diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 81b6095712..dbf2eeb5ad 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -29,6 +29,17 @@ jobs:
       fail-fast: false
       matrix:
         python-version: ["3.8", "3.9", "3.10"]
+        # A/B TESTING: add AB_<name> as needed. Alternatively you may use 'include'
+        # statements.
+        # For each A/B runtime version there must be two files:
+        # - AB_environment/AB_<name>.conda.yaml
+        # - AB_environment/AB_<name>.dask.yaml
+        # Search for "A/B TESTING" for further change points in this file
+        runtime-version: [latest]
+        # TODO comment out before merge
+        include:
+          - python-version: "3.9"
+            runtime-version: AB_sample
 
     steps:
       - uses: actions/checkout@v2
@@ -75,7 +86,7 @@ jobs:
           export PYTHON_VERSION_FORMATTED=$(echo "${{ matrix.python-version }}" | sed 's/\.//g' )
           export REF_NAME_FORMATTED=$(echo "$GITHUB_REF_NAME" | sed 's/\./-/g' )
           export COILED_SOFTWARE_NAME_HEAD=dask-engineering/coiled-runtime-${{ github.event_name }}
-          export COILED_SOFTWARE_NAME_TAIL=$GITHUB_RUN_ID-py$PYTHON_VERSION_FORMATTED
+          export COILED_SOFTWARE_NAME_TAIL=$GITHUB_RUN_ID-${{ matrix.runtime-version }}-py$PYTHON_VERSION_FORMATTED
 
           if [[ ${{ github.event_name }} = 'pull_request' ]]
           then
@@ -84,14 +95,23 @@ jobs:
             export COILED_SOFTWARE_NAME=$COILED_SOFTWARE_NAME_HEAD-$GITHUB_REF_TYPE-$REF_NAME_FORMATTED-$COILED_SOFTWARE_NAME_TAIL
           fi
 
-          # Create conda environment.yaml file for the latest software environment
-          python ci/create_latest_runtime_meta.py
-          export ENV_FILE=latest.yaml
+          if [[ ${{ matrix.runtime-version }} = 'latest' ]]
+          then
+            # Create conda environment.yaml file for the latest software environment
+            python ci/create_latest_runtime_meta.py
+            export COILED_SOFTWARE_ENV=""
+          else
+            cp AB_environments/${{ matrix.runtime-version }}.conda.yaml coiled_software_environment.yaml
+            export COILED_SOFTWARE_ENV=$(python ci/dask_config_to_env.py AB_environments/${{ matrix.runtime-version }}.dask.yaml) 
+          fi
+
+          export ENV_FILE=coiled_software_environment.yaml
           cat $ENV_FILE
 
           mamba install coiled
           echo "Creating Coiled software environment for $COILED_SOFTWARE_NAME"
-          coiled env create --name $COILED_SOFTWARE_NAME --conda $ENV_FILE
+          echo "Environment parameters: $COILED_SOFTWARE_ENV"
+          coiled env create --name $COILED_SOFTWARE_NAME --conda $ENV_FILE $COILED_SOFTWARE_ENV
 
           # Put COILED_SOFTWARE_NAME into a file so it can be downloaded in subsequent workflow jobs
           echo $COILED_SOFTWARE_NAME > software_name.txt
@@ -99,9 +119,9 @@ jobs:
       - name: Upload environment file
         uses: actions/upload-artifact@v3
         with:
-          name: software-environment-py${{ matrix.python-version }}
+          name: software-environment-${{ matrix.runtime-version }}-py${{ matrix.python-version }}
           path: |
-            latest.yaml
+            coiled_software_environment.yaml
             software_name.txt
             test_upstream.txt
 
@@ -113,9 +133,14 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: ["ubuntu-latest"]
+        os: [ubuntu-latest]
         python-version: ["3.9"]
-        runtime-version: ["latest", "0.0.4", "0.1.0"]
+        # A/B TESTING: add AB_<name> as needed (as specified in 'software')
+        # and remove what is not interesting for the test.
+        # You may also want to use include/exclude statements for specific
+        # combinations of python versions and OSs.
+        # runtime-version: [latest, "0.0.4", "0.1.0", AB_sample]
+        runtime-version: [latest, "0.0.4", "0.1.0", AB_sample]  # TODO revert before merging
 
     steps:
       - uses: actions/checkout@v2
@@ -132,10 +157,10 @@ jobs:
           environment-file: ci/environment.yml
 
       - name: Download software environment assets
-        if: matrix.runtime-version == 'latest'
+        if: matrix.runtime-version == 'latest' || startsWith(matrix.runtime-version, 'AB_')
         uses: actions/download-artifact@v3
         with:
-          name: software-environment-py${{ matrix.python-version }}
+          name: software-environment-${{ matrix.runtime-version }}-py${{ matrix.python-version }}
 
       - name: Install coiled-runtime
         env:
@@ -168,9 +193,14 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: ["ubuntu-latest"]
+        os: [ubuntu-latest]
         python-version: ["3.9"]
-        runtime-version: ["latest", "0.0.4", "0.1.0"]
+        # A/B TESTING: add AB_<name> as needed (as specified in 'software')
+        # and remove what is not interesting for the test.
+        # Alternatively you may use include/exclude statements for specific
+        # combinations of python versions and OSs.
+        # runtime-version: [latest, "0.0.4", "0.1.0", AB_sample]
+        runtime-version: [latest, "0.0.4", "0.1.0", AB_sample]  # TODO revert before merging
 
     steps:
       - uses: actions/checkout@v2
@@ -187,10 +217,10 @@ jobs:
           environment-file: ci/environment.yml
 
       - name: Download software environment assets
-        if: matrix.runtime-version == 'latest'
+        if: matrix.runtime-version == 'latest' || startsWith(matrix.runtime-version, 'AB_')
         uses: actions/download-artifact@v3
         with:
-          name: software-environment-py${{ matrix.python-version }}
+          name: software-environment-${{ matrix.runtime-version }}-py${{ matrix.python-version }}
 
       - name: Install coiled-runtime
         env:
@@ -223,16 +253,23 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: ["ubuntu-latest"]
+        os: [ubuntu-latest]
         python-version: ["3.8", "3.9", "3.10"]
-        runtime-version: ["latest", "0.0.4", "0.1.0"]
+        # A/B TESTING: add AB_<name> as needed (as specified in 'software')
+        # and remove what is not interesting for the test.
+        # Alternatively you may use include/exclude statements for specific
+        # combinations of python versions and OSs.
+        runtime-version: [latest, "0.0.4", "0.1.0"]
         include:
           - python-version: "3.9"
-            runtime-version: "latest"
-            os: "windows-latest"
+            runtime-version: latest
+            os: windows-latest
           - python-version: "3.9"
-            runtime-version: "latest"
-            os: "macos-latest"
+            runtime-version: latest
+            os: macos-latest
+          # TODO comment out before merging
+          - python-version: "3.9"
+            runtime-version: AB_sample
 
     steps:
       - uses: actions/checkout@v2
@@ -249,10 +286,10 @@ jobs:
           environment-file: ci/environment.yml
 
       - name: Download software environment assets
-        if: matrix.runtime-version == 'latest'
+        if: matrix.runtime-version == 'latest' || startsWith(matrix.runtime-version, 'AB_')
         uses: actions/download-artifact@v3
         with:
-          name: software-environment-py${{ matrix.python-version }}
+          name: software-environment-${{ matrix.runtime-version }}-py${{ matrix.python-version }}
 
       - name: Install coiled-runtime
         env:
diff --git a/.gitignore b/.gitignore
index c3d511b0c9..272b49eb25 100644
--- a/.gitignore
+++ b/.gitignore
@@ -120,6 +120,9 @@ venv.bak/
 # Rope project settings
 .ropeproject
 
+# PyCharm project settings
+.idea
+
 # mkdocs documentation
 /site
 
diff --git a/AB_environments/AB_sample.conda.yaml b/AB_environments/AB_sample.conda.yaml
new file mode 100644
index 0000000000..701adb51ff
--- /dev/null
+++ b/AB_environments/AB_sample.conda.yaml
@@ -0,0 +1,16 @@
+# Sample conda environment file for A/B testing
+# It *must* be called AB_<name>.conda.yaml
+# and *must* be accompanied by AB_<name>.dask.yaml
+channels:
+  - conda-forge
+dependencies:
+    - python=3.9
+    # Alternatively, we could use a nightly build, or no coiled-runtime at all
+    - coiled-runtime=0.1.0
+    - pip:
+      # Notes:
+      # - You can't install anything with conda which conflicts the versions
+      #   pinned in coiled-runtime. Pip packages ignore these restrictions.
+      # - You can point to your own git fork instead
+      - dask==2022.8.1
+      - git+https://github.com/dask/distributed@dd81b424971e81616e1a52fa09ce4698a5002d41
diff --git a/AB_environments/AB_sample.dask.yaml b/AB_environments/AB_sample.dask.yaml
new file mode 100644
index 0000000000..00c47f63ca
--- /dev/null
+++ b/AB_environments/AB_sample.dask.yaml
@@ -0,0 +1,7 @@
+# Sample dask config file for A/B testing
+# It *must* be called AB_<name>.dask.yaml
+# and *must* be accompanied by AB_<name>.conda.yaml
+# Leave empty if you don't want to override anything.
+distributed:
+  scheduler:
+    worker-saturation: 1.2
diff --git a/ci/create_latest_runtime_meta.py b/ci/create_latest_runtime_meta.py
index 16d1a8d3aa..4a7fa2680e 100644
--- a/ci/create_latest_runtime_meta.py
+++ b/ci/create_latest_runtime_meta.py
@@ -53,7 +53,7 @@ def main():
         "channels": ["conda-forge"],
         "dependencies": requirements,
     }
-    with open("latest.yaml", "w") as f:
+    with open("coiled_software_environment.yaml", "w") as f:
         yaml.dump(env, f)
 
 
diff --git a/ci/scripts/dask_config_to_env.py b/ci/scripts/dask_config_to_env.py
new file mode 100755
index 0000000000..6e18b59b9b
--- /dev/null
+++ b/ci/scripts/dask_config_to_env.py
@@ -0,0 +1,38 @@
+#!/usr/bin/env python
+"""Read a dask config file and print it out in the format `-e ENV=VALUE ENV=VALUE ...`
+This script is a work-around to not being able to upload dask config files to
+`conda env create`.
+"""
+from __future__ import annotations
+
+import sys
+from typing import Iterator
+
+import yaml
+
+
+def main(fname: str) -> None:
+    with open(fname) as fh:
+        cfg = yaml.safe_load(fh)
+    # Print nothing in case of empty file, comments only, or empty dict
+    if cfg:
+        print("-e " + " ".join(traverse(cfg, [])))
+
+
+def traverse(node: dict | list | str | float | None, path: list[str]) -> Iterator[str]:
+    if isinstance(node, dict):
+        for k, v in node.items():
+            k = k.upper().replace("-", "_")
+            yield from traverse(v, path + [k])
+        return
+
+    if not path:
+        raise ValueError("The top-level element must be a dict")
+    if isinstance(node, str) and "'" in node:
+        raise ValueError("Unsupported character: ' (single quote)")
+
+    yield "'DASK_" + "__".join(path) + f"={node}'"
+
+
+if __name__ == "__main__":
+    main(sys.argv[1])
diff --git a/ci/scripts/install_coiled_runtime.sh b/ci/scripts/install_coiled_runtime.sh
index aa52a4b748..a98a155bb4 100644
--- a/ci/scripts/install_coiled_runtime.sh
+++ b/ci/scripts/install_coiled_runtime.sh
@@ -5,10 +5,10 @@ set -o errexit
 set -o nounset
 set -o xtrace
 
-if [[ "$COILED_RUNTIME_VERSION" = 'latest' ]]
+if [[ "$COILED_RUNTIME_VERSION" =~ latest|AB_ ]]
 then
-  cat latest.yaml
-  mamba env update --file latest.yaml
+  cat coiled_software_environment.yaml
+  mamba env update --file coiled_software_environment.yaml
 else
   mamba install -c conda-forge coiled-runtime=$COILED_RUNTIME_VERSION
 fi
diff --git a/ci/scripts/run_tests.sh b/ci/scripts/run_tests.sh
index 85a2dca5b1..eea31ed9ed 100644
--- a/ci/scripts/run_tests.sh
+++ b/ci/scripts/run_tests.sh
@@ -5,7 +5,7 @@ set -o xtrace
 BENCHMARK="${BENCHMARK:-false}"
 
 # Ensure we run additional tests when testing the latest coiled-runtime
-if [[ $COILED_RUNTIME_VERSION = 'latest' ]]
+if [[ "$COILED_RUNTIME_VERSION" =~ latest|AB_ ]]
 then
   EXTRA_OPTIONS="--run-latest"
   export COILED_SOFTWARE_NAME=$(cat software_name.txt)