] StorageEntryMetadata {
+					name: DecodeDifferent::Decoded("ConditionalMap".to_string()),
+					modifier: StorageEntryModifier::Optional,
+					ty: StorageEntryType::Map {
+						key: DecodeDifferent::Decoded("u16".to_string()),
+						value: DecodeDifferent::Decoded("u32".to_string()),
+						hasher: StorageHasher::Twox64Concat,
+						unused: false,
+					},
+					default: DecodeDifferent::Decoded(vec![0]),
+					documentation: DecodeDifferent::Decoded(vec![]),
+				},
+				#[cfg(feature = "conditional-storage")] StorageEntryMetadata {
+					name: DecodeDifferent::Decoded("ConditionalDoubleMap".to_string()),
+					modifier: StorageEntryModifier::Optional,
+					ty: StorageEntryType::DoubleMap {
+						value: DecodeDifferent::Decoded("u32".to_string()),
+						key1: DecodeDifferent::Decoded("u8".to_string()),
+						key2: DecodeDifferent::Decoded("u16".to_string()),
+						hasher: StorageHasher::Blake2_128Concat,
+						key2_hasher: StorageHasher::Twox64Concat,
+					},
+					default: DecodeDifferent::Decoded(vec![0]),
+					documentation: DecodeDifferent::Decoded(vec![]),
+				},
 			]),
 		})),
 		calls: Some(DecodeDifferent::Decoded(vec![
diff --git a/frame/support/test/tests/pallet_compatibility.rs b/frame/support/test/tests/pallet_compatibility.rs
index 5b9001e0475fe..95e1c027eb3fa 100644
--- a/frame/support/test/tests/pallet_compatibility.rs
+++ b/frame/support/test/tests/pallet_compatibility.rs
@@ -247,10 +247,10 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic
 	{
-		System: frame_system::{Module, Call, Event<T>},
+		System: frame_system::{Pallet, Call, Event<T>},
 		// NOTE: name Example here is needed in order to have same module prefix
-		Example: pallet::{Module, Call, Event<T>, Config<T>, Storage},
-		PalletOld: pallet_old::{Module, Call, Event<T>, Config<T>, Storage},
+		Example: pallet::{Pallet, Call, Event<T>, Config<T>, Storage},
+		PalletOld: pallet_old::{Pallet, Call, Event<T>, Config<T>, Storage},
 	}
 );
 
diff --git a/frame/support/test/tests/pallet_compatibility_instance.rs b/frame/support/test/tests/pallet_compatibility_instance.rs
index d7de03ea46cfd..603c583ae217f 100644
--- a/frame/support/test/tests/pallet_compatibility_instance.rs
+++ b/frame/support/test/tests/pallet_compatibility_instance.rs
@@ -259,13 +259,13 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic
 	{
-		System: frame_system::{Module, Call, Event<T>},
-		Example: pallet::{Module, Call, Event<T>, Config<T>, Storage},
-		PalletOld: pallet_old::{Module, Call, Event<T>, Config<T>, Storage},
-		Instance2Example: pallet::<Instance2>::{Module, Call, Event<T>, Config<T>, Storage},
-		PalletOld2: pallet_old::<Instance2>::{Module, Call, Event<T>, Config<T>, Storage},
-		Instance3Example: pallet::<Instance3>::{Module, Call, Event<T>, Config<T>, Storage},
-		PalletOld3: pallet_old::<Instance3>::{Module, Call, Event<T>, Config<T>, Storage},
+		System: frame_system::{Pallet, Call, Event<T>},
+		Example: pallet::{Pallet, Call, Event<T>, Config<T>, Storage},
+		PalletOld: pallet_old::{Pallet, Call, Event<T>, Config<T>, Storage},
+		Instance2Example: pallet::<Instance2>::{Pallet, Call, Event<T>, Config<T>, Storage},
+		PalletOld2: pallet_old::<Instance2>::{Pallet, Call, Event<T>, Config<T>, Storage},
+		Instance3Example: pallet::<Instance3>::{Pallet, Call, Event<T>, Config<T>, Storage},
+		PalletOld3: pallet_old::<Instance3>::{Pallet, Call, Event<T>, Config<T>, Storage},
 	}
 );
 
diff --git a/frame/support/test/tests/pallet_instance.rs b/frame/support/test/tests/pallet_instance.rs
index 62654d53e19d7..1bf4c1af09280 100644
--- a/frame/support/test/tests/pallet_instance.rs
+++ b/frame/support/test/tests/pallet_instance.rs
@@ -288,13 +288,13 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic
 	{
-		System: frame_system::{Module, Call, Event<T>},
-		Example: pallet::{Module, Call, Event<T>, Config, Storage, Inherent, Origin<T>, ValidateUnsigned},
+		System: frame_system::{Pallet, Call, Event<T>},
+		Example: pallet::{Pallet, Call, Event<T>, Config, Storage, Inherent, Origin<T>, ValidateUnsigned},
 		Instance1Example: pallet::<Instance1>::{
-			Module, Call, Event<T>, Config, Storage, Inherent, Origin<T>, ValidateUnsigned
+			Pallet, Call, Event<T>, Config, Storage, Inherent, Origin<T>, ValidateUnsigned
 		},
-		Example2: pallet2::{Module, Call, Event<T>, Config<T>, Storage},
-		Instance1Example2: pallet2::<Instance1>::{Module, Call, Event<T>, Config<T>, Storage},
+		Example2: pallet2::{Pallet, Call, Event<T>, Config<T>, Storage},
+		Instance1Example2: pallet2::<Instance1>::{Pallet, Call, Event<T>, Config<T>, Storage},
 	}
 );
 
@@ -377,19 +377,19 @@ fn instance_expand() {
 #[test]
 fn pallet_expand_deposit_event() {
 	TestExternalities::default().execute_with(|| {
-		frame_system::Module::<Runtime>::set_block_number(1);
+		frame_system::Pallet::<Runtime>::set_block_number(1);
 		pallet::Call::<Runtime>::foo(3).dispatch_bypass_filter(None.into()).unwrap();
 		assert_eq!(
-			frame_system::Module::<Runtime>::events()[0].event,
+			frame_system::Pallet::<Runtime>::events()[0].event,
 			Event::pallet(pallet::Event::Something(3)),
 		);
 	});
 
 	TestExternalities::default().execute_with(|| {
-		frame_system::Module::<Runtime>::set_block_number(1);
+		frame_system::Pallet::<Runtime>::set_block_number(1);
 		pallet::Call::<Runtime, pallet::Instance1>::foo(3).dispatch_bypass_filter(None.into()).unwrap();
 		assert_eq!(
-			frame_system::Module::<Runtime>::events()[0].event,
+			frame_system::Pallet::<Runtime>::events()[0].event,
 			Event::pallet_Instance1(pallet::Event::Something(3)),
 		);
 	});
@@ -480,14 +480,14 @@ fn storage_expand() {
 #[test]
 fn pallet_hooks_expand() {
 	TestExternalities::default().execute_with(|| {
-		frame_system::Module::<Runtime>::set_block_number(1);
+		frame_system::Pallet::<Runtime>::set_block_number(1);
 
-		assert_eq!(AllModules::on_initialize(1), 21);
-		AllModules::on_finalize(1);
+		assert_eq!(AllPallets::on_initialize(1), 21);
+		AllPallets::on_finalize(1);
 
 		assert_eq!(pallet::Pallet::<Runtime>::storage_version(), None);
 		assert_eq!(pallet::Pallet::<Runtime, pallet::Instance1>::storage_version(), None);
-		assert_eq!(AllModules::on_runtime_upgrade(), 61);
+		assert_eq!(AllPallets::on_runtime_upgrade(), 61);
 		assert_eq!(
 			pallet::Pallet::<Runtime>::storage_version(),
 			Some(pallet::Pallet::<Runtime>::current_version()),
@@ -499,27 +499,27 @@ fn pallet_hooks_expand() {
 
 		// The order is indeed reversed due to https://github.com/paritytech/substrate/issues/6280
 		assert_eq!(
-			frame_system::Module::<Runtime>::events()[0].event,
+			frame_system::Pallet::<Runtime>::events()[0].event,
 			Event::pallet_Instance1(pallet::Event::Something(11)),
 		);
 		assert_eq!(
-			frame_system::Module::<Runtime>::events()[1].event,
+			frame_system::Pallet::<Runtime>::events()[1].event,
 			Event::pallet(pallet::Event::Something(10)),
 		);
 		assert_eq!(
-			frame_system::Module::<Runtime>::events()[2].event,
+			frame_system::Pallet::<Runtime>::events()[2].event,
 			Event::pallet_Instance1(pallet::Event::Something(21)),
 		);
 		assert_eq!(
-			frame_system::Module::<Runtime>::events()[3].event,
+			frame_system::Pallet::<Runtime>::events()[3].event,
 			Event::pallet(pallet::Event::Something(20)),
 		);
 		assert_eq!(
-			frame_system::Module::<Runtime>::events()[4].event,
+			frame_system::Pallet::<Runtime>::events()[4].event,
 			Event::pallet_Instance1(pallet::Event::Something(31)),
 		);
 		assert_eq!(
-			frame_system::Module::<Runtime>::events()[5].event,
+			frame_system::Pallet::<Runtime>::events()[5].event,
 			Event::pallet(pallet::Event::Something(30)),
 		);
 	})
diff --git a/frame/support/test/tests/pallet_ui/genesis_default_not_satisfied.stderr b/frame/support/test/tests/pallet_ui/genesis_default_not_satisfied.stderr
index a2998788736ac..8a6ee8b8f5045 100644
--- a/frame/support/test/tests/pallet_ui/genesis_default_not_satisfied.stderr
+++ b/frame/support/test/tests/pallet_ui/genesis_default_not_satisfied.stderr
@@ -1,10 +1,10 @@
 error[E0277]: the trait bound `pallet::GenesisConfig: std::default::Default` is not satisfied
-    --> $DIR/genesis_default_not_satisfied.rs:22:18
-     |
-22   |     impl<T: Config> GenesisBuild<T> for GenesisConfig {}
-     |                     ^^^^^^^^^^^^^^^ the trait `std::default::Default` is not implemented for `pallet::GenesisConfig`
-     |
-    ::: $WORKSPACE/frame/support/src/traits.rs
-     |
-     | pub trait GenesisBuild<T, I=()>: Default + MaybeSerializeDeserialize {
-     |                                  ------- required by this bound in `GenesisBuild`
+   --> $DIR/genesis_default_not_satisfied.rs:22:18
+    |
+22  |     impl<T: Config> GenesisBuild<T> for GenesisConfig {}
+    |                     ^^^^^^^^^^^^^^^ the trait `std::default::Default` is not implemented for `pallet::GenesisConfig`
+    |
+   ::: $WORKSPACE/frame/support/src/traits/hooks.rs
+    |
+    | pub trait GenesisBuild<T, I=()>: Default + MaybeSerializeDeserialize {
+    |                                  ------- required by this bound in `GenesisBuild`
diff --git a/frame/support/test/tests/pallet_ui/hooks_invalid_item.stderr b/frame/support/test/tests/pallet_ui/hooks_invalid_item.stderr
index 0379448f694fc..3812b433e20ca 100644
--- a/frame/support/test/tests/pallet_ui/hooks_invalid_item.stderr
+++ b/frame/support/test/tests/pallet_ui/hooks_invalid_item.stderr
@@ -1,5 +1,15 @@
-error[E0107]: wrong number of type arguments: expected 1, found 0
-  --> $DIR/hooks_invalid_item.rs:12:18
-   |
-12 |     impl<T: Config> Hooks for Pallet<T> {}
-   |                     ^^^^^ expected 1 type argument
+error[E0107]: missing generics for trait `Hooks`
+   --> $DIR/hooks_invalid_item.rs:12:18
+    |
+12  |     impl<T: Config> Hooks for Pallet<T> {}
+    |                     ^^^^^ expected 1 type argument
+    |
+note: trait defined here, with 1 type parameter: `BlockNumber`
+   --> $DIR/hooks.rs:206:11
+    |
+206 | pub trait Hooks<BlockNumber> {
+    |           ^^^^^ -----------
+help: use angle brackets to add missing type argument
+    |
+12  |     impl<T: Config> Hooks<BlockNumber> for Pallet<T> {}
+    |                          ^^^^^^^^^^^^^
diff --git a/frame/support/test/tests/pallet_version.rs b/frame/support/test/tests/pallet_version.rs
index 4cc93d395db2a..b3436b7baed9a 100644
--- a/frame/support/test/tests/pallet_version.rs
+++ b/frame/support/test/tests/pallet_version.rs
@@ -174,15 +174,15 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic
 	{
-		System: frame_system::{Module, Call, Event<T>},
-		Module1: module1::{Module, Call},
-		Module2: module2::{Module, Call},
-		Module2_1: module2::<Instance1>::{Module, Call},
-		Module2_2: module2::<Instance2>::{Module, Call},
-		Pallet3: pallet3::{Module, Call},
-		Pallet4: pallet4::{Module, Call},
-		Pallet4_1: pallet4::<Instance1>::{Module, Call},
-		Pallet4_2: pallet4::<Instance2>::{Module, Call},
+		System: frame_system::{Pallet, Call, Event<T>},
+		Module1: module1::{Pallet, Call},
+		Module2: module2::{Pallet, Call},
+		Module2_1: module2::<Instance1>::{Pallet, Call},
+		Module2_2: module2::<Instance2>::{Pallet, Call},
+		Pallet3: pallet3::{Pallet, Call},
+		Pallet4: pallet4::{Pallet, Call},
+		Pallet4_1: pallet4::<Instance1>::{Pallet, Call},
+		Pallet4_2: pallet4::<Instance2>::{Pallet, Call},
 	}
 );
 
@@ -218,7 +218,7 @@ fn check_pallet_version(pallet: &str) {
 #[test]
 fn on_runtime_upgrade_sets_the_pallet_versions_in_storage() {
 	sp_io::TestExternalities::new_empty().execute_with(|| {
-		AllModules::on_runtime_upgrade();
+		AllPallets::on_runtime_upgrade();
 
 		check_pallet_version("Module1");
 		check_pallet_version("Module2");
@@ -237,7 +237,7 @@ fn on_runtime_upgrade_overwrites_old_version() {
 		let key = get_pallet_version_storage_key_for_pallet("Module2");
 		sp_io::storage::set(&key, &SOME_TEST_VERSION.encode());
 
-		AllModules::on_runtime_upgrade();
+		AllPallets::on_runtime_upgrade();
 
 		check_pallet_version("Module1");
 		check_pallet_version("Module2");
diff --git a/frame/support/test/tests/pallet_with_name_trait_is_valid.rs b/frame/support/test/tests/pallet_with_name_trait_is_valid.rs
index b09beb04cd17c..05cedbdb91a07 100644
--- a/frame/support/test/tests/pallet_with_name_trait_is_valid.rs
+++ b/frame/support/test/tests/pallet_with_name_trait_is_valid.rs
@@ -109,8 +109,8 @@ mod tests {
 			NodeBlock = TestBlock,
 			UncheckedExtrinsic = TestUncheckedExtrinsic
 		{
-			System: frame_system::{Module, Call, Config, Storage, Event<T>},
-			PalletTest: pallet_test::{Module, Call, Storage, Event<T>, Config, ValidateUnsigned, Inherent},
+			System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+			PalletTest: pallet_test::{Pallet, Call, Storage, Event<T>, Config, ValidateUnsigned, Inherent},
 		}
 	);
 
diff --git a/frame/system/README.md b/frame/system/README.md
index 106a16bc209d6..a6da7c3816d22 100644
--- a/frame/system/README.md
+++ b/frame/system/README.md
@@ -64,8 +64,8 @@ decl_module! {
 		#[weight = 0]
 		pub fn system_module_example(origin) -> dispatch::DispatchResult {
 			let _sender = ensure_signed(origin)?;
-			let _extrinsic_count = <system::Module<T>>::extrinsic_count();
-			let _parent_hash = <system::Module<T>>::parent_hash();
+			let _extrinsic_count = <system::Pallet<T>>::extrinsic_count();
+			let _parent_hash = <system::Pallet<T>>::parent_hash();
 			Ok(())
 		}
 	}
diff --git a/frame/system/benches/bench.rs b/frame/system/benches/bench.rs
index 6ed3d456826c2..3ebee534a64e1 100644
--- a/frame/system/benches/bench.rs
+++ b/frame/system/benches/bench.rs
@@ -50,8 +50,8 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Module: module::{Module, Call, Event},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Module: module::{Pallet, Call, Event},
 	}
 );
 
diff --git a/frame/system/benchmarking/src/lib.rs b/frame/system/benchmarking/src/lib.rs
index bdb34e7944db5..7146bcd60645b 100644
--- a/frame/system/benchmarking/src/lib.rs
+++ b/frame/system/benchmarking/src/lib.rs
@@ -30,11 +30,11 @@ use frame_support::{
 	traits::Get,
 	weights::DispatchClass,
 };
-use frame_system::{Module as System, Call, RawOrigin, DigestItemOf};
+use frame_system::{Pallet as System, Call, RawOrigin, DigestItemOf};
 
 mod mock;
 
-pub struct Module<T: Config>(System<T>);
+pub struct Pallet<T: Config>(System<T>);
 pub trait Config: frame_system::Config {}
 
 benchmarks! {
@@ -145,7 +145,7 @@ benchmarks! {
 }
 
 impl_benchmark_test_suite!(
-	Module,
+	Pallet,
 	crate::mock::new_test_ext(),
 	crate::mock::Test,
 );
diff --git a/frame/system/benchmarking/src/mock.rs b/frame/system/benchmarking/src/mock.rs
index edc5dfebbd106..23da1fee5617a 100644
--- a/frame/system/benchmarking/src/mock.rs
+++ b/frame/system/benchmarking/src/mock.rs
@@ -34,7 +34,7 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
 	}
 );
 
diff --git a/frame/system/src/extensions/check_genesis.rs b/frame/system/src/extensions/check_genesis.rs
index de635b4fb91a6..aa6c1358790a4 100644
--- a/frame/system/src/extensions/check_genesis.rs
+++ b/frame/system/src/extensions/check_genesis.rs
@@ -16,7 +16,7 @@
 // limitations under the License.
 
 use codec::{Encode, Decode};
-use crate::{Config, Module};
+use crate::{Config, Pallet};
 use sp_runtime::{
 	traits::{SignedExtension, Zero},
 	transaction_validity::TransactionValidityError,
@@ -53,6 +53,6 @@ impl<T: Config + Send + Sync> SignedExtension for CheckGenesis<T> {
 	const IDENTIFIER: &'static str = "CheckGenesis";
 
 	fn additional_signed(&self) -> Result<Self::AdditionalSigned, TransactionValidityError> {
-		Ok(<Module<T>>::block_hash(T::BlockNumber::zero()))
+		Ok(<Pallet<T>>::block_hash(T::BlockNumber::zero()))
 	}
 }
diff --git a/frame/system/src/extensions/check_mortality.rs b/frame/system/src/extensions/check_mortality.rs
index 1e8eb32a3d3c2..b3e4c4ecfda86 100644
--- a/frame/system/src/extensions/check_mortality.rs
+++ b/frame/system/src/extensions/check_mortality.rs
@@ -16,7 +16,7 @@
 // limitations under the License.
 
 use codec::{Encode, Decode};
-use crate::{Config, Module, BlockHash};
+use crate::{Config, Pallet, BlockHash};
 use sp_runtime::{
 	generic::Era,
 	traits::{SignedExtension, DispatchInfoOf, SaturatedConversion},
@@ -62,7 +62,7 @@ impl<T: Config + Send + Sync> SignedExtension for CheckMortality<T> {
 		_info: &DispatchInfoOf<Self::Call>,
 		_len: usize,
 	) -> TransactionValidity {
-		let current_u64 = <Module<T>>::block_number().saturated_into::<u64>();
+		let current_u64 = <Pallet<T>>::block_number().saturated_into::<u64>();
 		let valid_till = self.0.death(current_u64);
 		Ok(ValidTransaction {
 			longevity: valid_till.saturating_sub(current_u64),
@@ -71,12 +71,12 @@ impl<T: Config + Send + Sync> SignedExtension for CheckMortality<T> {
 	}
 
 	fn additional_signed(&self) -> Result<Self::AdditionalSigned, TransactionValidityError> {
-		let current_u64 = <Module<T>>::block_number().saturated_into::<u64>();
+		let current_u64 = <Pallet<T>>::block_number().saturated_into::<u64>();
 		let n = self.0.birth(current_u64).saturated_into::<T::BlockNumber>();
 		if !<BlockHash<T>>::contains_key(n) {
 			Err(InvalidTransaction::AncientBirthBlock.into())
 		} else {
-			Ok(<Module<T>>::block_hash(n))
+			Ok(<Pallet<T>>::block_hash(n))
 		}
 	}
 }
diff --git a/frame/system/src/extensions/check_spec_version.rs b/frame/system/src/extensions/check_spec_version.rs
index 1fd8376d342b2..e41ce1725a549 100644
--- a/frame/system/src/extensions/check_spec_version.rs
+++ b/frame/system/src/extensions/check_spec_version.rs
@@ -15,7 +15,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use crate::{Config, Module};
+use crate::{Config, Pallet};
 use codec::{Encode, Decode};
 use sp_runtime::{
 	traits::SignedExtension,
@@ -53,6 +53,6 @@ impl<T: Config + Send + Sync> SignedExtension for CheckSpecVersion<T> {
 	const IDENTIFIER: &'static str = "CheckSpecVersion";
 
 	fn additional_signed(&self) -> Result<Self::AdditionalSigned, TransactionValidityError> {
-		Ok(<Module<T>>::runtime_version().spec_version)
+		Ok(<Pallet<T>>::runtime_version().spec_version)
 	}
 }
diff --git a/frame/system/src/extensions/check_tx_version.rs b/frame/system/src/extensions/check_tx_version.rs
index fa11a0a5727f1..ad23dc7e9dd05 100644
--- a/frame/system/src/extensions/check_tx_version.rs
+++ b/frame/system/src/extensions/check_tx_version.rs
@@ -15,7 +15,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use crate::{Config, Module};
+use crate::{Config, Pallet};
 use codec::{Encode, Decode};
 use sp_runtime::{
 	traits::SignedExtension,
@@ -53,6 +53,6 @@ impl<T: Config + Send + Sync> SignedExtension for CheckTxVersion<T> {
 	const IDENTIFIER: &'static str = "CheckTxVersion";
 
 	fn additional_signed(&self) -> Result<Self::AdditionalSigned, TransactionValidityError> {
-		Ok(<Module<T>>::runtime_version().transaction_version)
+		Ok(<Pallet<T>>::runtime_version().transaction_version)
 	}
 }
diff --git a/frame/system/src/extensions/check_weight.rs b/frame/system/src/extensions/check_weight.rs
index 70116f4b6524b..fc9898b778b8d 100644
--- a/frame/system/src/extensions/check_weight.rs
+++ b/frame/system/src/extensions/check_weight.rs
@@ -15,7 +15,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use crate::{limits::BlockWeights, Config, Module};
+use crate::{limits::BlockWeights, Config, Pallet};
 use codec::{Encode, Decode};
 use sp_runtime::{
 	traits::{SignedExtension, DispatchInfoOf, Dispatchable, PostDispatchInfoOf, Printable},
@@ -58,7 +58,7 @@ impl<T: Config + Send + Sync> CheckWeight<T> where
 		info: &DispatchInfoOf<T::Call>,
 	) -> Result<crate::ConsumedWeight, TransactionValidityError> {
 		let maximum_weight = T::BlockWeights::get();
-		let all_weight = Module::<T>::block_weight();
+		let all_weight = Pallet::<T>::block_weight();
 		calculate_consumed_weight::<T::Call>(maximum_weight, all_weight, info)
 	}
 
@@ -70,7 +70,7 @@ impl<T: Config + Send + Sync> CheckWeight<T> where
 		len: usize,
 	) -> Result<u32, TransactionValidityError> {
 		let length_limit = T::BlockLength::get();
-		let current_len = Module::<T>::all_extrinsics_len();
+		let current_len = Pallet::<T>::all_extrinsics_len();
 		let added_len = len as u32;
 		let next_len = current_len.saturating_add(added_len);
 		if next_len > *length_limit.max.get(info.class) {
diff --git a/frame/system/src/lib.rs b/frame/system/src/lib.rs
index ce9ab0dddc105..9d3ecd6f41f5d 100644
--- a/frame/system/src/lib.rs
+++ b/frame/system/src/lib.rs
@@ -1022,7 +1022,7 @@ pub enum IncRefError {
 	NoProviders,
 }
 
-impl<T: Config> Module<T> {
+impl<T: Config> Pallet<T> {
 	pub fn account_exists(who: &T::AccountId) -> bool {
 		Account::<T>::contains_key(who)
 	}
@@ -1083,7 +1083,7 @@ impl<T: Config> Module<T> {
 					(1, 0, 0) => {
 						// No providers left (and no consumers) and no sufficients. Account dead.
 
-						Module::<T>::on_killed_account(who.clone());
+						Pallet::<T>::on_killed_account(who.clone());
 						Ok(DecRefStatus::Reaped)
 					}
 					(1, c, _) if c > 0 => {
@@ -1136,7 +1136,7 @@ impl<T: Config> Module<T> {
 				}
 				match (account.sufficients, account.providers) {
 					(0, 0) | (1, 0) => {
-						Module::<T>::on_killed_account(who.clone());
+						Pallet::<T>::on_killed_account(who.clone());
 						DecRefStatus::Reaped
 					}
 					(x, _) => {
@@ -1201,11 +1201,22 @@ impl<T: Config> Module<T> {
 		Account::<T>::get(who).consumers
 	}
 
-	/// True if the account has some outstanding references.
+	/// True if the account has some outstanding consumer references.
 	pub fn is_provider_required(who: &T::AccountId) -> bool {
 		Account::<T>::get(who).consumers != 0
 	}
 
+	/// True if the account has no outstanding consumer references or more than one provider.
+	pub fn can_dec_provider(who: &T::AccountId) -> bool {
+		let a = Account::<T>::get(who);
+		a.consumers == 0 || a.providers > 1
+	}
+
+	/// True if the account has at least one provider reference.
+	pub fn can_inc_consumer(who: &T::AccountId) -> bool {
+		Account::<T>::get(who).providers > 0
+	}
+
 	/// Deposits an event into this block's event record.
 	pub fn deposit_event(event: impl Into<T::Event>) {
 		Self::deposit_event_indexed(&[], event.into());
@@ -1449,7 +1460,12 @@ impl<T: Config> Module<T> {
 			match r {
 				Ok(_) => Event::ExtrinsicSuccess(info),
 				Err(err) => {
-					sp_runtime::print(err);
+					log::trace!(
+						target: "runtime::system",
+						"Extrinsic failed at block({:?}): {:?}",
+						Self::block_number(),
+						err,
+					);
 					Event::ExtrinsicFailed(err.error, info)
 				},
 			}
@@ -1515,11 +1531,11 @@ impl<T: Config> Module<T> {
 pub struct Provider<T>(PhantomData<T>);
 impl<T: Config> HandleLifetime<T::AccountId> for Provider<T> {
 	fn created(t: &T::AccountId) -> Result<(), StoredMapError> {
-		Module::<T>::inc_providers(t);
+		Pallet::<T>::inc_providers(t);
 		Ok(())
 	}
 	fn killed(t: &T::AccountId) -> Result<(), StoredMapError> {
-		Module::<T>::dec_providers(t)
+		Pallet::<T>::dec_providers(t)
 			.map(|_| ())
 			.or_else(|e| match e {
 				DecRefError::ConsumerRemaining => Err(StoredMapError::ConsumerRemaining),
@@ -1531,11 +1547,11 @@ impl<T: Config> HandleLifetime<T::AccountId> for Provider<T> {
 pub struct SelfSufficient<T>(PhantomData<T>);
 impl<T: Config> HandleLifetime<T::AccountId> for SelfSufficient<T> {
 	fn created(t: &T::AccountId) -> Result<(), StoredMapError> {
-		Module::<T>::inc_sufficients(t);
+		Pallet::<T>::inc_sufficients(t);
 		Ok(())
 	}
 	fn killed(t: &T::AccountId) -> Result<(), StoredMapError> {
-		Module::<T>::dec_sufficients(t);
+		Pallet::<T>::dec_sufficients(t);
 		Ok(())
 	}
 }
@@ -1544,13 +1560,13 @@ impl<T: Config> HandleLifetime<T::AccountId> for SelfSufficient<T> {
 pub struct Consumer<T>(PhantomData<T>);
 impl<T: Config> HandleLifetime<T::AccountId> for Consumer<T> {
 	fn created(t: &T::AccountId) -> Result<(), StoredMapError> {
-		Module::<T>::inc_consumers(t)
+		Pallet::<T>::inc_consumers(t)
 			.map_err(|e| match e {
 				IncRefError::NoProviders => StoredMapError::NoProviders
 			})
 	}
 	fn killed(t: &T::AccountId) -> Result<(), StoredMapError> {
-		Module::<T>::dec_consumers(t);
+		Pallet::<T>::dec_consumers(t);
 		Ok(())
 	}
 }
diff --git a/frame/system/src/mock.rs b/frame/system/src/mock.rs
index 2b31929b5da81..43c7d8d252774 100644
--- a/frame/system/src/mock.rs
+++ b/frame/system/src/mock.rs
@@ -33,7 +33,7 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
 	}
 );
 
diff --git a/frame/system/src/offchain.rs b/frame/system/src/offchain.rs
index aa8bce966192e..fe601f995ce51 100644
--- a/frame/system/src/offchain.rs
+++ b/frame/system/src/offchain.rs
@@ -38,10 +38,10 @@
 //!
 //! To be able to use signing, the following trait should be implemented:
 //!
-//! - [`AppCrypto`](./trait.AppCrypto.html): where an application-specific key
-//!   is defined and can be used by this module's helpers for signing.
-//! - [`CreateSignedTransaction`](./trait.CreateSignedTransaction.html): where
-//!   the manner in which the transaction is constructed is defined.
+//! - [`AppCrypto`](./trait.AppCrypto.html): where an application-specific key is defined and can be
+//!   used by this module's helpers for signing.
+//! - [`CreateSignedTransaction`](./trait.CreateSignedTransaction.html): where the manner in which
+//!   the transaction is constructed is defined.
 //!
 //! #### Submit an unsigned transaction with a signed payload
 //!
@@ -53,7 +53,6 @@
 //! #### Submit a signed transaction
 //!
 //! [`Signer`](./struct.Signer.html) can be used to sign/verify payloads
-//!
 
 #![warn(missing_docs)]
 
@@ -473,7 +472,7 @@ pub trait SendTransactionTypes<LocalCall> {
 	/// The runtime's call type.
 	///
 	/// This has additional bound to be able to be created from pallet-local `Call` types.
-	type OverarchingCall: From<LocalCall>;
+	type OverarchingCall: From<LocalCall> + codec::Encode;
 }
 
 /// Create signed transaction.
diff --git a/frame/timestamp/src/benchmarking.rs b/frame/timestamp/src/benchmarking.rs
index b3e8eca889cb0..d64fa8dc691c7 100644
--- a/frame/timestamp/src/benchmarking.rs
+++ b/frame/timestamp/src/benchmarking.rs
@@ -24,7 +24,7 @@ use frame_system::RawOrigin;
 use frame_support::{ensure, traits::OnFinalize};
 use frame_benchmarking::{benchmarks, TrackedStorageKey, impl_benchmark_test_suite};
 
-use crate::Module as Timestamp;
+use crate::Pallet as Timestamp;
 
 const MAX_TIME: u32 = 100;
 
diff --git a/frame/timestamp/src/lib.rs b/frame/timestamp/src/lib.rs
index 2ef24a696ade9..d467551196850 100644
--- a/frame/timestamp/src/lib.rs
+++ b/frame/timestamp/src/lib.rs
@@ -19,9 +19,9 @@
 //!
 //! The Timestamp pallet provides functionality to get and set the on-chain time.
 //!
-//! - [`timestamp::Config`](./trait.Config.html)
-//! - [`Call`](./enum.Call.html)
-//! - [`Pallet`](./struct.Pallet.html)
+//! - [`Config`]
+//! - [`Call`]
+//! - [`Pallet`]
 //!
 //! ## Overview
 //!
@@ -319,8 +319,8 @@ mod tests {
 			NodeBlock = Block,
 			UncheckedExtrinsic = UncheckedExtrinsic,
 		{
-			System: frame_system::{Module, Call, Config, Storage, Event<T>},
-			Timestamp: pallet_timestamp::{Module, Call, Storage, Inherent},
+			System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+			Timestamp: pallet_timestamp::{Pallet, Call, Storage, Inherent},
 		}
 	);
 
diff --git a/frame/tips/src/lib.rs b/frame/tips/src/lib.rs
index 442df89428fcc..6d85df33f10c9 100644
--- a/frame/tips/src/lib.rs
+++ b/frame/tips/src/lib.rs
@@ -291,7 +291,8 @@ decl_module! {
 			Reasons::<T>::remove(&tip.reason);
 			Tips::<T>::remove(&hash);
 			if !tip.deposit.is_zero() {
-				let _ = T::Currency::unreserve(&who, tip.deposit);
+				let err_amount = T::Currency::unreserve(&who, tip.deposit);
+				debug_assert!(err_amount.is_zero());
 			}
 			Self::deposit_event(RawEvent::TipRetracted(hash));
 		}
@@ -401,7 +402,7 @@ decl_module! {
 
 			let tip = Tips::<T>::get(hash).ok_or(Error::<T>::UnknownTip)?;
 			let n = tip.closes.as_ref().ok_or(Error::<T>::StillOpen)?;
-			ensure!(system::Module::<T>::block_number() >= *n, Error::<T>::Premature);
+			ensure!(system::Pallet::<T>::block_number() >= *n, Error::<T>::Premature);
 			// closed.
 			Reasons::<T>::remove(&tip.reason);
 			Tips::<T>::remove(hash);
@@ -463,7 +464,7 @@ impl<T: Config> Module<T> {
 		Self::retain_active_tips(&mut tip.tips);
 		let threshold = (T::Tippers::count() + 1) / 2;
 		if tip.tips.len() >= threshold && tip.closes.is_none() {
-			tip.closes = Some(system::Module::<T>::block_number() + T::TipCountdown::get());
+			tip.closes = Some(system::Pallet::<T>::block_number() + T::TipCountdown::get());
 			true
 		} else {
 			false
@@ -505,7 +506,8 @@ impl<T: Config> Module<T> {
 
 		let mut payout = tips[tips.len() / 2].1.min(max_payout);
 		if !tip.deposit.is_zero() {
-			let _ = T::Currency::unreserve(&tip.finder, tip.deposit);
+			let err_amount = T::Currency::unreserve(&tip.finder, tip.deposit);
+			debug_assert!(err_amount.is_zero());
 		}
 
 		if tip.finders_fee && tip.finder != tip.who {
@@ -514,11 +516,13 @@ impl<T: Config> Module<T> {
 			payout -= finders_fee;
 			// this should go through given we checked it's at most the free balance, but still
 			// we only make a best-effort.
-			let _ = T::Currency::transfer(&treasury, &tip.finder, finders_fee, KeepAlive);
+			let res = T::Currency::transfer(&treasury, &tip.finder, finders_fee, KeepAlive);
+			debug_assert!(res.is_ok());
 		}
 
 		// same as above: best-effort only.
-		let _ = T::Currency::transfer(&treasury, &tip.who, payout, KeepAlive);
+		let res = T::Currency::transfer(&treasury, &tip.who, payout, KeepAlive);
+		debug_assert!(res.is_ok());
 		Self::deposit_event(RawEvent::TipClosed(hash, tip.who, payout));
 	}
 
diff --git a/frame/tips/src/tests.rs b/frame/tips/src/tests.rs
index 413e2dd9437e2..ef30962fc846f 100644
--- a/frame/tips/src/tests.rs
+++ b/frame/tips/src/tests.rs
@@ -40,10 +40,10 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
-		Treasury: pallet_treasury::{Module, Call, Storage, Config, Event<T>},
-		TipsModTestInst: tips::{Module, Call, Storage, Event<T>},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
+		Treasury: pallet_treasury::{Pallet, Call, Storage, Config, Event<T>},
+		TipsModTestInst: tips::{Pallet, Call, Storage, Event<T>},
 	}
 );
 
@@ -125,7 +125,7 @@ parameter_types! {
 }
 impl pallet_treasury::Config for Test {
 	type ModuleId = TreasuryModuleId;
-	type Currency = pallet_balances::Module<Test>;
+	type Currency = pallet_balances::Pallet<Test>;
 	type ApproveOrigin = frame_system::EnsureRoot<u128>;
 	type RejectOrigin = frame_system::EnsureRoot<u128>;
 	type Event = Event;
diff --git a/frame/transaction-payment/src/lib.rs b/frame/transaction-payment/src/lib.rs
index 709a8f69a487d..b2dc2c9859e0b 100644
--- a/frame/transaction-payment/src/lib.rs
+++ b/frame/transaction-payment/src/lib.rs
@@ -178,7 +178,7 @@ impl<T, S, V, M> Convert<Multiplier, Multiplier> for TargetedFeeAdjustment<T, S,
 		// the computed ratio is only among the normal class.
 		let normal_max_weight = weights.get(DispatchClass::Normal).max_total
 			.unwrap_or_else(|| weights.max_block);
-		let current_block_weight = <frame_system::Module<T>>::block_weight();
+		let current_block_weight = <frame_system::Pallet<T>>::block_weight();
 		let normal_block_weight = *current_block_weight
 			.get(DispatchClass::Normal)
 			.min(&normal_max_weight);
@@ -303,7 +303,7 @@ decl_module! {
 			target += addition;
 
 			sp_io::TestExternalities::new_empty().execute_with(|| {
-				<frame_system::Module<T>>::set_block_consumed_resources(target, 0);
+				<frame_system::Pallet<T>>::set_block_consumed_resources(target, 0);
 				let next = T::FeeMultiplierUpdate::convert(min_value);
 				assert!(next > min_value, "The minimum bound of the multiplier is too low. When \
 					block saturation is more than target by 1% and multiplier is minimal then \
@@ -630,9 +630,9 @@ mod tests {
 			NodeBlock = Block,
 			UncheckedExtrinsic = UncheckedExtrinsic,
 		{
-			System: system::{Module, Call, Config, Storage, Event<T>},
-			Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
-			TransactionPayment: pallet_transaction_payment::{Module, Storage},
+			System: system::{Pallet, Call, Config, Storage, Event<T>},
+			Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
+			TransactionPayment: pallet_transaction_payment::{Pallet, Storage},
 		}
 	);
 
diff --git a/frame/transaction-payment/src/payment.rs b/frame/transaction-payment/src/payment.rs
index f84b19d78c297..7292ef4dfee7e 100644
--- a/frame/transaction-payment/src/payment.rs
+++ b/frame/transaction-payment/src/payment.rs
@@ -117,6 +117,7 @@ where
 			// merge the imbalance caused by paying the fees and refunding parts of it again.
 			let adjusted_paid = paid
 				.offset(refund_imbalance)
+				.same()
 				.map_err(|_| TransactionValidityError::Invalid(InvalidTransaction::Payment))?;
 			// Call someone else to handle the imbalance (fee and tip separately)
 			let imbalances = adjusted_paid.split(tip);
diff --git a/frame/treasury/src/lib.rs b/frame/treasury/src/lib.rs
index b5e2c7881bb5f..cef50706b5173 100644
--- a/frame/treasury/src/lib.rs
+++ b/frame/treasury/src/lib.rs
@@ -20,8 +20,8 @@
 //! The Treasury module provides a "pot" of funds that can be managed by stakeholders in the system
 //! and a structure for making spending proposals from this pot.
 //!
-//! - [`treasury::Config`](./trait.Config.html)
-//! - [`Call`](./enum.Call.html)
+//! - [`Config`]
+//! - [`Call`]
 //!
 //! ## Overview
 //!
@@ -53,7 +53,7 @@
 //!
 //! ## GenesisConfig
 //!
-//! The Treasury module depends on the [`GenesisConfig`](./struct.GenesisConfig.html).
+//! The Treasury module depends on the [`GenesisConfig`].
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
@@ -377,7 +377,8 @@ impl<T: Config<I>, I: Instance> Module<T, I> {
 						<Proposals<T, I>>::remove(index);
 
 						// return their deposit.
-						let _ = T::Currency::unreserve(&p.proposer, p.bond);
+						let err_amount = T::Currency::unreserve(&p.proposer, p.bond);
+						debug_assert!(err_amount.is_zero());
 
 						// provide the allocation.
 						imbalance.subsume(T::Currency::deposit_creating(&p.beneficiary, p.value));
diff --git a/frame/treasury/src/tests.rs b/frame/treasury/src/tests.rs
index 3c70099843ea8..45fc3e629fb0b 100644
--- a/frame/treasury/src/tests.rs
+++ b/frame/treasury/src/tests.rs
@@ -43,9 +43,9 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
-		Treasury: treasury::{Module, Call, Storage, Config, Event<T>},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
+		Treasury: treasury::{Pallet, Call, Storage, Config, Event<T>},
 	}
 );
 
@@ -105,7 +105,7 @@ parameter_types! {
 }
 impl Config for Test {
 	type ModuleId = TreasuryModuleId;
-	type Currency = pallet_balances::Module<Test>;
+	type Currency = pallet_balances::Pallet<Test>;
 	type ApproveOrigin = frame_system::EnsureRoot<u128>;
 	type RejectOrigin = frame_system::EnsureRoot<u128>;
 	type Event = Event;
diff --git a/frame/utility/src/benchmarking.rs b/frame/utility/src/benchmarking.rs
index 79fb569c77a5c..de7f48d625c54 100644
--- a/frame/utility/src/benchmarking.rs
+++ b/frame/utility/src/benchmarking.rs
@@ -26,7 +26,7 @@ use frame_benchmarking::{benchmarks, account, whitelisted_caller, impl_benchmark
 const SEED: u32 = 0;
 
 fn assert_last_event<T: Config>(generic_event: <T as Config>::Event) {
-	let events = frame_system::Module::<T>::events();
+	let events = frame_system::Pallet::<T>::events();
 	let system_event: <T as frame_system::Config>::Event = generic_event.into();
 	// compare to the last event record
 	let EventRecord { event, .. } = &events[events.len() - 1];
@@ -70,7 +70,7 @@ benchmarks! {
 }
 
 impl_benchmark_test_suite!(
-	Module,
+	Pallet,
 	crate::tests::new_test_ext(),
 	crate::tests::Test,
 );
diff --git a/frame/utility/src/lib.rs b/frame/utility/src/lib.rs
index 28345e5ffe72d..983d24c74dbee 100644
--- a/frame/utility/src/lib.rs
+++ b/frame/utility/src/lib.rs
@@ -15,15 +15,15 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//! # Utility Module
-//! A stateless module with helpers for dispatch management which does no re-authentication.
+//! # Utility Pallet
+//! A stateless pallet with helpers for dispatch management which does no re-authentication.
 //!
-//! - [`utility::Config`](./trait.Config.html)
-//! - [`Call`](./enum.Call.html)
+//! - [`Config`]
+//! - [`Call`]
 //!
 //! ## Overview
 //!
-//! This module contains two basic pieces of functionality:
+//! This pallet contains two basic pieces of functionality:
 //! - Batch dispatch: A stateless operation, allowing any origin to execute multiple calls in a
 //!   single dispatch. This can be useful to amalgamate proposals, combining `set_code` with
 //!   corresponding `set_storage`s, for efficient multiple payouts with just a single signature
@@ -34,9 +34,9 @@
 //!   need multiple distinct accounts (e.g. as controllers for many staking accounts), but where
 //!   it's perfectly fine to have each of them controlled by the same underlying keypair.
 //!   Derivative accounts are, for the purposes of proxy filtering considered exactly the same as
-//!   the oigin and are thus hampered with the origin's filters.
+//!   the origin and are thus hampered with the origin's filters.
 //!
-//! Since proxy filters are respected in all dispatches of this module, it should never need to be
+//! Since proxy filters are respected in all dispatches of this pallet, it should never need to be
 //! filtered by any proxy.
 //!
 //! ## Interface
@@ -48,9 +48,6 @@
 //!
 //! #### For pseudonymal dispatch
 //! * `as_derivative` - Dispatch a call from a derivative signed origin.
-//!
-//! [`Call`]: ./enum.Call.html
-//! [`Config`]: ./trait.Config.html
 
 // Ensure we're `no_std` when compiling for Wasm.
 #![cfg_attr(not(feature = "std"), no_std)]
@@ -63,36 +60,45 @@ use sp_std::prelude::*;
 use codec::{Encode, Decode};
 use sp_core::TypeId;
 use sp_io::hashing::blake2_256;
-use frame_support::{decl_module, decl_event, decl_storage, Parameter, transactional};
 use frame_support::{
-	traits::{OriginTrait, UnfilteredDispatchable, Get},
-	weights::{Weight, GetDispatchInfo, DispatchClass, extract_actual_weight},
-	dispatch::{PostDispatchInfo, DispatchResultWithPostInfo},
+	transactional,
+	traits::{OriginTrait, UnfilteredDispatchable},
+	weights::{GetDispatchInfo, extract_actual_weight},
+	dispatch::PostDispatchInfo,
 };
-use frame_system::{ensure_signed, ensure_root};
-use sp_runtime::{DispatchError, traits::Dispatchable};
+use sp_runtime::traits::Dispatchable;
 pub use weights::WeightInfo;
 
-/// Configuration trait.
-pub trait Config: frame_system::Config {
-	/// The overarching event type.
-	type Event: From<Event> + Into<<Self as frame_system::Config>::Event>;
+pub use pallet::*;
 
-	/// The overarching call type.
-	type Call: Parameter + Dispatchable<Origin=Self::Origin, PostInfo=PostDispatchInfo>
-		+ GetDispatchInfo + From<frame_system::Call<Self>>
-		+ UnfilteredDispatchable<Origin=Self::Origin>;
+#[frame_support::pallet]
+pub mod pallet {
+	use frame_support::pallet_prelude::*;
+	use frame_system::pallet_prelude::*;
+	use super::*;
 
-	/// Weight information for extrinsics in this pallet.
-	type WeightInfo: WeightInfo;
-}
+	#[pallet::pallet]
+	#[pallet::generate_store(pub(super) trait Store)]
+	pub struct Pallet<T>(_);
 
-decl_storage! {
-	trait Store for Module<T: Config> as Utility {}
-}
 
-decl_event! {
-	/// Events type.
+	/// Configuration trait.
+	#[pallet::config]
+	pub trait Config: frame_system::Config {
+		/// The overarching event type.
+		type Event: From<Event> + IsType<<Self as frame_system::Config>::Event>;
+
+		/// The overarching call type.
+		type Call: Parameter + Dispatchable<Origin=Self::Origin, PostInfo=PostDispatchInfo>
+			+ GetDispatchInfo + From<frame_system::Call<Self>>
+			+ UnfilteredDispatchable<Origin=Self::Origin>;
+
+		/// Weight information for extrinsics in this pallet.
+		type WeightInfo: WeightInfo;
+	}
+
+	#[pallet::event]
+	#[pallet::generate_deposit(pub(super) fn deposit_event)]
 	pub enum Event {
 		/// Batch of dispatches did not complete fully. Index of first failing dispatch given, as
 		/// well as the error. \[index, error\]
@@ -100,21 +106,12 @@ decl_event! {
 		/// Batch of dispatches completed fully with no error.
 		BatchCompleted,
 	}
-}
 
-/// A module identifier. These are per module and should be stored in a registry somewhere.
-#[derive(Clone, Copy, Eq, PartialEq, Encode, Decode)]
-struct IndexedUtilityModuleId(u16);
-
-impl TypeId for IndexedUtilityModuleId {
-	const TYPE_ID: [u8; 4] = *b"suba";
-}
-
-decl_module! {
-	pub struct Module<T: Config> for enum Call where origin: T::Origin {
-		/// Deposit one of this module's events by using the default implementation.
-		fn deposit_event() = default;
+	#[pallet::hooks]
+	impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {}
 
+	#[pallet::call]
+	impl<T: Config> Pallet<T> {
 		/// Send a batch of dispatch calls.
 		///
 		/// May be called from any origin.
@@ -133,7 +130,7 @@ decl_module! {
 		/// `BatchInterrupted` event is deposited, along with the number of successful calls made
 		/// and the error of the failed call. If all were successful, then the `BatchCompleted`
 		/// event is deposited.
-		#[weight = {
+		#[pallet::weight({
 			let dispatch_infos = calls.iter().map(|call| call.get_dispatch_info()).collect::<Vec<_>>();
 			let dispatch_weight = dispatch_infos.iter()
 				.map(|di| di.weight)
@@ -150,8 +147,11 @@ decl_module! {
 				}
 			};
 			(dispatch_weight, dispatch_class)
-		}]
-		fn batch(origin, calls: Vec<<T as Config>::Call>) -> DispatchResultWithPostInfo {
+		})]
+		pub fn batch(
+			origin: OriginFor<T>,
+			calls: Vec<<T as Config>::Call>,
+		) -> DispatchResultWithPostInfo {
 			let is_root = ensure_root(origin.clone()).is_ok();
 			let calls_len = calls.len();
 			// Track the actual weight of each of the batch calls.
@@ -192,7 +192,7 @@ decl_module! {
 		/// NOTE: Prior to version *12, this was called `as_limited_sub`.
 		///
 		/// The dispatch origin for this call must be _Signed_.
-		#[weight = {
+		#[pallet::weight({
 			let dispatch_info = call.get_dispatch_info();
 			(
 				T::WeightInfo::as_derivative()
@@ -201,8 +201,12 @@ decl_module! {
 					.saturating_add(T::DbWeight::get().reads_writes(1, 1)),
 				dispatch_info.class,
 			)
-		}]
-		fn as_derivative(origin, index: u16, call: Box<<T as Config>::Call>) -> DispatchResultWithPostInfo {
+		})]
+		pub fn as_derivative(
+			origin: OriginFor<T>,
+			index: u16,
+			call: Box<<T as Config>::Call>,
+		) -> DispatchResultWithPostInfo {
 			let mut origin = origin;
 			let who = ensure_signed(origin.clone())?;
 			let pseudonym = Self::derivative_account_id(who, index);
@@ -232,7 +236,7 @@ decl_module! {
 		/// # <weight>
 		/// - Complexity: O(C) where C is the number of calls to be batched.
 		/// # </weight>
-		#[weight = {
+		#[pallet::weight({
 			let dispatch_infos = calls.iter().map(|call| call.get_dispatch_info()).collect::<Vec<_>>();
 			let dispatch_weight = dispatch_infos.iter()
 				.map(|di| di.weight)
@@ -249,9 +253,12 @@ decl_module! {
 				}
 			};
 			(dispatch_weight, dispatch_class)
-		}]
+		})]
 		#[transactional]
-		fn batch_all(origin, calls: Vec<<T as Config>::Call>) -> DispatchResultWithPostInfo {
+		pub fn batch_all(
+			origin: OriginFor<T>,
+			calls: Vec<<T as Config>::Call>,
+		) -> DispatchResultWithPostInfo {
 			let is_root = ensure_root(origin.clone()).is_ok();
 			let calls_len = calls.len();
 			// Track the actual weight of each of the batch calls.
@@ -279,9 +286,18 @@ decl_module! {
 			Ok(Some(base_weight + weight).into())
 		}
 	}
+
+}
+
+/// A pallet identifier. These are per pallet and should be stored in a registry somewhere.
+#[derive(Clone, Copy, Eq, PartialEq, Encode, Decode)]
+struct IndexedUtilityPalletId(u16);
+
+impl TypeId for IndexedUtilityPalletId {
+	const TYPE_ID: [u8; 4] = *b"suba";
 }
 
-impl<T: Config> Module<T> {
+impl<T: Config> Pallet<T> {
 	/// Derive a derivative account ID from the owner account and the sub-account index.
 	pub fn derivative_account_id(who: T::AccountId, index: u16) -> T::AccountId {
 		let entropy = (b"modlpy/utilisuba", who, index).using_encoded(blake2_256);
diff --git a/frame/utility/src/tests.rs b/frame/utility/src/tests.rs
index af31bbe96cbc4..3a8089519fac5 100644
--- a/frame/utility/src/tests.rs
+++ b/frame/utility/src/tests.rs
@@ -22,7 +22,7 @@
 use super::*;
 
 use frame_support::{
-	assert_ok, assert_noop, parameter_types, assert_err_ignore_postinfo,
+	assert_ok, assert_noop, parameter_types, assert_err_ignore_postinfo, decl_module,
 	weights::{Weight, Pays},
 	dispatch::{DispatchError, DispatchErrorWithPostInfo, Dispatchable},
 	traits::Filter,
@@ -35,7 +35,8 @@ use crate as utility;
 // example module to test behaviors.
 pub mod example {
 	use super::*;
-	use frame_support::dispatch::WithPostDispatchInfo;
+	use frame_system::ensure_signed;
+	use frame_support::dispatch::{DispatchResultWithPostInfo, WithPostDispatchInfo};
 	pub trait Config: frame_system::Config { }
 
 	decl_module! {
@@ -75,10 +76,10 @@ frame_support::construct_runtime!(
 		NodeBlock = Block,
 		UncheckedExtrinsic = UncheckedExtrinsic,
 	{
-		System: frame_system::{Module, Call, Config, Storage, Event<T>},
-		Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
-		Utility: utility::{Module, Call, Event},
-		Example: example::{Module, Call},
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
+		Utility: utility::{Pallet, Call, Event},
+		Example: example::{Pallet, Call},
 	}
 );
 
@@ -170,7 +171,7 @@ pub fn new_test_ext() -> sp_io::TestExternalities {
 }
 
 fn last_event() -> Event {
-	frame_system::Module::<Test>::events().pop().map(|e| e.event).expect("Event expected")
+	frame_system::Pallet::<Test>::events().pop().map(|e| e.event).expect("Event expected")
 }
 
 fn expect_event<E: Into<Event>>(e: E) {
diff --git a/frame/vesting/src/benchmarking.rs b/frame/vesting/src/benchmarking.rs
index 937f2b033d847..8d16a53fba2c1 100644
--- a/frame/vesting/src/benchmarking.rs
+++ b/frame/vesting/src/benchmarking.rs
@@ -21,11 +21,11 @@
 
 use super::*;
 
-use frame_system::{RawOrigin, Module as System};
+use frame_system::{RawOrigin, Pallet as System};
 use frame_benchmarking::{benchmarks, account, whitelisted_caller, impl_benchmark_test_suite};
 use sp_runtime::traits::Bounded;
 
-use crate::Module as Vesting;
+use crate::Pallet as Vesting;
 
 const SEED: u32 = 0;
 
diff --git a/frame/vesting/src/lib.rs b/frame/vesting/src/lib.rs
index 9cf9166b37c0c..c02e9dc78c13e 100644
--- a/frame/vesting/src/lib.rs
+++ b/frame/vesting/src/lib.rs
@@ -15,15 +15,15 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//! # Vesting Module
+//! # Vesting Pallet
 //!
-//! - [`vesting::Config`](./trait.Config.html)
-//! - [`Call`](./enum.Call.html)
+//! - [`Config`]
+//! - [`Call`]
 //!
 //! ## Overview
 //!
-//! A simple module providing a means of placing a linear curve on an account's locked balance. This
-//! module ensures that there is a lock in place preventing the balance to drop below the *unvested*
+//! A simple pallet providing a means of placing a linear curve on an account's locked balance. This
+//! pallet ensures that there is a lock in place preventing the balance to drop below the *unvested*
 //! amount for any reason other than transaction fee payment.
 //!
 //! As the amount vested increases over time, the amount unvested reduces. However, locks remain in
@@ -34,16 +34,13 @@
 //!
 //! ## Interface
 //!
-//! This module implements the `VestingSchedule` trait.
+//! This pallet implements the `VestingSchedule` trait.
 //!
 //! ### Dispatchable Functions
 //!
 //! - `vest` - Update the lock, reducing it in line with the amount "vested" so far.
 //! - `vest_other` - Update the lock of another account, reducing it in line with the amount
 //!   "vested" so far.
-//!
-//! [`Call`]: ./enum.Call.html
-//! [`Config`]: ./trait.Config.html
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
@@ -53,37 +50,21 @@ pub mod weights;
 use sp_std::prelude::*;
 use sp_std::fmt::Debug;
 use codec::{Encode, Decode};
-use sp_runtime::{DispatchResult, RuntimeDebug, traits::{
+use sp_runtime::{RuntimeDebug, traits::{
 	StaticLookup, Zero, AtLeast32BitUnsigned, MaybeSerializeDeserialize, Convert
 }};
-use frame_support::{decl_module, decl_event, decl_storage, decl_error, ensure};
+use frame_support::{ensure, pallet_prelude::*};
 use frame_support::traits::{
 	Currency, LockableCurrency, VestingSchedule, WithdrawReasons, LockIdentifier,
 	ExistenceRequirement, Get,
 };
-use frame_system::{ensure_signed, ensure_root};
+use frame_system::{ensure_signed, ensure_root, pallet_prelude::*};
 pub use weights::WeightInfo;
+pub use pallet::*;
 
 type BalanceOf<T> = <<T as Config>::Currency as Currency<<T as frame_system::Config>::AccountId>>::Balance;
 type MaxLocksOf<T> = <<T as Config>::Currency as LockableCurrency<<T as frame_system::Config>::AccountId>>::MaxLocks;
 
-pub trait Config: frame_system::Config {
-	/// The overarching event type.
-	type Event: From<Event<Self>> + Into<<Self as frame_system::Config>::Event>;
-
-	/// The currency trait.
-	type Currency: LockableCurrency<Self::AccountId>;
-
-	/// Convert the block number into a balance.
-	type BlockNumberToBalance: Convert<Self::BlockNumber, BalanceOf<Self>>;
-
-	/// The minimum amount transferred to call `vested_transfer`.
-	type MinVestedTransfer: Get<BalanceOf<Self>>;
-
-	/// Weight information for extrinsics in this pallet.
-	type WeightInfo: WeightInfo;
-}
-
 const VESTING_ID: LockIdentifier = *b"vesting ";
 
 /// Struct to encode the vesting schedule of an individual account.
@@ -119,23 +100,68 @@ impl<
 	}
 }
 
-decl_storage! {
-	trait Store for Module<T: Config> as Vesting {
-		/// Information regarding the vesting of a given account.
-		pub Vesting get(fn vesting):
-			map hasher(blake2_128_concat) T::AccountId
-			=> Option<VestingInfo<BalanceOf<T>, T::BlockNumber>>;
+#[frame_support::pallet]
+pub mod pallet {
+	use super::*;
+
+	#[pallet::config]
+	pub trait Config: frame_system::Config {
+		/// The overarching event type.
+		type Event: From<Event<Self>> + IsType<<Self as frame_system::Config>::Event>;
+
+		/// The currency trait.
+		type Currency: LockableCurrency<Self::AccountId>;
+
+		/// Convert the block number into a balance.
+		type BlockNumberToBalance: Convert<Self::BlockNumber, BalanceOf<Self>>;
+
+		/// The minimum amount transferred to call `vested_transfer`.
+		#[pallet::constant]
+		type MinVestedTransfer: Get<BalanceOf<Self>>;
+
+		/// Weight information for extrinsics in this pallet.
+		type WeightInfo: WeightInfo;
 	}
-	add_extra_genesis {
-		config(vesting): Vec<(T::AccountId, T::BlockNumber, T::BlockNumber, BalanceOf<T>)>;
-		build(|config: &GenesisConfig<T>| {
+
+	/// Information regarding the vesting of a given account.
+	#[pallet::storage]
+	#[pallet::getter(fn vesting)]
+	pub type Vesting<T: Config> = StorageMap<
+		_,
+		Blake2_128Concat,
+		T::AccountId,
+		VestingInfo<BalanceOf<T>, T::BlockNumber>,
+	>;
+
+	#[pallet::pallet]
+	#[pallet::generate_store(pub(super) trait Store)]
+	pub struct Pallet<T>(_);
+
+	#[pallet::genesis_config]
+	pub struct GenesisConfig<T: Config> {
+		pub vesting: Vec<(T::AccountId, T::BlockNumber, T::BlockNumber, BalanceOf<T>)>,
+	}
+
+	#[cfg(feature = "std")]
+	impl<T: Config> Default for GenesisConfig<T> {
+		fn default() -> Self {
+			GenesisConfig {
+				vesting: Default::default(),
+			}
+		}
+	}
+
+	#[pallet::genesis_build]
+	impl<T: Config> GenesisBuild<T> for GenesisConfig<T> {
+		fn build(&self) {
 			use sp_runtime::traits::Saturating;
+
 			// Generate initial vesting configuration
 			// * who - Account which we are generating vesting configuration for
 			// * begin - Block when the account will start to vest
 			// * length - Number of blocks from `begin` until fully vested
 			// * liquid - Number of units which can be spent before vesting begins
-			for &(ref who, begin, length, liquid) in config.vesting.iter() {
+			for &(ref who, begin, length, liquid) in self.vesting.iter() {
 				let balance = T::Currency::free_balance(who);
 				assert!(!balance.is_zero(), "Currencies must be init'd before vesting");
 				// Total genesis `balance` minus `liquid` equals funds locked for vesting
@@ -151,24 +177,24 @@ decl_storage! {
 				let reasons = WithdrawReasons::TRANSFER | WithdrawReasons::RESERVE;
 				T::Currency::set_lock(VESTING_ID, who, locked, reasons);
 			}
-		})
+		}
 	}
-}
 
-decl_event!(
-	pub enum Event<T> where AccountId = <T as frame_system::Config>::AccountId, Balance = BalanceOf<T> {
+	#[pallet::event]
+	#[pallet::generate_deposit(pub(super) fn deposit_event)]
+	#[pallet::metadata(T::AccountId = "AccountId", BalanceOf<T> = "Balance")]
+	pub enum Event<T: Config> {
 		/// The amount vested has been updated. This could indicate more funds are available. The
 		/// balance given is the amount which is left unvested (and thus locked).
 		/// \[account, unvested\]
-		VestingUpdated(AccountId, Balance),
+		VestingUpdated(T::AccountId, BalanceOf<T>),
 		/// An \[account\] has become fully vested. No further vesting can happen.
-		VestingCompleted(AccountId),
+		VestingCompleted(T::AccountId),
 	}
-);
 
-decl_error! {
-	/// Error for the vesting module.
-	pub enum Error for Module<T: Config> {
+	/// Error for the vesting pallet.
+	#[pallet::error]
+	pub enum Error<T> {
 		/// The account given is not vesting.
 		NotVesting,
 		/// An existing vesting schedule already exists for this account that cannot be clobbered.
@@ -176,22 +202,16 @@ decl_error! {
 		/// Amount being transferred is too low to create a vesting schedule.
 		AmountLow,
 	}
-}
-
-decl_module! {
-	/// Vesting module declaration.
-	pub struct Module<T: Config> for enum Call where origin: T::Origin {
-		type Error = Error<T>;
-
-		/// The minimum amount to be transferred to create a new vesting schedule.
-		const MinVestedTransfer: BalanceOf<T> = T::MinVestedTransfer::get();
 
-		fn deposit_event() = default;
+	#[pallet::hooks]
+	impl<T: Config> Hooks<BlockNumberFor<T>> for Pallet<T> {}
 
+	#[pallet::call]
+	impl<T: Config> Pallet<T> {
 		/// Unlock any vested funds of the sender account.
 		///
 		/// The dispatch origin for this call must be _Signed_ and the sender must have funds still
-		/// locked under this module.
+		/// locked under this pallet.
 		///
 		/// Emits either `VestingCompleted` or `VestingUpdated`.
 		///
@@ -201,10 +221,10 @@ decl_module! {
 		///     - Reads: Vesting Storage, Balances Locks, [Sender Account]
 		///     - Writes: Vesting Storage, Balances Locks, [Sender Account]
 		/// # </weight>
-		#[weight = T::WeightInfo::vest_locked(MaxLocksOf::<T>::get())
+		#[pallet::weight(T::WeightInfo::vest_locked(MaxLocksOf::<T>::get())
 			.max(T::WeightInfo::vest_unlocked(MaxLocksOf::<T>::get()))
-		]
-		fn vest(origin) -> DispatchResult {
+		)]
+		pub fn vest(origin: OriginFor<T>) -> DispatchResult {
 			let who = ensure_signed(origin)?;
 			Self::update_lock(who)
 		}
@@ -214,7 +234,7 @@ decl_module! {
 		/// The dispatch origin for this call must be _Signed_.
 		///
 		/// - `target`: The account whose vested funds should be unlocked. Must have funds still
-		/// locked under this module.
+		/// locked under this pallet.
 		///
 		/// Emits either `VestingCompleted` or `VestingUpdated`.
 		///
@@ -224,10 +244,10 @@ decl_module! {
 		///     - Reads: Vesting Storage, Balances Locks, Target Account
 		///     - Writes: Vesting Storage, Balances Locks, Target Account
 		/// # </weight>
-		#[weight = T::WeightInfo::vest_other_locked(MaxLocksOf::<T>::get())
+		#[pallet::weight(T::WeightInfo::vest_other_locked(MaxLocksOf::<T>::get())
 			.max(T::WeightInfo::vest_other_unlocked(MaxLocksOf::<T>::get()))
-		]
-		fn vest_other(origin, target: <T::Lookup as StaticLookup>::Source) -> DispatchResult {
+		)]
+		pub fn vest_other(origin: OriginFor<T>, target: <T::Lookup as StaticLookup>::Source) -> DispatchResult {
 			ensure_signed(origin)?;
 			Self::update_lock(T::Lookup::lookup(target)?)
 		}
@@ -248,9 +268,9 @@ decl_module! {
 		///     - Reads: Vesting Storage, Balances Locks, Target Account, [Sender Account]
 		///     - Writes: Vesting Storage, Balances Locks, Target Account, [Sender Account]
 		/// # </weight>
-		#[weight = T::WeightInfo::vested_transfer(MaxLocksOf::<T>::get())]
+		#[pallet::weight(T::WeightInfo::vested_transfer(MaxLocksOf::<T>::get()))]
 		pub fn vested_transfer(
-			origin,
+			origin: OriginFor<T>,
 			target: <T::Lookup as StaticLookup>::Source,
 			schedule: VestingInfo<BalanceOf<T>, T::BlockNumber>,
 		) -> DispatchResult {
@@ -285,9 +305,9 @@ decl_module! {
 		///     - Reads: Vesting Storage, Balances Locks, Target Account, Source Account
 		///     - Writes: Vesting Storage, Balances Locks, Target Account, Source Account
 		/// # </weight>
-		#[weight = T::WeightInfo::force_vested_transfer(MaxLocksOf::<T>::get())]
+		#[pallet::weight(T::WeightInfo::force_vested_transfer(MaxLocksOf::<T>::get()))]
 		pub fn force_vested_transfer(
-			origin,
+			origin: OriginFor<T>,
 			source: <T::Lookup as StaticLookup>::Source,
 			target: <T::Lookup as StaticLookup>::Source,
 			schedule: VestingInfo<BalanceOf<T>, T::BlockNumber>,
@@ -309,28 +329,28 @@ decl_module! {
 	}
 }
 
-impl<T: Config> Module<T> {
-	/// (Re)set or remove the module's currency lock on `who`'s account in accordance with their
+impl<T: Config> Pallet<T> {
+	/// (Re)set or remove the pallet's currency lock on `who`'s account in accordance with their
 	/// current unvested amount.
 	fn update_lock(who: T::AccountId) -> DispatchResult {
 		let vesting = Self::vesting(&who).ok_or(Error::<T>::NotVesting)?;
-		let now = <frame_system::Module<T>>::block_number();
+		let now = <frame_system::Pallet<T>>::block_number();
 		let locked_now = vesting.locked_at::<T::BlockNumberToBalance>(now);
 
 		if locked_now.is_zero() {
 			T::Currency::remove_lock(VESTING_ID, &who);
 			Vesting::<T>::remove(&who);
-			Self::deposit_event(RawEvent::VestingCompleted(who));
+			Self::deposit_event(Event::<T>::VestingCompleted(who));
 		} else {
 			let reasons = WithdrawReasons::TRANSFER | WithdrawReasons::RESERVE;
 			T::Currency::set_lock(VESTING_ID, &who, locked_now, reasons);
-			Self::deposit_event(RawEvent::VestingUpdated(who, locked_now));
+			Self::deposit_event(Event::<T>::VestingUpdated(who, locked_now));
 		}
 		Ok(())
 	}
 }
 
-impl<T: Config> VestingSchedule<T::AccountId> for Module<T> where
+impl<T: Config> VestingSchedule<T::AccountId> for Pallet<T> where
 	BalanceOf<T>: MaybeSerializeDeserialize + Debug
 {
 	type Moment = T::BlockNumber;
@@ -339,7 +359,7 @@ impl<T: Config> VestingSchedule<T::AccountId> for Module<T> where
 	/// Get the amount that is currently being vested and cannot be transferred out of this account.
 	fn vesting_balance(who: &T::AccountId) -> Option<BalanceOf<T>> {
 		if let Some(v) = Self::vesting(who) {
-			let now = <frame_system::Module<T>>::block_number();
+			let now = <frame_system::Pallet<T>>::block_number();
 			let locked_now = v.locked_at::<T::BlockNumberToBalance>(now);
 			Some(T::Currency::free_balance(who).min(locked_now))
 		} else {
@@ -374,7 +394,8 @@ impl<T: Config> VestingSchedule<T::AccountId> for Module<T> where
 		};
 		Vesting::<T>::insert(who, vesting_schedule);
 		// it can't fail, but even if somehow it did, we don't really care.
-		let _ = Self::update_lock(who.clone());
+		let res = Self::update_lock(who.clone());
+		debug_assert!(res.is_ok());
 		Ok(())
 	}
 
@@ -382,7 +403,8 @@ impl<T: Config> VestingSchedule<T::AccountId> for Module<T> where
 	fn remove_vesting_schedule(who: &T::AccountId) {
 		Vesting::<T>::remove(who);
 		// it can't fail, but even if somehow it did, we don't really care.
-		let _ = Self::update_lock(who.clone());
+		let res = Self::update_lock(who.clone());
+		debug_assert!(res.is_ok());
 	}
 }
 
@@ -408,9 +430,9 @@ mod tests {
 			NodeBlock = Block,
 			UncheckedExtrinsic = UncheckedExtrinsic,
 		{
-			System: frame_system::{Module, Call, Config, Storage, Event<T>},
-			Balances: pallet_balances::{Module, Call, Storage, Config<T>, Event<T>},
-			Vesting: pallet_vesting::{Module, Call, Storage, Event<T>, Config<T>},
+			System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+			Balances: pallet_balances::{Pallet, Call, Storage, Config<T>, Event<T>},
+			Vesting: pallet_vesting::{Pallet, Call, Storage, Event<T>, Config<T>},
 		}
 	);
 
diff --git a/primitives/arithmetic/fuzzer/src/per_thing_rational.rs b/primitives/arithmetic/fuzzer/src/per_thing_rational.rs
index ff172b8bd2704..47ba5a4803056 100644
--- a/primitives/arithmetic/fuzzer/src/per_thing_rational.rs
+++ b/primitives/arithmetic/fuzzer/src/per_thing_rational.rs
@@ -38,75 +38,75 @@ fn main() {
 
 			// peru16
 			let (smaller, bigger) = (u16_pair.0.min(u16_pair.1), u16_pair.0.max(u16_pair.1));
-			let ratio = PerU16::from_rational_approximation(smaller, bigger);
+			let ratio = PerU16::from_rational(smaller, bigger);
 			assert_per_thing_equal_error(
 				ratio,
-				PerU16::from_fraction(smaller as f64 / bigger.max(1) as f64),
+				PerU16::from_float(smaller as f64 / bigger.max(1) as f64),
 				1,
 			);
 			let (smaller, bigger) = (u32_pair.0.min(u32_pair.1), u32_pair.0.max(u32_pair.1));
-			let ratio = PerU16::from_rational_approximation(smaller, bigger);
+			let ratio = PerU16::from_rational(smaller, bigger);
 			assert_per_thing_equal_error(
 				ratio,
-				PerU16::from_fraction(smaller as f64 / bigger.max(1) as f64),
+				PerU16::from_float(smaller as f64 / bigger.max(1) as f64),
 				1,
 			);
 			let (smaller, bigger) = (u64_pair.0.min(u64_pair.1), u64_pair.0.max(u64_pair.1));
-			let ratio = PerU16::from_rational_approximation(smaller, bigger);
+			let ratio = PerU16::from_rational(smaller, bigger);
 			assert_per_thing_equal_error(
 				ratio,
-				PerU16::from_fraction(smaller as f64 / bigger.max(1) as f64),
+				PerU16::from_float(smaller as f64 / bigger.max(1) as f64),
 				1,
 			);
 
 			// percent
 			let (smaller, bigger) = (u16_pair.0.min(u16_pair.1), u16_pair.0.max(u16_pair.1));
-			let ratio = Percent::from_rational_approximation(smaller, bigger);
+			let ratio = Percent::from_rational(smaller, bigger);
 			assert_per_thing_equal_error(
 				ratio,
-				Percent::from_fraction(smaller as f64 / bigger.max(1) as f64),
+				Percent::from_float(smaller as f64 / bigger.max(1) as f64),
 				1,
 			);
 
 			let (smaller, bigger) = (u32_pair.0.min(u32_pair.1), u32_pair.0.max(u32_pair.1));
-			let ratio = Percent::from_rational_approximation(smaller, bigger);
+			let ratio = Percent::from_rational(smaller, bigger);
 			assert_per_thing_equal_error(
 				ratio,
-				Percent::from_fraction(smaller as f64 / bigger.max(1) as f64),
+				Percent::from_float(smaller as f64 / bigger.max(1) as f64),
 				1,
 			);
 
 			let (smaller, bigger) = (u64_pair.0.min(u64_pair.1), u64_pair.0.max(u64_pair.1));
-			let ratio = Percent::from_rational_approximation(smaller, bigger);
+			let ratio = Percent::from_rational(smaller, bigger);
 			assert_per_thing_equal_error(
 				ratio,
-				Percent::from_fraction(smaller as f64 / bigger.max(1) as f64),
+				Percent::from_float(smaller as f64 / bigger.max(1) as f64),
 				1,
 			);
 
 			// perbill
 			let (smaller, bigger) = (u32_pair.0.min(u32_pair.1), u32_pair.0.max(u32_pair.1));
-			let ratio = Perbill::from_rational_approximation(smaller, bigger);
+			let ratio = Perbill::from_rational(smaller, bigger);
 			assert_per_thing_equal_error(
 				ratio,
-				Perbill::from_fraction(smaller as f64 / bigger.max(1) as f64),
+				Perbill::from_float(smaller as f64 / bigger.max(1) as f64),
 				100,
 			);
 
 			let (smaller, bigger) = (u64_pair.0.min(u64_pair.1), u64_pair.0.max(u64_pair.1));
-			let ratio = Perbill::from_rational_approximation(smaller, bigger);
+			let ratio = Perbill::from_rational(smaller, bigger);
 			assert_per_thing_equal_error(
 				ratio,
-				Perbill::from_fraction(smaller as f64 / bigger.max(1) as f64),
+				Perbill::from_float(smaller as f64 / bigger.max(1) as f64),
 				100,
 			);
 
 			// perquintillion
 			let (smaller, bigger) = (u64_pair.0.min(u64_pair.1), u64_pair.0.max(u64_pair.1));
-			let ratio = Perquintill::from_rational_approximation(smaller, bigger);
+			let ratio = Perquintill::from_rational(smaller, bigger);
 			assert_per_thing_equal_error(
 				ratio,
-				Perquintill::from_fraction(smaller as f64 / bigger.max(1) as f64),
+				Perquintill::from_float(smaller as f64 / bigger.max(1) as f64),
 				1000,
 			);
 
diff --git a/primitives/arithmetic/src/fixed_point.rs b/primitives/arithmetic/src/fixed_point.rs
index 896d5f38451de..b837c360c7c54 100644
--- a/primitives/arithmetic/src/fixed_point.rs
+++ b/primitives/arithmetic/src/fixed_point.rs
@@ -376,7 +376,7 @@ macro_rules! implement_fixed {
 			}
 
 			#[cfg(any(feature = "std", test))]
-			pub fn from_fraction(x: f64) -> Self {
+			pub fn from_float(x: f64) -> Self {
 				Self((x * (<Self as FixedPointNumber>::DIV as f64)) as $inner_type)
 			}
 
diff --git a/primitives/arithmetic/src/lib.rs b/primitives/arithmetic/src/lib.rs
index 561c14a37e203..d6069ad5154d1 100644
--- a/primitives/arithmetic/src/lib.rs
+++ b/primitives/arithmetic/src/lib.rs
@@ -494,7 +494,7 @@ mod threshold_compare_tests {
 	fn peru16_rational_does_not_overflow() {
 		// A historical example that will panic only for per_thing type that are created with
 		// maximum capacity of their type, e.g. PerU16.
-		let _ = PerU16::from_rational_approximation(17424870u32, 17424870);
+		let _ = PerU16::from_rational(17424870u32, 17424870);
 	}
 
 	#[test]
diff --git a/primitives/arithmetic/src/per_things.rs b/primitives/arithmetic/src/per_things.rs
index f2b8c4f93b33f..29d5d2be73a1c 100644
--- a/primitives/arithmetic/src/per_things.rs
+++ b/primitives/arithmetic/src/per_things.rs
@@ -18,8 +18,9 @@
 #[cfg(feature = "std")]
 use serde::{Serialize, Deserialize};
 
-use sp_std::{ops, fmt, prelude::*, convert::TryInto};
+use sp_std::{ops, fmt, prelude::*, convert::{TryFrom, TryInto}};
 use codec::{Encode, CompactAs};
+use num_traits::Pow;
 use crate::traits::{
 	SaturatedConversion, UniqueSaturatedInto, Saturating, BaseArithmetic, Bounded, Zero, Unsigned,
 	One,
@@ -36,6 +37,7 @@ pub type UpperOf<P> = <P as PerThing>::Upper;
 /// `X`_.
 pub trait PerThing:
 	Sized + Saturating + Copy + Default + Eq + PartialEq + Ord + PartialOrd + Bounded + fmt::Debug
+	+ ops::Div<Output=Self> + ops::Mul<Output=Self> + Pow<usize, Output=Self>
 {
 	/// The data type used to build this per-thingy.
 	type Inner: BaseArithmetic + Unsigned + Copy + Into<u128> + fmt::Debug;
@@ -70,14 +72,14 @@ pub trait PerThing:
 	fn from_percent(x: Self::Inner) -> Self {
 		let a: Self::Inner = x.min(100.into());
 		let b: Self::Inner = 100.into();
-		Self::from_rational_approximation::<Self::Inner>(a, b)
+		Self::from_rational::<Self::Inner>(a, b)
 	}
 
 	/// Return the product of multiplication of this value by itself.
 	fn square(self) -> Self {
 		let p = Self::Upper::from(self.deconstruct());
 		let q = Self::Upper::from(Self::ACCURACY);
-		Self::from_rational_approximation::<Self::Upper>(p * p, q * q)
+		Self::from_rational::<Self::Upper>(p * p, q * q)
 	}
 
 	/// Return the part left when `self` is saturating-subtracted from `Self::one()`.
@@ -204,7 +206,12 @@ pub trait PerThing:
 
 	/// Converts a fraction into `Self`.
 	#[cfg(feature = "std")]
-	fn from_fraction(x: f64) -> Self;
+	fn from_float(x: f64) -> Self;
+
+	/// Same as `Self::from_float`.
+	#[deprecated = "Use from_float instead"]
+	#[cfg(feature = "std")]
+	fn from_fraction(x: f64) -> Self { Self::from_float(x) }
 
 	/// Approximate the fraction `p/q` into a per-thing fraction. This will never overflow.
 	///
@@ -219,16 +226,28 @@ pub trait PerThing:
 	/// # fn main () {
 	/// // 989/100 is technically closer to 99%.
 	/// assert_eq!(
-	/// 		Percent::from_rational_approximation(989u64, 1000),
+	/// 		Percent::from_rational(989u64, 1000),
 	/// 		Percent::from_parts(98),
 	/// 	);
 	/// # }
 	/// ```
-	fn from_rational_approximation<N>(p: N, q: N) -> Self
+	fn from_rational<N>(p: N, q: N) -> Self
 	where
 		N: Clone + Ord + TryInto<Self::Inner> + TryInto<Self::Upper> +
 			ops::Div<N, Output=N> + ops::Rem<N, Output=N> + ops::Add<N, Output=N> + Unsigned,
 		Self::Inner: Into<N>;
+
+	/// Same as `Self::from_rational`.
+	#[deprecated = "Use from_rational instead"]
+	fn from_rational_approximation<N>(p: N, q: N) -> Self
+		where
+			N: Clone + Ord + TryInto<Self::Inner> + TryInto<Self::Upper>
+			+ ops::Div<N, Output=N> + ops::Rem<N, Output=N> + ops::Add<N, Output=N> + Unsigned
+			+ Zero + One,
+			Self::Inner: Into<N>,
+	{
+		Self::from_rational(p, q)
+	}
 }
 
 /// The rounding method to use.
@@ -369,11 +388,11 @@ macro_rules! implement_per_thing {
 
 			/// NOTE: saturate to 0 or 1 if x is beyond `[0, 1]`
 			#[cfg(feature = "std")]
-			fn from_fraction(x: f64) -> Self {
+			fn from_float(x: f64) -> Self {
 				Self::from_parts((x.max(0.).min(1.) * $max as f64) as Self::Inner)
 			}
 
-			fn from_rational_approximation<N>(p: N, q: N) -> Self
+			fn from_rational<N>(p: N, q: N) -> Self
 			where
 				N: Clone + Ord + TryInto<Self::Inner> + TryInto<Self::Upper>
 				 + ops::Div<N, Output=N> + ops::Rem<N, Output=N> + ops::Add<N, Output=N> + Unsigned
@@ -471,20 +490,31 @@ macro_rules! implement_per_thing {
 				PerThing::square(self)
 			}
 
-			/// See [`PerThing::from_fraction`].
+			/// See [`PerThing::from_float`].
 			#[cfg(feature = "std")]
-			pub fn from_fraction(x: f64) -> Self {
-				<Self as PerThing>::from_fraction(x)
+			pub fn from_float(x: f64) -> Self {
+				<Self as PerThing>::from_float(x)
 			}
 
-			/// See [`PerThing::from_rational_approximation`].
+			/// See [`PerThing::from_rational`].
+			#[deprecated = "Use `PerThing::from_rational` instead"]
 			pub fn from_rational_approximation<N>(p: N, q: N) -> Self
 				where N: Clone + Ord + TryInto<$type> +
 					TryInto<$upper_type> + ops::Div<N, Output=N> + ops::Rem<N, Output=N> +
 					ops::Add<N, Output=N> + Unsigned,
 					$type: Into<N>,
 			{
-				<Self as PerThing>::from_rational_approximation(p, q)
+				<Self as PerThing>::from_rational(p, q)
+			}
+
+			/// See [`PerThing::from_rational`].
+			pub fn from_rational<N>(p: N, q: N) -> Self
+				where N: Clone + Ord + TryInto<$type> +
+					TryInto<$upper_type> + ops::Div<N, Output=N> + ops::Rem<N, Output=N> +
+					ops::Add<N, Output=N> + Unsigned,
+					$type: Into<N>,
+			{
+				<Self as PerThing>::from_rational(p, q)
 			}
 
 			/// See [`PerThing::mul_floor`].
@@ -561,37 +591,13 @@ macro_rules! implement_per_thing {
 			/// Saturating multiply. Compute `self * rhs`, saturating at the numeric bounds instead of
 			/// overflowing. This operation is lossy.
 			fn saturating_mul(self, rhs: Self) -> Self {
-				let a = self.0 as $upper_type;
-				let b = rhs.0 as $upper_type;
-				let m = <$upper_type>::from($max);
-				let parts = a * b / m;
-				// This will always fit into $type.
-				Self::from_parts(parts as $type)
+				self * rhs
 			}
 
 			/// Saturating exponentiation. Computes `self.pow(exp)`, saturating at the numeric
 			/// bounds instead of overflowing. This operation is lossy.
 			fn saturating_pow(self, exp: usize) -> Self {
-				if self.is_zero() || self.is_one() {
-					self
-				} else {
-					let p = <$name as PerThing>::Upper::from(self.deconstruct());
-					let q = <$name as PerThing>::Upper::from(Self::ACCURACY);
-					let mut s = Self::one();
-					for _ in 0..exp {
-						if s.is_zero() {
-							break;
-						} else {
-							// x^2 always fits in Self::Upper if x fits in Self::Inner.
-							// Verified by a test.
-							s = Self::from_rational_approximation(
-								<$name as PerThing>::Upper::from(s.deconstruct()) * p,
-								q * q,
-							);
-						}
-					}
-					s
-				}
+				self.pow(exp)
 			}
 		}
 
@@ -607,7 +613,7 @@ macro_rules! implement_per_thing {
 			}
 		}
 
-		impl crate::traits::Bounded for $name {
+		impl Bounded for $name {
 			fn min_value() -> Self {
 				<Self as PerThing>::zero()
 			}
@@ -617,13 +623,48 @@ macro_rules! implement_per_thing {
 			}
 		}
 
+		impl ops::Mul for $name {
+			type Output = Self;
+
+			fn mul(self, rhs: Self) -> Self::Output {
+				let a = self.0 as $upper_type;
+				let b = rhs.0 as $upper_type;
+				let m = <$upper_type>::from($max);
+				let parts = a * b / m;
+				// This will always fit into $type.
+				Self::from_parts(parts as $type)
+			}
+		}
+
+		impl Pow<usize> for $name {
+			type Output = Self;
+
+			fn pow(self, exp: usize) -> Self::Output {
+				if exp == 0 || self.is_one() {
+					return Self::one()
+				}
+				let mut result = self;
+				let mut exp = exp - 1;
+				while exp > 0 && !result.is_zero() {
+					if exp % 2 == 0 {
+						result = result.square();
+						exp /= 2;
+					} else {
+						result = result * self;
+						exp -= 1;
+					}
+				}
+				result
+			}
+		}
+
 		impl ops::Div for $name {
 			type Output = Self;
 
 			fn div(self, rhs: Self) -> Self::Output {
 				let p = self.0;
 				let q = rhs.0;
-				Self::from_rational_approximation(p, q)
+				Self::from_rational(p, q)
 			}
 		}
 
@@ -648,6 +689,13 @@ macro_rules! implement_per_thing {
 			}
 		}
 
+		impl<N> ops::Div<N> for $name where $type: TryFrom<N> {
+			type Output = Self;
+			fn div(self, b: N) -> Self::Output {
+				<$type>::try_from(b).map_or(Self::zero(), |d| Self::from_parts(self.0 / d))
+			}
+		}
+
 		#[cfg(test)]
 		mod $test_mod {
 			use codec::{Encode, Decode};
@@ -657,13 +705,13 @@ macro_rules! implement_per_thing {
 			#[test]
 			fn macro_expanded_correctly() {
 				// needed for the `from_percent` to work. UPDATE: this is no longer needed; yet note
-				// that tests that use percentage or fractions such as $name::from_fraction(0.2) to
+				// that tests that use percentage or fractions such as $name::from_float(0.2) to
 				// create values will most likely be inaccurate when used with per_things that are
 				// not multiples of 100.
 				// assert!($max >= 100);
 				// assert!($max % 100 == 0);
 
-				// needed for `from_rational_approximation`
+				// needed for `from_rational`
 				assert!(2 * ($max as $upper_type) < <$upper_type>::max_value());
 				assert!(<$upper_type>::from($max) < <$upper_type>::max_value());
 
@@ -737,11 +785,11 @@ macro_rules! implement_per_thing {
 				assert_eq!($name::from_percent(100), $name::from_parts($max));
 				assert_eq!($name::from_percent(200), $name::from_parts($max));
 
-				assert_eq!($name::from_fraction(0.0), $name::from_parts(Zero::zero()));
-				assert_eq!($name::from_fraction(0.1), $name::from_parts($max / 10));
-				assert_eq!($name::from_fraction(1.0), $name::from_parts($max));
-				assert_eq!($name::from_fraction(2.0), $name::from_parts($max));
-				assert_eq!($name::from_fraction(-1.0), $name::from_parts(Zero::zero()));
+				assert_eq!($name::from_float(0.0), $name::from_parts(Zero::zero()));
+				assert_eq!($name::from_float(0.1), $name::from_parts($max / 10));
+				assert_eq!($name::from_float(1.0), $name::from_parts($max));
+				assert_eq!($name::from_float(2.0), $name::from_parts($max));
+				assert_eq!($name::from_float(-1.0), $name::from_parts(Zero::zero()));
 			}
 
 			#[test]
@@ -763,7 +811,7 @@ macro_rules! implement_per_thing {
 				($num_type:tt) => {
 					// multiplication from all sort of from_percent
 					assert_eq!(
-						$name::from_fraction(1.0) * $num_type::max_value(),
+						$name::from_float(1.0) * $num_type::max_value(),
 						$num_type::max_value()
 					);
 					if $max % 100 == 0 {
@@ -773,7 +821,7 @@ macro_rules! implement_per_thing {
 							1,
 						);
 						assert_eq!(
-							$name::from_fraction(0.5) * $num_type::max_value(),
+							$name::from_float(0.5) * $num_type::max_value(),
 							$num_type::max_value() / 2,
 						);
 						assert_eq_error_rate!(
@@ -783,30 +831,30 @@ macro_rules! implement_per_thing {
 						);
 					} else {
 						assert_eq!(
-							$name::from_fraction(0.99) * <$num_type>::max_value(),
+							$name::from_float(0.99) * <$num_type>::max_value(),
 							(
 								(
-									u256ify!($name::from_fraction(0.99).0) *
+									u256ify!($name::from_float(0.99).0) *
 									u256ify!(<$num_type>::max_value()) /
 									u256ify!($max)
 								).as_u128()
 							) as $num_type,
 						);
 						assert_eq!(
-							$name::from_fraction(0.50) * <$num_type>::max_value(),
+							$name::from_float(0.50) * <$num_type>::max_value(),
 							(
 								(
-									u256ify!($name::from_fraction(0.50).0) *
+									u256ify!($name::from_float(0.50).0) *
 									u256ify!(<$num_type>::max_value()) /
 									u256ify!($max)
 								).as_u128()
 							) as $num_type,
 						);
 						assert_eq!(
-							$name::from_fraction(0.01) * <$num_type>::max_value(),
+							$name::from_float(0.01) * <$num_type>::max_value(),
 							(
 								(
-									u256ify!($name::from_fraction(0.01).0) *
+									u256ify!($name::from_float(0.01).0) *
 									u256ify!(<$num_type>::max_value()) /
 									u256ify!($max)
 								).as_u128()
@@ -814,7 +862,7 @@ macro_rules! implement_per_thing {
 						);
 					}
 
-					assert_eq!($name::from_fraction(0.0) * $num_type::max_value(), 0);
+					assert_eq!($name::from_float(0.0) * $num_type::max_value(), 0);
 
 					// // multiplication with bounds
 					assert_eq!($name::one() * $num_type::max_value(), $num_type::max_value());
@@ -828,7 +876,7 @@ macro_rules! implement_per_thing {
 
 				// accuracy test
 				assert_eq!(
-					$name::from_rational_approximation(1 as $type, 3) * 30 as $type,
+					$name::from_rational(1 as $type, 3) * 30 as $type,
 					10,
 				);
 
@@ -837,10 +885,10 @@ macro_rules! implement_per_thing {
 
 			#[test]
 			fn per_thing_mul_rounds_to_nearest_number() {
-				assert_eq!($name::from_fraction(0.33) * 10u64, 3);
-				assert_eq!($name::from_fraction(0.34) * 10u64, 3);
-				assert_eq!($name::from_fraction(0.35) * 10u64, 3);
-				assert_eq!($name::from_fraction(0.36) * 10u64, 4);
+				assert_eq!($name::from_float(0.33) * 10u64, 3);
+				assert_eq!($name::from_float(0.34) * 10u64, 3);
+				assert_eq!($name::from_float(0.35) * 10u64, 3);
+				assert_eq!($name::from_float(0.36) * 10u64, 4);
 			}
 
 			#[test]
@@ -858,33 +906,33 @@ macro_rules! implement_per_thing {
 				($num_type:tt) => {
 					// within accuracy boundary
 					assert_eq!(
-						$name::from_rational_approximation(1 as $num_type, 0),
+						$name::from_rational(1 as $num_type, 0),
 						$name::one(),
 					);
 					assert_eq!(
-						$name::from_rational_approximation(1 as $num_type, 1),
+						$name::from_rational(1 as $num_type, 1),
 						$name::one(),
 					);
 					assert_eq_error_rate!(
-						$name::from_rational_approximation(1 as $num_type, 3).0,
+						$name::from_rational(1 as $num_type, 3).0,
 						$name::from_parts($max / 3).0,
 						2
 					);
 					assert_eq!(
-						$name::from_rational_approximation(1 as $num_type, 10),
-						$name::from_fraction(0.10),
+						$name::from_rational(1 as $num_type, 10),
+						$name::from_float(0.10),
 					);
 					assert_eq!(
-						$name::from_rational_approximation(1 as $num_type, 4),
-						$name::from_fraction(0.25),
+						$name::from_rational(1 as $num_type, 4),
+						$name::from_float(0.25),
 					);
 					assert_eq!(
-						$name::from_rational_approximation(1 as $num_type, 4),
-						$name::from_rational_approximation(2 as $num_type, 8),
+						$name::from_rational(1 as $num_type, 4),
+						$name::from_rational(2 as $num_type, 8),
 					);
 					// no accurate anymore but won't overflow.
 					assert_eq_error_rate!(
-						$name::from_rational_approximation(
+						$name::from_rational(
 							$num_type::max_value() - 1,
 							$num_type::max_value()
 						).0 as $upper_type,
@@ -892,7 +940,7 @@ macro_rules! implement_per_thing {
 						2,
 					);
 					assert_eq_error_rate!(
-						$name::from_rational_approximation(
+						$name::from_rational(
 							$num_type::max_value() / 3,
 							$num_type::max_value()
 						).0 as $upper_type,
@@ -900,7 +948,7 @@ macro_rules! implement_per_thing {
 						2,
 					);
 					assert_eq!(
-						$name::from_rational_approximation(1, $num_type::max_value()),
+						$name::from_rational(1, $num_type::max_value()),
 						$name::zero(),
 					);
 				};
@@ -914,28 +962,28 @@ macro_rules! implement_per_thing {
 
 				// almost at the edge
 				assert_eq!(
-					$name::from_rational_approximation(max_value - 1, max_value + 1),
+					$name::from_rational(max_value - 1, max_value + 1),
 					$name::from_parts($max - 2),
 				);
 				assert_eq!(
-					$name::from_rational_approximation(1, $max - 1),
+					$name::from_rational(1, $max - 1),
 					$name::from_parts(1),
 				);
 				assert_eq!(
-					$name::from_rational_approximation(1, $max),
+					$name::from_rational(1, $max),
 					$name::from_parts(1),
 				);
 				assert_eq!(
-					$name::from_rational_approximation(2, 2 * max_value - 1),
+					$name::from_rational(2, 2 * max_value - 1),
 					$name::from_parts(1),
 				);
 				assert_eq!(
-					$name::from_rational_approximation(1, max_value + 1),
+					$name::from_rational(1, max_value + 1),
 					$name::zero(),
 				);
 				assert_eq!(
-					$name::from_rational_approximation(3 * max_value / 2, 3 * max_value),
-					$name::from_fraction(0.5),
+					$name::from_rational(3 * max_value / 2, 3 * max_value),
+					$name::from_float(0.5),
 				);
 
 				$(per_thing_from_rationale_approx_test!($test_units);)*
@@ -943,66 +991,66 @@ macro_rules! implement_per_thing {
 
 			#[test]
 			fn per_things_mul_operates_in_output_type() {
-				// assert_eq!($name::from_fraction(0.5) * 100u32, 50u32);
-				assert_eq!($name::from_fraction(0.5) * 100u64, 50u64);
-				assert_eq!($name::from_fraction(0.5) * 100u128, 50u128);
+				// assert_eq!($name::from_float(0.5) * 100u32, 50u32);
+				assert_eq!($name::from_float(0.5) * 100u64, 50u64);
+				assert_eq!($name::from_float(0.5) * 100u128, 50u128);
 			}
 
 			#[test]
 			fn per_thing_saturating_op_works() {
 				assert_eq_error_rate!(
-					$name::from_fraction(0.5).saturating_add($name::from_fraction(0.4)).0 as $upper_type,
-					$name::from_fraction(0.9).0 as $upper_type,
+					$name::from_float(0.5).saturating_add($name::from_float(0.4)).0 as $upper_type,
+					$name::from_float(0.9).0 as $upper_type,
 					2,
 				);
 				assert_eq_error_rate!(
-					$name::from_fraction(0.5).saturating_add($name::from_fraction(0.5)).0 as $upper_type,
+					$name::from_float(0.5).saturating_add($name::from_float(0.5)).0 as $upper_type,
 					$name::one().0 as $upper_type,
 					2,
 				);
 				assert_eq!(
-					$name::from_fraction(0.6).saturating_add($name::from_fraction(0.5)),
+					$name::from_float(0.6).saturating_add($name::from_float(0.5)),
 					$name::one(),
 				);
 
 				assert_eq_error_rate!(
-					$name::from_fraction(0.6).saturating_sub($name::from_fraction(0.5)).0 as $upper_type,
-					$name::from_fraction(0.1).0 as $upper_type,
+					$name::from_float(0.6).saturating_sub($name::from_float(0.5)).0 as $upper_type,
+					$name::from_float(0.1).0 as $upper_type,
 					2,
 				);
 				assert_eq!(
-					$name::from_fraction(0.6).saturating_sub($name::from_fraction(0.6)),
-					$name::from_fraction(0.0),
+					$name::from_float(0.6).saturating_sub($name::from_float(0.6)),
+					$name::from_float(0.0),
 				);
 				assert_eq!(
-					$name::from_fraction(0.6).saturating_sub($name::from_fraction(0.7)),
-					$name::from_fraction(0.0),
+					$name::from_float(0.6).saturating_sub($name::from_float(0.7)),
+					$name::from_float(0.0),
 				);
 
 				assert_eq_error_rate!(
-					$name::from_fraction(0.5).saturating_mul($name::from_fraction(0.5)).0 as $upper_type,
-					$name::from_fraction(0.25).0 as $upper_type,
+					$name::from_float(0.5).saturating_mul($name::from_float(0.5)).0 as $upper_type,
+					$name::from_float(0.25).0 as $upper_type,
 					2,
 				);
 				assert_eq_error_rate!(
-					$name::from_fraction(0.2).saturating_mul($name::from_fraction(0.2)).0 as $upper_type,
-					$name::from_fraction(0.04).0 as $upper_type,
+					$name::from_float(0.2).saturating_mul($name::from_float(0.2)).0 as $upper_type,
+					$name::from_float(0.04).0 as $upper_type,
 					2,
 				);
 				assert_eq_error_rate!(
-					$name::from_fraction(0.1).saturating_mul($name::from_fraction(0.1)).0 as $upper_type,
-					$name::from_fraction(0.01).0 as $upper_type,
+					$name::from_float(0.1).saturating_mul($name::from_float(0.1)).0 as $upper_type,
+					$name::from_float(0.01).0 as $upper_type,
 					1,
 				);
 			}
 
 			#[test]
 			fn per_thing_square_works() {
-				assert_eq!($name::from_fraction(1.0).square(), $name::from_fraction(1.0));
-				assert_eq!($name::from_fraction(0.5).square(), $name::from_fraction(0.25));
-				assert_eq!($name::from_fraction(0.1).square(), $name::from_fraction(0.01));
+				assert_eq!($name::from_float(1.0).square(), $name::from_float(1.0));
+				assert_eq!($name::from_float(0.5).square(), $name::from_float(0.25));
+				assert_eq!($name::from_float(0.1).square(), $name::from_float(0.01));
 				assert_eq!(
-					$name::from_fraction(0.02).square(),
+					$name::from_float(0.02).square(),
 					$name::from_parts((4 * <$upper_type>::from($max) / 100 / 100) as $type)
 				);
 			}
@@ -1011,30 +1059,30 @@ macro_rules! implement_per_thing {
 			fn per_things_div_works() {
 				// normal
 				assert_eq_error_rate!(
-					($name::from_fraction(0.1) / $name::from_fraction(0.20)).0 as $upper_type,
-					$name::from_fraction(0.50).0 as $upper_type,
+					($name::from_float(0.1) / $name::from_float(0.20)).0 as $upper_type,
+					$name::from_float(0.50).0 as $upper_type,
 					2,
 				);
 				assert_eq_error_rate!(
-					($name::from_fraction(0.1) / $name::from_fraction(0.10)).0 as $upper_type,
-					$name::from_fraction(1.0).0 as $upper_type,
+					($name::from_float(0.1) / $name::from_float(0.10)).0 as $upper_type,
+					$name::from_float(1.0).0 as $upper_type,
 					2,
 				);
 				assert_eq_error_rate!(
-					($name::from_fraction(0.1) / $name::from_fraction(0.0)).0 as $upper_type,
-					$name::from_fraction(1.0).0 as $upper_type,
+					($name::from_float(0.1) / $name::from_float(0.0)).0 as $upper_type,
+					$name::from_float(1.0).0 as $upper_type,
 					2,
 				);
 
 				// will not overflow
 				assert_eq_error_rate!(
-					($name::from_fraction(0.10) / $name::from_fraction(0.05)).0 as $upper_type,
-					$name::from_fraction(1.0).0 as $upper_type,
+					($name::from_float(0.10) / $name::from_float(0.05)).0 as $upper_type,
+					$name::from_float(1.0).0 as $upper_type,
 					2,
 				);
 				assert_eq_error_rate!(
-					($name::from_fraction(1.0) / $name::from_fraction(0.5)).0 as $upper_type,
-					$name::from_fraction(1.0).0 as $upper_type,
+					($name::from_float(1.0) / $name::from_float(0.5)).0 as $upper_type,
+					$name::from_float(1.0).0 as $upper_type,
 					2,
 				);
 			}
diff --git a/primitives/blockchain/src/backend.rs b/primitives/blockchain/src/backend.rs
index b5efcfb02198a..b00cbada9f476 100644
--- a/primitives/blockchain/src/backend.rs
+++ b/primitives/blockchain/src/backend.rs
@@ -21,7 +21,7 @@ use std::sync::Arc;
 
 use sp_runtime::traits::{Block as BlockT, Header as HeaderT, NumberFor};
 use sp_runtime::generic::BlockId;
-use sp_runtime::Justification;
+use sp_runtime::Justifications;
 use log::warn;
 use parking_lot::RwLock;
 
@@ -84,8 +84,8 @@ pub trait HeaderBackend<Block: BlockT>: Send + Sync {
 pub trait Backend<Block: BlockT>: HeaderBackend<Block> + HeaderMetadata<Block, Error=Error> {
 	/// Get block body. Returns `None` if block is not found.
 	fn body(&self, id: BlockId<Block>) -> Result<Option<Vec<<Block as BlockT>::Extrinsic>>>;
-	/// Get block justification. Returns `None` if justification does not exist.
-	fn justification(&self, id: BlockId<Block>) -> Result<Option<Justification>>;
+	/// Get block justifications. Returns `None` if no justification exists.
+	fn justifications(&self, id: BlockId<Block>) -> Result<Option<Justifications>>;
 	/// Get last finalized block hash.
 	fn last_finalized(&self) -> Result<Block::Hash>;
 	/// Returns data cache reference, if it is enabled on this backend.
@@ -216,15 +216,16 @@ pub trait Backend<Block: BlockT>: HeaderBackend<Block> + HeaderMetadata<Block, E
 		Ok(None)
 	}
 
-	/// Get single extrinsic by hash.
-	fn extrinsic(
+	/// Get single indexed transaction by content hash. Note that this will only fetch transactions
+	/// that are indexed by the runtime with `storage_index_transaction`.
+	fn indexed_transaction(
 		&self,
 		hash: &Block::Hash,
-	) -> Result<Option<<Block as BlockT>::Extrinsic>>;
+	) -> Result<Option<Vec<u8>>>;
 
-	/// Check if extrinsic exists.
-	fn have_extrinsic(&self, hash: &Block::Hash) -> Result<bool> {
-		Ok(self.extrinsic(hash)?.is_some())
+	/// Check if indexed transaction exists.
+	fn has_indexed_transaction(&self, hash: &Block::Hash) -> Result<bool> {
+		Ok(self.indexed_transaction(hash)?.is_some())
 	}
 }
 
diff --git a/primitives/consensus/aura/Cargo.toml b/primitives/consensus/aura/Cargo.toml
index 100c323024952..105c74bb317d7 100644
--- a/primitives/consensus/aura/Cargo.toml
+++ b/primitives/consensus/aura/Cargo.toml
@@ -21,6 +21,7 @@ sp-runtime = { version = "3.0.0", default-features = false, path = "../../runtim
 sp-inherents = { version = "3.0.0", default-features = false, path = "../../inherents" }
 sp-timestamp = { version = "3.0.0", default-features = false, path = "../../timestamp" }
 sp-consensus-slots = { version = "0.9.0", default-features = false, path = "../slots" }
+sp-consensus = { version = "0.9.0", path = "../common", optional = true }
 
 [features]
 default = ["std"]
@@ -32,4 +33,6 @@ std = [
 	"sp-runtime/std",
 	"sp-inherents/std",
 	"sp-timestamp/std",
+	"sp-consensus-slots/std",
+	"sp-consensus",
 ]
diff --git a/primitives/consensus/aura/src/inherents.rs b/primitives/consensus/aura/src/inherents.rs
index 750b13c77ff66..32af901311a30 100644
--- a/primitives/consensus/aura/src/inherents.rs
+++ b/primitives/consensus/aura/src/inherents.rs
@@ -51,12 +51,12 @@ impl AuraInherentData for InherentData {
 // TODO: Remove in the future. https://github.com/paritytech/substrate/issues/8029
 #[cfg(feature = "std")]
 pub struct InherentDataProvider {
-	slot_duration: u64,
+	slot_duration: std::time::Duration,
 }
 
 #[cfg(feature = "std")]
 impl InherentDataProvider {
-	pub fn new(slot_duration: u64) -> Self {
+	pub fn new(slot_duration: std::time::Duration) -> Self {
 		Self {
 			slot_duration
 		}
@@ -88,7 +88,7 @@ impl ProvideInherentData for InherentDataProvider {
 		use sp_timestamp::TimestampInherentData;
 
 		let timestamp = inherent_data.timestamp_inherent_data()?;
-		let slot = *timestamp / self.slot_duration;
+		let slot = *timestamp / self.slot_duration.as_millis() as u64;
 		inherent_data.put_data(INHERENT_IDENTIFIER, &slot)
 	}
 
diff --git a/primitives/consensus/aura/src/lib.rs b/primitives/consensus/aura/src/lib.rs
index 8c9c57567c43f..a28e681fda27f 100644
--- a/primitives/consensus/aura/src/lib.rs
+++ b/primitives/consensus/aura/src/lib.rs
@@ -84,14 +84,39 @@ pub enum ConsensusLog<AuthorityId: Codec> {
 sp_api::decl_runtime_apis! {
 	/// API necessary for block authorship with aura.
 	pub trait AuraApi<AuthorityId: Codec> {
-		/// Return the slot duration in seconds for Aura.
-		/// Currently, only the value provided by this type at genesis
-		/// will be used.
+		/// Returns the slot duration for Aura.
 		///
-		/// Dynamic slot duration may be supported in the future.
-		fn slot_duration() -> u64;
+		/// Currently, only the value provided by this type at genesis will be used.
+		fn slot_duration() -> SlotDuration;
 
 		// Return the current set of authorities.
 		fn authorities() -> Vec<AuthorityId>;
 	}
 }
+
+/// Aura slot duration.
+///
+/// Internally stored as milliseconds.
+#[derive(sp_runtime::RuntimeDebug, Encode, Decode, PartialEq, Clone, Copy)]
+pub struct SlotDuration(u64);
+
+impl SlotDuration {
+	/// Initialize from the given milliseconds.
+	pub fn from_millis(val: u64) -> Self {
+		Self(val)
+	}
+
+	/// Returns the slot duration in milli seconds.
+	pub fn get(&self) -> u64 {
+		self.0
+	}
+}
+
+#[cfg(feature = "std")]
+impl sp_consensus::SlotData for SlotDuration {
+	fn slot_duration(&self) -> std::time::Duration {
+		std::time::Duration::from_millis(self.0)
+	}
+
+	const SLOT_KEY: &'static [u8] = b"aura_slot_duration";
+}
diff --git a/primitives/consensus/babe/src/inherents.rs b/primitives/consensus/babe/src/inherents.rs
index 8aeab94df34a2..4c7c55f1cfd55 100644
--- a/primitives/consensus/babe/src/inherents.rs
+++ b/primitives/consensus/babe/src/inherents.rs
@@ -55,13 +55,13 @@ impl BabeInherentData for InherentData {
 // TODO: Remove in the future. https://github.com/paritytech/substrate/issues/8029
 #[cfg(feature = "std")]
 pub struct InherentDataProvider {
-	slot_duration: u64,
+	slot_duration: std::time::Duration,
 }
 
 #[cfg(feature = "std")]
 impl InherentDataProvider {
 	/// Constructs `Self`
-	pub fn new(slot_duration: u64) -> Self {
+	pub fn new(slot_duration: std::time::Duration) -> Self {
 		Self { slot_duration }
 	}
 }
@@ -83,7 +83,7 @@ impl ProvideInherentData for InherentDataProvider {
 
 	fn provide_inherent_data(&self, inherent_data: &mut InherentData) -> Result<(), Error> {
 		let timestamp = inherent_data.timestamp_inherent_data()?;
-		let slot = *timestamp / self.slot_duration;
+		let slot = *timestamp / self.slot_duration.as_millis() as u64;
 		inherent_data.put_data(INHERENT_IDENTIFIER, &slot)
 	}
 
diff --git a/primitives/consensus/babe/src/lib.rs b/primitives/consensus/babe/src/lib.rs
index 1b416c996fcf0..da9f089e4561c 100644
--- a/primitives/consensus/babe/src/lib.rs
+++ b/primitives/consensus/babe/src/lib.rs
@@ -242,8 +242,8 @@ impl AllowedSlots {
 
 #[cfg(feature = "std")]
 impl sp_consensus::SlotData for BabeGenesisConfiguration {
-	fn slot_duration(&self) -> u64 {
-		self.slot_duration
+	fn slot_duration(&self) -> std::time::Duration {
+		std::time::Duration::from_millis(self.slot_duration)
 	}
 
 	const SLOT_KEY: &'static [u8] = b"babe_configuration";
diff --git a/primitives/consensus/common/Cargo.toml b/primitives/consensus/common/Cargo.toml
index 8c5ae968158a2..6c3ae5fc060bf 100644
--- a/primitives/consensus/common/Cargo.toml
+++ b/primitives/consensus/common/Cargo.toml
@@ -16,7 +16,7 @@ targets = ["x86_64-unknown-linux-gnu"]
 
 [dependencies]
 thiserror = "1.0.21"
-libp2p = { version = "0.35.1", default-features = false }
+libp2p = { version = "0.36.0", default-features = false }
 log = "0.4.8"
 sp-core = { path= "../../core", version = "3.0.0"}
 sp-inherents = { version = "3.0.0", path = "../../inherents" }
@@ -34,6 +34,7 @@ parking_lot = "0.11.1"
 serde = { version = "1.0", features = ["derive"] }
 prometheus-endpoint = { package = "substrate-prometheus-endpoint", path = "../../../utils/prometheus", version = "0.9.0"}
 wasm-timer = "0.2.5"
+async-trait = "0.1.42"
 
 [dev-dependencies]
 futures = "0.3.9"
diff --git a/primitives/consensus/common/src/block_import.rs b/primitives/consensus/common/src/block_import.rs
index 00f84501dbb32..8d01da64b4cd6 100644
--- a/primitives/consensus/common/src/block_import.rs
+++ b/primitives/consensus/common/src/block_import.rs
@@ -18,7 +18,7 @@
 //! Block import helpers.
 
 use sp_runtime::traits::{Block as BlockT, DigestItemFor, Header as HeaderT, NumberFor, HashFor};
-use sp_runtime::Justification;
+use sp_runtime::{Justification, Justifications};
 use serde::{Serialize, Deserialize};
 use std::borrow::Cow;
 use std::collections::HashMap;
@@ -128,8 +128,8 @@ pub struct BlockImportParams<Block: BlockT, Transaction> {
 	/// re-executed in a runtime that checks digest equivalence -- the
 	/// post-runtime digests are pushed back on after.
 	pub header: Block::Header,
-	/// Justification provided for this block from the outside.
-	pub justification: Option<Justification>,
+	/// Justification(s) provided for this block from the outside.
+	pub justifications: Option<Justifications>,
 	/// Digest items that have been added after the runtime for external
 	/// work, like a consensus signature.
 	pub post_digests: Vec<DigestItemFor<Block>>,
@@ -146,7 +146,7 @@ pub struct BlockImportParams<Block: BlockT, Transaction> {
 	/// Intermediate values that are interpreted by block importers. Each block importer,
 	/// upon handling a value, removes it from the intermediate list. The final block importer
 	/// rejects block import if there are still intermediate values that remain unhandled.
-	pub intermediates: HashMap<Cow<'static, [u8]>, Box<dyn Any>>,
+	pub intermediates: HashMap<Cow<'static, [u8]>, Box<dyn Any + Send>>,
 	/// Auxiliary consensus data produced by the block.
 	/// Contains a list of key-value pairs. If values are `None`, the keys
 	/// will be deleted.
@@ -174,7 +174,7 @@ impl<Block: BlockT, Transaction> BlockImportParams<Block, Transaction> {
 	) -> Self {
 		Self {
 			origin, header,
-			justification: None,
+			justifications: None,
 			post_digests: Vec::new(),
 			body: None,
 			storage_changes: None,
@@ -219,7 +219,7 @@ impl<Block: BlockT, Transaction> BlockImportParams<Block, Transaction> {
 		BlockImportParams {
 			origin: self.origin,
 			header: self.header,
-			justification: self.justification,
+			justifications: self.justifications,
 			post_digests: self.post_digests,
 			body: self.body,
 			storage_changes: None,
@@ -264,14 +264,15 @@ impl<Block: BlockT, Transaction> BlockImportParams<Block, Transaction> {
 }
 
 /// Block import trait.
+#[async_trait::async_trait]
 pub trait BlockImport<B: BlockT> {
 	/// The error type.
 	type Error: std::error::Error + Send + 'static;
 	/// The transaction type used by the backend.
-	type Transaction;
+	type Transaction: Send + 'static;
 
 	/// Check block preconditions.
-	fn check_block(
+	async fn check_block(
 		&mut self,
 		block: BlockCheckParams<B>,
 	) -> Result<ImportResult, Self::Error>;
@@ -279,56 +280,64 @@ pub trait BlockImport<B: BlockT> {
 	/// Import a block.
 	///
 	/// Cached data can be accessed through the blockchain cache.
-	fn import_block(
+	async fn import_block(
 		&mut self,
 		block: BlockImportParams<B, Self::Transaction>,
 		cache: HashMap<CacheKeyId, Vec<u8>>,
 	) -> Result<ImportResult, Self::Error>;
 }
 
-impl<B: BlockT, Transaction> BlockImport<B> for crate::import_queue::BoxBlockImport<B, Transaction> {
+#[async_trait::async_trait]
+impl<B: BlockT, Transaction> BlockImport<B> for crate::import_queue::BoxBlockImport<B, Transaction>
+	where
+		Transaction: Send + 'static,
+{
 	type Error = crate::error::Error;
 	type Transaction = Transaction;
 
 	/// Check block preconditions.
-	fn check_block(
+	async fn check_block(
 		&mut self,
 		block: BlockCheckParams<B>,
 	) -> Result<ImportResult, Self::Error> {
-		(**self).check_block(block)
+		(**self).check_block(block).await
 	}
 
 	/// Import a block.
 	///
 	/// Cached data can be accessed through the blockchain cache.
-	fn import_block(
+	async fn import_block(
 		&mut self,
 		block: BlockImportParams<B, Transaction>,
 		cache: HashMap<CacheKeyId, Vec<u8>>,
 	) -> Result<ImportResult, Self::Error> {
-		(**self).import_block(block, cache)
+		(**self).import_block(block, cache).await
 	}
 }
 
+#[async_trait::async_trait]
 impl<B: BlockT, T, E: std::error::Error + Send + 'static, Transaction> BlockImport<B> for Arc<T>
-	where for<'r> &'r T: BlockImport<B, Error = E, Transaction = Transaction>
+	where
+		for<'r> &'r T: BlockImport<B, Error = E, Transaction = Transaction>,
+		T: Send + Sync,
+		Transaction: Send + 'static,
 {
 	type Error = E;
 	type Transaction = Transaction;
 
-	fn check_block(
+	async fn check_block(
 		&mut self,
 		block: BlockCheckParams<B>,
 	) -> Result<ImportResult, Self::Error> {
-		(&**self).check_block(block)
+		(&**self).check_block(block).await
 	}
 
-	fn import_block(
+	async fn import_block(
 		&mut self,
 		block: BlockImportParams<B, Transaction>,
 		cache: HashMap<CacheKeyId, Vec<u8>>,
 	) -> Result<ImportResult, Self::Error> {
-		(&**self).import_block(block, cache)
+		(&**self).import_block(block, cache).await
 	}
 }
 
diff --git a/primitives/consensus/common/src/import_queue.rs b/primitives/consensus/common/src/import_queue.rs
index 83f6271941fab..4220c7b14162d 100644
--- a/primitives/consensus/common/src/import_queue.rs
+++ b/primitives/consensus/common/src/import_queue.rs
@@ -28,7 +28,7 @@
 
 use std::collections::HashMap;
 
-use sp_runtime::{Justification, traits::{Block as BlockT, Header as _, NumberFor}};
+use sp_runtime::{Justifications, traits::{Block as BlockT, Header as _, NumberFor}};
 
 use crate::{
 	error::Error as ConsensusError,
@@ -68,8 +68,8 @@ pub struct IncomingBlock<B: BlockT> {
 	pub header: Option<<B as BlockT>::Header>,
 	/// Block body if requested.
 	pub body: Option<Vec<<B as BlockT>::Extrinsic>>,
-	/// Justification if requested.
-	pub justification: Option<Justification>,
+	/// Justification(s) if requested.
+	pub justifications: Option<Justifications>,
 	/// The peer, we received this from
 	pub origin: Option<Origin>,
 	/// Allow importing the block skipping state verification if parent state is missing.
@@ -82,15 +82,16 @@ pub struct IncomingBlock<B: BlockT> {
 pub type CacheKeyId = [u8; 4];
 
 /// Verify a justification of a block
+#[async_trait::async_trait]
 pub trait Verifier<B: BlockT>: Send + Sync {
 	/// Verify the given data and return the BlockImportParams and an optional
 	/// new set of validators to import. If not, err with an Error-Message
 	/// presented to the User in the logs.
-	fn verify(
+	async fn verify(
 		&mut self,
 		origin: BlockOrigin,
 		header: B::Header,
-		justification: Option<Justification>,
+		justifications: Option<Justifications>,
 		body: Option<Vec<B::Extrinsic>>,
 	) -> Result<(BlockImportParams<B, ()>, Option<Vec<(CacheKeyId, Vec<u8>)>>), String>;
 }
@@ -102,13 +103,13 @@ pub trait Verifier<B: BlockT>: Send + Sync {
 pub trait ImportQueue<B: BlockT>: Send {
 	/// Import bunch of blocks.
 	fn import_blocks(&mut self, origin: BlockOrigin, blocks: Vec<IncomingBlock<B>>);
-	/// Import a block justification.
-	fn import_justification(
+	/// Import block justifications.
+	fn import_justifications(
 		&mut self,
 		who: Origin,
 		hash: B::Hash,
 		number: NumberFor<B>,
-		justification: Justification
+		justifications: Justifications
 	);
 	/// Polls for actions to perform on the network.
 	///
@@ -163,18 +164,18 @@ pub enum BlockImportError {
 }
 
 /// Single block import function.
-pub fn import_single_block<B: BlockT, V: Verifier<B>, Transaction>(
-	import_handle: &mut dyn BlockImport<B, Transaction = Transaction, Error = ConsensusError>,
+pub async fn import_single_block<B: BlockT, V: Verifier<B>, Transaction: Send + 'static>(
+	import_handle: &mut impl BlockImport<B, Transaction = Transaction, Error = ConsensusError>,
 	block_origin: BlockOrigin,
 	block: IncomingBlock<B>,
 	verifier: &mut V,
 ) -> Result<BlockImportResult<NumberFor<B>>, BlockImportError> {
-	import_single_block_metered(import_handle, block_origin, block, verifier, None)
+	import_single_block_metered(import_handle, block_origin, block, verifier, None).await
 }
 
 /// Single block import function with metering.
-pub(crate) fn import_single_block_metered<B: BlockT, V: Verifier<B>, Transaction>(
-	import_handle: &mut dyn BlockImport<B, Transaction = Transaction, Error = ConsensusError>,
+pub(crate) async fn import_single_block_metered<B: BlockT, V: Verifier<B>, Transaction: Send + 'static>(
+	import_handle: &mut impl BlockImport<B, Transaction = Transaction, Error = ConsensusError>,
 	block_origin: BlockOrigin,
 	block: IncomingBlock<B>,
 	verifier: &mut V,
@@ -182,8 +183,8 @@ pub(crate) fn import_single_block_metered<B: BlockT, V: Verifier<B>, Transaction
 ) -> Result<BlockImportResult<NumberFor<B>>, BlockImportError> {
 	let peer = block.origin;
 
-	let (header, justification) = match (block.header, block.justification) {
-		(Some(header), justification) => (header, justification),
+	let (header, justifications) = match (block.header, block.justifications) {
+		(Some(header), justifications) => (header, justifications),
 		(None, _) => {
 			if let Some(ref peer) = peer {
 				debug!(target: "sync", "Header {} was not provided by {} ", block.hash, peer);
@@ -232,24 +233,28 @@ pub(crate) fn import_single_block_metered<B: BlockT, V: Verifier<B>, Transaction
 		parent_hash,
 		allow_missing_state: block.allow_missing_state,
 		import_existing: block.import_existing,
-	}))? {
+	}).await)? {
 		BlockImportResult::ImportedUnknown { .. } => (),
 		r => return Ok(r), // Any other successful result means that the block is already imported.
 	}
 
 	let started = wasm_timer::Instant::now();
-	let (mut import_block, maybe_keys) = verifier.verify(block_origin, header, justification, block.body)
-		.map_err(|msg| {
-			if let Some(ref peer) = peer {
-				trace!(target: "sync", "Verifying {}({}) from {} failed: {}", number, hash, peer, msg);
-			} else {
-				trace!(target: "sync", "Verifying {}({}) failed: {}", number, hash, msg);
-			}
-			if let Some(metrics) = metrics.as_ref() {
-				metrics.report_verification(false, started.elapsed());
-			}
-			BlockImportError::VerificationFailed(peer.clone(), msg)
-		})?;
+	let (mut import_block, maybe_keys) = verifier.verify(
+		block_origin,
+		header,
+		justifications,
+		block.body
+	).await.map_err(|msg| {
+		if let Some(ref peer) = peer {
+			trace!(target: "sync", "Verifying {}({}) from {} failed: {}", number, hash, peer, msg);
+		} else {
+			trace!(target: "sync", "Verifying {}({}) failed: {}", number, hash, msg);
+		}
+		if let Some(metrics) = metrics.as_ref() {
+			metrics.report_verification(false, started.elapsed());
+		}
+		BlockImportError::VerificationFailed(peer.clone(), msg)
+	})?;
 
 	if let Some(metrics) = metrics.as_ref() {
 		metrics.report_verification(true, started.elapsed());
@@ -261,7 +266,7 @@ pub(crate) fn import_single_block_metered<B: BlockT, V: Verifier<B>, Transaction
 	}
 	import_block.allow_missing_state = block.allow_missing_state;
 
-	let imported = import_handle.import_block(import_block.convert_transaction(), cache);
+	let imported = import_handle.import_block(import_block.convert_transaction(), cache).await;
 	if let Some(metrics) = metrics.as_ref() {
 		metrics.report_verification_and_import(started.elapsed());
 	}
diff --git a/primitives/consensus/common/src/import_queue/basic_queue.rs b/primitives/consensus/common/src/import_queue/basic_queue.rs
index f1b42e1460e59..7998ba1b3ec76 100644
--- a/primitives/consensus/common/src/import_queue/basic_queue.rs
+++ b/primitives/consensus/common/src/import_queue/basic_queue.rs
@@ -18,7 +18,7 @@
 use std::{pin::Pin, time::Duration, marker::PhantomData};
 use futures::{prelude::*, task::Context, task::Poll};
 use futures_timer::Delay;
-use sp_runtime::{Justification, traits::{Block as BlockT, Header as HeaderT, NumberFor}};
+use sp_runtime::{Justification, Justifications, traits::{Block as BlockT, Header as HeaderT, NumberFor}};
 use sp_utils::mpsc::{TracingUnboundedSender, tracing_unbounded, TracingUnboundedReceiver};
 use prometheus_endpoint::Registry;
 
@@ -112,22 +112,24 @@ impl<B: BlockT, Transaction: Send> ImportQueue<B> for BasicQueue<B, Transaction>
 		}
 	}
 
-	fn import_justification(
+	fn import_justifications(
 		&mut self,
 		who: Origin,
 		hash: B::Hash,
 		number: NumberFor<B>,
-		justification: Justification,
+		justifications: Justifications,
 	) {
-		let res = self.justification_sender.unbounded_send(
-			worker_messages::ImportJustification(who, hash, number, justification),
-		);
-
-		if res.is_err() {
-			log::error!(
-				target: "sync",
-				"import_justification: Background import task is no longer alive"
+		for justification in justifications {
+			let res = self.justification_sender.unbounded_send(
+				worker_messages::ImportJustification(who, hash, number, justification),
 			);
+
+			if res.is_err() {
+				log::error!(
+					target: "sync",
+					"import_justification: Background import task is no longer alive"
+				);
+			}
 		}
 	}
 
@@ -153,7 +155,7 @@ mod worker_messages {
 /// to be run.
 ///
 /// Returns when `block_import` ended.
-async fn block_import_process<B: BlockT, Transaction: Send>(
+async fn block_import_process<B: BlockT, Transaction: Send + 'static>(
 	mut block_import: BoxBlockImport<B, Transaction>,
 	mut verifier: impl Verifier<B>,
 	mut result_sender: BufferedLinkSender<B>,
@@ -193,7 +195,7 @@ struct BlockImportWorker<B: BlockT> {
 }
 
 impl<B: BlockT> BlockImportWorker<B> {
-	fn new<V: 'static + Verifier<B>, Transaction: Send>(
+	fn new<V: 'static + Verifier<B>, Transaction: Send + 'static>(
 		result_sender: BufferedLinkSender<B>,
 		verifier: V,
 		block_import: BoxBlockImport<B, Transaction>,
@@ -281,7 +283,7 @@ impl<B: BlockT> BlockImportWorker<B> {
 		who: Origin,
 		hash: B::Hash,
 		number: NumberFor<B>,
-		justification: Justification
+		justification: Justification,
 	) {
 		let started = wasm_timer::Instant::now();
 		let success = self.justification_import.as_mut().map(|justification_import| {
@@ -320,7 +322,7 @@ struct ImportManyBlocksResult<B: BlockT> {
 /// Import several blocks at once, returning import result for each block.
 ///
 /// This will yield after each imported block once, to ensure that other futures can be called as well.
-async fn import_many_blocks<B: BlockT, V: Verifier<B>, Transaction>(
+async fn import_many_blocks<B: BlockT, V: Verifier<B>, Transaction: Send + 'static>(
 	import_handle: &mut BoxBlockImport<B, Transaction>,
 	blocks_origin: BlockOrigin,
 	blocks: Vec<IncomingBlock<B>>,
@@ -369,7 +371,7 @@ async fn import_many_blocks<B: BlockT, V: Verifier<B>, Transaction>(
 				block,
 				verifier,
 				metrics.clone(),
-			)
+			).await
 		};
 
 		if let Some(metrics) = metrics.as_ref() {
@@ -437,30 +439,32 @@ mod tests {
 	use sp_test_primitives::{Block, BlockNumber, Extrinsic, Hash, Header};
 	use std::collections::HashMap;
 
+	#[async_trait::async_trait]
 	impl Verifier<Block> for () {
-		fn verify(
+		async fn verify(
 			&mut self,
 			origin: BlockOrigin,
 			header: Header,
-			_justification: Option<Justification>,
+			_justifications: Option<Justifications>,
 			_body: Option<Vec<Extrinsic>>,
 		) -> Result<(BlockImportParams<Block, ()>, Option<Vec<(CacheKeyId, Vec<u8>)>>), String> {
 			Ok((BlockImportParams::new(origin, header), None))
 		}
 	}
 
+	#[async_trait::async_trait]
 	impl BlockImport<Block> for () {
 		type Error = crate::Error;
 		type Transaction = Extrinsic;
 
-		fn check_block(
+		async fn check_block(
 			&mut self,
 			_block: BlockCheckParams<Block>,
 		) -> Result<ImportResult, Self::Error> {
 			Ok(ImportResult::imported(false))
 		}
 
-		fn import_block(
+		async fn import_block(
 			&mut self,
 			_block: BlockImportParams<Block, Self::Transaction>,
 			_cache: HashMap<CacheKeyId, Vec<u8>>,
@@ -541,7 +545,7 @@ mod tests {
 					hash,
 					header: Some(header),
 					body: None,
-					justification: None,
+					justifications: None,
 					origin: None,
 					allow_missing_state: false,
 					import_existing: false,
@@ -554,12 +558,11 @@ mod tests {
 
 		let mut import_justification = || {
 			let hash = Hash::random();
-
 			block_on(finality_sender.send(worker_messages::ImportJustification(
 				libp2p::PeerId::random(),
 				hash,
 				1,
-				Vec::new(),
+				(*b"TEST", Vec::new()),
 			)))
 			.unwrap();
 
diff --git a/primitives/consensus/common/src/lib.rs b/primitives/consensus/common/src/lib.rs
index b3aceb45e180f..27a43dbe02208 100644
--- a/primitives/consensus/common/src/lib.rs
+++ b/primitives/consensus/common/src/lib.rs
@@ -303,16 +303,8 @@ impl<Block: BlockT> CanAuthorWith<Block> for NeverCanAuthor {
 /// A type from which a slot duration can be obtained.
 pub trait SlotData {
 	/// Gets the slot duration.
-	fn slot_duration(&self) -> u64;
+	fn slot_duration(&self) -> sp_std::time::Duration;
 
 	/// The static slot key
 	const SLOT_KEY: &'static [u8];
 }
-
-impl SlotData for u64 {
-	fn slot_duration(&self) -> u64 {
-		*self
-	}
-
-	const SLOT_KEY: &'static [u8] = b"aura_slot_duration";
-}
diff --git a/primitives/core/src/crypto.rs b/primitives/core/src/crypto.rs
index 95192acc4cb17..aedfbd748650c 100644
--- a/primitives/core/src/crypto.rs
+++ b/primitives/core/src/crypto.rs
@@ -586,8 +586,9 @@ ss58_address_format!(
 		(65, "aventus", "Aventus Chain mainnet, standard account (*25519).")
 	CrustAccount =>
 		(66, "crust", "Crust Network, standard account (*25519).")
+	SocialAccount =>
+		(252, "social-network", "Social Network, standard account (*25519).")
 	// Note: 16384 and above are reserved.
-
 );
 
 /// Set the default "version" (actually, this is a bit of a misnomer and the version byte is
diff --git a/primitives/database/Cargo.toml b/primitives/database/Cargo.toml
index 4062ba292352f..aae7668b5ec80 100644
--- a/primitives/database/Cargo.toml
+++ b/primitives/database/Cargo.toml
@@ -13,3 +13,4 @@ readme = "README.md"
 [dependencies]
 parking_lot = "0.11.1"
 kvdb = "0.9.0"
+
diff --git a/primitives/database/src/kvdb.rs b/primitives/database/src/kvdb.rs
index b50ca53786f9f..d99fe6360ef7b 100644
--- a/primitives/database/src/kvdb.rs
+++ b/primitives/database/src/kvdb.rs
@@ -33,18 +33,73 @@ fn handle_err<T>(result: std::io::Result<T>) -> T {
 }
 
 /// Wrap RocksDb database into a trait object that implements `sp_database::Database`
-pub fn as_database<D: KeyValueDB + 'static, H: Clone>(db: D) -> std::sync::Arc<dyn Database<H>> {
+pub fn as_database<D, H>(db: D) -> std::sync::Arc<dyn Database<H>>
+	where D: KeyValueDB + 'static, H: Clone + AsRef<[u8]>
+{
 	std::sync::Arc::new(DbAdapter(db))
 }
 
-impl<D: KeyValueDB, H: Clone> Database<H> for DbAdapter<D> {
+impl <D: KeyValueDB> DbAdapter<D> {
+	// Returns counter key and counter value if it exists.
+	fn read_counter(&self, col: ColumnId, key: &[u8]) -> error::Result<(Vec<u8>, Option<u32>)> {
+		// Add a key suffix for the counter
+		let mut counter_key = key.to_vec();
+		counter_key.push(0);
+		Ok(match self.0.get(col, &counter_key).map_err(|e| error::DatabaseError(Box::new(e)))? {
+			Some(data) => {
+				let mut counter_data = [0; 4];
+				if data.len() != 4 {
+					return Err(error::DatabaseError(Box::new(
+								std::io::Error::new(std::io::ErrorKind::Other,
+									format!("Unexpected counter len {}", data.len())))
+					))
+				}
+				counter_data.copy_from_slice(&data);
+				let counter = u32::from_le_bytes(counter_data);
+				(counter_key, Some(counter))
+			},
+			None => (counter_key, None)
+		})
+	}
+}
+
+impl<D: KeyValueDB, H: Clone + AsRef<[u8]>> Database<H> for DbAdapter<D> {
 	fn commit(&self, transaction: Transaction<H>) -> error::Result<()> {
 		let mut tx = DBTransaction::new();
 		for change in transaction.0.into_iter() {
 			match change {
 				Change::Set(col, key, value) => tx.put_vec(col, &key, value),
 				Change::Remove(col, key) => tx.delete(col, &key),
-				_ => unimplemented!(),
+				Change::Store(col, key, value) => {
+					match self.read_counter(col, key.as_ref())? {
+						(counter_key, Some(mut counter)) => {
+							counter += 1;
+							tx.put(col, &counter_key, &counter.to_le_bytes());
+						},
+						(counter_key, None) => {
+							let d = 1u32.to_le_bytes();
+							tx.put(col, &counter_key, &d);
+							tx.put_vec(col, key.as_ref(), value);
+						},
+					}
+				}
+				Change::Reference(col, key) => {
+					if let (counter_key, Some(mut counter)) = self.read_counter(col, key.as_ref())? {
+						counter += 1;
+						tx.put(col, &counter_key, &counter.to_le_bytes());
+					}
+				}
+				Change::Release(col, key) => {
+					if let (counter_key, Some(mut counter)) = self.read_counter(col, key.as_ref())? {
+						counter -= 1;
+						if counter == 0 {
+							tx.delete(col, &counter_key);
+							tx.delete(col, key.as_ref());
+						} else {
+							tx.put(col, &counter_key, &counter.to_le_bytes());
+						}
+					}
+				}
 			}
 		}
 		self.0.write(tx).map_err(|e| error::DatabaseError(Box::new(e)))
@@ -54,7 +109,7 @@ impl<D: KeyValueDB, H: Clone> Database<H> for DbAdapter<D> {
 		handle_err(self.0.get(col, key))
 	}
 
-	fn lookup(&self, _hash: &H) -> Option<Vec<u8>> {
-		unimplemented!();
+	fn contains(&self, col: ColumnId, key: &[u8]) -> bool {
+		handle_err(self.0.has_key(col, key))
 	}
 }
diff --git a/primitives/database/src/lib.rs b/primitives/database/src/lib.rs
index 7107ea25c02c0..1fa0c8e49b015 100644
--- a/primitives/database/src/lib.rs
+++ b/primitives/database/src/lib.rs
@@ -32,16 +32,9 @@ pub type ColumnId = u32;
 pub enum Change<H> {
 	Set(ColumnId, Vec<u8>, Vec<u8>),
 	Remove(ColumnId, Vec<u8>),
-	Store(H, Vec<u8>),
-	Release(H),
-}
-
-/// An alteration to the database that references the data.
-pub enum ChangeRef<'a, H> {
-	Set(ColumnId, &'a [u8], &'a [u8]),
-	Remove(ColumnId, &'a [u8]),
-	Store(H, &'a [u8]),
-	Release(H),
+	Store(ColumnId, H, Vec<u8>),
+	Reference(ColumnId, H),
+	Release(ColumnId, H),
 }
 
 /// A series of changes to the database that can be committed atomically. They do not take effect
@@ -67,49 +60,27 @@ impl<H> Transaction<H> {
 		self.0.push(Change::Remove(col, key.to_vec()))
 	}
 	/// Store the `preimage` of `hash` into the database, so that it may be looked up later with
-	/// `Database::lookup`. This may be called multiple times, but `Database::lookup` but subsequent
+	/// `Database::get`. This may be called multiple times, but subsequent
 	/// calls will ignore `preimage` and simply increase the number of references on `hash`.
-	pub fn store(&mut self, hash: H, preimage: &[u8]) {
-		self.0.push(Change::Store(hash, preimage.to_vec()))
+	pub fn store(&mut self, col: ColumnId, hash: H, preimage: Vec<u8>) {
+		self.0.push(Change::Store(col, hash, preimage))
+	}
+	/// Increase the number of references for `hash` in the database.
+	pub fn reference(&mut self, col: ColumnId, hash: H) {
+		self.0.push(Change::Reference(col, hash))
 	}
 	/// Release the preimage of `hash` from the database. An equal number of these to the number of
-	/// corresponding `store`s must have been given before it is legal for `Database::lookup` to
+	/// corresponding `store`s must have been given before it is legal for `Database::get` to
 	/// be unable to provide the preimage.
-	pub fn release(&mut self, hash: H) {
-		self.0.push(Change::Release(hash))
+	pub fn release(&mut self, col: ColumnId, hash: H) {
+		self.0.push(Change::Release(col, hash))
 	}
 }
 
-pub trait Database<H: Clone>: Send + Sync {
+pub trait Database<H: Clone + AsRef<[u8]>>: Send + Sync {
 	/// Commit the `transaction` to the database atomically. Any further calls to `get` or `lookup`
 	/// will reflect the new state.
-	fn commit(&self, transaction: Transaction<H>) -> error::Result<()> {
-		for change in transaction.0.into_iter() {
-			match change {
-				Change::Set(col, key, value) => self.set(col, &key, &value),
-				Change::Remove(col, key) => self.remove(col, &key),
-				Change::Store(hash, preimage) => self.store(&hash, &preimage),
-				Change::Release(hash) => self.release(&hash),
-			}?;
-		}
-
-		Ok(())
-	}
-
-	/// Commit the `transaction` to the database atomically. Any further calls to `get` or `lookup`
-	/// will reflect the new state.
-	fn commit_ref<'a>(&self, transaction: &mut dyn Iterator<Item=ChangeRef<'a, H>>) -> error::Result<()> {
-		let mut tx = Transaction::new();
-		for change in transaction {
-			match change {
-				ChangeRef::Set(col, key, value) => tx.set(col, key, value),
-				ChangeRef::Remove(col, key) => tx.remove(col, key),
-				ChangeRef::Store(hash, preimage) => tx.store(hash, preimage),
-				ChangeRef::Release(hash) => tx.release(hash),
-			}
-		}
-		self.commit(tx)
-	}
+	fn commit(&self, transaction: Transaction<H>) -> error::Result<()>;
 
 	/// Retrieve the value previously stored against `key` or `None` if
 	/// `key` is not currently in the database.
@@ -120,6 +91,11 @@ pub trait Database<H: Clone>: Send + Sync {
 		self.get(col, key).is_some()
 	}
 
+	/// Check value size in the database possibly without retrieving it.
+	fn value_size(&self, col: ColumnId, key: &[u8]) -> Option<usize> {
+		self.get(col, key).map(|v| v.len())
+	}
+
 	/// Call `f` with the value previously stored against `key`.
 	///
 	/// This may be faster than `get` since it doesn't allocate.
@@ -127,50 +103,6 @@ pub trait Database<H: Clone>: Send + Sync {
 	fn with_get(&self, col: ColumnId, key: &[u8], f: &mut dyn FnMut(&[u8])) {
 		self.get(col, key).map(|v| f(&v));
 	}
-
-	/// Set the value of `key` in `col` to `value`, replacing anything that is there currently.
-	fn set(&self, col: ColumnId, key: &[u8], value: &[u8]) -> error::Result<()> {
-		let mut t = Transaction::new();
-		t.set(col, key, value);
-		self.commit(t)
-	}
-	/// Remove the value of `key` in `col`.
-	fn remove(&self, col: ColumnId, key: &[u8]) -> error::Result<()> {
-		let mut t = Transaction::new();
-		t.remove(col, key);
-		self.commit(t)
-	}
-
-	/// Retrieve the first preimage previously `store`d for `hash` or `None` if no preimage is
-	/// currently stored.
-	fn lookup(&self, hash: &H) -> Option<Vec<u8>>;
-
-	/// Call `f` with the preimage stored for `hash` and return the result, or `None` if no preimage
-	/// is currently stored.
-	///
-	/// This may be faster than `lookup` since it doesn't allocate.
-	/// Use `with_lookup` helper function if you need `f` to return a value from `f`
-	fn with_lookup(&self, hash: &H, f: &mut dyn FnMut(&[u8])) {
-		self.lookup(hash).map(|v| f(&v));
-	}
-
-	/// Store the `preimage` of `hash` into the database, so that it may be looked up later with
-	/// `Database::lookup`. This may be called multiple times, but `Database::lookup` but subsequent
-	/// calls will ignore `preimage` and simply increase the number of references on `hash`.
-	fn store(&self, hash: &H, preimage: &[u8]) -> error::Result<()> {
-		let mut t = Transaction::new();
-		t.store(hash.clone(), preimage);
-		self.commit(t)
-	}
-
-	/// Release the preimage of `hash` from the database. An equal number of these to the number of
-	/// corresponding `store`s must have been given before it is legal for `Database::lookup` to
-	/// be unable to provide the preimage.
-	fn release(&self, hash: &H) -> error::Result<()> {
-		let mut t = Transaction::new();
-		t.release(hash.clone());
-		self.commit(t)
-	}
 }
 
 impl<H> std::fmt::Debug for dyn Database<H> {
@@ -183,20 +115,13 @@ impl<H> std::fmt::Debug for dyn Database<H> {
 /// `key` is not currently in the database.
 ///
 /// This may be faster than `get` since it doesn't allocate.
-pub fn with_get<R, H: Clone>(db: &dyn Database<H>, col: ColumnId, key: &[u8], mut f: impl FnMut(&[u8]) -> R) -> Option<R> {
+pub fn with_get<R, H: Clone + AsRef<[u8]>>(
+	db: &dyn Database<H>,
+	col: ColumnId,
+	key: &[u8], mut f: impl FnMut(&[u8]) -> R
+) -> Option<R> {
 	let mut result: Option<R> = None;
 	let mut adapter = |k: &_| { result = Some(f(k)); };
 	db.with_get(col, key, &mut adapter);
 	result
 }
-
-/// Call `f` with the preimage stored for `hash` and return the result, or `None` if no preimage
-/// is currently stored.
-///
-/// This may be faster than `lookup` since it doesn't allocate.
-pub fn with_lookup<R, H: Clone>(db: &dyn Database<H>, hash: &H, mut f: impl FnMut(&[u8]) -> R) -> Option<R> {
-	let mut result: Option<R> = None;
-	let mut adapter = |k: &_| { result = Some(f(k)); };
-	db.with_lookup(hash, &mut adapter);
-	result
-}
diff --git a/primitives/database/src/mem.rs b/primitives/database/src/mem.rs
index 41af2e2f235c0..24ddf03319711 100644
--- a/primitives/database/src/mem.rs
+++ b/primitives/database/src/mem.rs
@@ -17,26 +17,41 @@
 
 //! In-memory implementation of `Database`
 
-use std::collections::HashMap;
+use std::collections::{HashMap, hash_map::Entry};
 use crate::{Database, Change, ColumnId, Transaction, error};
 use parking_lot::RwLock;
 
 #[derive(Default)]
 /// This implements `Database` as an in-memory hash map. `commit` is not atomic.
-pub struct MemDb<H: Clone + Send + Sync + Eq + PartialEq + Default + std::hash::Hash>
-	(RwLock<(HashMap<ColumnId, HashMap<Vec<u8>, Vec<u8>>>, HashMap<H, Vec<u8>>)>);
+pub struct MemDb(RwLock<HashMap<ColumnId, HashMap<Vec<u8>, (u32, Vec<u8>)>>>);
 
-impl<H> Database<H> for MemDb<H>
-	where H: Clone + Send + Sync + Eq + PartialEq + Default + std::hash::Hash
+impl<H> Database<H> for MemDb
+	where H: Clone + AsRef<[u8]>
 {
 	fn commit(&self, transaction: Transaction<H>) -> error::Result<()> {
 		let mut s = self.0.write();
 		for change in transaction.0.into_iter() {
 			match change {
-				Change::Set(col, key, value) => { s.0.entry(col).or_default().insert(key, value); },
-				Change::Remove(col, key) => { s.0.entry(col).or_default().remove(&key); },
-				Change::Store(hash, preimage) => { s.1.insert(hash, preimage); },
-				Change::Release(hash) => { s.1.remove(&hash); },
+				Change::Set(col, key, value) => { s.entry(col).or_default().insert(key, (1, value)); },
+				Change::Remove(col, key) => { s.entry(col).or_default().remove(&key); },
+				Change::Store(col, hash, value) => {
+					s.entry(col).or_default().entry(hash.as_ref().to_vec())
+						.and_modify(|(c, _)| *c += 1)
+						.or_insert_with(|| (1, value));
+				},
+				Change::Reference(col, hash) => {
+					if let Entry::Occupied(mut entry) = s.entry(col).or_default().entry(hash.as_ref().to_vec()) {
+						entry.get_mut().0 += 1;
+					}
+				}
+				Change::Release(col, hash) => {
+					if let Entry::Occupied(mut entry) = s.entry(col).or_default().entry(hash.as_ref().to_vec()) {
+						entry.get_mut().0 -= 1;
+						if entry.get().0 == 0 {
+							entry.remove();
+						}
+					}
+				}
 			}
 		}
 
@@ -45,18 +60,11 @@ impl<H> Database<H> for MemDb<H>
 
 	fn get(&self, col: ColumnId, key: &[u8]) -> Option<Vec<u8>> {
 		let s = self.0.read();
-		s.0.get(&col).and_then(|c| c.get(key).cloned())
-	}
-
-	fn lookup(&self, hash: &H) -> Option<Vec<u8>> {
-		let s = self.0.read();
-		s.1.get(hash).cloned()
+		s.get(&col).and_then(|c| c.get(key).map(|(_, v)| v.clone()))
 	}
 }
 
-impl<H> MemDb<H>
-	where H: Clone + Send + Sync + Eq + PartialEq + Default + std::hash::Hash
-{
+impl MemDb {
 	/// Create a new instance
 	pub fn new() -> Self {
 		MemDb::default()
@@ -65,7 +73,7 @@ impl<H> MemDb<H>
 	/// Count number of values in a column
 	pub fn count(&self, col: ColumnId) -> usize {
 		let s = self.0.read();
-		s.0.get(&col).map(|c| c.len()).unwrap_or(0)
+		s.get(&col).map(|c| c.len()).unwrap_or(0)
 	}
 }
 
diff --git a/primitives/externalities/src/lib.rs b/primitives/externalities/src/lib.rs
index 3ee37f5e31b93..1077f41048d59 100644
--- a/primitives/externalities/src/lib.rs
+++ b/primitives/externalities/src/lib.rs
@@ -228,6 +228,16 @@ pub trait Externalities: ExtensionStore {
 	/// no transaction is open that can be closed.
 	fn storage_commit_transaction(&mut self) -> Result<(), ()>;
 
+	/// Index specified transaction slice and store it.
+	fn storage_index_transaction(&mut self, _index: u32, _offset: u32) {
+		unimplemented!("storage_index_transaction");
+	}
+
+	/// Renew existing piece of transaction storage.
+	fn storage_renew_transaction_index(&mut self, _index: u32, _hash: &[u8], _size: u32) {
+		unimplemented!("storage_renew_transaction_index");
+	}
+
 	/// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 	/// Benchmarking related functionality and shouldn't be used anywhere else!
 	/// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
diff --git a/primitives/npos-elections/compact/Cargo.toml b/primitives/npos-elections/compact/Cargo.toml
index e2fff8e2db010..63432a36efc80 100644
--- a/primitives/npos-elections/compact/Cargo.toml
+++ b/primitives/npos-elections/compact/Cargo.toml
@@ -19,3 +19,9 @@ syn = { version = "1.0.58", features = ["full", "visit"] }
 quote = "1.0"
 proc-macro2 = "1.0.6"
 proc-macro-crate = "1.0.0"
+
+[dev-dependencies]
+parity-scale-codec = "2.0.1"
+sp-arithmetic = { path = "../../arithmetic" }
+sp-npos-elections = { path = ".." }
+trybuild = "1.0.41"
diff --git a/primitives/npos-elections/compact/src/assignment.rs b/primitives/npos-elections/compact/src/assignment.rs
index 12f5ca2b41735..2c8edefbfb379 100644
--- a/primitives/npos-elections/compact/src/assignment.rs
+++ b/primitives/npos-elections/compact/src/assignment.rs
@@ -125,7 +125,7 @@ pub(crate) fn into_impl(count: usize, per_thing: syn::Type) -> TokenStream2 {
 						let target = target_at(*t_idx).or_invalid_index()?;
 						Ok((target, *p))
 					})
-					.collect::<Result<Vec<(A, #per_thing)>, _npos::Error>>()?;
+					.collect::<Result<_npos::sp_std::prelude::Vec<(A, #per_thing)>, _npos::Error>>()?;
 
 				if sum >= #per_thing::one() {
 					return Err(_npos::Error::CompactStakeOverflow);
diff --git a/primitives/npos-elections/compact/src/codec.rs b/primitives/npos-elections/compact/src/codec.rs
index 6e8d4d9277dbd..f75f99682711c 100644
--- a/primitives/npos-elections/compact/src/codec.rs
+++ b/primitives/npos-elections/compact/src/codec.rs
@@ -49,14 +49,14 @@ fn decode_impl(
 		quote! {
 			let #name =
 			<
-				Vec<(_npos::codec::Compact<#voter_type>, _npos::codec::Compact<#target_type>)>
+				_npos::sp_std::prelude::Vec<(_npos::codec::Compact<#voter_type>, _npos::codec::Compact<#target_type>)>
 				as
 				_npos::codec::Decode
 			>::decode(value)?;
 			let #name = #name
 				.into_iter()
 				.map(|(v, t)| (v.0, t.0))
-				.collect::<Vec<_>>();
+				.collect::<_npos::sp_std::prelude::Vec<_>>();
 		}
 	};
 
@@ -65,7 +65,7 @@ fn decode_impl(
 		quote! {
 			let #name =
 			<
-				Vec<(
+				_npos::sp_std::prelude::Vec<(
 					_npos::codec::Compact<#voter_type>,
 					(_npos::codec::Compact<#target_type>, _npos::codec::Compact<#weight_type>),
 					_npos::codec::Compact<#target_type>,
@@ -76,7 +76,7 @@ fn decode_impl(
 			let #name = #name
 				.into_iter()
 				.map(|(v, (t1, w), t2)| (v.0, (t1.0, w.0), t2.0))
-				.collect::<Vec<_>>();
+				.collect::<_npos::sp_std::prelude::Vec<_>>();
 		}
 	};
 
@@ -90,7 +90,7 @@ fn decode_impl(
 		quote! {
 			let #name =
 			<
-				Vec<(
+				_npos::sp_std::prelude::Vec<(
 					_npos::codec::Compact<#voter_type>,
 					[(_npos::codec::Compact<#target_type>, _npos::codec::Compact<#weight_type>); #c-1],
 					_npos::codec::Compact<#target_type>,
@@ -104,7 +104,7 @@ fn decode_impl(
 					[ #inner_impl ],
 					t_last.0,
 				))
-				.collect::<Vec<_>>();
+				.collect::<_npos::sp_std::prelude::Vec<_>>();
 		}
 	}).collect::<TokenStream2>();
 
@@ -142,7 +142,7 @@ fn encode_impl(ident: syn::Ident, count: usize) -> TokenStream2 {
 					_npos::codec::Compact(v.clone()),
 					_npos::codec::Compact(t.clone()),
 				))
-				.collect::<Vec<_>>();
+				.collect::<_npos::sp_std::prelude::Vec<_>>();
 			#name.encode_to(&mut r);
 		}
 	};
@@ -160,7 +160,7 @@ fn encode_impl(ident: syn::Ident, count: usize) -> TokenStream2 {
 					),
 					_npos::codec::Compact(t2.clone()),
 				))
-				.collect::<Vec<_>>();
+				.collect::<_npos::sp_std::prelude::Vec<_>>();
 			#name.encode_to(&mut r);
 		}
 	};
@@ -184,14 +184,14 @@ fn encode_impl(ident: syn::Ident, count: usize) -> TokenStream2 {
 					[ #inners_compact_array ],
 					_npos::codec::Compact(t_last.clone()),
 				))
-				.collect::<Vec<_>>();
+				.collect::<_npos::sp_std::prelude::Vec<_>>();
 			#name.encode_to(&mut r);
 		}
 	}).collect::<TokenStream2>();
 
 	quote!(
 		impl _npos::codec::Encode for #ident {
-			fn encode(&self) -> Vec<u8> {
+			fn encode(&self) -> _npos::sp_std::prelude::Vec<u8> {
 				let mut r = vec![];
 				#encode_impl_single
 				#encode_impl_double
diff --git a/primitives/npos-elections/compact/src/lib.rs b/primitives/npos-elections/compact/src/lib.rs
index ed1837bae18b1..e558ae89ca93e 100644
--- a/primitives/npos-elections/compact/src/lib.rs
+++ b/primitives/npos-elections/compact/src/lib.rs
@@ -52,8 +52,14 @@ pub(crate) fn syn_err(message: &'static str) -> syn::Error {
 /// For example, the following generates a public struct with name `TestSolution` with `u16` voter
 /// type, `u8` target type and `Perbill` accuracy with maximum of 8 edges per voter.
 ///
-/// ```ignore
-/// generate_solution_type!(pub struct TestSolution<u16, u8, Perbill>::(8))
+/// ```
+/// # use sp_npos_elections_compact::generate_solution_type;
+/// # use sp_arithmetic::per_things::Perbill;
+/// generate_solution_type!(pub struct TestSolution::<
+/// 	VoterIndex = u16,
+/// 	TargetIndex = u8,
+/// 	Accuracy = Perbill,
+/// >(8));
 /// ```
 ///
 /// The given struct provides function to convert from/to Assignment:
@@ -65,11 +71,13 @@ pub(crate) fn syn_err(message: &'static str) -> syn::Error {
 /// lead to many 0s in the solution. If prefixed with `#[compact]`, then a custom compact encoding
 /// for numbers will be used, similar to how `parity-scale-codec`'s `Compact` works.
 ///
-/// ```ignore
+/// ```
+/// # use sp_npos_elections_compact::generate_solution_type;
+/// # use sp_arithmetic::per_things::Perbill;
 /// generate_solution_type!(
 ///     #[compact]
-///     pub struct TestSolutionCompact<u16, u8, Perbill>::(8)
-/// )
+///     pub struct TestSolutionCompact::<VoterIndex = u16, TargetIndex = u8, Accuracy = Perbill>(8)
+/// );
 /// ```
 #[proc_macro]
 pub fn generate_solution_type(item: TokenStream) -> TokenStream {
@@ -119,14 +127,14 @@ fn struct_def(
 		let name = field_name_for(1);
 		// NOTE: we use the visibility of the struct for the fields as well.. could be made better.
 		quote!(
-			#vis #name: Vec<(#voter_type, #target_type)>,
+			#vis #name: _npos::sp_std::prelude::Vec<(#voter_type, #target_type)>,
 		)
 	};
 
 	let doubles = {
 		let name = field_name_for(2);
 		quote!(
-			#vis #name: Vec<(#voter_type, (#target_type, #weight_type), #target_type)>,
+			#vis #name: _npos::sp_std::prelude::Vec<(#voter_type, (#target_type, #weight_type), #target_type)>,
 		)
 	};
 
@@ -135,7 +143,7 @@ fn struct_def(
 			let field_name = field_name_for(c);
 			let array_len = c - 1;
 			quote!(
-				#vis #field_name: Vec<(
+				#vis #field_name: _npos::sp_std::prelude::Vec<(
 					#voter_type,
 					[(#target_type, #weight_type); #array_len],
 					#target_type
@@ -194,20 +202,19 @@ fn struct_def(
 				all_edges
 			}
 
-			fn unique_targets(&self) -> Vec<Self::Target> {
+			fn unique_targets(&self) -> _npos::sp_std::prelude::Vec<Self::Target> {
 				// NOTE: this implementation returns the targets sorted, but we don't use it yet per
 				// se, nor is the API enforcing it.
-				let mut all_targets: Vec<Self::Target> = Vec::with_capacity(self.average_edge_count());
+				use _npos::sp_std::collections::btree_set::BTreeSet;
+
+				let mut all_targets: BTreeSet<Self::Target> = BTreeSet::new();
 				let mut maybe_insert_target = |t: Self::Target| {
-					match all_targets.binary_search(&t) {
-						Ok(_) => (),
-						Err(pos) => all_targets.insert(pos, t)
-					}
+					all_targets.insert(t);
 				};
 
 				#unique_targets_impl
 
-				all_targets
+				all_targets.into_iter().collect()
 			}
 
 			fn remove_voter(&mut self, to_remove: Self::Voter) -> bool {
@@ -216,7 +223,7 @@ fn struct_def(
 			}
 
 			fn from_assignment<FV, FT, A>(
-				assignments: Vec<_npos::Assignment<A, #weight_type>>,
+				assignments: _npos::sp_std::prelude::Vec<_npos::Assignment<A, #weight_type>>,
 				index_of_voter: FV,
 				index_of_target: FT,
 			) -> Result<Self, _npos::Error>
@@ -243,8 +250,8 @@ fn struct_def(
 				self,
 				voter_at: impl Fn(Self::Voter) -> Option<A>,
 				target_at: impl Fn(Self::Target) -> Option<A>,
-			) -> Result<Vec<_npos::Assignment<A, #weight_type>>, _npos::Error> {
-				let mut assignments: Vec<_npos::Assignment<A, #weight_type>> = Default::default();
+			) -> Result<_npos::sp_std::prelude::Vec<_npos::Assignment<A, #weight_type>>, _npos::Error> {
+				let mut assignments: _npos::sp_std::prelude::Vec<_npos::Assignment<A, #weight_type>> = Default::default();
 				#into_impl
 				Ok(assignments)
 			}
@@ -387,7 +394,7 @@ fn check_compact_attr(input: ParseStream) -> Result<bool> {
 	}
 }
 
-/// #[compact] pub struct CompactName::<u32, u32, u32>()
+/// #[compact] pub struct CompactName::<VoterIndex = u32, TargetIndex = u32, Accuracy = u32>()
 impl Parse for SolutionDef {
 	fn parse(input: ParseStream) -> syn::Result<Self> {
 		// optional #[compact]
@@ -406,9 +413,22 @@ impl Parse for SolutionDef {
 			return Err(syn_err("Must provide 3 generic args."))
 		}
 
-		let mut types: Vec<syn::Type> = generics.args.iter().map(|t|
+		let expected_types = ["VoterIndex", "TargetIndex", "Accuracy"];
+
+		let mut types: Vec<syn::Type> = generics.args.iter().zip(expected_types.iter()).map(|(t, expected)|
 			match t {
-				syn::GenericArgument::Type(ty) => Ok(ty.clone()),
+				syn::GenericArgument::Type(ty) => {
+					// this is now an error
+					Err(syn::Error::new_spanned(ty, format!("Expected binding: `{} = ...`", expected)))
+				},
+				syn::GenericArgument::Binding(syn::Binding{ident, ty, ..}) => {
+					// check that we have the right keyword for this position in the argument list
+					if ident == expected {
+						Ok(ty.clone())
+					} else {
+						Err(syn::Error::new_spanned(ident, format!("Expected `{}`", expected)))
+					}
+				}
 				_ => Err(syn_err("Wrong type of generic provided. Must be a `type`.")),
 			}
 		).collect::<Result<_>>()?;
@@ -437,3 +457,12 @@ impl Parse for SolutionDef {
 fn field_name_for(n: usize) -> Ident {
 	Ident::new(&format!("{}{}", PREFIX, n), Span::call_site())
 }
+
+#[cfg(test)]
+mod tests {
+	#[test]
+	fn ui_fail() {
+		let cases = trybuild::TestCases::new();
+		cases.compile_fail("tests/ui/fail/*.rs");
+	}
+}
diff --git a/primitives/npos-elections/compact/tests/ui/fail/missing_accuracy.rs b/primitives/npos-elections/compact/tests/ui/fail/missing_accuracy.rs
new file mode 100644
index 0000000000000..4bbf4960a9483
--- /dev/null
+++ b/primitives/npos-elections/compact/tests/ui/fail/missing_accuracy.rs
@@ -0,0 +1,9 @@
+use sp_npos_elections_compact::generate_solution_type;
+
+generate_solution_type!(pub struct TestSolution::<
+	VoterIndex = u16,
+	TargetIndex = u8,
+	Perbill,
+>(8));
+
+fn main() {}
diff --git a/primitives/npos-elections/compact/tests/ui/fail/missing_accuracy.stderr b/primitives/npos-elections/compact/tests/ui/fail/missing_accuracy.stderr
new file mode 100644
index 0000000000000..b6bb8f39ede61
--- /dev/null
+++ b/primitives/npos-elections/compact/tests/ui/fail/missing_accuracy.stderr
@@ -0,0 +1,5 @@
+error: Expected binding: `Accuracy = ...`
+ --> $DIR/missing_accuracy.rs:6:2
+  |
+6 |     Perbill,
+  |     ^^^^^^^
diff --git a/primitives/npos-elections/compact/tests/ui/fail/missing_target.rs b/primitives/npos-elections/compact/tests/ui/fail/missing_target.rs
new file mode 100644
index 0000000000000..7d7584340713c
--- /dev/null
+++ b/primitives/npos-elections/compact/tests/ui/fail/missing_target.rs
@@ -0,0 +1,9 @@
+use sp_npos_elections_compact::generate_solution_type;
+
+generate_solution_type!(pub struct TestSolution::<
+	VoterIndex = u16,
+	u8,
+	Accuracy = Perbill,
+>(8));
+
+fn main() {}
diff --git a/primitives/npos-elections/compact/tests/ui/fail/missing_target.stderr b/primitives/npos-elections/compact/tests/ui/fail/missing_target.stderr
new file mode 100644
index 0000000000000..d0c92c5bbd8e9
--- /dev/null
+++ b/primitives/npos-elections/compact/tests/ui/fail/missing_target.stderr
@@ -0,0 +1,5 @@
+error: Expected binding: `TargetIndex = ...`
+ --> $DIR/missing_target.rs:5:2
+  |
+5 |     u8,
+  |     ^^
diff --git a/primitives/npos-elections/compact/tests/ui/fail/missing_voter.rs b/primitives/npos-elections/compact/tests/ui/fail/missing_voter.rs
new file mode 100644
index 0000000000000..3ad77dc104ad7
--- /dev/null
+++ b/primitives/npos-elections/compact/tests/ui/fail/missing_voter.rs
@@ -0,0 +1,9 @@
+use sp_npos_elections_compact::generate_solution_type;
+
+generate_solution_type!(pub struct TestSolution::<
+	u16,
+	TargetIndex = u8,
+	Accuracy = Perbill,
+>(8));
+
+fn main() {}
diff --git a/primitives/npos-elections/compact/tests/ui/fail/missing_voter.stderr b/primitives/npos-elections/compact/tests/ui/fail/missing_voter.stderr
new file mode 100644
index 0000000000000..a825d460c2fa8
--- /dev/null
+++ b/primitives/npos-elections/compact/tests/ui/fail/missing_voter.stderr
@@ -0,0 +1,5 @@
+error: Expected binding: `VoterIndex = ...`
+ --> $DIR/missing_voter.rs:4:2
+  |
+4 |     u16,
+  |     ^^^
diff --git a/primitives/npos-elections/compact/tests/ui/fail/no_annotations.rs b/primitives/npos-elections/compact/tests/ui/fail/no_annotations.rs
new file mode 100644
index 0000000000000..aaebb857b3d8d
--- /dev/null
+++ b/primitives/npos-elections/compact/tests/ui/fail/no_annotations.rs
@@ -0,0 +1,9 @@
+use sp_npos_elections_compact::generate_solution_type;
+
+generate_solution_type!(pub struct TestSolution::<
+	u16,
+	u8,
+	Perbill,
+>(8));
+
+fn main() {}
diff --git a/primitives/npos-elections/compact/tests/ui/fail/no_annotations.stderr b/primitives/npos-elections/compact/tests/ui/fail/no_annotations.stderr
new file mode 100644
index 0000000000000..28f1c2091546f
--- /dev/null
+++ b/primitives/npos-elections/compact/tests/ui/fail/no_annotations.stderr
@@ -0,0 +1,5 @@
+error: Expected binding: `VoterIndex = ...`
+ --> $DIR/no_annotations.rs:4:2
+  |
+4 |     u16,
+  |     ^^^
diff --git a/primitives/npos-elections/compact/tests/ui/fail/swap_voter_target.rs b/primitives/npos-elections/compact/tests/ui/fail/swap_voter_target.rs
new file mode 100644
index 0000000000000..37124256b35e4
--- /dev/null
+++ b/primitives/npos-elections/compact/tests/ui/fail/swap_voter_target.rs
@@ -0,0 +1,9 @@
+use sp_npos_elections_compact::generate_solution_type;
+
+generate_solution_type!(pub struct TestSolution::<
+	TargetIndex = u16,
+	VoterIndex = u8,
+	Accuracy = Perbill,
+>(8));
+
+fn main() {}
diff --git a/primitives/npos-elections/compact/tests/ui/fail/swap_voter_target.stderr b/primitives/npos-elections/compact/tests/ui/fail/swap_voter_target.stderr
new file mode 100644
index 0000000000000..5759fee7472fa
--- /dev/null
+++ b/primitives/npos-elections/compact/tests/ui/fail/swap_voter_target.stderr
@@ -0,0 +1,5 @@
+error: Expected `VoterIndex`
+ --> $DIR/swap_voter_target.rs:4:2
+  |
+4 |     TargetIndex = u16,
+  |     ^^^^^^^^^^^
diff --git a/primitives/npos-elections/fuzzer/src/compact.rs b/primitives/npos-elections/fuzzer/src/compact.rs
index 91f734bb5b7cb..a49f6a535e5f0 100644
--- a/primitives/npos-elections/fuzzer/src/compact.rs
+++ b/primitives/npos-elections/fuzzer/src/compact.rs
@@ -4,7 +4,11 @@ use sp_npos_elections::sp_arithmetic::Percent;
 use sp_runtime::codec::{Encode, Error};
 
 fn main() {
-	generate_solution_type!(#[compact] pub struct InnerTestSolutionCompact::<u32, u32, Percent>(16));
+	generate_solution_type!(#[compact] pub struct InnerTestSolutionCompact::<
+		VoterIndex = u32,
+		TargetIndex = u32,
+		Accuracy = Percent,
+	>(16));
 	loop {
 		fuzz!(|fuzzer_data: &[u8]| {
 			let result_decoded: Result<InnerTestSolutionCompact, Error> =
diff --git a/primitives/npos-elections/fuzzer/src/phragmen_pjr.rs b/primitives/npos-elections/fuzzer/src/phragmen_pjr.rs
index 9727d1406ad24..49794f21fb256 100644
--- a/primitives/npos-elections/fuzzer/src/phragmen_pjr.rs
+++ b/primitives/npos-elections/fuzzer/src/phragmen_pjr.rs
@@ -112,7 +112,7 @@ fn iteration(mut candidate_count: usize, mut voter_count: usize, seed: u64) {
 	let threshold = standard_threshold(rounds, voters.iter().map(|voter| voter.budget()));
 
 	assert!(
-		pjr_check_core(&candidates, &voters, threshold),
+		pjr_check_core(&candidates, &voters, threshold).is_ok(),
 		"unbalanced sequential phragmen must satisfy PJR",
 	);
 }
diff --git a/primitives/npos-elections/src/helpers.rs b/primitives/npos-elections/src/helpers.rs
index 10a49a084f102..091efdd36ea5f 100644
--- a/primitives/npos-elections/src/helpers.rs
+++ b/primitives/npos-elections/src/helpers.rs
@@ -95,15 +95,15 @@ mod tests {
 			Assignment {
 				who: 1u32,
 				distribution: vec![
-					(10u32, Perbill::from_fraction(0.5)),
-					(20, Perbill::from_fraction(0.5)),
+					(10u32, Perbill::from_float(0.5)),
+					(20, Perbill::from_float(0.5)),
 				],
 			},
 			Assignment {
 				who: 2u32,
 				distribution: vec![
-					(10, Perbill::from_fraction(0.33)),
-					(20, Perbill::from_fraction(0.67)),
+					(10, Perbill::from_float(0.33)),
+					(20, Perbill::from_float(0.67)),
 				],
 			},
 		];
diff --git a/primitives/npos-elections/src/lib.rs b/primitives/npos-elections/src/lib.rs
index c87085ef9ff8f..05505d06f201e 100644
--- a/primitives/npos-elections/src/lib.rs
+++ b/primitives/npos-elections/src/lib.rs
@@ -119,6 +119,8 @@ pub use pjr::*;
 pub use codec;
 #[doc(hidden)]
 pub use sp_arithmetic;
+#[doc(hidden)]
+pub use sp_std;
 
 /// Simple Extension trait to easily convert `None` from index closures to `Err`.
 ///
@@ -142,10 +144,22 @@ pub trait CompactSolution: Sized {
 	const LIMIT: usize;
 
 	/// The voter type. Needs to be an index (convert to usize).
-	type Voter: UniqueSaturatedInto<usize> + TryInto<usize> + TryFrom<usize> + Debug + Copy + Clone;
+	type Voter: UniqueSaturatedInto<usize>
+		+ TryInto<usize>
+		+ TryFrom<usize>
+		+ Debug
+		+ Copy
+		+ Clone
+		+ Bounded;
 
 	/// The target type. Needs to be an index (convert to usize).
-	type Target: UniqueSaturatedInto<usize> + TryInto<usize> + TryFrom<usize> + Debug + Copy + Clone;
+	type Target: UniqueSaturatedInto<usize>
+		+ TryInto<usize>
+		+ TryFrom<usize>
+		+ Debug
+		+ Copy
+		+ Clone
+		+ Bounded;
 
 	/// The weight/accuracy type of each vote.
 	type Accuracy: PerThing128;
@@ -359,7 +373,7 @@ impl<AccountId: IdentifierT> Voter<AccountId> {
 			.edges
 			.into_iter()
 			.filter_map(|e| {
-				let per_thing = P::from_rational_approximation(e.weight, budget);
+				let per_thing = P::from_rational(e.weight, budget);
 			// trim zero edges.
 			if per_thing.is_zero() { None } else { Some((e.who, per_thing)) }
 		}).collect::<Vec<_>>();
@@ -539,7 +553,7 @@ impl<AccountId> StakedAssignment<AccountId> {
 		let distribution = self.distribution
 			.into_iter()
 			.filter_map(|(target, w)| {
-				let per_thing = P::from_rational_approximation(w, stake);
+				let per_thing = P::from_rational(w, stake);
 				if per_thing == Bounded::min_value() {
 					None
 				} else {
diff --git a/primitives/npos-elections/src/mock.rs b/primitives/npos-elections/src/mock.rs
index ea8f3780e0e6a..14e4139c5d324 100644
--- a/primitives/npos-elections/src/mock.rs
+++ b/primitives/npos-elections/src/mock.rs
@@ -345,7 +345,7 @@ pub(crate) fn run_and_compare<Output: PerThing128>(
 			for (candidate, per_thingy) in distribution {
 				if let Some(float_assignment) = float_assignments.1.iter().find(|x| x.0 == candidate ) {
 					assert_eq_error_rate!(
-						Output::from_fraction(float_assignment.1).deconstruct(),
+						Output::from_float(float_assignment.1).deconstruct(),
 						per_thingy.deconstruct(),
 						Output::Inner::one(),
 					);
diff --git a/primitives/npos-elections/src/phragmms.rs b/primitives/npos-elections/src/phragmms.rs
index ad93d2f18ef9a..644535d4c41c2 100644
--- a/primitives/npos-elections/src/phragmms.rs
+++ b/primitives/npos-elections/src/phragmms.rs
@@ -101,7 +101,7 @@ pub(crate) fn calculate_max_score<AccountId: IdentifierT, P: PerThing>(
 		for edge in voter.edges.iter() {
 			let edge_candidate = edge.candidate.borrow();
 			if edge_candidate.elected {
-				let edge_contribution: ExtendedBalance = P::from_rational_approximation(
+				let edge_contribution: ExtendedBalance = P::from_rational(
 					edge.weight,
 					edge_candidate.backed_stake,
 				).deconstruct().into();
diff --git a/primitives/npos-elections/src/pjr.rs b/primitives/npos-elections/src/pjr.rs
index 61e0b2deb79fc..290110b14e650 100644
--- a/primitives/npos-elections/src/pjr.rs
+++ b/primitives/npos-elections/src/pjr.rs
@@ -37,7 +37,6 @@ use crate::{
 use sp_std::{rc::Rc, vec::Vec};
 use sp_std::collections::btree_map::BTreeMap;
 use sp_arithmetic::{traits::Zero, Perbill};
-
 /// The type used as the threshold.
 ///
 /// Just some reading sugar; Must always be same as [`ExtendedBalance`];
@@ -74,7 +73,7 @@ pub fn pjr_check<AccountId: IdentifierT>(
 	supports: &Supports<AccountId>,
 	all_candidates: Vec<AccountId>,
 	all_voters: Vec<(AccountId, VoteWeight, Vec<AccountId>)>,
-) -> bool {
+) -> Result<(), AccountId> {
 	let t = standard_threshold(supports.len(), all_voters.iter().map(|voter| voter.1 as ExtendedBalance));
 	t_pjr_check(supports, all_candidates, all_voters, t)
 }
@@ -119,7 +118,7 @@ pub fn t_pjr_check<AccountId: IdentifierT>(
 	all_candidates: Vec<AccountId>,
 	all_voters: Vec<(AccountId, VoteWeight, Vec<AccountId>)>,
 	t: Threshold,
-) -> bool {
+) -> Result<(), AccountId> {
 	// First order of business: derive `(candidates, voters)` from `supports`.
 	let (candidates, voters) = prepare_pjr_input(
 		supports,
@@ -133,18 +132,99 @@ pub fn t_pjr_check<AccountId: IdentifierT>(
 /// The internal implementation of the PJR check after having the data converted.
 ///
 /// [`pjr_check`] or [`t_pjr_check`] are typically easier to work with.
+///
+/// This function returns an `AccountId` in the `Err` case. This is the counter_example: the ID of the
+/// unelected candidate with the highest prescore, such that `pre_score(counter_example) >= t`.
 pub fn pjr_check_core<AccountId: IdentifierT>(
 	candidates: &[CandidatePtr<AccountId>],
 	voters: &[Voter<AccountId>],
 	t: Threshold,
-) -> bool {
+) -> Result<(), AccountId> {
 	let unelected = candidates.iter().filter(|c| !c.borrow().elected);
 	let maybe_max_pre_score = unelected.map(|c| (pre_score(Rc::clone(c), voters, t), c.borrow().who.clone())).max();
 	// if unelected is empty then the solution is indeed PJR.
-	maybe_max_pre_score.map_or(true, |(max_pre_score, _)| max_pre_score < t)
+	match maybe_max_pre_score {
+		Some((max_pre_score, counter_example)) if max_pre_score >= t => Err(counter_example),
+		_ => Ok(()),
+	}
 }
 
+/// Validate a challenge to an election result.
+///
+/// A challenge to an election result is valid if there exists some counter_example for which
+/// `pre_score(counter_example) >= threshold`. Validating an existing counter_example is computationally
+/// cheaper than re-running the PJR check.
+///
+/// This function uses the standard threshold.
+///
+/// Returns `true` if the challenge is valid: the proposed solution does not satisfy PJR.
+/// Returns `false` if the challenge is invalid: the proposed solution does in fact satisfy PJR.
+pub fn validate_pjr_challenge<AccountId: IdentifierT>(
+	counter_example: AccountId,
+	supports: &Supports<AccountId>,
+	all_candidates: Vec<AccountId>,
+	all_voters: Vec<(AccountId, VoteWeight, Vec<AccountId>)>,
+) -> bool {
+	let threshold = standard_threshold(supports.len(), all_voters.iter().map(|voter| voter.1 as ExtendedBalance));
+	validate_t_pjr_challenge(counter_example, supports, all_candidates, all_voters, threshold)
+}
+
+/// Validate a challenge to an election result.
+///
+/// A challenge to an election result is valid if there exists some counter_example for which
+/// `pre_score(counter_example) >= threshold`. Validating an existing counter_example is computationally
+/// cheaper than re-running the PJR check.
+///
+/// This function uses a supplied threshold.
+///
+/// Returns `true` if the challenge is valid: the proposed solution does not satisfy PJR.
+/// Returns `false` if the challenge is invalid: the proposed solution does in fact satisfy PJR.
+pub fn validate_t_pjr_challenge<AccountId: IdentifierT>(
+	counter_example: AccountId,
+	supports: &Supports<AccountId>,
+	all_candidates: Vec<AccountId>,
+	all_voters: Vec<(AccountId, VoteWeight, Vec<AccountId>)>,
+	threshold: Threshold,
+) -> bool {
+	let (candidates, voters) = prepare_pjr_input(
+		supports,
+		all_candidates,
+		all_voters,
+	);
+	validate_pjr_challenge_core(counter_example, &candidates, &voters, threshold)
+}
 
+/// Validate a challenge to an election result.
+///
+/// A challenge to an election result is valid if there exists some counter_example for which
+/// `pre_score(counter_example) >= threshold`. Validating an existing counter_example is computationally
+/// cheaper than re-running the PJR check.
+///
+/// Returns `true` if the challenge is valid: the proposed solution does not satisfy PJR.
+/// Returns `false` if the challenge is invalid: the proposed solution does in fact satisfy PJR.
+fn validate_pjr_challenge_core<AccountId: IdentifierT>(
+	counter_example: AccountId,
+	candidates: &[CandidatePtr<AccountId>],
+	voters: &[Voter<AccountId>],
+	threshold: Threshold,
+) -> bool {
+	// Performing a linear search of the candidate list is not great, for obvious reasons. However,
+	// the alternatives are worse:
+	//
+	// - we could pre-sort the candidates list in `prepare_pjr_input` (n log n) which would let us
+	//   binary search for the appropriate one here (log n). Overall runtime is `n log n` which is
+	//   worse than the current runtime of `n`.
+	//
+	// - we could probably pre-sort the candidates list in `n` in `prepare_pjr_input` using some
+	//   unsafe code leveraging the existing `candidates_index`: allocate an uninitialized vector of
+	//   appropriate length, then copy in all the elements. We'd really prefer to avoid unsafe code
+	//   in the runtime, though.
+	let candidate = match candidates.iter().find(|candidate| candidate.borrow().who == counter_example) {
+		None => return false,
+		Some(candidate) => candidate.clone(),
+	};
+	pre_score(candidate, &voters, threshold) >= threshold
+}
 
 /// Convert the data types that the user runtime has into ones that can be used by this module.
 ///
@@ -283,7 +363,7 @@ fn slack<AccountId: IdentifierT>(voter: &Voter<AccountId>, t: Threshold) -> Exte
 		let candidate = edge.candidate.borrow();
 		if candidate.elected {
 			let extra =
-				Perbill::one().min(Perbill::from_rational_approximation(t, candidate.backed_stake))
+				Perbill::one().min(Perbill::from_rational(t, candidate.backed_stake))
 				* edge.weight;
 			acc.saturating_add(extra)
 		} else {
@@ -315,6 +395,15 @@ mod tests {
 		voter
 	}
 
+	fn assert_core_failure<AccountId: IdentifierT>(
+		candidates: &[CandidatePtr<AccountId>],
+		voters: &[Voter<AccountId>],
+		t: Threshold,
+	) {
+		let counter_example = pjr_check_core(candidates, voters, t).unwrap_err();
+		assert!(validate_pjr_challenge_core(counter_example, candidates, voters, t));
+	}
+
 	#[test]
 	fn slack_works() {
 		let voter = setup_voter(10, vec![(1, 10, true), (2, 20, true)]);
@@ -388,9 +477,9 @@ mod tests {
 
 		// fyi. this is not PJR, obviously because the votes of 3 can bump the stake a lot but they
 		// are being ignored.
-		assert!(!pjr_check_core(&candidates, &voters, 1));
-		assert!(!pjr_check_core(&candidates, &voters, 10));
-		assert!(!pjr_check_core(&candidates, &voters, 20));
+		assert_core_failure(&candidates, &voters, 1);
+		assert_core_failure(&candidates, &voters, 10);
+		assert_core_failure(&candidates, &voters, 20);
 	}
 
 	// These next tests ensure that the threshold phase change property holds for us, but that's not their real purpose.
@@ -476,7 +565,7 @@ mod tests {
 		let mut prev_threshold = 0;
 
 		// find the binary range containing the threshold beyond which the PJR check succeeds
-		while !pjr_check_core(&candidates, &voters, threshold) {
+		while pjr_check_core(&candidates, &voters, threshold).is_err() {
 			prev_threshold = threshold;
 			threshold = threshold.checked_mul(2).expect("pjr check must fail before we run out of capacity in u128");
 		}
@@ -488,7 +577,7 @@ mod tests {
 		while high_bound - low_bound > 1 {
 			// maintain the invariant that low_bound fails and high_bound passes
 			let test = low_bound + ((high_bound - low_bound) / 2);
-			if pjr_check_core(&candidates, &voters, test) {
+			if pjr_check_core(&candidates, &voters, test).is_ok() {
 				high_bound = test;
 			} else {
 				low_bound = test;
@@ -502,12 +591,12 @@ mod tests {
 		let mut unexpected_failures = Vec::new();
 		let mut unexpected_successes = Vec::new();
 		for t in 0..=low_bound {
-			if pjr_check_core(&candidates, &voters, t) {
+			if pjr_check_core(&candidates, &voters, t).is_ok() {
 				unexpected_successes.push(t);
 			}
 		}
 		for t in high_bound..(high_bound*2) {
-			if !pjr_check_core(&candidates, &voters, t) {
+			if pjr_check_core(&candidates, &voters, t).is_err() {
 				unexpected_failures.push(t);
 			}
 		}
diff --git a/primitives/npos-elections/src/tests.rs b/primitives/npos-elections/src/tests.rs
index edfea038ebc50..6304e50ec5868 100644
--- a/primitives/npos-elections/src/tests.rs
+++ b/primitives/npos-elections/src/tests.rs
@@ -1095,7 +1095,7 @@ mod score {
 			is_score_better(
 				claim.clone(),
 				initial.clone(),
-				Perbill::from_rational_approximation(1u32, 10_000),
+				Perbill::from_rational(1u32, 10_000),
 			),
 			true,
 		);
@@ -1104,7 +1104,7 @@ mod score {
 			is_score_better(
 				claim.clone(),
 				initial.clone(),
-				Perbill::from_rational_approximation(2u32, 10_000),
+				Perbill::from_rational(2u32, 10_000),
 			),
 			true,
 		);
@@ -1113,7 +1113,7 @@ mod score {
 			is_score_better(
 				claim.clone(),
 				initial.clone(),
-				Perbill::from_rational_approximation(3u32, 10_000),
+				Perbill::from_rational(3u32, 10_000),
 			),
 			true,
 		);
@@ -1122,7 +1122,7 @@ mod score {
 			is_score_better(
 				claim.clone(),
 				initial.clone(),
-				Perbill::from_rational_approximation(4u32, 10_000),
+				Perbill::from_rational(4u32, 10_000),
 			),
 			true,
 		);
@@ -1131,7 +1131,7 @@ mod score {
 			is_score_better(
 				claim.clone(),
 				initial.clone(),
-				Perbill::from_rational_approximation(5u32, 10_000),
+				Perbill::from_rational(5u32, 10_000),
 			),
 			false,
 		);
@@ -1148,7 +1148,11 @@ mod solution_type {
 
 	type TestAccuracy = Percent;
 
-	generate_solution_type!(pub struct TestSolutionCompact::<u32, u8, TestAccuracy>(16));
+	generate_solution_type!(pub struct TestSolutionCompact::<
+		VoterIndex = u32,
+		TargetIndex = u8,
+		Accuracy = TestAccuracy,
+	>(16));
 
 	#[allow(dead_code)]
 	mod __private {
@@ -1158,7 +1162,7 @@ mod solution_type {
 		use sp_arithmetic::Percent;
 		generate_solution_type!(
 			#[compact]
-			struct InnerTestSolutionCompact::<u32, u8, Percent>(12)
+			struct InnerTestSolutionCompact::<VoterIndex = u32, TargetIndex = u8, Accuracy = Percent>(12)
 		);
 	}
 
@@ -1166,7 +1170,11 @@ mod solution_type {
 	fn solution_struct_works_with_and_without_compact() {
 		// we use u32 size to make sure compact is smaller.
 		let without_compact = {
-			generate_solution_type!(pub struct InnerTestSolution::<u32, u32, Percent>(16));
+			generate_solution_type!(pub struct InnerTestSolution::<
+				VoterIndex = u32,
+				TargetIndex = u32,
+				Accuracy = Percent,
+			>(16));
 			let compact = InnerTestSolution {
 				votes1: vec![(2, 20), (4, 40)],
 				votes2: vec![
@@ -1180,7 +1188,11 @@ mod solution_type {
 		};
 
 		let with_compact = {
-			generate_solution_type!(#[compact] pub struct InnerTestSolutionCompact::<u32, u32, Percent>(16));
+			generate_solution_type!(#[compact] pub struct InnerTestSolutionCompact::<
+				VoterIndex = u32,
+				TargetIndex = u32,
+				Accuracy = Percent,
+			>(16));
 			let compact = InnerTestSolutionCompact {
 				votes1: vec![(2, 20), (4, 40)],
 				votes2: vec![
diff --git a/primitives/runtime/src/generic/block.rs b/primitives/runtime/src/generic/block.rs
index 7b2a10297f9c6..1b30d43ccaca7 100644
--- a/primitives/runtime/src/generic/block.rs
+++ b/primitives/runtime/src/generic/block.rs
@@ -30,7 +30,7 @@ use crate::traits::{
 	self, Member, Block as BlockT, Header as HeaderT, MaybeSerialize, MaybeMallocSizeOf,
 	NumberFor,
 };
-use crate::Justification;
+use crate::Justifications;
 
 /// Something to identify a block.
 #[derive(PartialEq, Eq, Clone, RuntimeDebug)]
@@ -112,5 +112,5 @@ pub struct SignedBlock<Block> {
 	/// Full block.
 	pub block: Block,
 	/// Block justification.
-	pub justification: Option<Justification>,
+	pub justifications: Option<Justifications>,
 }
diff --git a/primitives/runtime/src/lib.rs b/primitives/runtime/src/lib.rs
index c8b93a083be4e..090c9781eb13d 100644
--- a/primitives/runtime/src/lib.rs
+++ b/primitives/runtime/src/lib.rs
@@ -96,7 +96,65 @@ pub use either::Either;
 /// the block itself would allow swapping justifications to change the block's hash
 /// (and thus fork the chain). Sending a `Justification` alongside a block instead
 /// bypasses this problem.
-pub type Justification = Vec<u8>;
+///
+/// Each justification is provided as an encoded blob, and is tagged with an ID
+/// to identify the consensus engine that generated the proof (we might have
+/// multiple justifications from different engines for the same block).
+pub type Justification = (ConsensusEngineId, EncodedJustification);
+
+/// The encoded justification specific to a consensus engine.
+pub type EncodedJustification = Vec<u8>;
+
+/// Collection of justifications for a given block, multiple justifications may
+/// be provided by different consensus engines for the same block.
+#[cfg_attr(feature = "std", derive(Serialize, Deserialize))]
+#[derive(Debug, Clone, PartialEq, Eq, Encode, Decode)]
+pub struct Justifications(Vec<Justification>);
+
+impl Justifications {
+	/// Return an iterator over the justifications.
+	pub fn iter(&self) -> impl Iterator<Item = &Justification> {
+		self.0.iter()
+	}
+
+	/// Append a justification. Returns false if a justification with the same
+	/// `ConsensusEngineId` already exists, in which case the justification is
+	/// not inserted.
+	pub fn append(&mut self, justification: Justification) -> bool {
+		if self.get(justification.0).is_some() {
+			return false;
+		}
+		self.0.push(justification);
+		true
+	}
+
+	/// Return the encoded justification for the given consensus engine, if it
+	/// exists.
+	pub fn get(&self, engine_id: ConsensusEngineId) -> Option<&EncodedJustification> {
+		self.iter().find(|j| j.0 == engine_id).map(|j| &j.1)
+	}
+
+	/// Return a copy of the encoded justification for the given consensus
+	/// engine, if it exists.
+	pub fn into_justification(self, engine_id: ConsensusEngineId) -> Option<EncodedJustification> {
+		self.into_iter().find(|j| j.0 == engine_id).map(|j| j.1)
+	}
+}
+
+impl IntoIterator for Justifications {
+	type Item = Justification;
+	type IntoIter = sp_std::vec::IntoIter<Self::Item>;
+
+	fn into_iter(self) -> Self::IntoIter {
+		self.0.into_iter()
+	}
+}
+
+impl From<Justification> for Justifications {
+	fn from(justification: Justification) -> Self {
+		Self(vec![justification])
+	}
+}
 
 use traits::{Verify, Lazy};
 
@@ -392,7 +450,7 @@ pub type DispatchResult = sp_std::result::Result<(), DispatchError>;
 pub type DispatchResultWithInfo<T> = sp_std::result::Result<T, DispatchErrorWithPostInfo<T>>;
 
 /// Reason why a dispatch call failed.
-#[derive(Eq, PartialEq, Clone, Copy, Encode, Decode, RuntimeDebug)]
+#[derive(Eq, Clone, Copy, Encode, Decode, RuntimeDebug)]
 #[cfg_attr(feature = "std", derive(Serialize, Deserialize))]
 pub enum DispatchError {
 	/// Some error occurred.
@@ -416,6 +474,8 @@ pub enum DispatchError {
 	ConsumerRemaining,
 	/// There are no providers so the account cannot be created.
 	NoProviders,
+	/// An error to do with tokens.
+	Token(TokenError),
 }
 
 /// Result of a `Dispatchable` which contains the `DispatchResult` and additional information about
@@ -474,6 +534,49 @@ impl From<crate::traits::StoredMapError> for DispatchError {
 	}
 }
 
+/// Description of what went wrong when trying to complete an operation on a token.
+#[derive(Eq, PartialEq, Clone, Copy, Encode, Decode, RuntimeDebug)]
+#[cfg_attr(feature = "std", derive(Serialize, Deserialize))]
+pub enum TokenError {
+	/// Funds are unavailable.
+	NoFunds,
+	/// Account that must exist would die.
+	WouldDie,
+	/// Account cannot exist with the funds that would be given.
+	BelowMinimum,
+	/// Account cannot be created.
+	CannotCreate,
+	/// The asset in question is unknown.
+	UnknownAsset,
+	/// Funds exist but are frozen.
+	Frozen,
+	/// An underflow would occur.
+	Underflow,
+	/// An overflow would occur.
+	Overflow,
+}
+
+impl From<TokenError> for &'static str {
+	fn from(e: TokenError) -> &'static str {
+		match e {
+			TokenError::NoFunds => "Funds are unavailable",
+			TokenError::WouldDie => "Account that must exist would die",
+			TokenError::BelowMinimum => "Account cannot exist with the funds that would be given",
+			TokenError::CannotCreate => "Account cannot be created",
+			TokenError::UnknownAsset => "The asset in question is unknown",
+			TokenError::Frozen => "Funds exist but are frozen",
+			TokenError::Underflow => "An underflow would occur",
+			TokenError::Overflow => "An overflow would occur",
+		}
+	}
+}
+
+impl From<TokenError> for DispatchError {
+	fn from(e: TokenError) -> DispatchError {
+		DispatchError::Token(e)
+	}
+}
+
 impl From<&'static str> for DispatchError {
 	fn from(err: &'static str) -> DispatchError {
 		DispatchError::Other(err)
@@ -489,6 +592,7 @@ impl From<DispatchError> for &'static str {
 			DispatchError::Module { message, .. } => message.unwrap_or("Unknown module error"),
 			DispatchError::ConsumerRemaining => "Consumer remaining",
 			DispatchError::NoProviders => "No providers",
+			DispatchError::Token(e) => e.into(),
 		}
 	}
 }
@@ -517,6 +621,10 @@ impl traits::Printable for DispatchError {
 			}
 			Self::ConsumerRemaining => "Consumer remaining".print(),
 			Self::NoProviders => "No providers".print(),
+			Self::Token(e) => {
+				"Token error: ".print();
+				<&'static str>::from(*e).print();
+			}
 		}
 	}
 }
@@ -531,6 +639,29 @@ impl<T> traits::Printable for DispatchErrorWithPostInfo<T> where
 	}
 }
 
+impl PartialEq for DispatchError {
+	fn eq(&self, other: &Self) -> bool {
+		use DispatchError::*;
+
+		match (self, other) {
+			(CannotLookup, CannotLookup) |
+			(BadOrigin, BadOrigin) |
+			(ConsumerRemaining, ConsumerRemaining) |
+			(NoProviders, NoProviders) => true,
+
+			(Token(l), Token(r)) => l == r,
+			(Other(l), Other(r)) => l == r,
+
+			(
+				Module { index: index_l, error: error_l, .. },
+				Module { index: index_r, error: error_r, .. },
+			) => (index_l == index_r) && (error_l == error_r),
+
+			_ => false,
+		}
+	}
+}
+
 /// This type specifies the outcome of dispatching a call to a module.
 ///
 /// In case of failure an error specific to the module is returned.
@@ -768,6 +899,38 @@ mod tests {
 		);
 	}
 
+	#[test]
+	fn dispatch_error_equality() {
+		use DispatchError::*;
+
+		let variants = vec![
+			Other("foo"),
+			Other("bar"),
+			CannotLookup,
+			BadOrigin,
+			Module { index: 1, error: 1, message: None },
+			Module { index: 1, error: 2, message: None },
+			Module { index: 2, error: 1, message: None },
+			ConsumerRemaining,
+			NoProviders,
+		];
+		for (i, variant) in variants.iter().enumerate() {
+			for (j, other_variant) in variants.iter().enumerate() {
+				if i == j {
+					assert_eq!(variant, other_variant);
+				} else {
+					assert_ne!(variant, other_variant);
+				}
+			}
+		}
+
+		// Ignores `message` field in `Module` variant.
+		assert_eq!(
+			Module { index: 1, error: 1, message: Some("foo") },
+			Module { index: 1, error: 1, message: None},
+		);
+	}
+
 	#[test]
 	fn multi_signature_ecdsa_verify_works() {
 		let msg = &b"test-message"[..];
diff --git a/primitives/runtime/src/offchain/storage_lock.rs b/primitives/runtime/src/offchain/storage_lock.rs
index 4c66db6c385c0..1529de4ab591a 100644
--- a/primitives/runtime/src/offchain/storage_lock.rs
+++ b/primitives/runtime/src/offchain/storage_lock.rs
@@ -439,11 +439,11 @@ pub trait BlockNumberProvider {
 	///
 	/// In case of using crate `sp_runtime` without the crate `frame`
 	/// system, it is already implemented for
-	/// `frame_system::Module<T: Config>` as:
+	/// `frame_system::Pallet<T: Config>` as:
 	///
 	/// ```ignore
 	/// fn current_block_number() -> Self {
-	///     frame_system::Module<Config>::block_number()
+	///     frame_system::Pallet<Config>::block_number()
 	/// }
 	/// ```
 	/// .
diff --git a/primitives/sr-api/proc-macro/src/lib.rs b/primitives/sr-api/proc-macro/src/lib.rs
deleted file mode 100644
index 4c4aa0d7cb929..0000000000000
--- a/primitives/sr-api/proc-macro/src/lib.rs
+++ /dev/null
@@ -1,190 +0,0 @@
-// This file is part of Substrate.
-
-// Copyright (C) 2018-2021 Parity Technologies (UK) Ltd.
-// SPDX-License-Identifier: Apache-2.0
-
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// 	http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-//! Macros for declaring and implementing runtime apis.
-
-#![recursion_limit = "512"]
-
-use proc_macro::TokenStream;
-
-mod impl_runtime_apis;
-mod decl_runtime_apis;
-mod utils;
-
-/// Tags given trait implementations as runtime apis.
-///
-/// All traits given to this macro, need to be declared with the `decl_runtime_apis!` macro.
-/// The implementation of the trait should follow the declaration given to the `decl_runtime_apis!`
-/// macro, besides the `Block` type that is required as first generic parameter for each runtime
-/// api trait. When implementing a runtime api trait, it is required that the trait is referenced
-/// by a path, e.g. `impl my_trait::MyTrait for Runtime`. The macro will use this path to access
-/// the declaration of the trait for the runtime side.
-///
-/// The macro also generates the api implementations for the client side and provides it through
-/// the `RuntimeApi` type. The `RuntimeApi` is hidden behind a `feature` called `std`.
-///
-/// To expose version information about all implemented api traits, the constant
-/// `RUNTIME_API_VERSIONS` is generated. This constant should be used to instantiate the `apis`
-/// field of `RuntimeVersion`.
-///
-/// # Example
-///
-/// ```rust
-/// use sp_version::create_runtime_str;
-/// #
-/// # use sp_runtime::traits::{GetNodeBlockType, Block as BlockT};
-/// # use test_client::runtime::Block;
-/// #
-/// # /// The declaration of the `Runtime` type and the implementation of the `GetNodeBlockType`
-/// # /// trait are done by the `construct_runtime!` macro in a real runtime.
-/// # pub struct Runtime {}
-/// # impl GetNodeBlockType for Runtime {
-/// #     type NodeBlock = Block;
-/// # }
-/// #
-/// # sp_api::decl_runtime_apis! {
-/// #     /// Declare the api trait.
-/// #     pub trait Balance {
-/// #         /// Get the balance.
-/// #         fn get_balance() -> u64;
-/// #         /// Set the balance.
-/// #         fn set_balance(val: u64);
-/// #     }
-/// #     pub trait BlockBuilder {
-/// #        fn build_block() -> Block;
-/// #    }
-/// # }
-///
-/// /// All runtime api implementations need to be done in one call of the macro!
-/// sp_api::impl_runtime_apis! {
-/// #   impl sp_api::Core<Block> for Runtime {
-/// #       fn version() -> sp_version::RuntimeVersion {
-/// #           unimplemented!()
-/// #       }
-/// #       fn execute_block(_block: Block) {}
-/// #       fn initialize_block(_header: &<Block as BlockT>::Header) {}
-/// #   }
-///
-///     impl self::Balance<Block> for Runtime {
-///         fn get_balance() -> u64 {
-///             1
-///         }
-///         fn set_balance(_bal: u64) {
-///             // Store the balance
-///         }
-///     }
-///
-///     impl self::BlockBuilder<Block> for Runtime {
-///         fn build_block() -> Block {
-///              unimplemented!("Please implement me!")
-///         }
-///     }
-/// }
-///
-/// /// Runtime version. This needs to be declared for each runtime.
-/// pub const VERSION: sp_version::RuntimeVersion = sp_version::RuntimeVersion {
-///     spec_name: create_runtime_str!("node"),
-///     impl_name: create_runtime_str!("test-node"),
-///     authoring_version: 1,
-///     spec_version: 1,
-///     impl_version: 0,
-///     // Here we are exposing the runtime api versions.
-///     apis: RUNTIME_API_VERSIONS,
-///     transaction_version: 1,
-/// };
-///
-/// # fn main() {}
-/// ```
-#[proc_macro]
-pub fn impl_runtime_apis(input: TokenStream) -> TokenStream {
-	impl_runtime_apis::impl_runtime_apis_impl(input)
-}
-
-/// Declares given traits as runtime apis.
-///
-/// The macro will create two declarations, one for using on the client side and one for using
-/// on the runtime side. The declaration for the runtime side is hidden in its own module.
-/// The client side declaration gets two extra parameters per function,
-/// `&self` and `at: &BlockId<Block>`. The runtime side declaration will match the given trait
-/// declaration. Besides one exception, the macro adds an extra generic parameter `Block: BlockT`
-/// to the client side and the runtime side. This generic parameter is usable by the user.
-///
-/// For implementing these macros you should use the `impl_runtime_apis!` macro.
-///
-/// # Example
-///
-/// ```rust
-/// sp_api::decl_runtime_apis! {
-///     /// Declare the api trait.
-///     pub trait Balance {
-///         /// Get the balance.
-///         fn get_balance() -> u64;
-///         /// Set the balance.
-///         fn set_balance(val: u64);
-///     }
-///
-///     /// You can declare multiple api traits in one macro call.
-///     /// In one module you can call the macro at maximum one time.
-///     pub trait BlockBuilder {
-///         /// The macro adds an explicit `Block: BlockT` generic parameter for you.
-///         /// You can use this generic parameter as you would defined it manually.
-///         fn build_block() -> Block;
-///     }
-/// }
-///
-/// # fn main() {}
-/// ```
-///
-/// # Runtime api trait versioning
-///
-/// To support versioning of the traits, the macro supports the attribute `#[api_version(1)]`.
-/// The attribute supports any `u32` as version. By default, each trait is at version `1`, if no
-/// version is provided. We also support changing the signature of a method. This signature
-/// change is highlighted with the `#[changed_in(2)]` attribute above a method. A method that is
-/// tagged with this attribute is callable by the name `METHOD_before_version_VERSION`. This
-/// method will only support calling into wasm, trying to call into native will fail (change the
-/// spec version!). Such a method also does not need to be implemented in the runtime.
-///
-/// ```rust
-/// sp_api::decl_runtime_apis! {
-///     /// Declare the api trait.
-///     #[api_version(2)]
-///     pub trait Balance {
-///         /// Get the balance.
-///         fn get_balance() -> u64;
-///         /// Set balance.
-///         fn set_balance(val: u64);
-///         /// Set balance, old version.
-///         ///
-///         /// Is callable by `set_balance_before_version_2`.
-///         #[changed_in(2)]
-///         fn set_balance(val: u16);
-///         /// In version 2, we added this new function.
-///         fn increase_balance(val: u64);
-///     }
-/// }
-///
-/// # fn main() {}
-/// ```
-///
-/// To check if a given runtime implements a runtime api trait, the `RuntimeVersion` has the
-/// function `has_api<A>()`. Also the `ApiExt` provides a function `has_api<A>(at: &BlockId)` to
-/// check if the runtime at the given block id implements the requested runtime api trait.
-#[proc_macro]
-pub fn decl_runtime_apis(input: TokenStream) -> TokenStream {
-	decl_runtime_apis::decl_runtime_apis_impl(input)
-}
diff --git a/primitives/state-machine/src/ext.rs b/primitives/state-machine/src/ext.rs
index 7907cda6fb4e7..65b7b638a9a2e 100644
--- a/primitives/state-machine/src/ext.rs
+++ b/primitives/state-machine/src/ext.rs
@@ -18,7 +18,7 @@
 //! Concrete externalities implementation.
 
 use crate::{
-	StorageKey, StorageValue, OverlayedChanges,
+	StorageKey, StorageValue, OverlayedChanges, IndexOperation,
 	backend::Backend, overlayed_changes::OverlayedExtensions,
 };
 use hash_db::Hasher;
@@ -568,6 +568,36 @@ where
 		}
 	}
 
+	fn storage_index_transaction(&mut self, index: u32, offset: u32) {
+		trace!(
+			target: "state",
+			"{:04x}: IndexTransaction ({}): [{}..]",
+			self.id,
+			index,
+			offset,
+		);
+		self.overlay.add_transaction_index(IndexOperation::Insert {
+			extrinsic: index,
+			offset,
+		});
+	}
+
+	/// Renew existing piece of data storage.
+	fn storage_renew_transaction_index(&mut self, index: u32, hash: &[u8], size: u32) {
+		trace!(
+			target: "state",
+			"{:04x}: RenewTransactionIndex ({}) {} bytes",
+			self.id,
+			HexDisplay::from(&hash),
+			size,
+		);
+		self.overlay.add_transaction_index(IndexOperation::Renew {
+			extrinsic: index,
+			hash: hash.to_vec(),
+			size
+		});
+	}
+
 	#[cfg(not(feature = "std"))]
 	fn storage_changes_root(&mut self, _parent_hash: &[u8]) -> Result<Option<Vec<u8>>, ()> {
 		Ok(None)
diff --git a/primitives/state-machine/src/lib.rs b/primitives/state-machine/src/lib.rs
index 0167633d48070..0a664840df850 100644
--- a/primitives/state-machine/src/lib.rs
+++ b/primitives/state-machine/src/lib.rs
@@ -121,6 +121,7 @@ pub use crate::overlayed_changes::{
 	StorageChanges, StorageTransactionCache,
 	OffchainChangesCollection,
 	OffchainOverlayedChanges,
+	IndexOperation,
 };
 pub use crate::backend::Backend;
 pub use crate::trie_backend_essence::{TrieBackendStorage, Storage};
diff --git a/primitives/state-machine/src/overlayed_changes/mod.rs b/primitives/state-machine/src/overlayed_changes/mod.rs
index 285bf2a73a148..1d3cbb59ba0c1 100644
--- a/primitives/state-machine/src/overlayed_changes/mod.rs
+++ b/primitives/state-machine/src/overlayed_changes/mod.rs
@@ -103,12 +103,35 @@ pub struct OverlayedChanges {
 	children: Map<StorageKey, (OverlayedChangeSet, ChildInfo)>,
 	/// Offchain related changes.
 	offchain: OffchainOverlayedChanges,
+	/// Transaction index changes,
+	transaction_index_ops: Vec<IndexOperation>,
 	/// True if extrinsics stats must be collected.
 	collect_extrinsics: bool,
 	/// Collect statistic on this execution.
 	stats: StateMachineStats,
 }
 
+/// Transcation index operation.
+#[derive(Debug, Clone)]
+pub enum IndexOperation {
+	/// Insert transaction into index.
+	Insert {
+		/// Extrinsic index in the current block.
+		extrinsic: u32,
+		/// Data offset in the extrinsic.
+		offset: u32,
+	},
+	/// Renew existing transaction storage.
+	Renew {
+		/// Extrinsic index in the current block.
+		extrinsic: u32,
+		/// Referenced index hash.
+		hash: Vec<u8>,
+		/// Expected data size.
+		size: u32,
+	}
+}
+
 /// A storage changes structure that can be generated by the data collected in [`OverlayedChanges`].
 ///
 /// This contains all the changes to the storage and transactions to apply theses changes to the
@@ -137,6 +160,10 @@ pub struct StorageChanges<Transaction, H: Hasher, N: BlockNumber> {
 	/// Phantom data for block number until change trie support no_std.
 	#[cfg(not(feature = "std"))]
 	pub _ph: sp_std::marker::PhantomData<N>,
+
+	/// Changes to the transaction index,
+	#[cfg(feature = "std")]
+	pub transaction_index_changes: Vec<IndexOperation>,
 }
 
 #[cfg(feature = "std")]
@@ -149,6 +176,7 @@ impl<Transaction, H: Hasher, N: BlockNumber> StorageChanges<Transaction, H, N> {
 		Transaction,
 		H::Out,
 		Option<ChangesTrieTransaction<H, N>>,
+		Vec<IndexOperation>,
 	) {
 		(
 			self.main_storage_changes,
@@ -157,6 +185,7 @@ impl<Transaction, H: Hasher, N: BlockNumber> StorageChanges<Transaction, H, N> {
 			self.transaction,
 			self.transaction_storage_root,
 			self.changes_trie_transaction,
+			self.transaction_index_changes,
 		)
 	}
 }
@@ -214,6 +243,8 @@ impl<Transaction: Default, H: Hasher, N: BlockNumber> Default for StorageChanges
 			changes_trie_transaction: None,
 			#[cfg(not(feature = "std"))]
 			_ph: Default::default(),
+			#[cfg(feature = "std")]
+			transaction_index_changes: Default::default(),
 		}
 	}
 }
@@ -543,6 +574,9 @@ impl OverlayedChanges {
 		let (main_storage_changes, child_storage_changes) = self.drain_committed();
 		let offchain_storage_changes = self.offchain_drain_committed().collect();
 
+		#[cfg(feature = "std")]
+		let transaction_index_changes = std::mem::take(&mut self.transaction_index_ops);
+
 		Ok(StorageChanges {
 			main_storage_changes: main_storage_changes.collect(),
 			child_storage_changes: child_storage_changes.map(|(sk, it)| (sk, it.0.collect())).collect(),
@@ -551,6 +585,8 @@ impl OverlayedChanges {
 			transaction_storage_root,
 			#[cfg(feature = "std")]
 			changes_trie_transaction,
+			#[cfg(feature = "std")]
+			transaction_index_changes,
 			#[cfg(not(feature = "std"))]
 			_ph: Default::default(),
 		})
@@ -666,6 +702,11 @@ impl OverlayedChanges {
 			None => self.offchain.remove(STORAGE_PREFIX, key),
 		}
 	}
+
+	/// Add transaction index operation.
+	pub fn add_transaction_index(&mut self, op: IndexOperation) {
+		self.transaction_index_ops.push(op)
+	}
 }
 
 #[cfg(feature = "std")]
diff --git a/primitives/timestamp/src/lib.rs b/primitives/timestamp/src/lib.rs
index e6ef62b5c59c8..846ba67aec739 100644
--- a/primitives/timestamp/src/lib.rs
+++ b/primitives/timestamp/src/lib.rs
@@ -23,6 +23,7 @@ use codec::{Encode, Decode};
 #[cfg(feature = "std")]
 use sp_inherents::ProvideInherentData;
 use sp_inherents::{InherentIdentifier, IsFatalError, InherentData};
+use sp_std::time::Duration;
 
 use sp_runtime::RuntimeString;
 
@@ -43,6 +44,11 @@ impl Timestamp {
 	pub const fn new(inner: u64) -> Self {
 		Self(inner)
 	}
+
+	/// Returns `self` as [`Duration`].
+	pub fn as_duration(&self) -> Duration {
+		Duration::from_millis(self.0)
+	}
 }
 
 impl sp_std::ops::Deref for Timestamp {
@@ -100,8 +106,8 @@ impl From<Timestamp> for u64 {
 	}
 }
 
-impl From<sp_std::time::Duration> for Timestamp {
-	fn from(duration: sp_std::time::Duration) -> Self {
+impl From<Duration> for Timestamp {
+	fn from(duration: Duration) -> Self {
 		Timestamp(duration.as_millis() as u64)
 	}
 }
diff --git a/ss58-registry.json b/ss58-registry.json
index 23ea3f8b6ed13..97b3b064e96df 100644
--- a/ss58-registry.json
+++ b/ss58-registry.json
@@ -60,9 +60,9 @@
 			"network": "plasm",
 			"displayName": "Plasm Network",
 			"symbols": ["PLM"],
-			"decimals": null,
+			"decimals": [15],
 			"standardAccount": "*25519",
-			"website": null
+			"website": "https://plasmnet.io"
 		},
 		{
 			"prefix": 6,
@@ -477,6 +477,15 @@
 			"decimals": [12],
 			"standardAccount": "*25519",
 			"website": "https://crust.network"
+		},
+		{
+			"prefix": 252,
+			"network": "social-network",
+			"displayName": "Social Network",
+			"symbols": ["NET"],
+			"decimals": [18],
+			"standardAccount": "*25519",
+			"website": "https://social.network"
 		}
 	]
 }
diff --git a/test-utils/client/Cargo.toml b/test-utils/client/Cargo.toml
index df1cca2101ad7..925a69e41bb48 100644
--- a/test-utils/client/Cargo.toml
+++ b/test-utils/client/Cargo.toml
@@ -33,3 +33,4 @@ sp-keystore = { version = "0.9.0", path = "../../primitives/keystore" }
 sp-keyring = { version = "3.0.0", path = "../../primitives/keyring" }
 sp-runtime = { version = "3.0.0", path = "../../primitives/runtime" }
 sp-state-machine = { version = "0.9.0", path = "../../primitives/state-machine" }
+async-trait = "0.1.42"
diff --git a/test-utils/client/src/client_ext.rs b/test-utils/client/src/client_ext.rs
index db3e42f7e01c2..edba96d760fc2 100644
--- a/test-utils/client/src/client_ext.rs
+++ b/test-utils/client/src/client_ext.rs
@@ -24,7 +24,7 @@ use sp_consensus::{
 	BlockImportParams, BlockImport, BlockOrigin, Error as ConsensusError,
 	ForkChoiceStrategy,
 };
-use sp_runtime::Justification;
+use sp_runtime::{Justification, Justifications};
 use sp_runtime::traits::{Block as BlockT};
 use sp_runtime::generic::BlockId;
 use codec::alloc::collections::hash_map::HashMap;
@@ -43,23 +43,24 @@ pub trait ClientExt<Block: BlockT>: Sized {
 }
 
 /// Extension trait for a test client around block importing.
+#[async_trait::async_trait]
 pub trait ClientBlockImportExt<Block: BlockT>: Sized {
 	/// Import block to the chain. No finality.
-	fn import(&mut self, origin: BlockOrigin, block: Block) -> Result<(), ConsensusError>;
+	async fn import(&mut self, origin: BlockOrigin, block: Block) -> Result<(), ConsensusError>;
 
 	/// Import a block and make it our best block if possible.
-	fn import_as_best(&mut self, origin: BlockOrigin, block: Block) -> Result<(), ConsensusError>;
+	async fn import_as_best(&mut self, origin: BlockOrigin, block: Block) -> Result<(), ConsensusError>;
 
 	/// Import a block and finalize it.
-	fn import_as_final(&mut self, origin: BlockOrigin, block: Block)
+	async fn import_as_final(&mut self, origin: BlockOrigin, block: Block)
 		-> Result<(), ConsensusError>;
 
-	/// Import block with justification, finalizes block.
-	fn import_justified(
+	/// Import block with justification(s), finalizes block.
+	async fn import_justified(
 		&mut self,
 		origin: BlockOrigin,
 		block: Block,
-		justification: Justification
+		justifications: Justifications,
 	) -> Result<(), ConsensusError>;
 }
 
@@ -84,99 +85,132 @@ impl<B, E, RA, Block> ClientExt<Block> for Client<B, E, Block, RA>
 }
 
 /// This implementation is required, because of the weird api requirements around `BlockImport`.
+#[async_trait::async_trait]
 impl<Block: BlockT, T, Transaction> ClientBlockImportExt<Block> for std::sync::Arc<T>
-	where for<'r> &'r T: BlockImport<Block, Error = ConsensusError, Transaction = Transaction>
+	where
+		for<'r> &'r T: BlockImport<Block, Error = ConsensusError, Transaction = Transaction>,
+		Transaction: Send + 'static,
+		T: Send + Sync,
 {
-	fn import(&mut self, origin: BlockOrigin, block: Block) -> Result<(), ConsensusError> {
+	async fn import(
+		&mut self,
+		origin: BlockOrigin,
+		block: Block,
+	) -> Result<(), ConsensusError> {
 		let (header, extrinsics) = block.deconstruct();
 		let mut import = BlockImportParams::new(origin, header);
 		import.body = Some(extrinsics);
 		import.fork_choice = Some(ForkChoiceStrategy::LongestChain);
 
-		BlockImport::import_block(self, import, HashMap::new()).map(|_| ())
+		BlockImport::import_block(self, import, HashMap::new()).await.map(|_| ())
 	}
 
-	fn import_as_best(&mut self, origin: BlockOrigin, block: Block) -> Result<(), ConsensusError> {
+	async fn import_as_best(
+		&mut self,
+		origin: BlockOrigin,
+		block: Block,
+	) -> Result<(), ConsensusError> {
 		let (header, extrinsics) = block.deconstruct();
 		let mut import = BlockImportParams::new(origin, header);
 		import.body = Some(extrinsics);
 		import.fork_choice = Some(ForkChoiceStrategy::Custom(true));
 
-		BlockImport::import_block(self, import, HashMap::new()).map(|_| ())
+		BlockImport::import_block(self, import, HashMap::new()).await.map(|_| ())
 	}
 
-	fn import_as_final(&mut self, origin: BlockOrigin, block: Block) -> Result<(), ConsensusError> {
+	async fn import_as_final(
+		&mut self,
+		origin: BlockOrigin,
+		block: Block,
+	) -> Result<(), ConsensusError> {
 		let (header, extrinsics) = block.deconstruct();
 		let mut import = BlockImportParams::new(origin, header);
 		import.body = Some(extrinsics);
 		import.finalized = true;
 		import.fork_choice = Some(ForkChoiceStrategy::Custom(true));
 
-		BlockImport::import_block(self, import, HashMap::new()).map(|_| ())
+		BlockImport::import_block(self, import, HashMap::new()).await.map(|_| ())
 	}
 
-	fn import_justified(
+	async fn import_justified(
 		&mut self,
 		origin: BlockOrigin,
 		block: Block,
-		justification: Justification,
+		justifications: Justifications,
 	) -> Result<(), ConsensusError> {
 		let (header, extrinsics) = block.deconstruct();
 		let mut import = BlockImportParams::new(origin, header);
-		import.justification = Some(justification);
+		import.justifications = Some(justifications);
 		import.body = Some(extrinsics);
 		import.finalized = true;
 		import.fork_choice = Some(ForkChoiceStrategy::LongestChain);
 
-		BlockImport::import_block(self, import, HashMap::new()).map(|_| ())
+		BlockImport::import_block(self, import, HashMap::new()).await.map(|_| ())
 	}
 }
 
+#[async_trait::async_trait]
 impl<B, E, RA, Block: BlockT> ClientBlockImportExt<Block> for Client<B, E, Block, RA>
 	where
 		Self: BlockImport<Block, Error = ConsensusError>,
+		RA: Send,
+		B: Send + Sync,
+		E: Send,
+		<Self as BlockImport<Block>>::Transaction: Send,
 {
-	fn import(&mut self, origin: BlockOrigin, block: Block) -> Result<(), ConsensusError> {
+	async fn import(
+		&mut self,
+		origin: BlockOrigin,
+		block: Block,
+	) -> Result<(), ConsensusError> {
 		let (header, extrinsics) = block.deconstruct();
 		let mut import = BlockImportParams::new(origin, header);
 		import.body = Some(extrinsics);
 		import.fork_choice = Some(ForkChoiceStrategy::LongestChain);
 
-		BlockImport::import_block(self, import, HashMap::new()).map(|_| ())
+		BlockImport::import_block(self, import, HashMap::new()).await.map(|_| ())
 	}
 
-	fn import_as_best(&mut self, origin: BlockOrigin, block: Block) -> Result<(), ConsensusError> {
+	async fn import_as_best(
+		&mut self,
+		origin: BlockOrigin,
+		block: Block,
+	) -> Result<(), ConsensusError> {
 		let (header, extrinsics) = block.deconstruct();
 		let mut import = BlockImportParams::new(origin, header);
 		import.body = Some(extrinsics);
 		import.fork_choice = Some(ForkChoiceStrategy::Custom(true));
 
-		BlockImport::import_block(self, import, HashMap::new()).map(|_| ())
+		BlockImport::import_block(self, import, HashMap::new()).await.map(|_| ())
 	}
 
-	fn import_as_final(&mut self, origin: BlockOrigin, block: Block) -> Result<(), ConsensusError> {
+	async fn import_as_final(
+		&mut self,
+		origin: BlockOrigin,
+		block: Block,
+	) -> Result<(), ConsensusError> {
 		let (header, extrinsics) = block.deconstruct();
 		let mut import = BlockImportParams::new(origin, header);
 		import.body = Some(extrinsics);
 		import.finalized = true;
 		import.fork_choice = Some(ForkChoiceStrategy::Custom(true));
 
-		BlockImport::import_block(self, import, HashMap::new()).map(|_| ())
+		BlockImport::import_block(self, import, HashMap::new()).await.map(|_| ())
 	}
 
-	fn import_justified(
+	async fn import_justified(
 		&mut self,
 		origin: BlockOrigin,
 		block: Block,
-		justification: Justification,
+		justifications: Justifications,
 	) -> Result<(), ConsensusError> {
 		let (header, extrinsics) = block.deconstruct();
 		let mut import = BlockImportParams::new(origin, header);
-		import.justification = Some(justification);
+		import.justifications = Some(justifications);
 		import.body = Some(extrinsics);
 		import.finalized = true;
 		import.fork_choice = Some(ForkChoiceStrategy::LongestChain);
 
-		BlockImport::import_block(self, import, HashMap::new()).map(|_| ())
+		BlockImport::import_block(self, import, HashMap::new()).await.map(|_| ())
 	}
 }
diff --git a/test-utils/runtime/Cargo.toml b/test-utils/runtime/Cargo.toml
index 89da7929e64b8..96b7efff83380 100644
--- a/test-utils/runtime/Cargo.toml
+++ b/test-utils/runtime/Cargo.toml
@@ -53,6 +53,7 @@ serde = { version = "1.0.101", optional = true, features = ["derive"] }
 sc-block-builder = { version = "0.9.0", path = "../../client/block-builder" }
 sc-executor = { version = "0.9.0", path = "../../client/executor" }
 substrate-test-runtime-client = { version = "2.0.0", path = "./client" }
+futures = "0.3.9"
 
 [build-dependencies]
 substrate-wasm-builder = { version = "4.0.0", path = "../../utils/wasm-builder" }
diff --git a/test-utils/runtime/client/src/trait_tests.rs b/test-utils/runtime/client/src/trait_tests.rs
index 5a8083065ec0d..32d94dd618a7d 100644
--- a/test-utils/runtime/client/src/trait_tests.rs
+++ b/test-utils/runtime/client/src/trait_tests.rs
@@ -32,6 +32,7 @@ use substrate_test_runtime::{self, Transfer};
 use sp_runtime::generic::BlockId;
 use sp_runtime::traits::{Block as BlockT, HashFor};
 use sc_block_builder::BlockBuilderProvider;
+use futures::executor::block_on;
 
 /// helper to test the `leaves` implementation for various backends
 pub fn test_leaves_for_backend<B: 'static>(backend: Arc<B>) where
@@ -57,7 +58,7 @@ pub fn test_leaves_for_backend<B: 'static>(backend: Arc<B>) where
 
 	// G -> A1
 	let a1 = client.new_block(Default::default()).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a1.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a1.clone())).unwrap();
 	assert_eq!(
 		blockchain.leaves().unwrap(),
 		vec![a1.hash()],
@@ -69,7 +70,7 @@ pub fn test_leaves_for_backend<B: 'static>(backend: Arc<B>) where
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a2.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a2.clone())).unwrap();
 
 	#[allow(deprecated)]
 	assert_eq!(
@@ -83,7 +84,7 @@ pub fn test_leaves_for_backend<B: 'static>(backend: Arc<B>) where
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a3.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a3.clone())).unwrap();
 
 	assert_eq!(
 		blockchain.leaves().unwrap(),
@@ -96,7 +97,7 @@ pub fn test_leaves_for_backend<B: 'static>(backend: Arc<B>) where
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a4.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a4.clone())).unwrap();
 	assert_eq!(
 		blockchain.leaves().unwrap(),
 		vec![a4.hash()],
@@ -109,7 +110,7 @@ pub fn test_leaves_for_backend<B: 'static>(backend: Arc<B>) where
 		false,
 	).unwrap().build().unwrap().block;
 
-	client.import(BlockOrigin::Own, a5.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a5.clone())).unwrap();
 	assert_eq!(
 		blockchain.leaves().unwrap(),
 		vec![a5.hash()],
@@ -130,7 +131,7 @@ pub fn test_leaves_for_backend<B: 'static>(backend: Arc<B>) where
 		nonce: 0,
 	}).unwrap();
 	let b2 = builder.build().unwrap().block;
-	client.import(BlockOrigin::Own, b2.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, b2.clone())).unwrap();
 	assert_eq!(
 		blockchain.leaves().unwrap(),
 		vec![a5.hash(), b2.hash()],
@@ -143,7 +144,7 @@ pub fn test_leaves_for_backend<B: 'static>(backend: Arc<B>) where
 		false,
 	).unwrap().build().unwrap().block;
 
-	client.import(BlockOrigin::Own, b3.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, b3.clone())).unwrap();
 	assert_eq!(
 		blockchain.leaves().unwrap(),
 		vec![a5.hash(), b3.hash()],
@@ -155,7 +156,7 @@ pub fn test_leaves_for_backend<B: 'static>(backend: Arc<B>) where
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, b4.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, b4.clone())).unwrap();
 	assert_eq!(
 		blockchain.leaves().unwrap(),
 		vec![a5.hash(), b4.hash()],
@@ -175,7 +176,7 @@ pub fn test_leaves_for_backend<B: 'static>(backend: Arc<B>) where
 		nonce: 1,
 	}).unwrap();
 	let c3 = builder.build().unwrap().block;
-	client.import(BlockOrigin::Own, c3.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, c3.clone())).unwrap();
 	assert_eq!(
 		blockchain.leaves().unwrap(),
 		vec![a5.hash(), b4.hash(), c3.hash()],
@@ -195,7 +196,7 @@ pub fn test_leaves_for_backend<B: 'static>(backend: Arc<B>) where
 		nonce: 0,
 	}).unwrap();
 	let d2 = builder.build().unwrap().block;
-	client.import(BlockOrigin::Own, d2.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, d2.clone())).unwrap();
 	assert_eq!(
 		blockchain.leaves().unwrap(),
 		vec![a5.hash(), b4.hash(), c3.hash(), d2.hash()],
@@ -220,7 +221,7 @@ pub fn test_children_for_backend<B: 'static>(backend: Arc<B>) where
 
 	// G -> A1
 	let a1 = client.new_block(Default::default()).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a1.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a1.clone())).unwrap();
 
 	// A1 -> A2
 	let a2 = client.new_block_at(
@@ -228,7 +229,7 @@ pub fn test_children_for_backend<B: 'static>(backend: Arc<B>) where
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a2.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a2.clone())).unwrap();
 
 	// A2 -> A3
 	let a3 = client.new_block_at(
@@ -236,7 +237,7 @@ pub fn test_children_for_backend<B: 'static>(backend: Arc<B>) where
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a3.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a3.clone())).unwrap();
 
 	// A3 -> A4
 	let a4 = client.new_block_at(
@@ -244,7 +245,7 @@ pub fn test_children_for_backend<B: 'static>(backend: Arc<B>) where
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a4.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a4.clone())).unwrap();
 
 	// A4 -> A5
 	let a5 = client.new_block_at(
@@ -252,7 +253,7 @@ pub fn test_children_for_backend<B: 'static>(backend: Arc<B>) where
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a5.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a5.clone())).unwrap();
 
 	// A1 -> B2
 	let mut builder = client.new_block_at(
@@ -268,7 +269,7 @@ pub fn test_children_for_backend<B: 'static>(backend: Arc<B>) where
 		nonce: 0,
 	}).unwrap();
 	let b2 = builder.build().unwrap().block;
-	client.import(BlockOrigin::Own, b2.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, b2.clone())).unwrap();
 
 	// B2 -> B3
 	let b3 = client.new_block_at(
@@ -276,7 +277,7 @@ pub fn test_children_for_backend<B: 'static>(backend: Arc<B>) where
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, b3.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, b3.clone())).unwrap();
 
 	// B3 -> B4
 	let b4 = client.new_block_at(
@@ -284,7 +285,7 @@ pub fn test_children_for_backend<B: 'static>(backend: Arc<B>) where
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, b4).unwrap();
+	block_on(client.import(BlockOrigin::Own, b4)).unwrap();
 
 	// // B2 -> C3
 	let mut builder = client.new_block_at(
@@ -300,7 +301,7 @@ pub fn test_children_for_backend<B: 'static>(backend: Arc<B>) where
 		nonce: 1,
 	}).unwrap();
 	let c3 = builder.build().unwrap().block;
-	client.import(BlockOrigin::Own, c3.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, c3.clone())).unwrap();
 
 	// A1 -> D2
 	let mut builder = client.new_block_at(
@@ -316,7 +317,7 @@ pub fn test_children_for_backend<B: 'static>(backend: Arc<B>) where
 		nonce: 0,
 	}).unwrap();
 	let d2 = builder.build().unwrap().block;
-	client.import(BlockOrigin::Own, d2.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, d2.clone())).unwrap();
 
 	let genesis_hash = client.chain_info().genesis_hash;
 
@@ -349,7 +350,7 @@ pub fn test_blockchain_query_by_number_gets_canonical<B: 'static>(backend: Arc<B
 
 	// G -> A1
 	let a1 = client.new_block(Default::default()).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a1.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a1.clone())).unwrap();
 
 	// A1 -> A2
 	let a2 = client.new_block_at(
@@ -357,7 +358,7 @@ pub fn test_blockchain_query_by_number_gets_canonical<B: 'static>(backend: Arc<B
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a2.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a2.clone())).unwrap();
 
 	// A2 -> A3
 	let a3 = client.new_block_at(
@@ -365,7 +366,7 @@ pub fn test_blockchain_query_by_number_gets_canonical<B: 'static>(backend: Arc<B
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a3.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a3.clone())).unwrap();
 
 	// A3 -> A4
 	let a4 = client.new_block_at(
@@ -373,7 +374,7 @@ pub fn test_blockchain_query_by_number_gets_canonical<B: 'static>(backend: Arc<B
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a4.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a4.clone())).unwrap();
 
 	// A4 -> A5
 	let a5 = client.new_block_at(
@@ -381,7 +382,7 @@ pub fn test_blockchain_query_by_number_gets_canonical<B: 'static>(backend: Arc<B
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, a5.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, a5.clone())).unwrap();
 
 	// A1 -> B2
 	let mut builder = client.new_block_at(
@@ -397,7 +398,7 @@ pub fn test_blockchain_query_by_number_gets_canonical<B: 'static>(backend: Arc<B
 		nonce: 0,
 	}).unwrap();
 	let b2 = builder.build().unwrap().block;
-	client.import(BlockOrigin::Own, b2.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, b2.clone())).unwrap();
 
 	// B2 -> B3
 	let b3 = client.new_block_at(
@@ -405,7 +406,7 @@ pub fn test_blockchain_query_by_number_gets_canonical<B: 'static>(backend: Arc<B
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, b3.clone()).unwrap();
+	block_on(client.import(BlockOrigin::Own, b3.clone())).unwrap();
 
 	// B3 -> B4
 	let b4 = client.new_block_at(
@@ -413,7 +414,7 @@ pub fn test_blockchain_query_by_number_gets_canonical<B: 'static>(backend: Arc<B
 		Default::default(),
 		false,
 	).unwrap().build().unwrap().block;
-	client.import(BlockOrigin::Own, b4).unwrap();
+	block_on(client.import(BlockOrigin::Own, b4)).unwrap();
 
 	// // B2 -> C3
 	let mut builder = client.new_block_at(
@@ -429,7 +430,7 @@ pub fn test_blockchain_query_by_number_gets_canonical<B: 'static>(backend: Arc<B
 		nonce: 1,
 	}).unwrap();
 	let c3 = builder.build().unwrap().block;
-	client.import(BlockOrigin::Own, c3).unwrap();
+	block_on(client.import(BlockOrigin::Own, c3)).unwrap();
 
 	// A1 -> D2
 	let mut builder = client.new_block_at(
@@ -445,7 +446,7 @@ pub fn test_blockchain_query_by_number_gets_canonical<B: 'static>(backend: Arc<B
 		nonce: 0,
 	}).unwrap();
 	let d2 = builder.build().unwrap().block;
-	client.import(BlockOrigin::Own, d2).unwrap();
+	block_on(client.import(BlockOrigin::Own, d2)).unwrap();
 
 	let genesis_hash = client.chain_info().genesis_hash;
 
diff --git a/test-utils/runtime/src/lib.rs b/test-utils/runtime/src/lib.rs
index 5f80dc93a95f2..460494bfbd93a 100644
--- a/test-utils/runtime/src/lib.rs
+++ b/test-utils/runtime/src/lib.rs
@@ -451,13 +451,13 @@ impl From<frame_system::Event<Runtime>> for Event {
 impl frame_support::traits::PalletInfo for Runtime {
 	fn index<P: 'static>() -> Option<usize> {
 		let type_id = sp_std::any::TypeId::of::<P>();
-		if type_id == sp_std::any::TypeId::of::<system::Module<Runtime>>() {
+		if type_id == sp_std::any::TypeId::of::<system::Pallet<Runtime>>() {
 			return Some(0)
 		}
-		if type_id == sp_std::any::TypeId::of::<pallet_timestamp::Module<Runtime>>() {
+		if type_id == sp_std::any::TypeId::of::<pallet_timestamp::Pallet<Runtime>>() {
 			return Some(1)
 		}
-		if type_id == sp_std::any::TypeId::of::<pallet_babe::Module<Runtime>>() {
+		if type_id == sp_std::any::TypeId::of::<pallet_babe::Pallet<Runtime>>() {
 			return Some(2)
 		}
 
@@ -465,13 +465,13 @@ impl frame_support::traits::PalletInfo for Runtime {
 	}
 	fn name<P: 'static>() -> Option<&'static str> {
 		let type_id = sp_std::any::TypeId::of::<P>();
-		if type_id == sp_std::any::TypeId::of::<system::Module<Runtime>>() {
+		if type_id == sp_std::any::TypeId::of::<system::Pallet<Runtime>>() {
 			return Some("System")
 		}
-		if type_id == sp_std::any::TypeId::of::<pallet_timestamp::Module<Runtime>>() {
+		if type_id == sp_std::any::TypeId::of::<pallet_timestamp::Pallet<Runtime>>() {
 			return Some("Timestamp")
 		}
-		if type_id == sp_std::any::TypeId::of::<pallet_babe::Module<Runtime>>() {
+		if type_id == sp_std::any::TypeId::of::<pallet_babe::Pallet<Runtime>>() {
 			return Some("Babe")
 		}
 
@@ -762,7 +762,10 @@ cfg_if! {
 			}
 
 			impl sp_consensus_aura::AuraApi<Block, AuraId> for Runtime {
-				fn slot_duration() -> u64 { 1000 }
+				fn slot_duration() -> sp_consensus_aura::SlotDuration {
+					sp_consensus_aura::SlotDuration::from_millis(1000)
+				}
+
 				fn authorities() -> Vec<AuraId> {
 					system::authorities().into_iter().map(|a| {
 						let authority: sr25519::Public = a.into();
@@ -779,21 +782,21 @@ cfg_if! {
 						c: (3, 10),
 						genesis_authorities: system::authorities()
 							.into_iter().map(|x|(x, 1)).collect(),
-						randomness: <pallet_babe::Module<Runtime>>::randomness(),
+						randomness: <pallet_babe::Pallet<Runtime>>::randomness(),
 						allowed_slots: AllowedSlots::PrimaryAndSecondaryPlainSlots,
 					}
 				}
 
 				fn current_epoch_start() -> Slot {
-					<pallet_babe::Module<Runtime>>::current_epoch_start()
+					<pallet_babe::Pallet<Runtime>>::current_epoch_start()
 				}
 
 				fn current_epoch() -> sp_consensus_babe::Epoch {
-					<pallet_babe::Module<Runtime>>::current_epoch()
+					<pallet_babe::Pallet<Runtime>>::current_epoch()
 				}
 
 				fn next_epoch() -> sp_consensus_babe::Epoch {
-					<pallet_babe::Module<Runtime>>::next_epoch()
+					<pallet_babe::Pallet<Runtime>>::next_epoch()
 				}
 
 				fn submit_report_equivocation_unsigned_extrinsic(
@@ -1020,7 +1023,10 @@ cfg_if! {
 			}
 
 			impl sp_consensus_aura::AuraApi<Block, AuraId> for Runtime {
-				fn slot_duration() -> u64 { 1000 }
+				fn slot_duration() -> sp_consensus_aura::SlotDuration {
+					sp_consensus_aura::SlotDuration::from_millis(1000)
+				}
+
 				fn authorities() -> Vec<AuraId> {
 					system::authorities().into_iter().map(|a| {
 						let authority: sr25519::Public = a.into();
@@ -1037,21 +1043,21 @@ cfg_if! {
 						c: (3, 10),
 						genesis_authorities: system::authorities()
 							.into_iter().map(|x|(x, 1)).collect(),
-						randomness: <pallet_babe::Module<Runtime>>::randomness(),
+						randomness: <pallet_babe::Pallet<Runtime>>::randomness(),
 						allowed_slots: AllowedSlots::PrimaryAndSecondaryPlainSlots,
 					}
 				}
 
 				fn current_epoch_start() -> Slot {
-					<pallet_babe::Module<Runtime>>::current_epoch_start()
+					<pallet_babe::Pallet<Runtime>>::current_epoch_start()
 				}
 
 				fn current_epoch() -> sp_consensus_babe::Epoch {
-					<pallet_babe::Module<Runtime>>::current_epoch()
+					<pallet_babe::Pallet<Runtime>>::current_epoch()
 				}
 
 				fn next_epoch() -> sp_consensus_babe::Epoch {
-					<pallet_babe::Module<Runtime>>::next_epoch()
+					<pallet_babe::Pallet<Runtime>>::next_epoch()
 				}
 
 				fn submit_report_equivocation_unsigned_extrinsic(
@@ -1255,7 +1261,7 @@ mod tests {
 			(BlockId::Hash(hash), block)
 		};
 
-		client.import(BlockOrigin::Own, block).unwrap();
+		futures::executor::block_on(client.import(BlockOrigin::Own, block)).unwrap();
 
 		// Allocation of 1024k while having ~2048k should succeed.
 		let ret = client.runtime_api().vec_with_capacity(&new_block_id, 1048576);
diff --git a/test-utils/test-runner/Cargo.toml b/test-utils/test-runner/Cargo.toml
new file mode 100644
index 0000000000000..4d9d6125bd4e4
--- /dev/null
+++ b/test-utils/test-runner/Cargo.toml
@@ -0,0 +1,60 @@
+[package]
+name = "test-runner"
+version = "0.9.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+edition = "2018"
+publish = false
+
+[dependencies]
+# client deps
+sc-executor = { version = "0.9.0", path = "../../client/executor" }
+sc-service = { version = "0.9.0", path = "../../client/service" }
+sc-informant = { version = "0.9.0", path = "../../client/informant" }
+sc-network = { version = "0.9.0", path = "../../client/network" }
+sc-cli = { version = "0.9.0", path = "../../client/cli" }
+sc-basic-authorship = { version = "0.9.0", path = "../../client/basic-authorship" }
+sc-rpc = { version = "3.0.0", path = "../../client/rpc" }
+sc-transaction-pool = { version = "3.0.0", path = "../../client/transaction-pool" }
+sc-transaction-graph = { version = "3.0.0", path = "../../client/transaction-pool/graph" }
+sc-client-api = { version = "3.0.0", path = "../../client/api" }
+sc-rpc-server = { version = "3.0.0", path = "../../client/rpc-servers" }
+manual-seal = { package = "sc-consensus-manual-seal", version = "0.9.0", path = "../../client/consensus/manual-seal" }
+
+# primitive deps
+sp-core = { version = "3.0.0", path = "../../primitives/core" }
+sp-blockchain = { version = "3.0.0", path = "../../primitives/blockchain" }
+sp-block-builder = { version = "3.0.0", path = "../../primitives/block-builder" }
+sp-api = { version = "3.0.0", path = "../../primitives/api" }
+sp-io = { version = "3.0.0", path = "../../primitives/io" }
+sp-transaction-pool = { version = "3.0.0", path = "../../primitives/transaction-pool" }
+sp-consensus = { version = "0.9.0", path = "../../primitives/consensus/common" }
+sp-keystore = { version = "0.9.0", path = "../../primitives/keystore" }
+sp-runtime = { version = "3.0.0", path = "../../primitives/runtime" }
+sp-session = { version = "3.0.0", path = "../../primitives/session" }
+sp-offchain = { version = "3.0.0", path = "../../primitives/offchain" }
+sp-inherents = { version = "3.0.0", path = "../../primitives/inherents" }
+sp-keyring = { version = "3.0.0", path = "../../primitives/keyring" }
+
+sp-externalities = { version = "0.9.0", path = "../../primitives/externalities" }
+sp-state-machine = { version = "0.9.0", path = "../../primitives/state-machine" }
+sp-wasm-interface = { version = "3.0.0", path = "../../primitives/wasm-interface" }
+sp-runtime-interface = { version = "3.0.0", path = "../../primitives/runtime-interface" }
+
+# pallets
+frame-system = { version = "3.0.0", path = "../../frame/system" }
+
+parity-scale-codec = "1.3.1"
+env_logger = "0.7.1"
+log = "0.4.8"
+futures01 = { package = "futures", version = "0.1.29" }
+futures = { package = "futures", version = "0.3", features = ["compat"] }
+rand = "0.7"
+tokio = { version = "0.2", features = ["full"] }
+
+# Calling RPC
+jsonrpc-core = "15.1"
+[dev-dependencies]
+sc-finality-grandpa = { version = "0.9.0", path = "../../client/finality-grandpa" }
+sc-consensus-babe = { version = "0.9.0", path = "../../client/consensus/babe" }
+sp-consensus-babe = { version = "0.9.0", path = "../../primitives/consensus/babe" }
+node-cli = { version = "2.0.0", path = "../../bin/node/cli" }
diff --git a/test-utils/test-runner/src/host_functions.rs b/test-utils/test-runner/src/host_functions.rs
new file mode 100644
index 0000000000000..ca8790683e6c4
--- /dev/null
+++ b/test-utils/test-runner/src/host_functions.rs
@@ -0,0 +1,70 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+#[macro_export]
+macro_rules! override_host_functions {
+    ($($fn_name:expr, $name:ident,)*) => {{
+        let mut host_functions = vec![];
+        $(
+            struct $name;
+            impl sp_wasm_interface::Function for $name {
+                fn name(&self) -> &str {
+                    &$fn_name
+                }
+
+                fn signature(&self) -> sp_wasm_interface::Signature {
+                    sp_wasm_interface::Signature {
+                        args: std::borrow::Cow::Owned(vec![
+                            sp_wasm_interface::ValueType::I32,
+                            sp_wasm_interface::ValueType::I64,
+                            sp_wasm_interface::ValueType::I32,
+                        ]),
+                        return_value: Some(sp_wasm_interface::ValueType::I32),
+                    }
+                }
+
+                fn execute(
+                    &self,
+                    context: &mut dyn sp_wasm_interface::FunctionContext,
+                    _args: &mut dyn Iterator<Item = sp_wasm_interface::Value>,
+                ) -> Result<Option<sp_wasm_interface::Value>, String> {
+                    <bool as sp_runtime_interface::host::IntoFFIValue>::into_ffi_value(true, context)
+                        .map(sp_wasm_interface::IntoValue::into_value)
+                        .map(Some)
+                }
+            }
+            host_functions.push(&$name as &'static dyn sp_wasm_interface::Function);
+        )*
+        host_functions
+   }};
+}
+
+/// Provides host functions that overrides runtime signature verification
+/// to always return true.
+pub struct SignatureVerificationOverride;
+
+impl sp_wasm_interface::HostFunctions for SignatureVerificationOverride {
+    fn host_functions() -> Vec<&'static dyn sp_wasm_interface::Function> {
+        override_host_functions!(
+            "ext_crypto_ecdsa_verify_version_1", EcdsaVerify,
+            "ext_crypto_ed25519_verify_version_1", Ed25519Verify,
+            "ext_crypto_sr25519_verify_version_1", Sr25519Verify,
+            "ext_crypto_sr25519_verify_version_2", Sr25519VerifyV2,
+        )
+    }
+}
diff --git a/test-utils/test-runner/src/lib.rs b/test-utils/test-runner/src/lib.rs
new file mode 100644
index 0000000000000..87ec4336d9523
--- /dev/null
+++ b/test-utils/test-runner/src/lib.rs
@@ -0,0 +1,312 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+//! Test runner
+//! # Substrate Test Runner
+//!
+//! Allows you to test
+//! <br />
+//!
+//! -   Migrations
+//! -   Runtime Upgrades
+//! -   Pallets and general runtime functionality.
+//!
+//! This works by running a full node with a Manual Seal-BABE™ hybrid consensus for block authoring.
+//!
+//! <h2>Note</h2>
+//! The running node has no signature verification, which allows us author extrinsics for any account on chain.
+//!     <br/>
+//!     <br/>
+//!
+//! <h2>How do I Use this?</h2>
+//!
+//!
+//! ```rust,ignore
+//! use test_runner::{Node, ChainInfo, SignatureVerificationOverride, base_path, NodeConfig};
+//! use sc_finality_grandpa::GrandpaBlockImport;
+//! use sc_service::{
+//!     TFullBackend, TFullClient, Configuration, TaskManager, new_full_parts, BasePath,
+//!     DatabaseConfig, KeepBlocks, TransactionStorageMode, ChainSpec, Role,
+//!     config::{NetworkConfiguration, KeystoreConfig},
+//! };
+//! use std::sync::Arc;
+//! use sp_inherents::InherentDataProviders;
+//! use sc_consensus_babe::BabeBlockImport;
+//! use sp_keystore::SyncCryptoStorePtr;
+//! use sp_keyring::sr25519::Keyring::{Alice, Bob};
+//! use node_cli::chain_spec::development_config;
+//! use sp_consensus_babe::AuthorityId;
+//! use manual_seal::{ConsensusDataProvider, consensus::babe::BabeConsensusDataProvider};
+//! use sp_runtime::{traits::IdentifyAccount, MultiSigner, generic::Era};
+//! use sc_executor::WasmExecutionMethod;
+//! use sc_network::{multiaddr, config::TransportConfig};
+//! use sc_client_api::execution_extensions::ExecutionStrategies;
+//! use sc_informant::OutputFormat;
+//! use sp_api::TransactionFor;
+//!
+//! type BlockImport<B, BE, C, SC> = BabeBlockImport<B, C, GrandpaBlockImport<BE, B, C, SC>>;
+//!
+//! sc_executor::native_executor_instance!(
+//! 	pub Executor,
+//! 	node_runtime::api::dispatch,
+//! 	node_runtime::native_version,
+//! 	SignatureVerificationOverride,
+//! );
+//!
+//! struct Requirements;
+//!
+//! impl ChainInfo for Requirements {
+//!     /// Provide a Block type with an OpaqueExtrinsic
+//!     type Block = node_primitives::Block;
+//!     /// Provide an Executor type for the runtime
+//!     type Executor = Executor;
+//!     /// Provide the runtime itself
+//!     type Runtime = node_runtime::Runtime;
+//!     /// A touch of runtime api
+//!     type RuntimeApi = node_runtime::RuntimeApi;
+//!     /// A pinch of SelectChain implementation
+//!     type SelectChain = sc_consensus::LongestChain<TFullBackend<Self::Block>, Self::Block>;
+//!     /// A slice of concrete BlockImport type
+//! 	type BlockImport = BlockImport<
+//! 		Self::Block,
+//! 		TFullBackend<Self::Block>,
+//! 		TFullClient<Self::Block, Self::RuntimeApi, Self::Executor>,
+//! 		Self::SelectChain,
+//!     >;
+//!     /// and a dash of SignedExtensions
+//! 	type SignedExtras = node_runtime::SignedExtra;
+//!
+//!     /// Create your signed extras here.
+//! 	fn signed_extras(
+//! 		from: <Self::Runtime as frame_system::Config>::AccountId,
+//! 	) -> Self::SignedExtension {
+//! 		let nonce = frame_system::Pallet::<Self::Runtime>::account_nonce(from);
+//!
+//! 		(
+//! 			frame_system::CheckSpecVersion::<Self::Runtime>::new(),
+//! 			frame_system::CheckTxVersion::<Self::Runtime>::new(),
+//! 			frame_system::CheckGenesis::<Self::Runtime>::new(),
+//! 			frame_system::CheckMortality::<Self::Runtime>::from(Era::Immortal),
+//! 			frame_system::CheckNonce::<Self::Runtime>::from(nonce),
+//! 			frame_system::CheckWeight::<Self::Runtime>::new(),
+//! 			pallet_transaction_payment::ChargeTransactionPayment::<Self::Runtime>::from(0),
+//! 		)
+//! 	}
+//!
+//!     /// The function signature tells you all you need to know. ;)
+//! 	fn create_client_parts(config: &Configuration) -> Result<
+//! 		(
+//! 			Arc<TFullClient<Self::Block, Self::RuntimeApi, Self::Executor>>,
+//! 			Arc<TFullBackend<Self::Block>>,
+//! 			KeyStorePtr,
+//! 			TaskManager,
+//! 			InherentDataProviders,
+//! 			Option<Box<
+//! 				dyn ConsensusDataProvider<
+//! 					Self::Block,
+//! 					Transaction = TransactionFor<
+//! 						TFullClient<Self::Block, Self::RuntimeApi, Self::Executor>,
+//! 						Self::Block
+//! 					>,
+//! 				>
+//! 			>>,
+//! 			Self::SelectChain,
+//! 			Self::BlockImport
+//! 		),
+//! 		sc_service::Error
+//! 	> {
+//! 		let (
+//! 			client,
+//! 			backend,
+//! 			keystore,
+//! 			task_manager,
+//! 		) = new_full_parts::<Self::Block, Self::RuntimeApi, Self::Executor>(config)?;
+//! 		let client = Arc::new(client);
+//!
+//! 		let inherent_providers = InherentDataProviders::new();
+//! 		let select_chain = sc_consensus::LongestChain::new(backend.clone());
+//!
+//! 		let (grandpa_block_import, ..) =
+//! 			sc_finality_grandpa::block_import(client.clone(), &(client.clone() as Arc<_>), select_chain.clone())?;
+//!
+//! 		let (block_import, babe_link) = sc_consensus_babe::block_import(
+//! 			sc_consensus_babe::Config::get_or_compute(&*client)?,
+//! 			grandpa_block_import,
+//! 			client.clone(),
+//! 		)?;
+//!
+//! 		let consensus_data_provider = BabeConsensusDataProvider::new(
+//! 			client.clone(),
+//! 			keystore.clone(),
+//! 			&inherent_providers,
+//! 			babe_link.epoch_changes().clone(),
+//! 			vec![(AuthorityId::from(Alice.public()), 1000)]
+//! 		)
+//! 		.expect("failed to create ConsensusDataProvider");
+//!
+//! 		Ok((
+//! 			client,
+//! 			backend,
+//! 			keystore,
+//! 			task_manager,
+//! 			inherent_providers,
+//! 			Some(Box::new(consensus_data_provider)),
+//! 			select_chain,
+//! 			block_import
+//! 		))
+//! 	}
+//!
+//! 	fn dispatch_with_root(call: <Self::Runtime as frame_system::Config>::Call, node: &mut Node<Self>) {
+//!         let alice = MultiSigner::from(Alice.public()).into_account();
+//! 		// for chains that support sudo, otherwise, you'd have to use pallet-democracy here.
+//!         let call = pallet_sudo::Call::sudo(Box::new(call));
+//!         node.submit_extrinsic(call, alice);
+//!         node.seal_blocks(1);
+//!     }
+//! }
+//!
+//! /// And now for the most basic test
+//!
+//! #[test]
+//! fn simple_balances_test() {
+//! 	// given
+//! 	let config = NodeConfig {
+//!			execution_strategies: ExecutionStrategies {
+//!				syncing: sc_client_api::ExecutionStrategy::NativeWhenPossible,
+//!				importing: sc_client_api::ExecutionStrategy::NativeWhenPossible,
+//!				block_construction: sc_client_api::ExecutionStrategy::NativeWhenPossible,
+//!				offchain_worker: sc_client_api::ExecutionStrategy::NativeWhenPossible,
+//!				other: sc_client_api::ExecutionStrategy::NativeWhenPossible,
+//! 		},
+//! 		chain_spec: Box::new(development_config()),
+//! 		log_targets: vec![],
+//! 	};
+//! 	let mut node = Node::<Requirements>::new(config).unwrap();
+//!
+//! 	type Balances = pallet_balances::Pallet<node_runtime::Runtime>;
+//!
+//! 	let (alice, bob) = (Alice.pair(), Bob.pair());
+//! 	let (alice_account_id, bob_acount_id) = (
+//!         MultiSigner::from(alice.public()).into_account(),
+//!         MultiSigner::from(bob.public()).into_account()
+//!     );
+//!
+//!     /// the function with_state allows us to read state, pretty cool right? :D
+//! 	let old_balance = node.with_state(|| Balances::free_balance(alice_account_id.clone()));
+//!
+//!     // 70 dots
+//!     let amount = 70_000_000_000_000;
+//!
+//!     /// Send extrinsic in action.
+//! 	node.submit_extrinsic(BalancesCall::transfer(bob_acount_id.clone(), amount), alice_account_id.clone());
+//!
+//!     /// Produce blocks in action, Powered by manual-seal™.
+//! 	node.seal_blocks(1);
+//!
+//!     /// we can check the new state :D
+//! 	let new_balance = node.with_state(|| Balances::free_balance(alice_account_id));
+//!
+//!     /// we can now make assertions on how state has changed.
+//! 	assert_eq!(old_balance + amount, new_balance);
+//! }
+//! ```
+
+use manual_seal::consensus::ConsensusDataProvider;
+use sc_executor::NativeExecutionDispatch;
+use sc_service::{Configuration, TFullBackend, TFullClient, TaskManager};
+use sp_api::{ConstructRuntimeApi, TransactionFor};
+use sp_consensus::{BlockImport, SelectChain};
+use sp_inherents::InherentDataProviders;
+use sp_keystore::SyncCryptoStorePtr;
+use sp_runtime::traits::{Block as BlockT, SignedExtension};
+use std::sync::Arc;
+
+mod node;
+mod utils;
+mod host_functions;
+
+pub use host_functions::*;
+pub use node::*;
+
+/// Wrapper trait for concrete type required by this testing framework.
+pub trait ChainInfo: Sized {
+	/// Opaque block type
+	type Block: BlockT;
+
+	/// Executor type
+	type Executor: NativeExecutionDispatch + 'static;
+
+	/// Runtime
+	type Runtime: frame_system::Config;
+
+	/// RuntimeApi
+	type RuntimeApi: Send
+		+ Sync
+		+ 'static
+		+ ConstructRuntimeApi<Self::Block, TFullClient<Self::Block, Self::RuntimeApi, Self::Executor>>;
+
+	/// select chain type.
+	type SelectChain: SelectChain<Self::Block> + 'static;
+
+	/// Block import type.
+	type BlockImport: Send
+		+ Sync
+		+ Clone
+		+ BlockImport<
+			Self::Block,
+			Error = sp_consensus::Error,
+			Transaction = TransactionFor<TFullClient<Self::Block, Self::RuntimeApi, Self::Executor>, Self::Block>,
+		> + 'static;
+
+	/// The signed extras required by the runtime
+	type SignedExtras: SignedExtension;
+
+	/// Signed extras, this function is caled in an externalities provided environment.
+	fn signed_extras(from: <Self::Runtime as frame_system::Config>::AccountId) -> Self::SignedExtras;
+
+	/// Attempt to create client parts, including block import,
+	/// select chain strategy and consensus data provider.
+	fn create_client_parts(
+		config: &Configuration,
+	) -> Result<
+		(
+			Arc<TFullClient<Self::Block, Self::RuntimeApi, Self::Executor>>,
+			Arc<TFullBackend<Self::Block>>,
+			SyncCryptoStorePtr,
+			TaskManager,
+			InherentDataProviders,
+			Option<
+				Box<
+					dyn ConsensusDataProvider<
+						Self::Block,
+						Transaction = TransactionFor<
+							TFullClient<Self::Block, Self::RuntimeApi, Self::Executor>,
+							Self::Block,
+						>,
+					>,
+				>,
+			>,
+			Self::SelectChain,
+			Self::BlockImport,
+		),
+		sc_service::Error,
+	>;
+
+	/// Given a call and a handle to the node, execute the call with root privileges.
+	fn dispatch_with_root(call: <Self::Runtime as frame_system::Config>::Call, node: &mut Node<Self>);
+}
diff --git a/test-utils/test-runner/src/node.rs b/test-utils/test-runner/src/node.rs
new file mode 100644
index 0000000000000..6965c6a804dbe
--- /dev/null
+++ b/test-utils/test-runner/src/node.rs
@@ -0,0 +1,476 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+use std::sync::Arc;
+
+use futures::{FutureExt, SinkExt, channel::{mpsc, oneshot}};
+use jsonrpc_core::MetaIoHandler;
+use manual_seal::{run_manual_seal, EngineCommand, ManualSealParams};
+use sc_cli::build_runtime;
+use sc_client_api::{
+	backend::{self, Backend}, CallExecutor, ExecutorProvider,
+	execution_extensions::ExecutionStrategies,
+};
+use sc_service::{
+	build_network, spawn_tasks, BuildNetworkParams, SpawnTasksParams, TFullBackend,
+	TFullCallExecutor, TFullClient, TaskManager, TaskType, ChainSpec, BasePath,
+	Configuration, DatabaseConfig, KeepBlocks, TransactionStorageMode, config::KeystoreConfig,
+};
+use sc_transaction_pool::BasicPool;
+use sp_api::{ApiExt, ConstructRuntimeApi, Core, Metadata, OverlayedChanges, StorageTransactionCache};
+use sp_block_builder::BlockBuilder;
+use sp_blockchain::HeaderBackend;
+use sp_core::ExecutionContext;
+use sp_offchain::OffchainWorkerApi;
+use sp_runtime::traits::{Block as BlockT, Extrinsic};
+use sp_runtime::{generic::BlockId, transaction_validity::TransactionSource, MultiSignature, MultiAddress};
+use sp_runtime::{generic::UncheckedExtrinsic, traits::NumberFor};
+use sp_session::SessionKeys;
+use sp_state_machine::Ext;
+use sp_transaction_pool::runtime_api::TaggedTransactionQueue;
+use sp_transaction_pool::TransactionPool;
+
+pub use crate::utils::{logger, base_path};
+use crate::ChainInfo;
+use log::LevelFilter;
+use sp_keyring::sr25519::Keyring::Alice;
+use sc_network::{multiaddr, config::{NetworkConfiguration, TransportConfig, Role}};
+use sc_informant::OutputFormat;
+use sc_executor::WasmExecutionMethod;
+
+/// This holds a reference to a running node on another thread,
+/// the node process is dropped when this struct is dropped
+/// also holds logs from the process.
+pub struct Node<T: ChainInfo> {
+	/// rpc handler for communicating with the node over rpc.
+	rpc_handler: Arc<MetaIoHandler<sc_rpc::Metadata, sc_rpc_server::RpcMiddleware>>,
+	/// Stream of log lines
+	log_stream: mpsc::UnboundedReceiver<String>,
+	/// node tokio runtime
+	_runtime: tokio::runtime::Runtime,
+	/// handle to the running node.
+	_task_manager: Option<TaskManager>,
+	/// client instance
+	client: Arc<TFullClient<T::Block, T::RuntimeApi, T::Executor>>,
+	/// transaction pool
+	pool: Arc<
+		dyn TransactionPool<
+			Block = T::Block,
+			Hash = <T::Block as BlockT>::Hash,
+			Error = sc_transaction_pool::error::Error,
+			InPoolTransaction = sc_transaction_graph::base_pool::Transaction<
+				<T::Block as BlockT>::Hash,
+				<T::Block as BlockT>::Extrinsic,
+			>,
+		>,
+	>,
+	/// channel to communicate with manual seal on.
+	manual_seal_command_sink: mpsc::Sender<EngineCommand<<T::Block as BlockT>::Hash>>,
+	/// backend type.
+	backend: Arc<TFullBackend<T::Block>>,
+	/// Block number at initialization of this Node.
+	initial_block_number: NumberFor<T::Block>
+}
+
+/// Configuration options for the node.
+pub struct NodeConfig {
+	/// A set of log targets you'd like to enable/disbale
+	pub log_targets: Vec<(&'static str, LevelFilter)>,
+
+	/// ChainSpec for the runtime
+	pub chain_spec: Box<dyn ChainSpec>,
+
+	/// wasm execution strategies.
+	pub execution_strategies: ExecutionStrategies,
+}
+
+type EventRecord<T> = frame_system::EventRecord<<T as frame_system::Config>::Event, <T as frame_system::Config>::Hash>;
+
+impl<T: ChainInfo> Node<T> {
+	/// Starts a node with the manual-seal authorship.
+	pub fn new(node_config: NodeConfig) -> Result<Self, sc_service::Error>
+	where
+		<T::RuntimeApi as ConstructRuntimeApi<T::Block, TFullClient<T::Block, T::RuntimeApi, T::Executor>>>::RuntimeApi:
+			Core<T::Block>
+				+ Metadata<T::Block>
+				+ OffchainWorkerApi<T::Block>
+				+ SessionKeys<T::Block>
+				+ TaggedTransactionQueue<T::Block>
+				+ BlockBuilder<T::Block>
+				+ ApiExt<T::Block, StateBackend = <TFullBackend<T::Block> as Backend<T::Block>>::State>,
+	{
+		let NodeConfig { log_targets, mut chain_spec, execution_strategies } = node_config;
+		let tokio_runtime = build_runtime().unwrap();
+
+		// unbounded logs, should be fine, test is shortlived.
+		let (log_sink, log_stream) = mpsc::unbounded();
+
+		logger(log_targets, tokio_runtime.handle().clone(), log_sink);
+		let runtime_handle = tokio_runtime.handle().clone();
+
+		let task_executor = move |fut, task_type| match task_type {
+			TaskType::Async => runtime_handle.spawn(fut).map(drop),
+			TaskType::Blocking => runtime_handle
+				.spawn_blocking(move || futures::executor::block_on(fut))
+				.map(drop),
+		};
+
+		let base_path = if let Some(base) = base_path() {
+			BasePath::new(base)
+		} else {
+			BasePath::new_temp_dir().expect("couldn't create a temp dir")
+		};
+		let root_path = base_path.path().to_path_buf().join("chains").join(chain_spec.id());
+
+		let key_seed = Alice.to_seed();
+		let storage = chain_spec
+			.as_storage_builder()
+			.build_storage()
+			.expect("could not build storage");
+
+		chain_spec.set_storage(storage);
+
+		let mut network_config = NetworkConfiguration::new(
+			format!("Test Node for: {}", key_seed),
+			"network/test/0.1",
+			Default::default(),
+			None,
+		);
+		let informant_output_format = OutputFormat { enable_color: false };
+
+		network_config.allow_non_globals_in_dht = true;
+
+		network_config
+			.listen_addresses
+			.push(multiaddr::Protocol::Memory(rand::random()).into());
+
+		network_config.transport = TransportConfig::MemoryOnly;
+
+		let config = Configuration {
+			impl_name: "test-node".to_string(),
+			impl_version: "0.1".to_string(),
+			role: Role::Authority,
+			task_executor: task_executor.into(),
+			transaction_pool: Default::default(),
+			network: network_config,
+			keystore: KeystoreConfig::Path {
+				path: root_path.join("key"),
+				password: None,
+			},
+			database: DatabaseConfig::RocksDb {
+				path: root_path.join("db"),
+				cache_size: 128,
+			},
+			state_cache_size: 16777216,
+			state_cache_child_ratio: None,
+			chain_spec,
+			wasm_method: WasmExecutionMethod::Interpreted,
+			execution_strategies,
+			rpc_http: None,
+			rpc_ws: None,
+			rpc_ipc: None,
+			rpc_ws_max_connections: None,
+			rpc_cors: None,
+			rpc_methods: Default::default(),
+			prometheus_config: None,
+			telemetry_endpoints: None,
+			telemetry_external_transport: None,
+			default_heap_pages: None,
+			offchain_worker: Default::default(),
+			force_authoring: false,
+			disable_grandpa: false,
+			dev_key_seed: Some(key_seed),
+			tracing_targets: None,
+			tracing_receiver: Default::default(),
+			max_runtime_instances: 8,
+			announce_block: true,
+			base_path: Some(base_path),
+			wasm_runtime_overrides: None,
+			informant_output_format,
+			disable_log_reloading: false,
+			keystore_remote: None,
+			keep_blocks: KeepBlocks::All,
+			state_pruning: Default::default(),
+			transaction_storage: TransactionStorageMode::BlockBody,
+		};
+
+		let (
+			client,
+			backend,
+			keystore,
+			mut task_manager,
+			inherent_data_providers,
+			consensus_data_provider,
+			select_chain,
+			block_import,
+		) = T::create_client_parts(&config)?;
+
+		let import_queue =
+			manual_seal::import_queue(Box::new(block_import.clone()), &task_manager.spawn_essential_handle(), None);
+
+		let transaction_pool = BasicPool::new_full(
+			config.transaction_pool.clone(),
+			true.into(),
+			config.prometheus_registry(),
+			task_manager.spawn_handle(),
+			client.clone(),
+		);
+
+		let (network, network_status_sinks, system_rpc_tx, network_starter) = {
+			let params = BuildNetworkParams {
+				config: &config,
+				client: client.clone(),
+				transaction_pool: transaction_pool.clone(),
+				spawn_handle: task_manager.spawn_handle(),
+				import_queue,
+				on_demand: None,
+				block_announce_validator_builder: None,
+			};
+			build_network(params)?
+		};
+
+		sc_service::build_offchain_workers(
+			&config,
+			task_manager.spawn_handle(),
+			client.clone(),
+			network.clone(),
+		);
+
+		// Proposer object for block authorship.
+		let env = sc_basic_authorship::ProposerFactory::new(
+			task_manager.spawn_handle(),
+			client.clone(),
+			transaction_pool.clone(),
+			config.prometheus_registry(),
+			None
+		);
+
+		// Channel for the rpc handler to communicate with the authorship task.
+		let (command_sink, commands_stream) = mpsc::channel(10);
+
+		let rpc_handlers = {
+			let params = SpawnTasksParams {
+				config,
+				client: client.clone(),
+				backend: backend.clone(),
+				task_manager: &mut task_manager,
+				keystore,
+				on_demand: None,
+				transaction_pool: transaction_pool.clone(),
+				rpc_extensions_builder: Box::new(move |_, _| jsonrpc_core::IoHandler::default()),
+				remote_blockchain: None,
+				network,
+				network_status_sinks,
+				system_rpc_tx,
+				telemetry: None
+			};
+			spawn_tasks(params)?
+		};
+
+		// Background authorship future.
+		let authorship_future = run_manual_seal(ManualSealParams {
+			block_import,
+			env,
+			client: client.clone(),
+			pool: transaction_pool.pool().clone(),
+			commands_stream,
+			select_chain,
+			consensus_data_provider,
+			inherent_data_providers,
+		});
+
+		// spawn the authorship task as an essential task.
+		task_manager
+			.spawn_essential_handle()
+			.spawn("manual-seal", authorship_future);
+
+		network_starter.start_network();
+		let rpc_handler = rpc_handlers.io_handler();
+		let initial_number = client.info().best_number;
+
+		Ok(Self {
+			rpc_handler,
+			_task_manager: Some(task_manager),
+			_runtime: tokio_runtime,
+			client,
+			pool: transaction_pool,
+			backend,
+			log_stream,
+			manual_seal_command_sink: command_sink,
+			initial_block_number: initial_number,
+		})
+	}
+
+	/// Returns a reference to the rpc handlers.
+	pub fn rpc_handler(&self) -> Arc<MetaIoHandler<sc_rpc::Metadata, sc_rpc_server::RpcMiddleware>> {
+		self.rpc_handler.clone()
+	}
+
+	/// Return a reference to the Client
+	pub fn client(&self) -> Arc<TFullClient<T::Block, T::RuntimeApi, T::Executor>> {
+		self.client.clone()
+	}
+
+	/// Executes closure in an externalities provided environment.
+	pub fn with_state<R>(&self, closure: impl FnOnce() -> R) -> R
+	where
+		<TFullCallExecutor<T::Block, T::Executor> as CallExecutor<T::Block>>::Error: std::fmt::Debug,
+	{
+		let id = BlockId::Hash(self.client.info().best_hash);
+		let mut overlay = OverlayedChanges::default();
+		let changes_trie = backend::changes_tries_state_at_block(&id, self.backend.changes_trie_storage()).unwrap();
+		let mut cache =
+			StorageTransactionCache::<T::Block, <TFullBackend<T::Block> as Backend<T::Block>>::State>::default();
+		let mut extensions = self
+			.client
+			.execution_extensions()
+			.extensions(&id, ExecutionContext::BlockConstruction);
+		let state_backend = self
+			.backend
+			.state_at(id.clone())
+			.expect(&format!("State at block {} not found", id));
+
+		let mut ext = Ext::new(
+			&mut overlay,
+			&mut cache,
+			&state_backend,
+			changes_trie.clone(),
+			Some(&mut extensions),
+		);
+		sp_externalities::set_and_run_with_externalities(&mut ext, closure)
+	}
+
+	/// submit some extrinsic to the node, providing the sending account.
+	pub fn submit_extrinsic(
+		&mut self,
+		call: impl Into<<T::Runtime as frame_system::Config>::Call>,
+		from: <T::Runtime as frame_system::Config>::AccountId,
+	) -> <T::Block as BlockT>::Hash
+	where
+		<T::Block as BlockT>::Extrinsic: From<
+			UncheckedExtrinsic<
+				MultiAddress<
+					<T::Runtime as frame_system::Config>::AccountId,
+					<T::Runtime as frame_system::Config>::Index,
+				>,
+				<T::Runtime as frame_system::Config>::Call,
+				MultiSignature,
+				T::SignedExtras,
+			>,
+		>,
+	{
+		let extra = self.with_state(|| T::signed_extras(from.clone()));
+		let signed_data = Some((from.into(), MultiSignature::Sr25519(Default::default()), extra));
+		let ext = UncheckedExtrinsic::<
+			MultiAddress<
+				<T::Runtime as frame_system::Config>::AccountId,
+				<T::Runtime as frame_system::Config>::Index,
+			>,
+			<T::Runtime as frame_system::Config>::Call,
+			MultiSignature,
+			T::SignedExtras,
+		>::new(call.into(), signed_data)
+		.expect("UncheckedExtrinsic::new() always returns Some");
+		let at = self.client.info().best_hash;
+
+		self._runtime
+			.block_on(
+				self.pool.submit_one(&BlockId::Hash(at), TransactionSource::Local, ext.into()),
+			)
+			.unwrap()
+	}
+
+	/// Get the events of the most recently produced block
+	pub fn events(&self) -> Vec<EventRecord<T::Runtime>> {
+		self.with_state(|| frame_system::Pallet::<T::Runtime>::events())
+	}
+
+	/// Checks the node logs for a specific entry.
+	pub fn assert_log_line(&mut self, content: &str) {
+		futures::executor::block_on(async {
+			use futures::StreamExt;
+
+			while let Some(log_line) = self.log_stream.next().await {
+				if log_line.contains(content) {
+					return;
+				}
+			}
+
+			panic!("Could not find {} in logs content", content);
+		});
+	}
+
+	/// Instructs manual seal to seal new, possibly empty blocks.
+	pub fn seal_blocks(&mut self, num: usize) {
+		let (tokio, sink) = (&mut self._runtime, &mut self.manual_seal_command_sink);
+
+		for count in 0..num {
+			let (sender, future_block) = oneshot::channel();
+			let future = sink.send(EngineCommand::SealNewBlock {
+				create_empty: true,
+				finalize: false,
+				parent_hash: None,
+				sender: Some(sender),
+			});
+
+			tokio.block_on(async {
+				const ERROR: &'static str = "manual-seal authorship task is shutting down";
+				future.await.expect(ERROR);
+
+				match future_block.await.expect(ERROR) {
+					Ok(block) => log::info!("sealed {} (hash: {}) of {} blocks", count + 1, block.hash, num),
+					Err(err) => log::error!("failed to seal block {} of {}, error: {:?}", count + 1, num, err),
+				}
+			});
+		}
+	}
+
+	/// Revert count number of blocks from the chain.
+	pub fn revert_blocks(&self, count: NumberFor<T::Block>) {
+		self.backend.revert(count, true).expect("Failed to revert blocks: ");
+	}
+
+	/// Revert all blocks added since creation of the node.
+	pub fn clean(&self) {
+		// if a db path was specified, revert all blocks we've added
+		if let Some(_) = base_path() {
+			let diff = self.client.info().best_number - self.initial_block_number;
+			self.revert_blocks(diff);
+		}
+	}
+
+	/// Performs a runtime upgrade given a wasm blob.
+	pub fn upgrade_runtime(&mut self, wasm: Vec<u8>)
+		where
+			<T::Runtime as frame_system::Config>::Call: From<frame_system::Call<T::Runtime>>
+	{
+		let call = frame_system::Call::set_code(wasm);
+		T::dispatch_with_root(call.into(), self);
+	}
+}
+
+impl<T: ChainInfo> Drop for Node<T> {
+	fn drop(&mut self) {
+		self.clean();
+
+		if let Some(mut task_manager) = self._task_manager.take() {
+			// if this isn't called the node will live forever
+			task_manager.terminate()
+		}
+	}
+}
diff --git a/test-utils/test-runner/src/utils.rs b/test-utils/test-runner/src/utils.rs
new file mode 100644
index 0000000000000..7cd512e2d4869
--- /dev/null
+++ b/test-utils/test-runner/src/utils.rs
@@ -0,0 +1,56 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2020-2021 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+use futures::{Sink, SinkExt};
+use std::fmt;
+use std::io::Write;
+use log::LevelFilter;
+
+/// Base db path gotten from env
+pub fn base_path() -> Option<String> {
+	std::env::var("DB_BASE_PATH").ok()
+}
+
+/// Builds the global logger.
+pub fn logger<S>(
+	log_targets: Vec<(&'static str, LevelFilter)>,
+	executor: tokio::runtime::Handle,
+	log_sink: S,
+)
+where
+	S: Sink<String> + Clone + Unpin + Send + Sync + 'static,
+	S::Error: Send + Sync + fmt::Debug,
+{
+	let mut builder = env_logger::builder();
+	builder.format(move |buf: &mut env_logger::fmt::Formatter, record: &log::Record| {
+		let entry = format!("{} {} {}", record.level(), record.target(), record.args());
+		let res = writeln!(buf, "{}", entry);
+
+		let mut log_sink_clone = log_sink.clone();
+		let _ = executor.spawn(async move {
+			log_sink_clone.send(entry).await.expect("log_stream is dropped");
+		});
+		res
+	});
+	builder.write_style(env_logger::WriteStyle::Always);
+
+	for (module, level) in log_targets {
+		builder.filter_module(module, level);
+	}
+	let _ = builder.is_test(true).try_init();
+}
diff --git a/utils/browser/Cargo.toml b/utils/browser/Cargo.toml
index 764d2d18a61b7..3a11df62dc254 100644
--- a/utils/browser/Cargo.toml
+++ b/utils/browser/Cargo.toml
@@ -16,7 +16,7 @@ targets = ["x86_64-unknown-linux-gnu"]
 futures = { version = "0.3", features = ["compat"] }
 futures01 = { package = "futures", version = "0.1.29" }
 log = "0.4.8"
-libp2p-wasm-ext = { version = "0.27", features = ["websocket"] }
+libp2p-wasm-ext = { version = "0.28", features = ["websocket"] }
 console_error_panic_hook = "0.1.6"
 js-sys = "0.3.34"
 wasm-bindgen = "0.2.57"
diff --git a/utils/frame/benchmarking-cli/src/lib.rs b/utils/frame/benchmarking-cli/src/lib.rs
index 19f4596e92fd6..6784b1ecabf41 100644
--- a/utils/frame/benchmarking-cli/src/lib.rs
+++ b/utils/frame/benchmarking-cli/src/lib.rs
@@ -21,11 +21,17 @@ mod writer;
 use sc_cli::{ExecutionStrategy, WasmExecutionMethod};
 use std::fmt::Debug;
 
+// Add a more relaxed parsing for pallet names by allowing pallet directory names with `-` to be used
+// like crate names with `_`
+fn parse_pallet_name(pallet: &str) -> String {
+	pallet.replace("-", "_")
+}
+
 /// The `benchmark` command used to benchmark FRAME Pallets.
 #[derive(Debug, structopt::StructOpt)]
 pub struct BenchmarkCmd {
 	/// Select a FRAME Pallet to benchmark, or `*` for all (in which case `extrinsic` must be `*`).
-	#[structopt(short, long)]
+	#[structopt(short, long, parse(from_str = parse_pallet_name))]
 	pub pallet: String,
 
 	/// Select an extrinsic inside the pallet to benchmark, or `*` for all.
diff --git a/utils/frame/remote-externalities/Cargo.toml b/utils/frame/remote-externalities/Cargo.toml
index de90933e17978..b8bee6380006a 100644
--- a/utils/frame/remote-externalities/Cargo.toml
+++ b/utils/frame/remote-externalities/Cargo.toml
@@ -25,9 +25,10 @@ codec = { package = "parity-scale-codec", version = "2.0.0" }
 
 sp-io = { version = "3.0.0", path = "../../../primitives/io" }
 sp-core = { version = "3.0.0", path = "../../../primitives/core" }
+sp-runtime = { version = "3.0.0", path = "../../../primitives/runtime" }
 
 [dev-dependencies]
-async-std = { version = "1.6.5", features = ["attributes"] }
+tokio = { version = "0.2", features = ["macros"] }
 
 [features]
 remote-test = []
diff --git a/utils/frame/remote-externalities/src/lib.rs b/utils/frame/remote-externalities/src/lib.rs
index 8211274c46298..8cca728c1ffaa 100644
--- a/utils/frame/remote-externalities/src/lib.rs
+++ b/utils/frame/remote-externalities/src/lib.rs
@@ -18,7 +18,7 @@
 //! # Remote Externalities
 //!
 //! An equivalent of `sp_io::TestExternalities` that can load its state from a remote substrate
-//! based chain, or a local cache file.
+//! based chain, or a local state snapshot file.
 //!
 //! #### Runtime to Test Against
 //!
@@ -76,7 +76,7 @@
 //!             assert_eq!(
 //!                 // note: the hash corresponds to 3098546. We can check only the parent.
 //!                 // https://polkascan.io/kusama/block/3098546
-//!                 <frame_system::Module<Runtime>>::block_hash(3098545u32),
+//!                 <frame_system::Pallet<Runtime>>::block_hash(3098545u32),
 //!                 parent,
 //!             )
 //!         });
@@ -106,7 +106,7 @@ use std::{
 	path::{Path, PathBuf},
 };
 use log::*;
-use sp_core::{hashing::twox_128};
+use sp_core::hashing::twox_128;
 pub use sp_io::TestExternalities;
 use sp_core::{
 	hexdisplay::HexDisplay,
@@ -115,62 +115,62 @@ use sp_core::{
 use codec::{Encode, Decode};
 use jsonrpsee_http_client::{HttpClient, HttpConfig};
 
+use sp_runtime::traits::Block as BlockT;
+
 type KeyPair = (StorageKey, StorageData);
-type Hash = sp_core::H256;
-// TODO: make these two generic.
 
 const LOG_TARGET: &str = "remote-ext";
 const TARGET: &str = "http://localhost:9933";
 
 jsonrpsee_proc_macros::rpc_client_api! {
-	RpcApi {
+	RpcApi<B: BlockT> {
 		#[rpc(method = "state_getPairs", positional_params)]
-		fn storage_pairs(prefix: StorageKey, hash: Option<Hash>) -> Vec<(StorageKey, StorageData)>;
+		fn storage_pairs(prefix: StorageKey, hash: Option<B::Hash>) -> Vec<(StorageKey, StorageData)>;
 		#[rpc(method = "chain_getFinalizedHead")]
-		fn finalized_head() -> Hash;
+		fn finalized_head() -> B::Hash;
 	}
 }
 
 /// The execution mode.
 #[derive(Clone)]
-pub enum Mode {
+pub enum Mode<B: BlockT> {
 	/// Online.
-	Online(OnlineConfig),
-	/// Offline. Uses a cached file and needs not any client config.
+	Online(OnlineConfig<B>),
+	/// Offline. Uses a state snapshot file and needs not any client config.
 	Offline(OfflineConfig),
 }
 
 /// configuration of the online execution.
 ///
-/// A cache config must be present.
+/// A state snapshot config must be present.
 #[derive(Clone)]
 pub struct OfflineConfig {
-	/// The configuration of the cache file to use. It must be present.
-	pub cache: CacheConfig,
+	/// The configuration of the state snapshot file to use. It must be present.
+	pub state_snapshot: SnapshotConfig,
 }
 
 /// Configuration of the online execution.
 ///
-/// A cache config may be present and will be written to in that case.
+/// A state snapshot config may be present and will be written to in that case.
 #[derive(Clone)]
-pub struct OnlineConfig {
+pub struct OnlineConfig<B: BlockT> {
 	/// The HTTP uri to use.
 	pub uri: String,
 	/// The block number at which to connect. Will be latest finalized head if not provided.
-	pub at: Option<Hash>,
-	/// An optional cache file to WRITE to, not for reading. Not cached if set to `None`.
-	pub cache: Option<CacheConfig>,
+	pub at: Option<B::Hash>,
+	/// An optional state snapshot file to WRITE to, not for reading. Not written if set to `None`.
+	pub state_snapshot: Option<SnapshotConfig>,
 	/// The modules to scrape. If empty, entire chain state will be scraped.
 	pub modules: Vec<String>,
 }
 
-impl Default for OnlineConfig {
+impl<B: BlockT> Default for OnlineConfig<B> {
 	fn default() -> Self {
-		Self { uri: TARGET.to_owned(), at: None, cache: None, modules: Default::default() }
+		Self { uri: TARGET.to_owned(), at: None, state_snapshot: None, modules: Default::default() }
 	}
 }
 
-impl OnlineConfig {
+impl<B: BlockT> OnlineConfig<B> {
 	/// Return a new http rpc client.
 	fn rpc(&self) -> HttpClient {
 		HttpClient::new(&self.uri, HttpConfig { max_request_body_size: u32::MAX })
@@ -178,54 +178,50 @@ impl OnlineConfig {
 	}
 }
 
-/// Configuration of the cache.
+/// Configuration of the state snapshot.
 #[derive(Clone)]
-pub struct CacheConfig {
-	// TODO: I could mix these two into one filed, but I think separate is better bc one can be
-	// configurable while one not.
-	/// File name.
-	pub name: String,
-	/// Base directory.
-	pub directory: String,
+pub struct SnapshotConfig {
+	/// The path to the snapshot file.
+	pub path: PathBuf,
 }
 
-impl Default for CacheConfig {
-	fn default() -> Self {
-		Self { name: "CACHE".into(), directory: ".".into() }
+impl SnapshotConfig {
+	pub fn new<P: Into<PathBuf>>(path: P) -> Self {
+		Self { path: path.into() }
 	}
 }
 
-impl CacheConfig {
-	fn path(&self) -> PathBuf {
-		Path::new(&self.directory).join(self.name.clone())
+impl Default for SnapshotConfig {
+	fn default() -> Self {
+		Self { path: Path::new("SNAPSHOT").into() }
 	}
 }
 
 /// Builder for remote-externalities.
-pub struct Builder {
+pub struct Builder<B: BlockT> {
 	inject: Vec<KeyPair>,
-	mode: Mode,
+	mode: Mode<B>,
 }
 
-impl Default for Builder {
+impl<B: BlockT> Default for Builder<B> {
 	fn default() -> Self {
 		Self {
 			inject: Default::default(),
-			mode: Mode::Online(OnlineConfig::default())
+			mode: Mode::Online(OnlineConfig::default()),
 		}
 	}
 }
 
 // Mode methods
-impl Builder {
-	fn as_online(&self) -> &OnlineConfig {
+impl<B: BlockT> Builder<B> {
+	fn as_online(&self) -> &OnlineConfig<B> {
 		match &self.mode {
 			Mode::Online(config) => &config,
 			_ => panic!("Unexpected mode: Online"),
 		}
 	}
 
-	fn as_online_mut(&mut self) -> &mut OnlineConfig {
+	fn as_online_mut(&mut self) -> &mut OnlineConfig<B> {
 		match &mut self.mode {
 			Mode::Online(config) => config,
 			_ => panic!("Unexpected mode: Online"),
@@ -234,13 +230,13 @@ impl Builder {
 }
 
 // RPC methods
-impl Builder {
-	async fn rpc_get_head(&self) -> Result<Hash, &'static str> {
+impl<B: BlockT> Builder<B> {
+	async fn rpc_get_head(&self) -> Result<B::Hash, &'static str> {
 		trace!(target: LOG_TARGET, "rpc: finalized_head");
-		RpcApi::finalized_head(&self.as_online().rpc()).await.map_err(|e| {
+		RpcApi::<B>::finalized_head(&self.as_online().rpc()).await.map_err(|e| {
 			error!("Error = {:?}", e);
 			"rpc finalized_head failed."
-			})
+		})
 	}
 
 	/// Relay the request to `state_getPairs` rpc endpoint.
@@ -249,28 +245,28 @@ impl Builder {
 	async fn rpc_get_pairs(
 		&self,
 		prefix: StorageKey,
-		at: Hash,
+		at: B::Hash,
 	) -> Result<Vec<KeyPair>, &'static str> {
 		trace!(target: LOG_TARGET, "rpc: storage_pairs: {:?} / {:?}", prefix, at);
-		RpcApi::storage_pairs(&self.as_online().rpc(), prefix, Some(at)).await.map_err(|e| {
+		RpcApi::<B>::storage_pairs(&self.as_online().rpc(), prefix, Some(at)).await.map_err(|e| {
 			error!("Error = {:?}", e);
 			"rpc storage_pairs failed"
-			})
+		})
 	}
 }
 
 // Internal methods
-impl Builder {
-	/// Save the given data as cache.
-	fn save_cache(&self, data: &[KeyPair], path: &Path) -> Result<(), &'static str> {
-		info!(target: LOG_TARGET, "writing to cache file {:?}", path);
+impl<B: BlockT> Builder<B> {
+	/// Save the given data as state snapshot.
+	fn save_state_snapshot(&self, data: &[KeyPair], path: &Path) -> Result<(), &'static str> {
+		info!(target: LOG_TARGET, "writing to state snapshot file {:?}", path);
 		fs::write(path, data.encode()).map_err(|_| "fs::write failed.")?;
 		Ok(())
 	}
 
-	/// initialize `Self` from cache. Panics if the file does not exist.
-	fn load_cache(&self, path: &Path) -> Result<Vec<KeyPair>, &'static str> {
-		info!(target: LOG_TARGET, "scraping keypairs from cache {:?}", path,);
+	/// initialize `Self` from state snapshot. Panics if the file does not exist.
+	fn load_state_snapshot(&self, path: &Path) -> Result<Vec<KeyPair>, &'static str> {
+		info!(target: LOG_TARGET, "scraping keypairs from state snapshot {:?}", path,);
 		let bytes = fs::read(path).map_err(|_| "fs::read failed.")?;
 		Decode::decode(&mut &*bytes).map_err(|_| "decode failed")
 	}
@@ -319,12 +315,12 @@ impl Builder {
 
 	async fn pre_build(mut self) -> Result<Vec<KeyPair>, &'static str> {
 		let mut base_kv = match self.mode.clone() {
-			Mode::Offline(config) => self.load_cache(&config.cache.path())?,
+			Mode::Offline(config) => self.load_state_snapshot(&config.state_snapshot.path)?,
 			Mode::Online(config) => {
 				self.init_remote_client().await?;
 				let kp = self.load_remote().await?;
-				if let Some(c) = config.cache {
-					self.save_cache(&kp, &c.path())?;
+				if let Some(c) = config.state_snapshot {
+					self.save_state_snapshot(&kp, &c.path)?;
 				}
 				kp
 			}
@@ -341,7 +337,7 @@ impl Builder {
 }
 
 // Public methods
-impl Builder {
+impl<B: BlockT> Builder<B> {
 	/// Create a new builder.
 	pub fn new() -> Self {
 		Default::default()
@@ -355,8 +351,8 @@ impl Builder {
 		self
 	}
 
-	/// Configure a cache to be used.
-	pub fn mode(mut self, mode: Mode) -> Self {
+	/// Configure a state snapshot to be used.
+	pub fn mode(mut self, mode: Mode<B>) -> Self {
 		self.mode = mode;
 		self
 	}
@@ -375,62 +371,75 @@ impl Builder {
 	}
 }
 
-#[cfg(feature = "remote-test")]
 #[cfg(test)]
-mod tests {
-	use super::*;
+mod test_prelude {
+	pub(crate) use super::*;
+	pub(crate) use sp_runtime::testing::{H256 as Hash, Block as RawBlock, ExtrinsicWrapper};
 
-	fn init_logger() {
+	pub(crate) type Block = RawBlock<ExtrinsicWrapper<Hash>>;
+
+	pub(crate) fn init_logger() {
 		let _ = env_logger::Builder::from_default_env()
 			.format_module_path(false)
 			.format_level(true)
 			.try_init();
 	}
+}
 
-	#[async_std::test]
-	async fn can_build_one_pallet() {
+#[cfg(test)]
+mod tests {
+	use super::test_prelude::*;
+
+	#[tokio::test]
+	async fn can_load_state_snapshot() {
 		init_logger();
-		Builder::new()
-			.mode(Mode::Online(OnlineConfig {
-				modules: vec!["Proxy".into()],
-				..Default::default()
+		Builder::<Block>::new()
+			.mode(Mode::Offline(OfflineConfig {
+				state_snapshot: SnapshotConfig { path: "test_data/proxy_test".into() },
 			}))
 			.build()
 			.await
-			.unwrap()
+			.expect("Can't read state snapshot file")
 			.execute_with(|| {});
 	}
+}
+
+#[cfg(all(test, feature = "remote-test"))]
+mod remote_tests {
+	use super::test_prelude::*;
 
-	#[async_std::test]
-	async fn can_load_cache() {
+	#[tokio::test]
+	async fn can_build_one_pallet() {
 		init_logger();
-		Builder::new()
-			.mode(Mode::Offline(OfflineConfig {
-				cache: CacheConfig { name: "proxy_test".into(), ..Default::default() },
+		Builder::<Block>::new()
+			.mode(Mode::Online(OnlineConfig {
+				modules: vec!["Proxy".into()],
+				..Default::default()
 			}))
 			.build()
 			.await
-			.unwrap()
+			.expect("Can't reach the remote node. Is it running?")
 			.execute_with(|| {});
 	}
 
-	#[async_std::test]
-	async fn can_create_cache() {
+	#[tokio::test]
+	async fn can_create_state_snapshot() {
 		init_logger();
-		Builder::new()
+		Builder::<Block>::new()
 			.mode(Mode::Online(OnlineConfig {
-				cache: Some(CacheConfig {
-					name: "test_cache_to_remove.bin".into(),
+				state_snapshot: Some(SnapshotConfig {
+					name: "test_snapshot_to_remove.bin".into(),
 					..Default::default()
 				}),
 				..Default::default()
 			}))
 			.build()
 			.await
+			.expect("Can't reach the remote node. Is it running?")
 			.unwrap()
 			.execute_with(|| {});
 
-		let to_delete = std::fs::read_dir(CacheConfig::default().directory)
+		let to_delete = std::fs::read_dir(SnapshotConfig::default().directory)
 			.unwrap()
 			.into_iter()
 			.map(|d| d.unwrap())
@@ -444,9 +453,13 @@ mod tests {
 		}
 	}
 
-	#[async_std::test]
+	#[tokio::test]
 	async fn can_build_all() {
 		init_logger();
-		Builder::new().build().await.unwrap().execute_with(|| {});
+		Builder::<Block>::new()
+			.build()
+			.await
+			.expect("Can't reach the remote node. Is it running?")
+			.execute_with(|| {});
 	}
 }
diff --git a/utils/frame/remote-externalities/test_data/proxy_test b/utils/frame/remote-externalities/test_data/proxy_test
new file mode 100644
index 0000000000000..548ce9cdba4f1
Binary files /dev/null and b/utils/frame/remote-externalities/test_data/proxy_test differ
diff --git a/utils/frame/try-runtime/cli/src/lib.rs b/utils/frame/try-runtime/cli/src/lib.rs
index 4ab38692a5cfa..8e407f3b2d739 100644
--- a/utils/frame/try-runtime/cli/src/lib.rs
+++ b/utils/frame/try-runtime/cli/src/lib.rs
@@ -18,7 +18,7 @@
 //! `Structopt`-ready struct for `try-runtime`.
 
 use parity_scale_codec::Decode;
-use std::{fmt::Debug, str::FromStr};
+use std::{fmt::Debug, path::PathBuf, str::FromStr};
 use sc_service::Configuration;
 use sc_cli::{CliConfiguration, ExecutionStrategy, WasmExecutionMethod};
 use sc_executor::NativeExecutor;
@@ -37,10 +37,6 @@ pub struct TryRuntimeCmd {
 	#[structopt(flatten)]
 	pub shared_params: sc_cli::SharedParams,
 
-	/// The state to use to run the migration. Should be a valid FILE or HTTP URI.
-	#[structopt(short, long, default_value = "http://localhost:9933")]
-	pub state: State,
-
 	/// The execution strategy that should be used for benchmarks
 	#[structopt(
 		long = "execution",
@@ -60,32 +56,64 @@ pub struct TryRuntimeCmd {
 		default_value = "Interpreted"
 	)]
 	pub wasm_method: WasmExecutionMethod,
+
+	/// The state to use to run the migration.
+	#[structopt(subcommand)]
+	pub state: State,
 }
 
 /// The state to use for a migration dry-run.
-#[derive(Debug)]
+#[derive(Debug, structopt::StructOpt)]
 pub enum State {
-	/// A snapshot. Inner value is a file path.
-	Snap(String),
+	/// Use a state snapshot as state to run the migration.
+	Snap {
+		snapshot_path: PathBuf,
+	},
+
+	/// Use a live chain to run the migration.
+	Live {
+		/// An optional state snapshot file to WRITE to. Not written if set to `None`.
+		#[structopt(short, long)]
+		snapshot_path: Option<PathBuf>,
+
+		/// The block hash at which to connect.
+		/// Will be latest finalized head if not provided.
+		#[structopt(short, long, multiple = false, parse(try_from_str = parse_hash))]
+		block_at: Option<String>,
+
+		/// The modules to scrape. If empty, entire chain state will be scraped.
+		#[structopt(short, long, require_delimiter = true)]
+		modules: Option<Vec<String>>,
+
+		/// The url to connect to.
+		#[structopt(default_value = "http://localhost:9933", parse(try_from_str = parse_url))]
+		url: String,
+	},
+}
 
-	/// A live chain. Inner value is the HTTP uri.
-	Live(String),
+fn parse_hash(block_number: &str) -> Result<String, String> {
+	let block_number = if block_number.starts_with("0x") {
+		&block_number[2..]
+	} else {
+		block_number
+	};
+
+	if let Some(pos) = block_number.chars().position(|c| !c.is_ascii_hexdigit()) {
+		Err(format!(
+			"Expected block hash, found illegal hex character at position: {}",
+			2 + pos,
+		))
+	} else {
+		Ok(block_number.into())
+	}
 }
 
-impl FromStr for State {
-	type Err = &'static str;
-	fn from_str(s: &str) -> Result<Self, Self::Err> {
-		match s.get(..7) {
-			// could use Url crate as well, but lets keep it simple for now.
-			Some("http://") => Ok(State::Live(s.to_string())),
-			Some("file://") => s
-				.split("//")
-				.collect::<Vec<_>>()
-				.get(1)
-				.map(|s| State::Snap(s.to_string()))
-				.ok_or("invalid file URI"),
-			_ => Err("invalid format. Must be a valid HTTP or File URI"),
-		}
+fn parse_url(s: &str) -> Result<String, &'static str> {
+	if s.starts_with("http://") {
+		// could use Url crate as well, but lets keep it simple for now.
+		Ok(s.to_string())
+	} else {
+		Err("not a valid HTTP url: must start with 'http://'")
 	}
 }
 
@@ -93,6 +121,10 @@ impl TryRuntimeCmd {
 	pub async fn run<B, ExecDispatch>(&self, config: Configuration) -> sc_cli::Result<()>
 	where
 		B: BlockT,
+		B::Hash: FromStr,
+		<B::Hash as FromStr>::Err: Debug,
+		NumberFor<B>: FromStr,
+		<NumberFor<B> as FromStr>::Err: Debug,
 		ExecDispatch: NativeExecutionDispatch + 'static,
 	{
 		let spec = config.chain_spec;
@@ -121,13 +153,26 @@ impl TryRuntimeCmd {
 		);
 
 		let ext = {
-			use remote_externalities::{Builder, Mode, CacheConfig, OfflineConfig, OnlineConfig};
+			use remote_externalities::{Builder, Mode, SnapshotConfig, OfflineConfig, OnlineConfig};
 			let builder = match &self.state {
-				State::Snap(file_path) => Builder::new().mode(Mode::Offline(OfflineConfig {
-					cache: CacheConfig { name: file_path.into(), ..Default::default() },
-				})),
-				State::Live(http_uri) => Builder::new().mode(Mode::Online(OnlineConfig {
-					uri: http_uri.into(),
+				State::Snap { snapshot_path } => {
+					Builder::<B>::new().mode(Mode::Offline(OfflineConfig {
+						state_snapshot: SnapshotConfig::new(snapshot_path),
+					}))
+				},
+				State::Live {
+					url,
+					snapshot_path,
+					block_at,
+					modules
+				} => Builder::<B>::new().mode(Mode::Online(OnlineConfig {
+					uri: url.into(),
+					state_snapshot: snapshot_path.as_ref().map(SnapshotConfig::new),
+					modules: modules.clone().unwrap_or_default(),
+					at: match block_at {
+						Some(b) => Some(b.parse().map_err(|e| format!("Could not parse hash: {:?}", e))?),
+						None => None,
+					},
 					..Default::default()
 				})),
 			};