diff --git a/.github/workflows/workflow.yml b/.github/workflows/workflow.yml
index 0ad8b5599b8..78476df70bf 100644
--- a/.github/workflows/workflow.yml
+++ b/.github/workflows/workflow.yml
@@ -110,7 +110,7 @@ jobs:
         run: opam install ./dune-configurator.opam
         if: ${{ matrix.configurator == true }}
 
-  dkml:
+  dkml-4_12_1:
     strategy:
       fail-fast: false
       matrix:
@@ -122,7 +122,37 @@ jobs:
             abi_pattern: win32-windows_x86_64
             dkml_host_abi: windows_x86_64
     runs-on: ${{ matrix.gh_os }}
-    name: MSVC / ${{ matrix.dkml_host_abi }}
+    name: MSVC 4.12.1 / ${{ matrix.dkml_host_abi }}
+
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Setup DKML on a Windows host
+        if: startsWith(matrix.dkml_host_abi, 'windows_')
+        uses: ./ci/setup-dkml/gh-windows-4.12.1/pre
+
+      - name: Build and test the package on Windows host
+        if: startsWith(matrix.dkml_host_abi, 'windows_')
+        shell: msys2 {0}
+        run: ci/build-test.sh
+
+      - name: Teardown DKML on a Windows host
+        if: startsWith(matrix.dkml_host_abi, 'windows_')
+        uses: ./ci/setup-dkml/gh-windows-4.12.1/post
+
+  dkml-current:
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - gh_os: windows-2019
+            abi_pattern: win32-windows_x86
+            dkml_host_abi: windows_x86
+          - gh_os: windows-2019
+            abi_pattern: win32-windows_x86_64
+            dkml_host_abi: windows_x86_64
+    runs-on: ${{ matrix.gh_os }}
+    name: MSVC 4.14.0 / ${{ matrix.dkml_host_abi }}
 
     steps:
       - uses: actions/checkout@v3
diff --git a/CHANGES.md b/CHANGES.md
index 5a1f22cd9ae..869176d3ad4 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -101,6 +101,8 @@ Unreleased
 - Add a `dune cache size` command for displaying the size of the cache (#6638,
   @Alizter)
 
+- Add 4.14.0 MSVC to CI (#6917, @jonahbeckford)
+
 3.6.2 (2022-12-21)
 ------------------
 
diff --git a/Makefile b/Makefile
index b961ea07d3d..16b2959bf51 100644
--- a/Makefile
+++ b/Makefile
@@ -31,7 +31,7 @@ ctypes \
 # Dependencies recommended for developing dune locally,
 # but not wanted in CI
 DEV_DEPS := \
-"dkml-workflows>=1.1.0" \
+"dkml-workflows>=1.2.0" \
 patdiff
 
 TEST_OCAMLVERSION := 4.14.0
diff --git a/ci/setup-dkml/README.md b/ci/setup-dkml/README.md
index e2f74277730..90ea2158e85 100644
--- a/ci/setup-dkml/README.md
+++ b/ci/setup-dkml/README.md
@@ -18,6 +18,16 @@ make update-dkml
 ```
 
 Of course that only works if there are updates available.
+And it will only do updates for the latest OCaml compiler.
+
+### Can we test more than one OCaml compiler?
+
+Technically no; `setup-dkml` follows the supported OCaml compiler of DKML. What
+we've done in this project is rename the directories that supported the older
+DKML versions (`4.12.1`). Essentially, the older DKML versions are frozen and
+will no longer get updates. You may want to eventually drop the older DKML
+versions by removing those directories and removing those versions from
+`workflow.yml`.
 
 ### What is the version of MSVC targeted? What is the required environment to execute the `desktop-ci-*` targets in the main `Makefile`?
 
diff --git a/ci/setup-dkml/gh-windows-4.12.1/post/action.yml b/ci/setup-dkml/gh-windows-4.12.1/post/action.yml
new file mode 100644
index 00000000000..df095393bbd
--- /dev/null
+++ b/ci/setup-dkml/gh-windows-4.12.1/post/action.yml
@@ -0,0 +1,102 @@
+# setup-dkml
+#   Short form: sd4
+
+# Any GitHub Job that includes this action must be in a strategy matrix.
+# The matrix variables must include:
+# - gh_os: windows-2019
+#   abi_pattern: win32-windows_x86
+#   dkml_host_abi: windows_x86
+
+name: post-dkml
+author: Diskuv, Inc.
+description: Teardown after building OCaml native executables for Windows
+
+runs:
+  using: "composite"
+
+  steps:
+    - name: Full matrix variables
+      shell: bash # bash on Windows is Git Bash (an non-upgradable MSYS2 system)
+      # Every matrix variable lookup in this Action should use the output of this step. Even
+      # the matrix variables that the user must specify (ex. dkml_host_abi) should be
+      # referenced using [steps.full_matrix_vars.outputs.dkml_host_abi] rather than
+      # [matrix.dkml_host_abi] so that there is a single place to edit for variable changes.
+      id: full_matrix_vars
+      run: |
+        # Select correct Windows matrix variables
+        case "${{ matrix.dkml_host_abi }}" in
+        
+        windows_x86)
+          dkml_host_os='windows';
+          opam_root_cacheable='D:/.opam';
+          abi_pattern='win32-windows_x86';
+          gh_os='windows-2019';
+          gh_unix_shell='msys2 {0}';
+          msys2_system='MINGW32';
+          msys2_packages='mingw-w64-i686-pkg-config';
+          exe_ext='.exe';
+          bootstrap_opam_version='2.2.0-dkml20220801T155940Z';
+          opam_abi='windows_x86';
+          dkml_host_abi='windows_x86';
+          opam_root='D:/.opam';
+          vsstudio_hostarch='x64';
+          vsstudio_arch='x86';
+          ocaml_options='ocaml-option-32bit' ;;
+          
+        windows_x86_64)
+          dkml_host_os='windows';
+          opam_root_cacheable='D:/.opam';
+          abi_pattern='win32-windows_x86_64';
+          gh_os='windows-2019';
+          gh_unix_shell='msys2 {0}';
+          msys2_system='CLANG64';
+          msys2_packages='mingw-w64-clang-x86_64-pkg-config';
+          exe_ext='.exe';
+          bootstrap_opam_version='2.2.0-dkml20220801T155940Z';
+          opam_abi='windows_x86_64';
+          dkml_host_abi='windows_x86_64';
+          opam_root='D:/.opam';
+          vsstudio_hostarch='x64';
+          vsstudio_arch='x64' ;;
+          
+        *)  echo "FATAL: Unsupported dkml_host_abi=$dkml_host_abi in Windows action.yml"; exit 107 ;;
+        esac
+
+        add() {
+          echo "$1=$2" | tee -a $GITHUB_OUTPUT | tee -a $GITHUB_ENV
+        }
+
+        add dkml_host_abi "$dkml_host_abi"
+        add abi_pattern "$abi_pattern"
+        add opam_root "$opam_root"
+        add opam_root_cacheable "$opam_root_cacheable"
+        add exe_ext "${exe_ext:-}"
+        add bootstrap_opam_version "${bootstrap_opam_version:-}"
+        add ocaml_options "${ocaml_options:-}"
+
+    - name: Teardown DKML build apparatus
+      shell: msys2 {0}
+      env:
+        _STUB_FOR_AUTOGEN: "ON" # 
+
+        # autogen from global_env_vars.
+        DEFAULT_DKML_COMPILER: '4.12.1-v1.0.2'
+        PIN_BASE: 'v0.14.3'
+        PIN_BIGSTRINGAF: '0.8.0'
+        PIN_CORE_KERNEL: 'v0.14.2'
+        PIN_CTYPES_FOREIGN: '0.19.2-windowssupport-r4'
+        PIN_CTYPES: '0.19.2-windowssupport-r4'
+        PIN_CURLY: '0.2.1-windows-env_r2'
+        PIN_DIGESTIF: '1.0.1'
+        PIN_DUNE: '2.9.3+shim.1.0.2~r0'
+        PIN_DUNE_CONFIGURATOR: '2.9.3'
+        PIN_DKML_APPS: '1.0.1'
+        PIN_OCAMLBUILD: '0.14.0'
+        PIN_OCAMLFIND: '1.9.1'
+        PIN_OCP_INDENT: '1.8.2-windowssupport'
+        PIN_PPX_EXPECT: 'v0.14.1'
+        PIN_PTIME: '0.8.6-msvcsupport'
+        PIN_TIME_NOW: 'v0.14.0'
+        PIN_WITH_DKML: '1.0.1'
+      run: |
+        sh .ci/sd4/run-teardown-dkml.sh GITHUB_WORKSPACE "$GITHUB_WORKSPACE"
diff --git a/ci/setup-dkml/gh-windows-4.12.1/post/dune b/ci/setup-dkml/gh-windows-4.12.1/post/dune
new file mode 100644
index 00000000000..a6daa52cb0c
--- /dev/null
+++ b/ci/setup-dkml/gh-windows-4.12.1/post/dune
@@ -0,0 +1,17 @@
+; DO NOT EDIT THIS FILE. It is auto-generated by generate-setup-dkml-scaffold
+; Typical upgrade steps:
+;   opam upgrade dkml-workflows && opam exec -- generate-setup-dkml-scaffold && dune build '@gen-dkml' --auto-promote
+
+(rule
+ (alias gen-dkml-4.12.1)
+ (target action.gen.yml)
+ (action
+  (setenv
+   OCAMLRUNPARAM
+   b
+   (run gh-dkml-action-yml --phase post --output-windows %{target}))))
+
+(rule
+ (alias gen-dkml-4.12.1)
+ (action
+  (diff action.yml action.gen.yml)))
diff --git a/ci/setup-dkml/gh-windows-4.12.1/pre/action.yml b/ci/setup-dkml/gh-windows-4.12.1/pre/action.yml
new file mode 100644
index 00000000000..bf1de9115d6
--- /dev/null
+++ b/ci/setup-dkml/gh-windows-4.12.1/pre/action.yml
@@ -0,0 +1,1864 @@
+# setup-dkml
+#   Short form: sd4
+
+# Any GitHub Job that includes this action must be in a strategy matrix.
+# The matrix variables must include:
+# - gh_os: windows-2019
+#   abi_pattern: win32-windows_x86
+#   dkml_host_abi: windows_x86
+
+name: pre-dkml
+author: Diskuv, Inc.
+description: Setup before building OCaml native executables for Windows
+
+inputs:
+  FDOPEN_OPAMEXE_BOOTSTRAP:
+    description: "Use opam.exe from fdopen on Windows. Typically only used when bootstrapping Opam for the first time. May be needed to solve '\"create_process\" failed on sleep: Bad file descriptor' which may need https://github.com/ocaml/opam/commit/417b97d8cfada35682a0f4107eb2e4f9e24fba91"
+    required: false
+    default: 'false'
+  CACHE_PREFIX:
+    description: The prefix of the cache keys.
+    required: false
+    default: "v1"
+  OCAML_COMPILER:
+    description: "The version of the OCaml compiler, as tagged by the https://github.com/diskuv/dkml-base-compiler repository. If not specified the latest compiler, or the version associated with the 'dkml-compiler' input, is used. Currently only 4.12.1 is supported"
+    required: false
+  DKML_COMPILER:
+    description: "Git branch, tag or commit for dkml-compiler. However if OCAML_COMPILER is specified the 'dkml-base-compiler' version is taken from OCAML_COMPILER."
+    required: false
+    default: "" # "@repository@" = Opam ; "" = latest from default branch of git clone
+  CONF_DKML_CROSS_TOOLCHAIN:
+    description: "Git branch, tag or commit for conf-dkml-cross-toolchain"
+    required: false
+    default: "@repository@" # "@repository@" = Opam ; "" = latest from default branch of git clone
+  DISKUV_OPAM_REPOSITORY:
+    description: "Git branch, tag or commit for diskuv-opam-repository"
+    required: false
+    default: "" # DEFAULT_DISKUV_OPAM_REPOSITORY_TAG is used as default for empty strings
+  VERBOSE:
+    description: "Turn on verbose logging"
+    required: false
+    default: 'false'
+  SECONDARY_SWITCH:
+    description: "Turn on secondary 'two' switch"
+    required: false
+    default: 'false'
+
+runs:
+  using: "composite"
+
+  steps:
+    - name: Full matrix variables
+      shell: bash # bash on Windows is Git Bash (an non-upgradable MSYS2 system)
+      # Every matrix variable lookup in this Action should use the output of this step. Even
+      # the matrix variables that the user must specify (ex. dkml_host_abi) should be
+      # referenced using [steps.full_matrix_vars.outputs.dkml_host_abi] rather than
+      # [matrix.dkml_host_abi] so that there is a single place to edit for variable changes.
+      id: full_matrix_vars
+      run: |
+        # Select correct Windows matrix variables
+        case "${{ matrix.dkml_host_abi }}" in
+        
+        windows_x86)
+          dkml_host_os='windows';
+          opam_root_cacheable='D:/.opam';
+          abi_pattern='win32-windows_x86';
+          gh_os='windows-2019';
+          gh_unix_shell='msys2 {0}';
+          msys2_system='MINGW32';
+          msys2_packages='mingw-w64-i686-pkg-config';
+          exe_ext='.exe';
+          bootstrap_opam_version='2.2.0-dkml20220801T155940Z';
+          opam_abi='windows_x86';
+          dkml_host_abi='windows_x86';
+          opam_root='D:/.opam';
+          vsstudio_hostarch='x64';
+          vsstudio_arch='x86';
+          ocaml_options='ocaml-option-32bit' ;;
+          
+        windows_x86_64)
+          dkml_host_os='windows';
+          opam_root_cacheable='D:/.opam';
+          abi_pattern='win32-windows_x86_64';
+          gh_os='windows-2019';
+          gh_unix_shell='msys2 {0}';
+          msys2_system='CLANG64';
+          msys2_packages='mingw-w64-clang-x86_64-pkg-config';
+          exe_ext='.exe';
+          bootstrap_opam_version='2.2.0-dkml20220801T155940Z';
+          opam_abi='windows_x86_64';
+          dkml_host_abi='windows_x86_64';
+          opam_root='D:/.opam';
+          vsstudio_hostarch='x64';
+          vsstudio_arch='x64' ;;
+          
+        *)  echo "FATAL: Unsupported dkml_host_abi=$dkml_host_abi in Windows action.yml"; exit 107 ;;
+        esac
+
+        add() {
+          echo "$1=$2" | tee -a $GITHUB_OUTPUT | tee -a $GITHUB_ENV
+        }
+
+        add dkml_host_abi "$dkml_host_abi"
+        add abi_pattern "$abi_pattern"
+        add opam_root "$opam_root"
+        add opam_root_cacheable "$opam_root_cacheable"
+        add exe_ext "${exe_ext:-}"
+        add bootstrap_opam_version "${bootstrap_opam_version:-}"
+        add ocaml_options "${ocaml_options:-}"
+
+        add msys2_system "${msys2_system:-}"
+        add msys2_packages "${msys2_packages:-}"
+        add vsstudio_hostarch "${vsstudio_hostarch:-}"
+        add vsstudio_arch "${vsstudio_arch:-}"
+        add vsstudio_dir "${vsstudio_dir:-}"
+        add vsstudio_vcvarsver "${vsstudio_vcvarsver:-}"
+        add vsstudio_winsdkver "${vsstudio_winsdkver:-}"
+        add vsstudio_msvspreference "${vsstudio_msvspreference:-}"
+        add vsstudio_cmakegenerator "${vsstudio_cmakegenerator:-}"
+
+    - name: Install MSYS2 (Windows)
+      uses: msys2/setup-msys2@v2
+      with:
+        msystem: "${{ steps.full_matrix_vars.outputs.msys2_system }}"
+        update: true
+        install: >-
+          ${{ steps.full_matrix_vars.outputs.msys2_packages }}
+          wget
+          make
+          rsync
+          diffutils
+          patch
+          unzip
+          git
+          tar
+          xz
+
+    - name: Uninstall MSYS2 conflicting executables (Windows)
+      # link.exe interferes with MSVC's link.exe
+      run: rm -vf /usr/bin/link.exe
+      shell: msys2 {0}
+
+    - name: Write POSIX shell and AWK scripts
+      shell: bash
+      run: |
+        install -d .ci/sd4
+
+        cat > .ci/sd4/common-values.sh <<'end_of_script'
+        #!/bin/sh
+
+        # ------------------------ Log Formatting ------------------------
+
+        TXT_SECTION="\e[94m" # bright blue
+        TXT_CLEAR="\e[0m"
+
+        if [ "${GITLAB_CI:-}" = "true" ]; then
+            # https://docs.gitlab.com/ee/ci/jobs/#expand-and-collapse-job-log-sections
+            print_section_start() {
+                print_section_start_NAME=$1
+                shift
+                printf "\e[0Ksection_start:%s:%s[collapsed=true]\r\e[0K" \
+                    "$(date +%s)" \
+                    "$print_section_start_NAME"
+            }
+            print_section_end() {
+                print_section_end_NAME=$1
+                shift
+                printf "\e[0Ksection_end:%s:%s\r\e[0K\n" \
+                    "$(date +%s)" \
+                    "$print_section_end_NAME"
+            }
+        elif [ -n "${GITHUB_ENV:-}" ]; then
+            # https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#grouping-log-lines
+            print_section_start() {
+                print_section_start_NAME=$1
+                shift
+                printf "::group::"
+            }
+            print_section_end() {
+                print_section_end_NAME=$1
+                shift
+                printf "::endgroup::\n"
+            }
+        else
+            print_section_start() {
+                print_section_start_NAME=$1
+                shift
+            }
+            print_section_end() {
+                print_section_end_NAME=$1
+                shift
+            }
+        fi
+
+        section_begin() {
+            # https://docs.gitlab.com/ee/ci/yaml/script.html#add-color-codes-to-script-output
+            section_NAME=$1
+            shift
+            section_HEADER=$1
+            shift
+            print_section_start "$section_NAME"
+            printf "${TXT_SECTION}%s${TXT_CLEAR}\n" "$section_HEADER"
+        }
+
+        section_end() {
+            section_NAME=$1
+            shift
+            print_section_end "$section_NAME"
+        }
+
+        # ------------------- Other Functions -----------------
+
+        transfer_dir() {
+            transfer_dir_SRC=$1
+            shift
+            transfer_dir_DST=$1
+            shift
+            # Remove the destination directory completely, but make sure the parent of the
+            # destination directory exists so `mv` will work
+            install -d "$transfer_dir_DST"
+            rm -rf "$transfer_dir_DST"
+            # Move
+            mv "$transfer_dir_SRC" "$transfer_dir_DST"
+        }
+
+        # Set TEMP variable which is used, among other things, for OCaml's
+        # [Filename.temp_dir_name] on Win32, and by with-dkml.exe on Windows
+        export_temp_for_windows() {
+            if [ -x /usr/bin/cygpath ]; then
+                if [ -n "${RUNNER_TEMP:-}" ]; then
+                    # GitHub Actions
+                    TEMP=$(cygpath -am "$RUNNER_TEMP")
+                else
+                    # GitLab CI/CD or desktop
+                    install -d .ci/tmp
+                    TEMP=$(cygpath -am ".ci/tmp")
+                fi
+                export TEMP
+            fi
+        }
+
+        # Fixup opam_root on Windows to be mixed case.
+        # On input the following variables must be present:
+        # - opam_root
+        # - opam_root_cacheable
+        # On output the input variables will be modified _and_ the
+        # following variables will be available:
+        # - original_opam_root
+        # - original_opam_root_cacheable
+        # - unix_opam_root
+        # - unix_opam_root_cacheable
+        fixup_opam_root() {
+            # shellcheck disable=SC2034
+            original_opam_root=$opam_root
+            # shellcheck disable=SC2034
+            original_opam_root_cacheable=$opam_root_cacheable
+            if [ -x /usr/bin/cygpath ]; then
+                opam_root=$(/usr/bin/cygpath -m "$opam_root")
+                opam_root_cacheable=$(/usr/bin/cygpath -m "$opam_root_cacheable")
+                unix_opam_root=$(/usr/bin/cygpath -u "$opam_root")
+                unix_opam_root_cacheable=$(/usr/bin/cygpath -u "$opam_root_cacheable")
+            else
+                # shellcheck disable=SC2034
+                unix_opam_root=$opam_root
+                # shellcheck disable=SC2034
+                unix_opam_root_cacheable=$opam_root_cacheable
+            fi
+        }
+        end_of_script
+
+        cat > .ci/sd4/run-checkout-code.sh <<'end_of_script'
+        #!/bin/sh
+
+        # ================
+        # checkout-code.sh
+        # ================
+        #
+        # Checkouts all of the git source code.
+        #
+        # This should be done outside of
+        # dockcross (used by Linux) since a Docker-in-Docker container can have
+        # difficulties doing a git checkout (the Git credentials for any private
+        # repositories are likely not present). We don't care about any private
+        # repositories for DKML but any code that extends this (ex. DKSDK) may
+        # need to use private repositories.
+
+        set -euf
+
+        setup_WORKSPACE_VARNAME=$1
+        shift
+        setup_WORKSPACE=$1
+        shift
+
+        # ------------------------ Functions ------------------------
+
+        # shellcheck source=./common-values.sh
+        . .ci/sd4/common-values.sh
+
+        # Disable automatic garbage collection
+        git_disable_gc() {
+            git_disable_gc_NAME=$1
+            shift
+            git -C ".ci/sd4/g/$git_disable_gc_NAME" config --local gc.auto 0
+        }
+
+        # Mimic the behavior of GitHub's actions/checkout@v3
+        # - the plus symbol in 'git fetch ... origin +REF:refs/tags/v0.0' overrides any existing REF
+        git_checkout() {
+            git_checkout_NAME=$1
+            shift
+            git_checkout_URL=$1
+            shift
+            git_checkout_REF=$1
+            shift
+
+            if [ -e ".ci/sd4/g/$git_checkout_NAME" ]; then
+                git_disable_gc "$git_checkout_NAME"
+                git -C ".ci/sd4/g/$git_checkout_NAME" remote set-url origin "$git_checkout_URL"
+                git -C ".ci/sd4/g/$git_checkout_NAME" fetch --no-tags --progress --no-recurse-submodules --depth=1 origin "+${git_checkout_REF}:refs/tags/v0.0"
+            else
+                install -d ".ci/sd4/g/$git_checkout_NAME"
+                git -C ".ci/sd4/g/$git_checkout_NAME" -c init.defaultBranch=main init
+                git_disable_gc "$git_checkout_NAME"
+                git -C ".ci/sd4/g/$git_checkout_NAME" remote add origin "$git_checkout_URL"
+                git -C ".ci/sd4/g/$git_checkout_NAME" fetch --no-tags --prune --progress --no-recurse-submodules --depth=1 origin "+${git_checkout_REF}:refs/tags/v0.0"
+            fi
+            git -C ".ci/sd4/g/$git_checkout_NAME" -c advice.detachedHead=false checkout --progress --force refs/tags/v0.0
+            git -C ".ci/sd4/g/$git_checkout_NAME" log -1 --format='%H'
+        }
+
+        # ---------------------------------------------------------------------
+
+        section_begin checkout-info "Summary: code checkout"
+
+        # shellcheck disable=SC2154
+        echo "
+        ================
+        checkout-code.sh
+        ================
+        .
+        ---------
+        Arguments
+        ---------
+        WORKSPACE_VARNAME=$setup_WORKSPACE_VARNAME
+        WORKSPACE=$setup_WORKSPACE
+        .
+        ------
+        Inputs
+        ------
+        VERBOSE=${VERBOSE:-}
+        .
+        ------
+        Matrix
+        ------
+        dkml_host_abi=$dkml_host_abi
+        .
+        "
+
+        section_end checkout-info
+
+        install -d .ci/sd4/g
+
+        # dkml-runtime-distribution
+
+        case "$dkml_host_abi" in
+        windows_*)
+            section_begin checkout-dkml-runtime-distribution 'Checkout dkml-runtime-distribution'
+            git_checkout dkml-runtime-distribution https://github.com/diskuv/dkml-runtime-distribution.git "1a3ec82dd851751a95e6a4797387a8163c51520e"
+            section_end checkout-dkml-runtime-distribution
+            ;;
+        esac
+
+        end_of_script
+
+        cat > .ci/sd4/run-setup-dkml.sh <<'end_of_script'
+        #!/bin/sh
+        set -euf
+
+        # Constants
+        SHA512_DEVNULL='cf83e1357eefb8bdf1542850d66d8007d620e4050b5715dc83f4a921d36ce9ce47d0d13c5d85f2b0ff8318d2877eec2f63b931bd47417a81a538327af927da3e'
+        #   Edited by https://gitlab.com/diskuv/diskuv-ocaml/contributors/release.sh
+        DEFAULT_DISKUV_OPAM_REPOSITORY_TAG=cc9518fa5630bfbe24d4c5e0e2cc29af513037ce
+        # Constants
+        #   Should be edited by release.sh, but ...
+        #   Can't be 1.0.0 or later until https://github.com/ocaml/opam-repository/pull/21704 ocaml-option-32bit
+        #   can come back in.
+        DKML_VERSION=0.4.0
+
+        setup_WORKSPACE_VARNAME=$1
+        shift
+        setup_WORKSPACE=$1
+        shift
+
+        # ------------------ Variables and functions ------------------------
+
+        # shellcheck source=./common-values.sh
+        . .ci/sd4/common-values.sh
+
+        if [ "${VERBOSE:-}" = "true" ]; then
+            do_tar_rf() {
+                tar rvf "$@"
+            }
+        else
+            do_tar_rf() {
+                tar rf "$@"
+            }
+        fi
+
+        # Make the standard input work as an OCaml string.
+        # This currently only escapes backslashes and double quotes.
+        escape_arg_as_ocaml_string() {
+            escape_arg_as_ocaml_string_ARG=$1
+            shift
+            printf "%s" "$escape_arg_as_ocaml_string_ARG" | sed 's#\\#\\\\#g; s#"#\\"#g;'
+        }
+
+        # Fixup opam_root on Windows to be mixed case. Set original_* and unix_* as well.
+        fixup_opam_root
+
+        # Set TEMP variable for Windows
+        export_temp_for_windows
+
+        # Load VS studio environment
+        if [ -e .ci/sd4/vsenv.sh ]; then
+            # shellcheck disable=SC1091
+            . .ci/sd4/vsenv.sh
+        fi
+
+        # -------------------------------------------------------------------
+
+        section_begin setup-info "Summary: setup-dkml"
+
+        # shellcheck disable=SC2154
+        echo "
+        =============
+        setup-dkml.sh
+        =============
+        .
+        ---------
+        Arguments
+        ---------
+        WORKSPACE_VARNAME=$setup_WORKSPACE_VARNAME
+        WORKSPACE=$setup_WORKSPACE
+        .
+        ------
+        Inputs
+        ------
+        FDOPEN_OPAMEXE_BOOTSTRAP=${FDOPEN_OPAMEXE_BOOTSTRAP:-}
+        DISKUV_OPAM_REPOSITORY=${DISKUV_OPAM_REPOSITORY:-}
+        DKML_COMPILER=${DKML_COMPILER:-}
+        OCAML_COMPILER=${OCAML_COMPILER:-}
+        CONF_DKML_CROSS_TOOLCHAIN=${CONF_DKML_CROSS_TOOLCHAIN:-}
+        SECONDARY_SWITCH=${SECONDARY_SWITCH:-}
+        MANYLINUX=${MANYLINUX:-}
+        VERBOSE=${VERBOSE:-}
+        .
+        -------------------
+        Generated Constants
+        -------------------
+        DKML_VERSION=$DKML_VERSION
+        DEFAULT_DISKUV_OPAM_REPOSITORY_TAG=$DEFAULT_DISKUV_OPAM_REPOSITORY_TAG
+        DEFAULT_DKML_COMPILER=$DEFAULT_DKML_COMPILER
+        .
+        ------
+        Matrix
+        ------
+        dkml_host_abi=$dkml_host_abi
+        bootstrap_opam_version=$bootstrap_opam_version
+        abi_pattern=$abi_pattern
+        opam_root=${opam_root}
+        opam_root_cacheable=${opam_root_cacheable}
+        original_opam_root=${original_opam_root}
+        original_opam_root_cacheable=${original_opam_root_cacheable}
+        unix_opam_root=${unix_opam_root}
+        unix_opam_root_cacheable=${unix_opam_root_cacheable}
+        dockcross_image=${dockcross_image:-}
+        dockcross_image_custom_prefix=${dockcross_image_custom_prefix:-}
+        dockcross_run_extra_args=${dockcross_run_extra_args:-}
+        docker_runner=${docker_runner:-}
+        in_docker=${in_docker:-}
+        ocaml_options=${ocaml_options:-}
+        .
+        ----
+        Pins
+        ----
+        PIN_BASE=${PIN_BASE}
+        PIN_BIGSTRINGAF=${PIN_BIGSTRINGAF}
+        PIN_CORE_KERNEL=${PIN_CORE_KERNEL}
+        PIN_CTYPES=${PIN_CTYPES}
+        PIN_CTYPES_FOREIGN=${PIN_CTYPES_FOREIGN}
+        PIN_CURLY=${PIN_CURLY}
+        PIN_DIGESTIF=${PIN_DIGESTIF}
+        PIN_DKML_APPS=${PIN_DKML_APPS}
+        PIN_DUNE=${PIN_DUNE}
+        PIN_DUNE_CONFIGURATOR=${PIN_DUNE_CONFIGURATOR}
+        PIN_OCAMLBUILD=${PIN_OCAMLBUILD}
+        PIN_OCAMLFIND=${PIN_OCAMLFIND}
+        PIN_OCP_INDENT=${PIN_OCP_INDENT}
+        PIN_PPX_EXPECT=${PIN_PPX_EXPECT}
+        PIN_PTIME=${PIN_PTIME}
+        PIN_TIME_NOW=${PIN_TIME_NOW}
+        PIN_WITH_DKML=${PIN_WITH_DKML}
+        .
+        "
+        case "$dkml_host_abi" in
+        windows_*)
+            # shellcheck disable=SC2153
+            echo "
+        -------------
+        Visual Studio
+        -------------
+        VS_DIR=$VS_DIR
+        VS_VCVARSVER=$VS_VCVARSVER
+        VS_WINSDKVER=$VS_WINSDKVER
+        VS_MSVSPREFERENCE=$VS_MSVSPREFERENCE
+        VS_CMAKEGENERATOR=$VS_CMAKEGENERATOR
+        .
+        "
+            ;;
+        esac
+        section_end setup-info
+
+        do_bootstrap() {
+            # Bootstrap from historical release
+            runit_BOOTSTRAPPED=0
+
+            #   Bootstrap opam from fdopen (Windows)
+            if [ "$runit_BOOTSTRAPPED" = 0 ] && [ "${FDOPEN_OPAMEXE_BOOTSTRAP:-}" = "true" ]; then
+                if [ -e .ci/sd4/opam64/bin/opam.exe ] && [ -e .ci/sd4/opam64/bin/opam-installer.exe ]; then
+                    runit_BOOTSTRAPPED=1
+                else
+                    case "$dkml_host_abi" in
+                    windows_*)
+                        echo 'Bootstrap opam from fdopen (Windows) ...'
+                        install -d .ci/sd4/bs/bin
+                        wget -O "$setup_WORKSPACE"/.ci/sd4/opam64.tar.xz https://github.com/fdopen/opam-repository-mingw/releases/download/0.0.0.2/opam64.tar.xz
+
+                        # this stalls: tar xvCfJ "$setup_WORKSPACE"/.ci/sd4 "$setup_WORKSPACE"/.ci/sd4/opam64.tar.xz
+                        xz -v -d "$setup_WORKSPACE"/.ci/sd4/opam64.tar.xz
+                        tar xvCf .ci/sd4 .ci/sd4/opam64.tar
+
+                        rm -rf "$setup_WORKSPACE"/.ci/sd4/bs/bin/Opam.Runtime.amd64
+                        mv -v "$setup_WORKSPACE"/.ci/sd4/opam64/bin/Opam.Runtime.amd64/ "$setup_WORKSPACE"/.ci/sd4/bs/bin/
+                        mv -v "$setup_WORKSPACE"/.ci/sd4/opam64/bin/opam.exe "$setup_WORKSPACE"/.ci/sd4/bs/bin/
+                        mv -v "$setup_WORKSPACE"/.ci/sd4/opam64/bin/opam-installer.exe "$setup_WORKSPACE"/.ci/sd4/bs/bin/
+
+                        # diagnostics
+                        ldd "$setup_WORKSPACE"/.ci/sd4/bs/bin/opam.exe
+                        ldd "$setup_WORKSPACE"/.ci/sd4/bs/bin/opam-installer.exe
+
+                        runit_BOOTSTRAPPED=1
+                        ;;
+                    esac
+                fi
+            fi
+
+            #   Bootstrap from historical release
+            if [ "$runit_BOOTSTRAPPED" = 0 ] && [ "$bootstrap_opam_version" != "os" ]; then
+                install -d .ci/sd4/bs
+                cd .ci/sd4/bs
+
+                if [ ! -e version ] || [ "$(cat version)" != "$bootstrap_opam_version" ]; then
+                    echo 'Bootstrap opam from historical release (non-Windows; Windows non-fdopen) ...'
+                    if command -v curl; then
+                        curl -L -o opam.tar.gz "https://github.com/diskuv/dkml-component-opam/releases/download/v${bootstrap_opam_version}/dkml-component-staging-opam.tar.gz"
+                    else
+                        wget -O opam.tar.gz "https://github.com/diskuv/dkml-component-opam/releases/download/v${bootstrap_opam_version}/dkml-component-staging-opam.tar.gz"
+                    fi
+                    tar tvfz opam.tar.gz
+                    tar xfz opam.tar.gz "./staging-files/${dkml_host_abi}/"
+                    rm -rf bin/
+                    mv "staging-files/${dkml_host_abi}/bin" .
+                    rm -rf "${abi_pattern}"
+                    printf "%s" "${bootstrap_opam_version}" >version
+                fi
+
+                rm -f opam.tar.gz
+                cd ../../..
+
+                runit_BOOTSTRAPPED=1
+            fi
+
+            #   Bootstrap from package manager or GitHub ocaml/opam release
+            case "$runit_BOOTSTRAPPED,$bootstrap_opam_version,$dkml_host_abi" in
+            0,os,darwin_*)
+                if ! command -v opam; then
+                    echo 'Bootstrap opam from package manager (macOS) ...'
+                    brew install gpatch
+                    brew install opam
+                fi
+                runit_BOOTSTRAPPED=1
+                ;;
+            0,os,linux_x86)
+                if [ ! -x .ci/sd4/bs/bin/opam ]; then
+                    echo 'Bootstrap opam from GitHub ocaml/opam release (Linux x86) ...'
+                    install -d .ci/sd4/bs/bin
+                    wget -O .ci/sd4/bs/bin/opam.tmp https://github.com/ocaml/opam/releases/download/2.1.2/opam-2.1.2-i686-linux
+                    sha512_check=$(openssl sha512 2>&1 </dev/null | cut -f 2 -d ' ')
+                    if [ "$SHA512_DEVNULL" = "$sha512_check" ]; then
+                        sha512=$(openssl sha512 ".ci/sd4/bs/bin/opam.tmp" 2>/dev/null | cut -f 2 -d ' ')
+                        check="85a480d60e09a7d37fa0d0434ed97a3187434772ceb4e7e8faa5b06bc18423d004af3ad5849c7d35e72dca155103257fd6b1178872df8291583929eb8f884b6a"
+                        test "$sha512" = "$check"
+                        chmod +x .ci/sd4/bs/bin/opam.tmp
+                        mv .ci/sd4/bs/bin/opam.tmp .ci/sd4/bs/bin/opam
+                    else
+                        echo "openssl 512 option unsupported."
+                        exit 61
+                    fi
+                fi
+                runit_BOOTSTRAPPED=1
+                ;;
+            0,os,linux_x86_64)
+                if [ ! -x .ci/sd4/bs/bin/opam ]; then
+                    echo 'Bootstrap opam from GitHub ocaml/opam release (Linux x86_64) ...'
+                    install -d .ci/sd4/bs/bin
+                    wget -O .ci/sd4/bs/bin/opam.tmp https://github.com/ocaml/opam/releases/download/2.1.2/opam-2.1.2-x86_64-linux
+                    sha512_check=$(openssl sha512 2>&1 </dev/null | cut -f 2 -d ' ')
+                    if [ "$SHA512_DEVNULL" = "$sha512_check" ]; then
+                        sha512=$(openssl sha512 ".ci/sd4/bs/bin/opam.tmp" 2>/dev/null | cut -f 2 -d ' ')
+                        check="c0657ecbd4dc212587a4da70c5ff0402df95d148867be0e1eb1be8863a2851015f191437c3c99b7c2b153fcaa56cac99169c76ec94c5787750d7a59cd1fbb68b"
+                        test "$sha512" = "$check"
+                        chmod +x .ci/sd4/bs/bin/opam.tmp
+                        mv .ci/sd4/bs/bin/opam.tmp .ci/sd4/bs/bin/opam
+                    else
+                        echo "openssl 512 option unsupported."
+                        exit 61
+                    fi
+                fi
+                runit_BOOTSTRAPPED=1
+                ;;
+            esac
+        }
+        section_begin bootstrap-opam 'Bootstrap opam'
+        do_bootstrap
+        section_end bootstrap-opam
+
+        # Start environment distribution tarball
+        #   We use .tar rather than .tar.gz/.tar.bz2 because we can repeatedly add to an uncompressed .tar. But we need to
+        #   start with an empty tarball since some tar programs will only add ('tar rf xyz.tar') to an existing .tar.
+        install -d .ci/sd4/dist
+        tar cf .ci/sd4/dist/opam-with-env.tar -T /dev/null
+
+        do_get_dockcross() {
+            if [ -n "${dockcross_image:-}" ]; then
+                # The dockcross script is super-slow
+                section_begin get-dockcross 'Get dockcross binary (ManyLinux)'
+                install -d .ci/sd4
+                #   shellcheck disable=SC2086
+                docker run ${dockcross_run_extra_args:-} --rm "${dockcross_image_custom_prefix:-}${dockcross_image:-}" >.ci/sd4/dockcross.gen
+
+                # PROBLEM 1
+                # ---------
+                # Super-annoying stderr output from dockcross at line:
+                #    tty -s && [ -z "$MSYS" ] && TTY_ARGS=-ti
+                # When there is no tty, get:
+                #   tty: ignoring all arguments
+                #   not a tty
+                # So replace 'tty -s &&' with 'false &&'
+                sed 's/tty -s &&/false \&\&/' .ci/sd4/dockcross.gen >.ci/sd4/dockcross-real
+                rm -f .ci/sd4/dockcross.gen
+                chmod +x .ci/sd4/dockcross-real
+
+                # PROBLEM 2
+                # ---------
+                # By default dockcross for ManyLinux will chown -R all python packages; super-slow (~10 seconds)!
+                # Confer: https://github.com/dockcross/dockcross/blob/master/manylinux-common/pre_exec.sh
+                # That kills speed for any repetitive dockcross invocation.
+                #
+                # BUT it is unnecessary to chown -R when the current user is root, because inside the Docker container
+                # the files are already root!
+                #
+                # The chown -R (within pre_exec.sh) is not run when the user ids are not passed in.
+                # Confer: https://github.com/dockcross/dockcross/blob/96d87416f639af0204bdd42553e4b99315ca8476/imagefiles/entrypoint.sh#L21-L53
+                #
+                # So explicitly call the entrypoint if root!
+                case "$dkml_host_abi" in
+                #       https://github.com/dockcross/dockcross/blob/master/linux-x86/linux32-entrypoint.sh
+                linux_x86)  dockcross_entrypoint=/dockcross/linux32-entrypoint.sh ;;
+                *)          dockcross_entrypoint=/dockcross/entrypoint.sh ;;
+                esac
+                cat > .ci/sd4/dockcross <<EOF
+        #!/bin/bash
+        set -euf
+        BUILDER_UID="\$( id -u )"
+        BUILDER_GID="\$( id -g )"
+        if [ "\$BUILDER_UID" = 0 ] && [ "\$BUILDER_GID" = 0 ]; then
+            # ---------- Start of dockcross script snippet -------
+            # Verbatim from
+            # https://github.com/dockcross/dockcross/blob/96d87416f639af0204bdd42553e4b99315ca8476/imagefiles/dockcross#L175-L204
+            # except 1) disabling of USER_IDS
+
+            # Bash on Ubuntu on Windows
+            UBUNTU_ON_WINDOWS=\$([ -e /proc/version ] && grep -l Microsoft /proc/version || echo "")
+            # MSYS, Git Bash, etc.
+            MSYS=\$([ -e /proc/version ] && grep -l MINGW /proc/version || echo "")
+            # CYGWIN
+            CYGWIN=\$([ -e /proc/version ] && grep -l CYGWIN /proc/version || echo "")
+
+            #if [ -z "\$UBUNTU_ON_WINDOWS" -a -z "\$MSYS" -a "\$OCI_EXE" != "podman" ]; then
+            #    USER_IDS=(-e BUILDER_UID="\$( id -u )" -e BUILDER_GID="\$( id -g )" -e BUILDER_USER="\$( id -un )" -e BUILDER_GROUP="\$( id -gn )")
+            #fi
+
+            # Change the PWD when working in Docker on Windows
+            if [ -n "\$UBUNTU_ON_WINDOWS" ]; then
+                WSL_ROOT="/mnt/"
+                CFG_FILE=/etc/wsl.conf
+                    if [ -f "\$CFG_FILE" ]; then
+                            CFG_CONTENT=\$(cat \$CFG_FILE | sed -r '/[^=]+=[^=]+/!d' | sed -r 's/\s+=\s/=/g')
+                            eval "\$CFG_CONTENT"
+                            if [ -n "\$root" ]; then
+                                    WSL_ROOT=\$root
+                            fi
+                    fi
+                HOST_PWD=\`pwd -P\`
+                HOST_PWD=\${HOST_PWD/\$WSL_ROOT//}
+            elif [ -n "\$MSYS" ]; then
+                HOST_PWD=\$PWD
+                HOST_PWD=\${HOST_PWD/\//}
+                HOST_PWD=\${HOST_PWD/\//:\/}
+            elif [ -n "\$CYGWIN" ]; then
+                for f in pwd readlink cygpath ; do
+                    test -n "\$(type "\${f}" )" || { echo >&2 "Missing functionality (\${f}) (in cygwin)." ; exit 1 ; } ;
+                done ;
+                HOST_PWD="\$( cygpath -w "\$( readlink -f "\$( pwd ;)" ; )" ; )" ;
+            else
+                HOST_PWD=\$PWD
+                [ -L \$HOST_PWD ] && HOST_PWD=\$(readlink \$HOST_PWD)
+            fi
+
+            # ---------- End of dockcross script snippet -------
+
+            # Handle: dockcross --args "-v X:Y --platform P"
+            ARGS=
+            if [ "\$#" -ge 1 ] && [ "\$1" = "--args" ]; then
+                shift
+                ARGS=\$1
+                shift
+            fi
+
+            # Directly invoke entrypoint
+            exec docker run --entrypoint /bin/bash \
+                --rm \
+                \${ARGS:-} \
+                 -v "\$HOST_PWD":/work \
+                ${dockcross_image_custom_prefix:-}${dockcross_image:-} ${dockcross_entrypoint} "\$@"
+        else
+            HERE=\$(dirname "\$0")
+            HERE=\$(cd "\$HERE" && pwd)
+            exec "\$HERE/dockcross-real" "\$@"
+        fi
+        EOF
+                chmod +x .ci/sd4/dockcross
+
+                # Bundle for consumers of setup-dkml.yml
+                do_tar_rf .ci/sd4/dist/opam-with-env.tar .ci/sd4/dockcross .ci/sd4/dockcross-real
+
+                section_end get-dockcross
+            fi
+        }
+        do_get_dockcross
+
+        if [ -n "${dockcross_image:-}" ]; then
+            # rsync needs to be available, even after Docker container disappears
+            if [ ! -e .ci/sd4/bs/bin/rsync ]; then
+                section_begin get-opam-prereqs-in-dockcross 'Get Opam prerequisites (ManyLinux)'
+                install -d .ci/sd4/bs/bin
+                #   shellcheck disable=SC2016
+                .ci/sd4/dockcross --args "${dockcross_run_extra_args:-}" sh -c 'sudo yum install -y rsync && install $(command -v rsync) .ci/sd4/bs/bin'
+                section_end get-opam-prereqs-in-dockcross
+            fi
+        fi
+
+        # Opam prerequisites for using opam (not for installing opam)
+
+        {
+            if [ -n "${docker_runner:-}" ]; then
+                # rsync needs to be available, even after Docker container disappears
+                if [ ! -e .ci/sd4/bs/bin/rsync.deps ]; then
+                    section_begin get-opam-prereqs-in-docker 'Get Opam prerequisites (Linux Docker)'
+                    install -d .ci/sd4/bs/bin
+                    ${docker_runner} sh -c '
+                    apt-get update &&
+                    apt-get install -y rsync &&
+                    ldd /usr/bin/rsync &&
+                    ls -l /lib/i386-linux-gnu/libpopt.so.0 /lib/i386-linux-gnu/libacl.so.1 /lib/i386-linux-gnu/libattr.so.1 &&
+                    tar cCfhz / /work/.ci/sd4/bs/bin/deps.tar.gz /usr/bin/rsync /lib/i386-linux-gnu/libpopt.so.0
+                '
+                    touch .ci/sd4/bs/bin/rsync.deps
+                    section_end get-opam-prereqs-in-docker
+                fi
+            fi
+
+            # Bundle Opam prerequisites (ManyLinux or Linux Docker)
+            if [ -n "${docker_runner:-}" ] || [ -n "${dockcross_image:-}" ]; then
+                # Bundle for consumers of setup-dkml.yml
+                do_tar_rf .ci/sd4/dist/opam-with-env.tar .ci/sd4/bs/bin/rsync
+            fi
+        }
+
+        # Get Opam Cache
+        do_get_opam_cache() {
+            if [ "$unix_opam_root_cacheable" = "$unix_opam_root" ]; then return; fi
+            if [ ! -e "$unix_opam_root_cacheable" ]; then return; fi
+            section_begin get-opam-cache "Transferring Opam cache to $original_opam_root_cacheable"
+            echo Starting transfer # need some output or GitLab CI will not display the section duration
+            transfer_dir "$unix_opam_root_cacheable" "$unix_opam_root"
+            echo Finished transfer
+            section_end get-opam-cache
+        }
+        do_get_opam_cache
+
+        # Setup Opam
+
+        do_write_opam_scripts() {
+            case "${FDOPEN_OPAMEXE_BOOTSTRAP:-},$dkml_host_abi" in
+            true,windows_*)
+                # With fdopen's opam.exe, 'os-distribution = "cygwinports"'. But native Windows opam.exe has 'os-distribution = "win32"'.
+                # But on Windows we always want MSYS2 or native Windows libraries, not Cygwin. If cygwinports then
+                # code like https://github.com/ocaml/opam-repository/blob/08cbb8258bd4bf30cd6f307c958911a29d537b54/packages/conf-pkg-config/conf-pkg-config.2/opam#L36
+                # will fail. So always set 'os-distribution = "win32"' on Windows.
+                PATCH_OS_DISTRIBUTION_WIN32=true
+                # With fdopen's opam.exe, no 'exe = ".exe"' is set because Cygwin does not need file extensions.
+                # Native Windows requires a .exe extension.
+                PATCH_EXE_WIN32=true
+                ;;
+            *)
+                PATCH_OS_DISTRIBUTION_WIN32=false
+                PATCH_EXE_WIN32=false
+                ;;
+            esac
+
+            # ---------------------
+            # Empty opam repository
+            # ---------------------
+
+            install -d .ci/sd4/eor
+            cat >.ci/sd4/eor/repo <<EOF
+        opam-version: "2.0"
+        browse: "https://opam.ocaml.org/pkg/"
+        upstream: "https://github.com/ocaml/opam-repository/tree/master/"
+        EOF
+
+            # ---------------
+            # Create Opam troubleshooting script
+            # ---------------
+
+            cat >.ci/sd4/troubleshoot-opam.sh <<EOF
+        #!/bin/sh
+        set -euf
+        OPAMROOT=\$1
+        shift
+        printf "\n\n========= [START OF TROUBLESHOOTING] ===========\n\n" >&2
+        find "\$OPAMROOT"/log -mindepth 1 -maxdepth 1 -name "*.out" ! -name "log-*.out" ! -name "ocaml-variants-*.out" | while read -r dump_on_error_LOG; do
+            dump_on_error_BLOG=\$(basename "\$dump_on_error_LOG")
+            printf "\n\n========= [TROUBLESHOOTING] %s ===========\n\n" "\$dump_on_error_BLOG" >&2
+            awk -v BLOG="\$dump_on_error_BLOG" '{print "[" BLOG "]", \$0}' "\$dump_on_error_LOG" >&2
+        done
+        printf "\nScroll up to see the [TROUBLESHOOTING] logs that begin at the [START OF TROUBLESHOOTING] line\n" >&2
+        EOF
+
+            chmod +x .ci/sd4/troubleshoot-opam.sh
+            do_tar_rf .ci/sd4/dist/opam-with-env.tar .ci/sd4/troubleshoot-opam.sh
+
+            # ---------------
+            # Create Opam support scripts (not needed for all platforms)
+            #   The PATH to find opam must work internally in setup-dkml.yml (sd4/bs/bin) and
+            #   by consumers of setup-dkml.yml (sd4/opamexe)
+            # ---------------
+
+            USER_ID=$(id -u)
+            GROUP_ID=$(id -g)
+            USER_NAME=$(id -un)
+            GROUP_NAME=$(id -gn)
+
+            case "${opam_root}" in
+            /* | ?:*) # /a/b/c or C:\Windows
+                validate_supports_docker() {
+                    echo "Docker only supported with relative paths for the opam root, not: ${opam_root}" >&2
+                    exit 3
+                }
+                ;;
+            *) # relative path
+                validate_supports_docker() {
+                    true
+                }
+                cat >.ci/sd4/opam-in-docker <<EOF
+        #!/bin/sh
+        set -euf
+        export PATH="/work/.ci/sd4/bs/bin:/work/.ci/sd4/opamexe:\$PATH"
+        export OPAMROOT=/work/${opam_root}
+        export OPAMROOTISOK=1
+        if [ "${PATCH_OS_DISTRIBUTION_WIN32}" = true ]; then export OPAMVAR_os_distribution=win32; fi
+        if [ "${PATCH_EXE_WIN32}" = true ]; then export OPAMVAR_exe=.exe; fi
+
+        # Reset environment so no conflicts with a parent Opam or OCaml system
+        unset OPAM_SWITCH_PREFIX
+        unset OPAMSWITCH
+        unset CAML_LD_LIBRARY_PATH
+        unset OCAMLLIB
+        unset OCAML_TOPLEVEL_PATH
+
+        # Optionally skip troubleshooting
+        troubleshooting=1
+        if [ "\$#" -ge 1 ] && [ "\$1" = "--no-troubleshooting" ]; then
+            shift
+            troubleshooting=0
+        fi
+
+        echo "Running inside Docker container: opam \$*" >&2
+        set +e
+        opam "\$@"
+        exitcode=\$?
+        if [ \$troubleshooting = 1 ]; then
+            [ \$exitcode = 0 ] || "/work/.ci/sd4/troubleshoot-opam.sh" \$OPAMROOT
+        fi
+        exit \$exitcode
+        EOF
+                chmod +x .ci/sd4/opam-in-docker
+                ;;
+            esac
+
+            cat >.ci/sd4/deescalate <<EOF
+        #!/bin/sh
+        set -euf
+
+        if [ -e /work/.ci/sd4/bs/bin/deps.tar.gz ]; then
+            tar xCfz / /work/.ci/sd4/bs/bin/deps.tar.gz
+        fi
+
+        groupadd -g ${GROUP_ID} ${GROUP_NAME}
+        useradd -l -m -u ${USER_ID} -g ${GROUP_ID} ${USER_NAME}
+        exec runuser -u ${USER_NAME} -g ${GROUP_NAME} -- "\$@"
+        EOF
+
+            chmod +x .ci/sd4/deescalate
+
+            # -----------------------------------
+            # Create opam-with-env
+            # -----------------------------------
+
+            install -d .ci/sd4/dist
+
+            if [ -x .ci/sd4/dockcross ]; then
+                # Adding empty dockcross root volume avoids:
+                #    cp: target ‘/home/root/’ is not a directory
+                #    chown: cannot access ‘/home/root’: No such file or directory
+                # from https://github.com/dockcross/dockcross/blob/96d87416f639af0204bdd42553e4b99315ca8476/imagefiles/entrypoint.sh#L31-L32
+                install -d .ci/sd4/edr
+
+                cat >.ci/sd4/opam-with-env <<EOF
+        #!/bin/sh
+        set -euf
+
+        HERE=\$(dirname "\$0")
+        HERE=\$(cd "\$HERE" && pwd)
+        PROJECT_DIR=\$(cd "\$HERE"/../.. && pwd)
+
+        # Optionally enable terminal if and only if '-it' option given
+        termargs=
+        if [ "\$#" -ge 1 ] && [ "\$1" = "-it" ]; then
+            shift
+            termargs=-it
+        fi
+
+        exec bash "\${PROJECT_DIR}"/.ci/sd4/dockcross --args "\${termargs} -v \${PROJECT_DIR}/.ci/sd4/edr:/home/root ${dockcross_run_extra_args:-}" /work/.ci/sd4/opam-in-docker "\$@"
+        EOF
+                chmod +x .ci/sd4/opam-with-env
+
+                validate_supports_docker
+
+                # Bundle for consumers of setup-dkml.yml
+                echo '__ opam-in-docker __' >&2
+                cat .ci/sd4/opam-in-docker >&2
+                echo '________________________' >&2
+                do_tar_rf .ci/sd4/dist/opam-with-env.tar .ci/sd4/opam-with-env .ci/sd4/opam-in-docker .ci/sd4/edr
+
+            elif [ -n "${docker_runner:-}" ]; then
+
+                cat >.ci/sd4/opam-with-env <<EOF
+        #!/bin/sh
+        set -euf
+        exec ${docker_runner:-} /work/.ci/sd4/deescalate /work/.ci/sd4/opam-in-docker "\$@"
+        EOF
+                chmod +x .ci/sd4/opam-with-env
+
+                validate_supports_docker
+
+                # Bundle for consumers of setup-dkml.yml
+                echo '__ opam-in-docker __' >&2
+                cat .ci/sd4/opam-in-docker >&2
+                echo '________________________' >&2
+                echo '__ deescalate __' >&2
+                cat .ci/sd4/deescalate >&2
+                echo '________________' >&2
+                do_tar_rf .ci/sd4/dist/opam-with-env.tar .ci/sd4/opam-with-env .ci/sd4/opam-in-docker .ci/sd4/deescalate
+
+            else
+
+                cat >.ci/sd4/opam-with-env <<EOF
+        #!/bin/sh
+        set -euf
+
+        HERE=\$(dirname "\$0")
+        HERE=\$(cd "\$HERE" && pwd)
+        PROJECT_DIR=\$(cd "\$HERE"/../.. && pwd)
+
+        export PATH="\${PROJECT_DIR}/.ci/sd4/bs/bin:\${PROJECT_DIR}/.ci/sd4/opamexe:\$PATH"
+        export OPAMROOT='${opam_root}'
+        export OPAMROOTISOK=1
+        if [ "${PATCH_OS_DISTRIBUTION_WIN32}" = true ]; then export OPAMVAR_os_distribution=win32; fi
+        if [ "${PATCH_EXE_WIN32}" = true ]; then export OPAMVAR_exe=.exe; fi
+
+        # Reset environment so no conflicts with a parent Opam or OCaml system
+        unset OPAM_SWITCH_PREFIX
+        unset OPAMSWITCH
+        unset CAML_LD_LIBRARY_PATH
+        unset OCAMLLIB
+        unset OCAML_TOPLEVEL_PATH
+
+        # Optionally skip troubleshooting
+        troubleshooting=1
+        if [ "\$#" -ge 1 ] && [ "\$1" = "--no-troubleshooting" ]; then
+            shift
+            troubleshooting=0
+        fi
+
+        echo "Running: opam \$*" >&2
+        set +e
+        opam "\$@"
+        exitcode=\$?
+        if [ \$troubleshooting = 1 ]; then
+            [ \$exitcode = 0 ] || "\${PROJECT_DIR}/.ci/sd4/troubleshoot-opam.sh" \$OPAMROOT
+        fi
+        exit \$exitcode
+        EOF
+                chmod +x .ci/sd4/opam-with-env
+
+                # Bundle for consumers of setup-dkml.yml
+                do_tar_rf .ci/sd4/dist/opam-with-env.tar .ci/sd4/opam-with-env
+
+            fi
+            echo '__ opam-with-env __' >&2
+            cat .ci/sd4/opam-with-env >&2
+            echo '___________________' >&2
+
+            # -------
+            # opamrun
+            # -------
+
+            install -d .ci/sd4/opamrun
+            cat >.ci/sd4/opamrun/opamrun <<EOF
+        #!/bin/sh
+        set -euf
+
+        HERE=\$(dirname "\$0")
+        HERE=\$(cd "\$HERE" && pwd)
+        PROJECT_DIR=\$(cd "\$HERE"/../../.. && pwd)
+
+        # Add MSVC compiler environment if available
+        if [ -e "\${PROJECT_DIR}/.ci/sd4/msvcenv" ]; then
+            _oldpath="\$PATH"
+            # shellcheck disable=SC1091
+            . "\${PROJECT_DIR}/.ci/sd4/msvcenv"
+            PATH="\$PATH:\$_oldpath"
+
+            # MSVC (link.exe) needs a TMP as well.
+            # Confer: https://docs.microsoft.com/en-us/cpp/build/reference/linking?view=msvc-170#link-environment-variables
+            if [ -z "\${TMP:-}" ]; then
+                # GitHub Actions as of 2022-10 does not set TMP. GitLab CI/CD does.
+                TMP="\$RUNNER_TEMP"
+            fi
+            export TMP
+            if [ -x /usr/bin/cygpath ]; then
+                TMP=\$(/usr/bin/cygpath -aw "\$TMP")
+            fi
+        fi
+
+        # Windows
+        if [ -n "\${COMSPEC:-}" ]; then
+            # We must place MSYS2 in front of path so that MSYS2
+            # tar.exe is used instead of Windows tar.exe.
+            PATH="/usr/bin:\$PATH"
+        fi
+
+        exec "\${PROJECT_DIR}/.ci/sd4/opam-with-env" "\$@"
+        EOF
+            chmod +x .ci/sd4/opamrun/opamrun
+
+            # Bundle for consumers of setup-dkml.yml
+            do_tar_rf .ci/sd4/dist/opam-with-env.tar .ci/sd4/opamrun
+        }
+        section_begin 'write-opam-scripts' 'Write opam scripts'
+        do_write_opam_scripts
+        section_end 'write-opam-scripts'
+
+        # Expose opamrun (also used for consumers of setup-dkml.yml) to GitHub
+        if [ -n "${GITHUB_PATH:-}" ]; then
+            opamrunabs="$setup_WORKSPACE/.ci/sd4/opamrun"
+            if [ -x /usr/bin/cygpath ]; then opamrunabs=$(/usr/bin/cygpath -aw "$opamrunabs"); fi
+            echo "$opamrunabs" >>"$GITHUB_PATH"
+            # Special case: GITHUB_PATH does not influence msys2.CMD of msys2/setup-msys2@v2, so place in real MSYS2 PATH
+            if [ -n "${MSYSTEM:-}" ]; then
+                install -d /usr/local/bin
+                install .ci/sd4/opamrun/opamrun /usr/local/bin/opamrun
+            fi
+        fi
+
+        # Place opamrun in the immediate PATH
+        PATH="$setup_WORKSPACE/.ci/sd4/opamrun:$PATH"
+
+        #   Complicated Opam sequence is because:
+        #   1. Opam's default curl does not work on Windows,
+        #      and `opam init` does not provide a way to change it (TODO: need
+        #      a PR!).
+        #   2. We have to separate the Opam download cache from the other Opam
+        #      caches
+        if [ ! -s "$opam_root/.ci.root-init" ]; then # non-empty init file so can be cached irrespective of existence
+            section_begin opam-init 'Initialize opam root'
+
+            # Clear any partial previous attempt
+            rm -rf "$opam_root"
+
+            case "$dkml_host_abi,${in_docker:-}" in
+            windows_*,*)
+                eor=$(cygpath -am "$setup_WORKSPACE"/.ci/sd4/eor)
+                opamrun init --disable-sandboxing --no-setup --kind local --bare "$eor"
+                case "$(opamrun --version)" in
+                2.0.*) echo 'download-command: wget' >>"$opam_root/config" ;;
+                *) opamrun option --yes --global download-command=wget ;;
+                esac
+                ;;
+            *,true)
+                opamrun init --disable-sandboxing --no-setup --kind local --bare "/work/.ci/sd4/eor"
+                ;;
+            *)
+                opamrun init --disable-sandboxing --no-setup --kind local --bare "$setup_WORKSPACE/.ci/sd4/eor"
+                ;;
+            esac
+            echo yes > "$opam_root/.ci.root-init"
+
+            section_end opam-init
+        fi
+
+        section_begin opam-vars "Summary: opam global variables"
+        opamrun --no-troubleshooting var --global || true
+        section_end opam-vars
+
+        # Build OCaml
+
+        do_switch_create() {
+            do_switch_create_NAME=$1
+            shift
+
+            section_begin "switch-create-$do_switch_create_NAME" "Create opam switch '$do_switch_create_NAME'"
+            # Create, or recreate, the Opam switch. The Opam switch should not be
+            # cached except for the compiler (confer docs for setup-ocaml GitHub
+            # Action) which is the 'dkml' switch (or the 'two' switch).
+            # Check if the switch name is present in the Opam root (which may come from cache)
+            NOMINALLY_PRESENT=false
+            if opamrun switch list --short | grep "^${do_switch_create_NAME}\$"; then NOMINALLY_PRESENT=true; fi
+
+            # Check if the switch is actually present in case of cache incoherence
+            # or corrupt Opam state that could result in:
+            #   Error:  No config file found for switch dkml. Switch broken?
+            if [ $NOMINALLY_PRESENT = true ] && [ ! -e "$opam_root/$do_switch_create_NAME/.opam-switch/switch-config" ]; then
+                # Remove the switch name from Opam root, and any partial switch state.
+                # Ignore inevitable warnings/failure about missing switch.
+                opamrun --no-troubleshooting switch remove "$do_switch_create_NAME" --yes || true
+                rm -rf "${opam_root:?}/$do_switch_create_NAME"
+                NOMINALLY_PRESENT=false
+            fi
+
+            if [ $NOMINALLY_PRESENT = false ]; then
+                opamrun switch create "$do_switch_create_NAME" --empty --yes
+            fi
+            section_end "switch-create-$do_switch_create_NAME"
+        }
+        do_switch_create dkml
+        if [ "${SECONDARY_SWITCH:-}" = "true" ]; then
+            do_switch_create two
+        else
+            section_begin "switch-create-two" "Create empty opam switch 'two'"
+            # Always create a secondary switch ... just empty. Avoid problems with cache content missing
+            # and idempotency.
+            opamrun --no-troubleshooting switch remove two --yes || true
+            rm -rf "$opam_root/two"
+            opamrun switch create two --empty --yes
+            section_end "switch-create-two"
+        fi
+
+        do_switch_active() {
+            section_begin "switch-active" "Set dkml as active switch"
+            opamrun switch set dkml --yes
+            section_end "switch-active"
+        }
+        do_switch_active
+
+        do_opam_repositories_add() {
+            section_begin "opam-repo-add" "Add 'diskuv' opam repository"
+            if ! opamrun --no-troubleshooting repository list -s | grep '^diskuv'; then
+                opamrun repository add diskuv "git+https://github.com/diskuv/diskuv-opam-repository.git#${DISKUV_OPAM_REPOSITORY:-$DEFAULT_DISKUV_OPAM_REPOSITORY_TAG}" --yes --dont-select
+            fi
+            section_end "opam-repo-add"
+        }
+        do_opam_repositories_add
+
+        do_opam_repositories_config() {
+            do_opam_repositories_config_NAME=$1
+            shift
+
+            section_begin "opam-repo-$do_opam_repositories_config_NAME" "Attach repositories to $do_opam_repositories_config_NAME"
+
+            if [ ! -s "$opam_root/.ci.$do_opam_repositories_config_NAME.repo-init" ]; then # non-empty init file so can be cached irrespective of existence
+                opamrun --no-troubleshooting repository remove default --switch "$do_opam_repositories_config_NAME" --yes || true
+                opamrun --no-troubleshooting repository remove diskuv --switch "$do_opam_repositories_config_NAME" --yes || true
+                opamrun repository add default --switch "$do_opam_repositories_config_NAME" --yes
+                opamrun repository add diskuv --switch "$do_opam_repositories_config_NAME" --yes
+                echo yes > "$opam_root/.ci.$do_opam_repositories_config_NAME.repo-init"
+            fi
+
+            section_end "opam-repo-$do_opam_repositories_config_NAME"
+        }
+        do_opam_repositories_config dkml
+        if [ "${SECONDARY_SWITCH:-}" = "true" ]; then
+            do_opam_repositories_config two
+        fi
+
+        do_opam_repositories_update() {
+            section_begin "opam-repo-update" "Update opam repositories"
+            # The default repository may be the initial 'eor' (empty) repository
+            opamrun repository set-url default https://opam.ocaml.org --yes
+            # Always set the `diskuv` repository url since it can change
+            opamrun repository set-url diskuv "git+https://github.com/diskuv/diskuv-opam-repository.git#${DISKUV_OPAM_REPOSITORY:-$DEFAULT_DISKUV_OPAM_REPOSITORY_TAG}" --yes --dont-select
+            # Update both `default` and `diskuv` Opam repositories
+            opamrun update default diskuv
+            section_end "opam-repo-update"
+        }
+        do_opam_repositories_update
+
+        do_pins() {
+            do_pins_NAME=$1
+            shift
+
+            # dkml-base-compiler
+
+            if [ "${DKML_COMPILER:-}" != '@repository@' ] && [ -z "${DKML_COMPILER:-}" ] && [ -z "${OCAML_COMPILER:-}" ]; then
+                section_begin checkout-dkml-base-compiler "Pin dkml-base-compiler to default ${DEFAULT_DKML_COMPILER} (neither dkml-base-compiler nor OCAML_COMPILER specified) for $do_pins_NAME switch"
+                opamrun pin add --switch "$do_pins_NAME" --yes --no-action dkml-base-compiler "https://github.com/diskuv/dkml-compiler.git#${DEFAULT_DKML_COMPILER}"
+                section_end checkout-dkml-base-compiler
+            elif [ "${DKML_COMPILER:-}" != '@repository@' ] && [ -n "${DKML_COMPILER:-}" ] && [ -z "${OCAML_COMPILER:-}" ]; then
+                section_begin checkout-dkml-base-compiler "Pin dkml-base-compiler to $DKML_COMPILER (dkml-base-compiler specified; no OCAML_COMPILER specified) for $do_pins_NAME switch"
+                opamrun pin add --switch "$do_pins_NAME" --yes --no-action dkml-base-compiler "https://github.com/diskuv/dkml-compiler.git#${DKML_COMPILER}"
+                section_end checkout-dkml-base-compiler
+            elif [ -n "${OCAML_COMPILER:-}" ]; then
+                # Validate OCAML_COMPILER (OCAML_COMPILER specified)
+                case "${OCAML_COMPILER:-}" in
+                4.12.1) true ;;
+                *)
+                    echo "OCAML_COMPILER version ${OCAML_COMPILER:-} is not supported" >&2
+                    exit 109
+                    ;;
+                esac
+
+                section_begin checkout-dkml-base-compiler "Pin dkml-base-compiler (OCAML_COMPILER specified) for $do_pins_NAME switch"
+                opamrun pin add --switch "$do_pins_NAME" --yes --no-action dkml-base-compiler "https://github.com/diskuv/dkml-compiler.git#${OCAML_COMPILER}-v${DKML_VERSION}"
+                section_end checkout-dkml-base-compiler
+            fi
+
+            # conf-dkml-cross-toolchain
+
+            if [ "${CONF_DKML_CROSS_TOOLCHAIN:-}" != '@repository@' ]; then
+                section_begin checkout-conf-dkml-cross-toolchain "Pin conf-dkml-cross-toolchain for $do_pins_NAME switch"
+                opamrun pin add --switch "$do_pins_NAME" --yes --no-action conf-dkml-cross-toolchain "https://github.com/diskuv/conf-dkml-cross-toolchain.git#$CONF_DKML_CROSS_TOOLCHAIN"
+                section_end checkout-conf-dkml-cross-toolchain
+            fi
+
+            # patches necessary for Windows in diskuv-opam-repository
+            #
+            # - ocamlfind and ocamlbuild
+            #
+            # - dune-configurator (and hence Dune)
+            # Dune 2.9.1 and 3.0.2 will fail to build jst-config.v0.14.1 because for jst-config/discover/discover.ml Dune does:
+            #   cl -nologo -O2 -Gy- -MD    -I Z:/.opam_root-cached-8/installer-ocaml/lib/ocaml -o C:\Users\beckf\AppData\Local\Temp\build_f18aec_dune\ocaml-configurator4d3858\c-test-31\test.obj -c C:\Users\beckf\AppData\Local\Temp\build_f18aec_dune\ocaml-configurator4d3858\c-test-31\test.c advapi32.lib ws2_32.lib version.lib
+            # instead of
+            #   cl -nologo -O2 -Gy- -MD    -I Z:/.opam_root-cached-8/installer-ocaml/lib/ocaml /FoC:\Users\beckf\AppData\Local\Temp\build_f18aec_dune\ocaml-configurator4d3858\c-test-31\test.obj -c C:\Users\beckf\AppData\Local\Temp\build_f18aec_dune\ocaml-configurator4d3858\c-test-31\test.c advapi32.lib ws2_32.lib version.lib
+            # with the (irrelevant) test.c file:
+            #    #include <stdio.h>
+            #    #include <caml/config.h>
+            #
+            #    #ifdef ARCH_BIG_ENDIAN
+            #    const char *s0 = "BEGIN-0-true-END";
+            #    #else
+            #    const char *s0 = "BEGIN-0-false-END";
+            #    #endif
+            #
+            #    #ifdef ARCH_SIXTYFOUR
+            #    const char *s1 = "BEGIN-1-true-END";
+            #    #else
+            #    const char *s1 = "BEGIN-1-false-END";
+            #    #endif
+            #
+            # The actual problem is dune-configurator ... we only have patches in Diskuv
+            # repository up until 2.9.3. Need to upstream fix the problem.
+            #
+            # - ppx_expect; only patch is for v0.14.1. Need to upstream fix the problem.
+            # - base; patches for v0.14.1/2/3. Need to upstream fix the problem.
+            section_begin "opam-pins-$do_pins_NAME" "Opam pins for $do_pins_NAME switch"
+            opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version base "${PIN_BASE}"
+            opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version bigstringaf "${PIN_BIGSTRINGAF}"
+            opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version core_kernel "${PIN_CORE_KERNEL}"
+            opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version ctypes "${PIN_CTYPES}"
+            opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version ctypes-foreign "${PIN_CTYPES_FOREIGN}"
+            opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version curly "${PIN_CURLY}"
+            opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version digestif "${PIN_DIGESTIF}"
+            opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version dkml-apps "${PIN_DKML_APPS}"
+            opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version dune "${PIN_DUNE}"
+            opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version dune-configurator "${PIN_DUNE_CONFIGURATOR}"
+            opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version ocamlbuild "${PIN_OCAMLBUILD}"
+            opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version ocamlfind "${PIN_OCAMLFIND}"
+            opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version ocp-indent "${PIN_OCP_INDENT}"
+            opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version ppx_expect "${PIN_PPX_EXPECT}"
+            opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version ptime "${PIN_PTIME}"
+            opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version time_now "${PIN_TIME_NOW}"
+            opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version with-dkml "${PIN_WITH_DKML}"
+            section_end "opam-pins-$do_pins_NAME"
+        }
+
+        do_pins dkml
+        if [ "${SECONDARY_SWITCH:-}" = "true" ]; then
+            do_pins two
+        fi
+
+        do_use_vsstudio() {
+            do_use_vsstudio_NAME=$1
+            shift
+            case "$dkml_host_abi" in
+            windows_*)
+                section_begin "use-vsstudio-$do_use_vsstudio_NAME" "Use Visual Studio in dkml-* Opam packages (Windows) for $do_use_vsstudio_NAME switch"
+
+                # shellcheck disable=SC2153
+                E_VS_DIR=$(escape_arg_as_ocaml_string "$VS_DIR")
+                # shellcheck disable=SC2153
+                E_VS_VCVARSVER=$(escape_arg_as_ocaml_string "$VS_VCVARSVER")
+                # shellcheck disable=SC2153
+                E_VS_WINSDKVER=$(escape_arg_as_ocaml_string "$VS_WINSDKVER")
+                # shellcheck disable=SC2153
+                E_VS_MSVSPREFERENCE=$(escape_arg_as_ocaml_string "$VS_MSVSPREFERENCE")
+                # shellcheck disable=SC2153
+                E_VS_CMAKEGENERATOR=$(escape_arg_as_ocaml_string "$VS_CMAKEGENERATOR")
+
+                case "$(opamrun --version)" in
+                2.0.*)
+                    if [ "${in_docker}" = "true" ]; then
+                        echo Opam 2.0 support in dockcross to use a portable opam var prefix not yet implemented
+                        exit 67
+                    fi
+                    OP=$(opamrun var prefix --switch "$do_use_vsstudio_NAME")
+                    OPSC=$OP/.opam-switch/switch-config
+                    if grep setenv: "$OPSC"; then
+                        echo "INFO: Updating switch-config. Old was:"
+                        awk '{print ">> " $0}' "$OPSC"
+
+                        awk '$1=="setenv:"{x=1} x==0{print} x==1 && $0=="]"{x=0}' "$OPSC" >"$OPSC".trimmed
+                        mv "$OPSC".trimmed "$OPSC"
+                    fi
+                    echo 'setenv: [' >>"$OPSC"
+                    echo '  [DKML_COMPILE_SPEC = "1"]' >>"$OPSC"
+                    echo '  [DKML_COMPILE_TYPE = "VS"]' >>"$OPSC"
+                    echo "  [DKML_COMPILE_VS_DIR = \"$E_VS_DIR\"]" >>"$OPSC"
+                    echo "  [DKML_COMPILE_VS_VCVARSVER = \"$E_VS_VCVARSVER\"]" >>"$OPSC"
+                    echo "  [DKML_COMPILE_VS_WINSDKVER = \"$E_VS_WINSDKVER\"]" >>"$OPSC"
+                    echo "  [DKML_COMPILE_VS_MSVSPREFERENCE = \"$E_VS_MSVSPREFERENCE\"]" >>"$OPSC"
+                    echo "  [DKML_COMPILE_VS_CMAKEGENERATOR = \"$E_VS_CMAKEGENERATOR\"]" >>"$OPSC"
+                    echo "  [DKML_HOST_ABI = \"${dkml_host_abi}\"]" >>"$OPSC"
+                    echo ']' >>"$OPSC"
+                    cat "$OPSC" >&2 # print
+                    ;;
+                *)
+                    opamrun option --switch "$do_use_vsstudio_NAME" setenv= # reset
+                    opamrun option --switch "$do_use_vsstudio_NAME" setenv+='DKML_COMPILE_SPEC = "1"'
+                    opamrun option --switch "$do_use_vsstudio_NAME" setenv+='DKML_COMPILE_TYPE = "VS"'
+                    opamrun option --switch "$do_use_vsstudio_NAME" setenv+="DKML_COMPILE_VS_DIR = \"$E_VS_DIR\""
+                    opamrun option --switch "$do_use_vsstudio_NAME" setenv+="DKML_COMPILE_VS_VCVARSVER = \"$E_VS_VCVARSVER\""
+                    opamrun option --switch "$do_use_vsstudio_NAME" setenv+="DKML_COMPILE_VS_WINSDKVER = \"$E_VS_WINSDKVER\""
+                    opamrun option --switch "$do_use_vsstudio_NAME" setenv+="DKML_COMPILE_VS_MSVSPREFERENCE = \"$E_VS_MSVSPREFERENCE\""
+                    opamrun option --switch "$do_use_vsstudio_NAME" setenv+="DKML_COMPILE_VS_CMAKEGENERATOR = \"$E_VS_CMAKEGENERATOR\""
+                    opamrun option --switch "$do_use_vsstudio_NAME" setenv+="DKML_HOST_ABI = \"${dkml_host_abi}\""
+                    opamrun option --switch "$do_use_vsstudio_NAME" setenv # print
+                    ;;
+                esac
+
+                # shellcheck disable=SC2016
+                opamrun exec --switch "$do_use_vsstudio_NAME" -- sh -c 'echo $VCToolsRedistDir'
+
+                section_end "use-vsstudio-$do_use_vsstudio_NAME"
+                ;;
+            esac
+        }
+        if [ "${SECONDARY_SWITCH:-}" = "true" ]; then
+            do_use_vsstudio two
+        fi
+        do_use_vsstudio dkml
+
+        # Because dune.X.Y.Z+shim (and any user DKML packages) requires DKML installed (after all, it is just
+        # a with-dkml.exe shim), we need either dkmlvars-v2.sexp or DKML environment
+        # variables. Confer: Dkml_runtimelib.Dkml_context.get_dkmlversion
+        #
+        # grep matches either:
+        #   [... [DiskuvOCamlVersion = "1.0.1"] ...]
+        #   DiskuvOCamlVersion = "1.0.1"
+        do_setenv() {
+            do_setenv_SWITCH=$1
+            shift
+            opamrun option --switch "$do_setenv_SWITCH" setenv > ".ci/sd4/setenv.$do_setenv_SWITCH.txt"
+            if ! grep -q '\(^|\[\)DiskuvOCamlVarsVersion ' ".ci/sd4/setenv.$do_setenv_SWITCH.txt"; then
+                opamrun option --switch "$do_setenv_SWITCH" setenv+='DiskuvOCamlVarsVersion = "2"'
+            fi
+            if ! grep -q '\(^|\[\)DiskuvOCamlVersion ' ".ci/sd4/setenv.$do_setenv_SWITCH.txt"; then
+                opamrun option --switch "$do_setenv_SWITCH" setenv+="DiskuvOCamlVersion = \"$DKML_VERSION\""
+            fi
+            case "${dkml_host_abi}" in
+            windows_*)
+                if ! grep -q '\(^|\[\)DiskuvOCamlMSYS2Dir ' ".ci/sd4/setenv.$do_setenv_SWITCH.txt"; then
+                    if [ -x /usr/bin/cygpath ]; then
+                        MSYS2_DIR_NATIVE=$(/usr/bin/cygpath -aw /)
+                    else
+                        # If we are already inside MSYS2 then MSYSTEM_PREFIX should be set. But cygpath should be there as well!!
+                        echo "FATAL: Could not locate MSYS2: there was no cygpath" >&2
+                        exit 3
+                    fi
+                    MSYS2_DIR_NATIVE_ESCAPED=$(printf "%s" "$MSYS2_DIR_NATIVE" | sed 's/\\/\\\\/g')
+                    opamrun option --switch "$do_setenv_SWITCH" setenv+="DiskuvOCamlMSYS2Dir = \"$MSYS2_DIR_NATIVE_ESCAPED\""
+                fi
+            esac
+        }
+        if [ "${SECONDARY_SWITCH:-}" = "true" ]; then
+            do_setenv two
+        fi
+        do_setenv dkml
+
+        do_install_compiler() {
+            do_install_compiler_NAME=$1
+            shift
+            section_begin "install-compiler-$do_install_compiler_NAME" "Install OCaml compiler for $do_install_compiler_NAME switch"
+            opamrun pin list --switch "$do_install_compiler_NAME"
+            # shellcheck disable=SC2086
+            opamrun upgrade --switch "$do_install_compiler_NAME" --yes dkml-base-compiler conf-dkml-cross-toolchain ${ocaml_options:-}
+            section_end "install-compiler-$do_install_compiler_NAME"
+        }
+        do_install_compiler dkml
+        if [ "${SECONDARY_SWITCH:-}" = "true" ]; then
+            do_install_compiler two
+        fi
+
+        do_summary() {
+            do_summary_NAME=$1
+            shift
+            section_begin "summary-$do_summary_NAME" "Summary: $do_summary_NAME switch"
+            opamrun var --switch "$do_summary_NAME"
+            opamrun exec --switch "$do_summary_NAME" -- ocamlc -config
+            section_end "summary-$do_summary_NAME"
+        }
+        do_summary dkml
+        if [ "${SECONDARY_SWITCH:-}" = "true" ]; then
+            do_summary two
+        fi
+
+        end_of_script
+
+        cat > .ci/sd4/run-teardown-dkml.sh <<'end_of_script'
+        #!/bin/sh
+        set -euf
+
+        teardown_WORKSPACE_VARNAME=$1
+        shift
+        teardown_WORKSPACE=$1
+        shift
+
+        # ------------------ Variables and functions ------------------------
+
+        # shellcheck source=./common-values.sh
+        . .ci/sd4/common-values.sh
+
+        # Fixup opam_root on Windows to be mixed case. Set original_* and unix_* as well.
+        fixup_opam_root
+
+        # Set TEMP variable for Windows
+        export_temp_for_windows
+
+        # -------------------------------------------------------------------
+
+        section_begin teardown-info "Summary: teardown-dkml"
+
+        # shellcheck disable=SC2154
+        echo "
+        ================
+        teardown-dkml.sh
+        ================
+        .
+        ---------
+        Arguments
+        ---------
+        WORKSPACE_VARNAME=$teardown_WORKSPACE_VARNAME
+        WORKSPACE=$teardown_WORKSPACE
+        .
+        ------
+        Inputs
+        ------
+        VERBOSE=${VERBOSE:-}
+        .
+        ------
+        Matrix
+        ------
+        dkml_host_abi=$dkml_host_abi
+        opam_root=${opam_root}
+        opam_root_cacheable=${opam_root_cacheable}
+        original_opam_root=${original_opam_root}
+        original_opam_root_cacheable=${original_opam_root_cacheable}
+        unix_opam_root=${unix_opam_root}
+        unix_opam_root_cacheable=${unix_opam_root_cacheable}
+        .
+        "
+        section_end teardown-info
+
+        # Done with Opam cache!
+        do_save_opam_cache() {
+            if [ "$unix_opam_root_cacheable" = "$unix_opam_root" ]; then return; fi
+            section_begin save-opam-cache "Transfer Opam cache to $original_opam_root"
+            echo Starting transfer # need some output or GitLab CI will not display the section duration
+            transfer_dir "$unix_opam_root" "$unix_opam_root_cacheable"
+            echo Finished transfer
+            section_end save-opam-cache
+        }
+        do_save_opam_cache
+
+        do_fill_skipped_cache_entries() {
+            section_begin fill-skipped-cache-entries "Populate skipped cache entries"
+
+            # Needed to stop GitLab CI/CD cache warnings 'no matching files', etc.
+            if [ ! -e .ci/sd4/vsenv.sh ]; then
+                install -d .ci/sd4
+                rm -f .ci/sd4/vsenv.sh
+                touch .ci/sd4/vsenv.sh
+                chmod +x .ci/sd4/vsenv.sh
+                echo "Created empty vsenv.sh"
+            else
+                echo "Found vsenv.sh"
+            fi
+
+            if [ ! -e msys64 ]; then
+                rm -rf msys64
+                install -d msys64
+                touch msys64/.keep
+                echo "Created empty msys64"
+            else
+                echo "Found msys64/"
+            fi
+
+            if [ -s "$unix_opam_root_cacheable/.ci.dkml.repo-init" ]; then
+                echo "Found non-empty $unix_opam_root_cacheable/.ci.dkml.repo-init"
+            else
+                touch "$unix_opam_root_cacheable/.ci.dkml.repo-init"
+                echo "Created empty $unix_opam_root_cacheable/.ci.dkml.repo-init"
+            fi
+
+            if [ -s "$unix_opam_root_cacheable/.ci.two.repo-init" ]; then
+                echo "Found non-empty $unix_opam_root_cacheable/.ci.two.repo-init"
+            else
+                touch "$unix_opam_root_cacheable/.ci.two.repo-init"
+                echo "Created empty $unix_opam_root_cacheable/.ci.two.repo-init"
+            fi
+
+            section_end fill-skipped-cache-entries
+        }
+        do_fill_skipped_cache_entries
+
+        do_at_least_one_artifact() {
+            install -d dist
+            find dist -mindepth 1 -maxdepth 1 >.ci/dist.files
+            if [ ! -s .ci/dist.files ]; then
+                section_begin one-artifact "Create empty artifact file"
+
+                # Avoid confusing "ERROR: No files to upload" in GitLab CI
+                touch dist/.keep
+                echo "Created dist/.keep"
+
+                section_end one-artifact
+            fi
+        }
+        do_at_least_one_artifact
+
+        end_of_script
+
+        install -d .ci/sd4
+
+        cat > .ci/sd4/msvcenv.awk <<'end_of_script'
+        # MSVC environment variables:
+        # 1. https://docs.microsoft.com/en-us/cpp/build/reference/cl-environment-variables?view=msvc-170
+        # 2. https://docs.microsoft.com/en-us/cpp/build/reference/linking?view=msvc-170#link-environment-variables (except TMP)
+        # 3. VCToolsRedistDir: https://docs.microsoft.com/en-us/cpp/windows/redistributing-visual-cpp-files?view=msvc-170#locate-the-redistributable-files
+        BEGIN{FS="="}
+        $1=="CL"||$1=="_CL_"||$1=="INCLUDE"||$1=="LIBPATH" {print "export " $0}
+        $1=="LINK"||$1=="_LINK_"||$1=="LIB"||$1=="PATH"    {print "export " $0}
+        $1=="VCToolsRedistDir"                             {print "export " $0}
+
+        end_of_script
+
+        cat > .ci/sd4/msvcpath.awk <<'end_of_script'
+        {
+            # trim leading and trailing space
+            sub(/^ */, "");
+            sub(/ *$/, "");
+
+            print "export PATH='" $0 "'";
+        }
+        end_of_script
+
+    - name: Write PowerShell and Batch scripts
+      shell: pwsh
+      run: |
+        $Content = @'
+        # Diagnose Visual Studio environment variables (Windows)
+        # This wastes time and has lots of rows! Only run if "VERBOSE" GitHub input key.
+        if ( "${env:VERBOSE}" -eq "true" ) {
+            if (Test-Path -Path "C:\Program Files (x86)\Windows Kits\10\include") {
+                Get-ChildItem "C:\Program Files (x86)\Windows Kits\10\include"
+            }
+            if (Test-Path -Path "C:\Program Files (x86)\Windows Kits\10\Extension SDKs\WindowsDesktop") {
+                Get-ChildItem "C:\Program Files (x86)\Windows Kits\10\Extension SDKs\WindowsDesktop"
+            }
+
+            $env:PSModulePath += "$([System.IO.Path]::PathSeparator).ci\sd4\g\dkml-runtime-distribution\src\windows"
+            Import-Module Machine
+
+            $allinstances = Get-VSSetupInstance
+            $allinstances | ConvertTo-Json -Depth 5
+        }
+
+        # Make export expression [SN]NAME=[SV]VALUE[EV]
+        # where [SN] is start name and [SV] and [EV] are start and end value
+        if (("${env:GITLAB_CI}" -eq "true") -or ("${env:PC_CI}" -eq "true")) {
+            # Executed immediately in POSIX shell, so must be a real POSIX shell variable declaration
+            $ExportSN = "export "
+            $ExportSV = "'"
+            $ExportEV = "'"
+            $ExportExt = ".sh"
+        } else {
+            # Goes into $env:GITHUB_ENV, so must be plain NAME=VALUE
+            $ExportSN = ""
+            $ExportSV = ""
+            $ExportEV = ""
+            $ExportExt = ".github"
+        }
+
+        # Locate Visual Studio (Windows)
+        if ("${env:vsstudio_dir}" -eq "" -and (!(Test-Path -Path .ci/sd4/vsenv${ExportExt}))) {
+            $env:PSModulePath += "$([System.IO.Path]::PathSeparator).ci\sd4\g\dkml-runtime-distribution\src\windows"
+            Import-Module Machine
+
+            $CompatibleVisualStudios = Get-CompatibleVisualStudios -ErrorIfNotFound
+            $CompatibleVisualStudios
+            $ChosenVisualStudio = ($CompatibleVisualStudios | Select-Object -First 1)
+            $VisualStudioProps = Get-VisualStudioProperties -VisualStudioInstallation $ChosenVisualStudio
+            $VisualStudioProps
+
+            Write-Output "${ExportSN}VS_DIR=${ExportSV}$($VisualStudioProps.InstallPath)${ExportEV}" > .ci/sd4/vsenv${ExportExt}
+            Write-Output "${ExportSN}VS_VCVARSVER=${ExportSV}$($VisualStudioProps.VcVarsVer)${ExportEV}" >> .ci/sd4/vsenv${ExportExt}
+            Write-Output "${ExportSN}VS_WINSDKVER=${ExportSV}$($VisualStudioProps.WinSdkVer)${ExportEV}" >> .ci/sd4/vsenv${ExportExt}
+            Write-Output "${ExportSN}VS_MSVSPREFERENCE=${ExportSV}$($VisualStudioProps.MsvsPreference)${ExportEV}" >> .ci/sd4/vsenv${ExportExt}
+            Write-Output "${ExportSN}VS_CMAKEGENERATOR=${ExportSV}$($VisualStudioProps.CMakeGenerator)${ExportEV}" >> .ci/sd4/vsenv${ExportExt}
+        }
+
+        # Link to hardcoded Visual Studio (Windows)
+        if ("${env:vsstudio_dir}" -ne "") {
+            Write-Output "${ExportSN}VS_DIR=${ExportSV}${env:vsstudio_dir}${ExportEV}" > .ci/sd4/vsenv${ExportExt}
+            Write-Output "${ExportSN}VS_VCVARSVER=${ExportSV}${env:vsstudio_vcvarsver}${ExportEV}" >> .ci/sd4/vsenv${ExportExt}
+            Write-Output "${ExportSN}VS_WINSDKVER=${ExportSV}${env:vsstudio_winsdkver}${ExportEV}" >> .ci/sd4/vsenv${ExportExt}
+            Write-Output "${ExportSN}VS_MSVSPREFERENCE=${ExportSV}${env:vsstudio_msvspreference}${ExportEV}" >> .ci/sd4/vsenv${ExportExt}
+            Write-Output "${ExportSN}VS_CMAKEGENERATOR=${ExportSV}${env:vsstudio_cmakegenerator}${ExportEV}" >> .ci/sd4/vsenv${ExportExt}
+        }
+
+        '@
+        Set-Content -Path ".ci\sd4\config-vsstudio.ps1" -Encoding Unicode -Value $Content
+
+        $Content = @'
+        @ECHO OFF
+
+        REM The OCaml dkml-base-compiler will compile fine but any other
+        REM packages (ocamlbuild, etc.) which
+        REM need a native compiler will fail without the MSVC compiler in the
+        REM PATH. There isn't a `with-dkml.exe` alternative available at
+        REM this stage of the GitHub workflow.
+        call "%VS_DIR%\Common7\Tools\VsDevCmd.bat" -no_logo -host_arch=%vsstudio_hostarch% -arch=%vsstudio_arch% -vcvars_ver=%VS_VCVARSVER% -winsdk=%VS_WINSDKVER%
+        if %ERRORLEVEL% neq 0 (
+            echo.
+            echo.The "%VS_DIR%\Common7\Tools\VsDevCmd.bat" command failed
+            echo.with exit code %ERRORLEVEL%.
+            echo.
+            exit /b %ERRORLEVEL%
+        )
+
+        REM VsDevCmd.bat turns off echo; be explicit if we want it on or off
+        @echo OFF
+
+        REM MSVC environment variables in Unix format.
+        echo %PATH% > .ci\sd4\msvcpath
+
+
+        REM * We can't use `msys2 -c` directly to query for all MSVC environment variables
+        REM   because it stomps over the PATH. So we are inside a Batch script to do the query.
+        msys2 -c "set | grep -v '^PATH=' | awk -f .ci/sd4/msvcenv.awk > .ci/sd4/msvcenv"
+
+        REM (For some reason no shell commands can happen after the last msys2 -c in GitHub Actions
+        REM so split into multiple steps!
+        '@
+        Set-Content -Path ".ci\sd4\get-msvcpath-into-msys2.cmd" -Encoding Default -Value $Content
+
+    - name: Prepare cache keys
+      # An undocumented bug with GitHub Actions is that a space in the key
+      # will "succeed" but it never gets restored. So we will hash a
+      # user-friendly file instead.
+      shell: bash
+      run: |
+        set -x
+        echo '317446-${{ inputs.FDOPEN_OPAMEXE_BOOTSTRAP }}-${{ steps.full_matrix_vars.outputs.dkml_host_abi }}-${{ steps.full_matrix_vars.outputs.opam_abi }}-${{ steps.full_matrix_vars.outputs.bootstrap_opam_version }}' > .ci/sd4/cachekey.opam.binaries
+        echo '${{ steps.full_matrix_vars.outputs.abi_pattern }}-${{ steps.full_matrix_vars.outputs.vsstudio_arch }}-${{ steps.full_matrix_vars.outputs.vsstudio_hostarch }}-${{ steps.full_matrix_vars.outputs.vsstudio_dir }}-${{ steps.full_matrix_vars.outputs.vsstudio_vcvarsver }}-${{ steps.full_matrix_vars.outputs.vsstudio_winsdkver }}-${{ steps.full_matrix_vars.outputs.vsstudio_msvspreference }}-${{ steps.full_matrix_vars.outputs.vsstudio_cmakegenerator }}' > .ci/sd4/cachekey.vsstudio
+        echo '${{ inputs.OCAML_COMPILER }}-${{ inputs.DISKUV_OPAM_REPOSITORY }}-${{ inputs.DKML_COMPILER }}-${{ inputs.CONF_DKML_CROSS_TOOLCHAIN }}' > .ci/sd4/cachekey.ci.inputs
+
+    # Bootstrapping Opam
+
+    - name: Cache Opam bootstrap by OS
+      uses: actions/cache@v3
+      id: cache-sd4-bs
+      with:
+        path: .ci/sd4/bs
+        key:
+          "1_${{ inputs.CACHE_PREFIX }}_${{ runner.os }}-sd4-bs-${{ hashFiles('.ci/sd4/cachekey.opam.binaries') }}"
+
+    - name: Cache Opam root by (host,target)
+      uses: actions/cache@v3
+      id: cache-sd4-opamroot
+      with:
+        path: |
+          ${{ steps.full_matrix_vars.outputs.opam_root_cacheable }}/config
+          ${{ steps.full_matrix_vars.outputs.opam_root_cacheable }}/dkml
+          ${{ steps.full_matrix_vars.outputs.opam_root_cacheable }}/two
+          ${{ steps.full_matrix_vars.outputs.opam_root_cacheable }}/repo
+          ${{ steps.full_matrix_vars.outputs.opam_root_cacheable }}/download-cache
+          ${{ steps.full_matrix_vars.outputs.opam_root_cacheable }}/.ci.root-init
+          ${{ steps.full_matrix_vars.outputs.opam_root_cacheable }}/.ci.dkml.repo-init
+          ${{ steps.full_matrix_vars.outputs.opam_root_cacheable }}/.ci.two.repo-init
+        key:
+          "1_${{ inputs.CACHE_PREFIX }}_${{ env.DKML_VERSION }}_${{ steps.full_matrix_vars.outputs.abi_pattern }}-sd4-opamroot-${{ hashFiles('.ci/sd4/cachekey.opam.binaries') }}-${{ hashFiles('cachekey.ci.inputs') }}"
+
+    # The action/checkout steps used for pinning will re-use existing Git objects
+    # because of caching
+    - name: Cache Git checkouts of Opam pins by OS
+      uses: actions/cache@v3
+      id: cache-sd4-git
+      with:
+        path: .ci/sd4/g
+        key:
+          "1_${{ inputs.CACHE_PREFIX }}_${{ runner.os }}-sd4-git-${{ hashFiles('.ci/sd4/cachekey.ci.inputs') }}"
+
+    # Checkout code
+
+    - name: Checkout DKML code
+      shell: bash
+      env:
+        # Push down inputs variables for GitHub/GitLab portable scripts
+        VERBOSE:          "${{ inputs.VERBOSE }}"
+      run: 'sh .ci/sd4/run-checkout-code.sh GITHUB_WORKSPACE "$GITHUB_WORKSPACE"'
+
+    # Setup C compiler
+
+    - name: Cache Visual Studio environment variables by (host,target)
+      uses: actions/cache@v3
+      id: cache-sd4-vsenv
+      with:
+        path: .ci/sd4/vsenv.github
+        key: "1_${{ inputs.CACHE_PREFIX }}_sd4-vsenv-${{ hashFiles('cachekey.vsstudio') }}"
+
+    - name: Configure Visual Studio (Windows)
+      shell: pwsh
+      run: |
+        .ci\sd4\config-vsstudio.ps1
+
+    - name: Export Visual Studio location and type (Windows)
+      shell: pwsh
+      run: |
+        Get-Content ${env:GITHUB_WORKSPACE}/.ci/sd4/vsenv.github
+        Get-Content ${env:GITHUB_WORKSPACE}/.ci/sd4/vsenv.github >> $env:GITHUB_ENV
+
+    - name: Capture Visual Studio compiler environment (1/2) (Windows)
+      shell: cmd
+      run: |
+        call .ci\sd4\get-msvcpath-into-msys2.cmd
+
+    - name: Capture Visual Studio compiler environment (2/2) (Windows)
+      shell: msys2 {0}
+      run: |
+        #!/bin/sh
+        set -euf
+        cat .ci/sd4/msvcpath | tr -d '\r' | cygpath --path -f - | awk -f .ci/sd4/msvcpath.awk >> .ci/sd4/msvcenv
+
+        tail -n100 .ci/sd4/msvcpath .ci/sd4/msvcenv >&2
+
+    - name: Compile 'dkml' switch
+      shell: msys2 {0}
+      env:
+        # Push down inputs variables for GitHub/GitLab portable scripts
+        #   When non-empty, instead of building the standard components from the
+        #   central Opam repository, use the github/gitlab development repositories
+        #   directly.
+        FDOPEN_OPAMEXE_BOOTSTRAP:         "${{ inputs.FDOPEN_OPAMEXE_BOOTSTRAP }}"
+        CONF_DKML_CROSS_TOOLCHAIN:        "${{ inputs.CONF_DKML_CROSS_TOOLCHAIN }}"
+        DISKUV_OPAM_REPOSITORY:           "${{ inputs.DISKUV_OPAM_REPOSITORY }}"
+        DKML_COMPILER:                    "${{ inputs.DKML_COMPILER }}"
+        OCAML_COMPILER:                   "${{ inputs.OCAML_COMPILER }}"
+        SECONDARY_SWITCH:                 "${{ inputs.SECONDARY_SWITCH }}"
+        VERBOSE:                          "${{ inputs.VERBOSE }}"
+
+        # autogen from global_env_vars.
+        DEFAULT_DKML_COMPILER: '4.12.1-v1.0.2'
+        PIN_BASE: 'v0.14.3'
+        PIN_BIGSTRINGAF: '0.8.0'
+        PIN_CORE_KERNEL: 'v0.14.2'
+        PIN_CTYPES_FOREIGN: '0.19.2-windowssupport-r4'
+        PIN_CTYPES: '0.19.2-windowssupport-r4'
+        PIN_CURLY: '0.2.1-windows-env_r2'
+        PIN_DIGESTIF: '1.0.1'
+        PIN_DUNE: '2.9.3+shim.1.0.2~r0'
+        PIN_DUNE_CONFIGURATOR: '2.9.3'
+        PIN_DKML_APPS: '1.0.1'
+        PIN_OCAMLBUILD: '0.14.0'
+        PIN_OCAMLFIND: '1.9.1'
+        PIN_OCP_INDENT: '1.8.2-windowssupport'
+        PIN_PPX_EXPECT: 'v0.14.1'
+        PIN_PTIME: '0.8.6-msvcsupport'
+        PIN_TIME_NOW: 'v0.14.0'
+        PIN_WITH_DKML: '1.0.1'
+      run: |
+        sh .ci/sd4/run-setup-dkml.sh GITHUB_WORKSPACE "$GITHUB_WORKSPACE"
+
+        #   During cache read (the "Cache Opam root by (host,target)" step) we get:
+        #      Cache Size: ~212 MB (222698916 B)
+        #      C:\Windows\System32\tar.exe -z -xf D:/a/_temp/9b656ed6-e727-4499-b4f8-b34d5979d42b/cache.tgz -P -C D:/a/dkml-workflows-regular-example/dkml-workflows-regular-example
+        #      ../../.opam/download-cache/md5/65/65e6dc9b305ccbed1267275fe180f538: Can't create '\\\\?\\D:\\a\\dkml-workflows-regular-example\\dkml-workflows-regular-example\\..\\..\\.opam\\download-cache\\md5\\65\\65e6dc9b305ccbed1267275fe180f538'
+        #      ../../.opam/download-cache/md5/63/63b2ecad76cf56102074f3203fc8c0be: Can't create '\\\\?\\D:\\a\\dkml-workflows-regular-example\\dkml-workflows-regular-example\\..\\..\\.opam\\download-cache\\md5\\63\\63b2ecad76cf56102074f3203fc8c0be'
+        #      tar.exe: Error exit delayed from previous errors.
+        #      Warning: Failed to restore: Tar failed with error: The process 'C:\Windows\System32\tar.exe' failed with exit code 1
+        #      Cache not found for input keys: v1_win32-windows_x86-sd4-opamroot-f674af417c46862703911bc9aee57c19d6c436776c657533610dc233fae8e8af-5850674459249f5d9ea150785baa5177201737ce2c7d59834aa7457c06c929e7
+        #   So get rid of Opam's md5 download cache.
+        rm -rf "${opam_root}/download-cache/md5"
+
+        # Expose opamrun to remaining GitHub Action steps
+        opamrunabs="$GITHUB_WORKSPACE/.ci/sd4/opamrun"
+        if [ -x /usr/bin/cygpath ]; then opamrunabs=$(/usr/bin/cygpath -aw "$opamrunabs"); fi
+        echo "$opamrunabs" >> $GITHUB_PATH
+
+        #   Special case: GITHUB_PATH does not influence msys2.CMD of msys2/setup-msys2@v2, so place in real MSYS2 PATH
+        if [ -n "${MSYSTEM:-}" ]; then
+          install -d /usr/local/bin
+          install -v .ci/sd4/opamrun/opamrun /usr/local/bin/opamrun
+        fi
diff --git a/ci/setup-dkml/gh-windows-4.12.1/pre/dune b/ci/setup-dkml/gh-windows-4.12.1/pre/dune
new file mode 100644
index 00000000000..ad811726bb1
--- /dev/null
+++ b/ci/setup-dkml/gh-windows-4.12.1/pre/dune
@@ -0,0 +1,17 @@
+; DO NOT EDIT THIS FILE. It is auto-generated by generate-setup-dkml-scaffold
+; Typical upgrade steps:
+;   opam upgrade dkml-workflows && opam exec -- generate-setup-dkml-scaffold && dune build '@gen-dkml' --auto-promote
+
+(rule
+ (alias gen-dkml-4.12.1)
+ (target action.gen.yml)
+ (action
+  (setenv
+   OCAMLRUNPARAM
+   b
+   (run gh-dkml-action-yml --phase pre --output-windows %{target}))))
+
+(rule
+ (alias gen-dkml-4.12.1)
+ (action
+  (diff action.yml action.gen.yml)))
diff --git a/ci/setup-dkml/gh-windows/post/action.yml b/ci/setup-dkml/gh-windows/post/action.yml
index df095393bbd..8f27009763f 100644
--- a/ci/setup-dkml/gh-windows/post/action.yml
+++ b/ci/setup-dkml/gh-windows/post/action.yml
@@ -35,7 +35,7 @@ runs:
           msys2_system='MINGW32';
           msys2_packages='mingw-w64-i686-pkg-config';
           exe_ext='.exe';
-          bootstrap_opam_version='2.2.0-dkml20220801T155940Z';
+          bootstrap_opam_version='2.2.0-alpha-20221104';
           opam_abi='windows_x86';
           dkml_host_abi='windows_x86';
           opam_root='D:/.opam';
@@ -52,7 +52,7 @@ runs:
           msys2_system='CLANG64';
           msys2_packages='mingw-w64-clang-x86_64-pkg-config';
           exe_ext='.exe';
-          bootstrap_opam_version='2.2.0-dkml20220801T155940Z';
+          bootstrap_opam_version='2.2.0-alpha-20221104';
           opam_abi='windows_x86_64';
           dkml_host_abi='windows_x86_64';
           opam_root='D:/.opam';
@@ -80,23 +80,28 @@ runs:
         _STUB_FOR_AUTOGEN: "ON" # 
 
         # autogen from global_env_vars.
-        DEFAULT_DKML_COMPILER: '4.12.1-v1.0.2'
-        PIN_BASE: 'v0.14.3'
-        PIN_BIGSTRINGAF: '0.8.0'
-        PIN_CORE_KERNEL: 'v0.14.2'
-        PIN_CTYPES_FOREIGN: '0.19.2-windowssupport-r4'
-        PIN_CTYPES: '0.19.2-windowssupport-r4'
+        DEFAULT_DKML_COMPILER: '4.14.0-v1.1.0-prerel15'
+        PIN_ALCOTEST: '1.6.0'
+        PIN_ALCOTEST_ASYNC: '1.6.0'
+        PIN_ALCOTEST_JS: '1.6.0'
+        PIN_ALCOTEST_LWT: '1.6.0'
+        PIN_ALCOTEST_MIRAGE: '1.6.0'
+        PIN_BASE: 'v0.15.1'
+        PIN_BASE_BIGSTRING: 'v0.15.0'
+        PIN_BIGSTRINGAF: '0.9.0+msvc'
+        PIN_CORE: 'v0.15.1'
+        PIN_CORE_KERNEL: 'v0.15.0'
+        PIN_CTYPES_FOREIGN: '0.19.2-windowssupport-r5'
+        PIN_CTYPES: '0.19.2-windowssupport-r5'
         PIN_CURLY: '0.2.1-windows-env_r2'
-        PIN_DIGESTIF: '1.0.1'
-        PIN_DUNE: '2.9.3+shim.1.0.2~r0'
-        PIN_DUNE_CONFIGURATOR: '2.9.3'
-        PIN_DKML_APPS: '1.0.1'
+        PIN_DKML_APPS: '1.2.0~prerel8'
+        PIN_DKML_EXE: '1.2.0~prerel8'
+        PIN_DUNE: '3.6.2'
+        PIN_FEATHER: '0.3.0'
         PIN_OCAMLBUILD: '0.14.0'
         PIN_OCAMLFIND: '1.9.1'
         PIN_OCP_INDENT: '1.8.2-windowssupport'
-        PIN_PPX_EXPECT: 'v0.14.1'
-        PIN_PTIME: '0.8.6-msvcsupport'
-        PIN_TIME_NOW: 'v0.14.0'
-        PIN_WITH_DKML: '1.0.1'
+        PIN_PPX_EXPECT: 'v0.15.1'
+        PIN_WITH_DKML: '1.2.0~prerel8'
       run: |
         sh .ci/sd4/run-teardown-dkml.sh GITHUB_WORKSPACE "$GITHUB_WORKSPACE"
diff --git a/ci/setup-dkml/gh-windows/pre/action.yml b/ci/setup-dkml/gh-windows/pre/action.yml
index bf1de9115d6..a0cee4f5339 100644
--- a/ci/setup-dkml/gh-windows/pre/action.yml
+++ b/ci/setup-dkml/gh-windows/pre/action.yml
@@ -39,6 +39,10 @@ inputs:
     description: "Turn on verbose logging"
     required: false
     default: 'false'
+  PRIMARY_SWITCH_SKIP_INSTALL:
+    description: "Disable install of dkml-base-compiler in 'dkml' switch"
+    required: false
+    default: 'false'
   SECONDARY_SWITCH:
     description: "Turn on secondary 'two' switch"
     required: false
@@ -68,7 +72,7 @@ runs:
           msys2_system='MINGW32';
           msys2_packages='mingw-w64-i686-pkg-config';
           exe_ext='.exe';
-          bootstrap_opam_version='2.2.0-dkml20220801T155940Z';
+          bootstrap_opam_version='2.2.0-alpha-20221104';
           opam_abi='windows_x86';
           dkml_host_abi='windows_x86';
           opam_root='D:/.opam';
@@ -85,7 +89,7 @@ runs:
           msys2_system='CLANG64';
           msys2_packages='mingw-w64-clang-x86_64-pkg-config';
           exe_ext='.exe';
-          bootstrap_opam_version='2.2.0-dkml20220801T155940Z';
+          bootstrap_opam_version='2.2.0-alpha-20221104';
           opam_abi='windows_x86_64';
           dkml_host_abi='windows_x86_64';
           opam_root='D:/.opam';
@@ -290,6 +294,10 @@ runs:
         setup_WORKSPACE=$1
         shift
 
+        if [ -x /usr/bin/cygpath ]; then
+            setup_WORKSPACE=$(/usr/bin/cygpath -au "$setup_WORKSPACE")
+        fi
+
         # ------------------------ Functions ------------------------
 
         # shellcheck source=./common-values.sh
@@ -361,6 +369,10 @@ runs:
 
         # dkml-runtime-distribution
 
+        #   For 'Diagnose Visual Studio environment variables (Windows)' we need dkml-runtime-distribution
+        #   so that 'Import-Module Machine' and 'Get-VSSetupInstance' can be run.
+        #   The version doesn't matter too much, as long as it has a functioning Get-VSSetupInstance.
+        #   commit 1a3ec82dd851751a95e6a4797387a8163c51520e = tag v0.4.0-prerel20
         case "$dkml_host_abi" in
         windows_*)
             section_begin checkout-dkml-runtime-distribution 'Checkout dkml-runtime-distribution'
@@ -378,18 +390,19 @@ runs:
         # Constants
         SHA512_DEVNULL='cf83e1357eefb8bdf1542850d66d8007d620e4050b5715dc83f4a921d36ce9ce47d0d13c5d85f2b0ff8318d2877eec2f63b931bd47417a81a538327af927da3e'
         #   Edited by https://gitlab.com/diskuv/diskuv-ocaml/contributors/release.sh
-        DEFAULT_DISKUV_OPAM_REPOSITORY_TAG=cc9518fa5630bfbe24d4c5e0e2cc29af513037ce
+        DEFAULT_DISKUV_OPAM_REPOSITORY_TAG=638195f6db6f54f121a7211515f26d946494eb95
         # Constants
-        #   Should be edited by release.sh, but ...
-        #   Can't be 1.0.0 or later until https://github.com/ocaml/opam-repository/pull/21704 ocaml-option-32bit
-        #   can come back in.
-        DKML_VERSION=0.4.0
+        DKML_VERSION=1.2.0-prerel8
 
         setup_WORKSPACE_VARNAME=$1
         shift
         setup_WORKSPACE=$1
         shift
 
+        if [ -x /usr/bin/cygpath ]; then
+            setup_WORKSPACE=$(/usr/bin/cygpath -au "$setup_WORKSPACE")
+        fi
+
         # ------------------ Variables and functions ------------------------
 
         # shellcheck source=./common-values.sh
@@ -449,8 +462,10 @@ runs:
         DKML_COMPILER=${DKML_COMPILER:-}
         OCAML_COMPILER=${OCAML_COMPILER:-}
         CONF_DKML_CROSS_TOOLCHAIN=${CONF_DKML_CROSS_TOOLCHAIN:-}
+        PRIMARY_SWITCH_SKIP_INSTALL=${PRIMARY_SWITCH_SKIP_INSTALL:-}
         SECONDARY_SWITCH=${SECONDARY_SWITCH:-}
         MANYLINUX=${MANYLINUX:-}
+        DKML_HOME=${DKML_HOME:-}
         VERBOSE=${VERBOSE:-}
         .
         -------------------
@@ -482,22 +497,27 @@ runs:
         ----
         Pins
         ----
+        PIN_ALCOTEST=${PIN_ALCOTEST}
+        PIN_ALCOTEST_ASYNC=${PIN_ALCOTEST_ASYNC}
+        PIN_ALCOTEST_JS=${PIN_ALCOTEST_JS}
+        PIN_ALCOTEST_LWT=${PIN_ALCOTEST_LWT}
+        PIN_ALCOTEST_MIRAGE=${PIN_ALCOTEST_MIRAGE}
         PIN_BASE=${PIN_BASE}
+        PIN_BASE_BIGSTRING=${PIN_BASE_BIGSTRING}
         PIN_BIGSTRINGAF=${PIN_BIGSTRINGAF}
+        PIN_CORE=${PIN_CORE}
         PIN_CORE_KERNEL=${PIN_CORE_KERNEL}
-        PIN_CTYPES=${PIN_CTYPES}
         PIN_CTYPES_FOREIGN=${PIN_CTYPES_FOREIGN}
+        PIN_CTYPES=${PIN_CTYPES}
         PIN_CURLY=${PIN_CURLY}
-        PIN_DIGESTIF=${PIN_DIGESTIF}
         PIN_DKML_APPS=${PIN_DKML_APPS}
+        PIN_DKML_EXE=${PIN_DKML_EXE}
         PIN_DUNE=${PIN_DUNE}
-        PIN_DUNE_CONFIGURATOR=${PIN_DUNE_CONFIGURATOR}
+        PIN_FEATHER=${PIN_FEATHER}
         PIN_OCAMLBUILD=${PIN_OCAMLBUILD}
         PIN_OCAMLFIND=${PIN_OCAMLFIND}
         PIN_OCP_INDENT=${PIN_OCP_INDENT}
         PIN_PPX_EXPECT=${PIN_PPX_EXPECT}
-        PIN_PTIME=${PIN_PTIME}
-        PIN_TIME_NOW=${PIN_TIME_NOW}
         PIN_WITH_DKML=${PIN_WITH_DKML}
         .
         "
@@ -841,6 +861,7 @@ runs:
 
             # ---------------
             # Create Opam troubleshooting script
+            #   Dump logs modified within the last 4 hours
             # ---------------
 
             cat >.ci/sd4/troubleshoot-opam.sh <<EOF
@@ -848,8 +869,13 @@ runs:
         set -euf
         OPAMROOT=\$1
         shift
+        if find . -maxdepth 0 -mmin -240 2>/dev/null >/dev/null; then
+            FINDARGS="-mmin -240" # is -mmin supported? BSD (incl. macOS), MSYS2, GNU
+        else
+            FINDARGS="-mtime -1" # use 1 day instead. Solaris
+        fi
         printf "\n\n========= [START OF TROUBLESHOOTING] ===========\n\n" >&2
-        find "\$OPAMROOT"/log -mindepth 1 -maxdepth 1 -name "*.out" ! -name "log-*.out" ! -name "ocaml-variants-*.out" | while read -r dump_on_error_LOG; do
+        find "\$OPAMROOT"/log -mindepth 1 -maxdepth 1 \$FINDARGS -name "*.out" ! -name "log-*.out" ! -name "ocaml-variants-*.out" | while read -r dump_on_error_LOG; do
             dump_on_error_BLOG=\$(basename "\$dump_on_error_LOG")
             printf "\n\n========= [TROUBLESHOOTING] %s ===========\n\n" "\$dump_on_error_BLOG" >&2
             awk -v BLOG="\$dump_on_error_BLOG" '{print "[" BLOG "]", \$0}' "\$dump_on_error_LOG" >&2
@@ -1254,6 +1280,7 @@ runs:
                 # Validate OCAML_COMPILER (OCAML_COMPILER specified)
                 case "${OCAML_COMPILER:-}" in
                 4.12.1) true ;;
+                4.14.0) true ;;
                 *)
                     echo "OCAML_COMPILER version ${OCAML_COMPILER:-} is not supported" >&2
                     exit 109
@@ -1304,22 +1331,31 @@ runs:
             # - ppx_expect; only patch is for v0.14.1. Need to upstream fix the problem.
             # - base; patches for v0.14.1/2/3. Need to upstream fix the problem.
             section_begin "opam-pins-$do_pins_NAME" "Opam pins for $do_pins_NAME switch"
+            opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version alcotest "${PIN_ALCOTEST}"
+            opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version alcotest-async "${PIN_ALCOTEST_ASYNC}"
+            opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version alcotest-js "${PIN_ALCOTEST_JS}"
+            opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version alcotest-lwt "${PIN_ALCOTEST_LWT}"
+            opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version alcotest-mirage "${PIN_ALCOTEST_MIRAGE}"
             opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version base "${PIN_BASE}"
+            opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version base_bigstring "${PIN_BASE_BIGSTRING}"
             opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version bigstringaf "${PIN_BIGSTRINGAF}"
+            opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version core "${PIN_CORE}"
             opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version core_kernel "${PIN_CORE_KERNEL}"
             opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version ctypes "${PIN_CTYPES}"
             opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version ctypes-foreign "${PIN_CTYPES_FOREIGN}"
             opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version curly "${PIN_CURLY}"
-            opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version digestif "${PIN_DIGESTIF}"
+            opamrun pin remove --switch "$do_pins_NAME"  --yes --no-action digestif # this used to be pinned, so any cached opamroot needs it unpinned
             opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version dkml-apps "${PIN_DKML_APPS}"
+            opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version dkml-exe "${PIN_DKML_EXE}"
             opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version dune "${PIN_DUNE}"
-            opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version dune-configurator "${PIN_DUNE_CONFIGURATOR}"
+            opamrun pin remove --switch "$do_pins_NAME"  --yes --no-action dune-configurator # this used to be pinned, so any cached opamroot needs it unpinned
+            opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version feather "${PIN_FEATHER}"
             opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version ocamlbuild "${PIN_OCAMLBUILD}"
             opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version ocamlfind "${PIN_OCAMLFIND}"
             opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version ocp-indent "${PIN_OCP_INDENT}"
             opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version ppx_expect "${PIN_PPX_EXPECT}"
-            opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version ptime "${PIN_PTIME}"
-            opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version time_now "${PIN_TIME_NOW}"
+            opamrun pin remove --switch "$do_pins_NAME"  --yes --no-action ptime # this used to be pinned, so any cached opamroot needs it unpinned
+            opamrun pin remove --switch "$do_pins_NAME"  --yes --no-action time_now # this used to be pinned, so any cached opamroot needs it unpinned
             opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version with-dkml "${PIN_WITH_DKML}"
             section_end "opam-pins-$do_pins_NAME"
         }
@@ -1410,6 +1446,7 @@ runs:
         do_setenv() {
             do_setenv_SWITCH=$1
             shift
+            section_begin "setenv-$do_setenv_SWITCH" "Set opam option for $do_setenv_SWITCH switch"
             opamrun option --switch "$do_setenv_SWITCH" setenv > ".ci/sd4/setenv.$do_setenv_SWITCH.txt"
             if ! grep -q '\(^|\[\)DiskuvOCamlVarsVersion ' ".ci/sd4/setenv.$do_setenv_SWITCH.txt"; then
                 opamrun option --switch "$do_setenv_SWITCH" setenv+='DiskuvOCamlVarsVersion = "2"'
@@ -1417,6 +1454,25 @@ runs:
             if ! grep -q '\(^|\[\)DiskuvOCamlVersion ' ".ci/sd4/setenv.$do_setenv_SWITCH.txt"; then
                 opamrun option --switch "$do_setenv_SWITCH" setenv+="DiskuvOCamlVersion = \"$DKML_VERSION\""
             fi
+            if [ "$do_setenv_SWITCH" = dkml ] && [ -n "${DKML_HOME:-}" ]; then
+              do_setenv_DKMLHOME_ESCAPED="$DKML_HOME"
+              do_setenv_USRBIN_ESCAPED="$DKML_HOME/usr/bin"
+              do_setenv_BIN_ESCAPED="$DKML_HOME/bin"
+              if [ -x /usr/bin/cygpath ]; then
+                do_setenv_DKMLHOME_ESCAPED=$(/usr/bin/cygpath -aw "$do_setenv_DKMLHOME_ESCAPED" | sed 's/\\/\\\\/g')
+                do_setenv_USRBIN_ESCAPED=$(/usr/bin/cygpath -aw "$do_setenv_USRBIN_ESCAPED" | sed 's/\\/\\\\/g')
+                do_setenv_BIN_ESCAPED=$(/usr/bin/cygpath -aw "$do_setenv_BIN_ESCAPED" | sed 's/\\/\\\\/g')
+              fi
+              if ! grep -q '\(^|\[\)DiskuvOCamlHome ' ".ci/sd4/setenv.$do_setenv_SWITCH.txt"; then
+                  opamrun option --switch "$do_setenv_SWITCH" setenv+="DiskuvOCamlHome = \"$do_setenv_DKMLHOME_ESCAPED\""
+              fi
+              if ! grep -q '\(^|\[\)DiskuvOCamlBinaryPaths ' ".ci/sd4/setenv.$do_setenv_SWITCH.txt"; then
+                  opamrun option --switch "$do_setenv_SWITCH" setenv+="DiskuvOCamlBinaryPaths = \"$do_setenv_USRBIN_ESCAPED;$do_setenv_BIN_ESCAPED\""
+              fi
+              if ! grep -q '\(^|\[\)DiskuvOCamlDeploymentId ' ".ci/sd4/setenv.$do_setenv_SWITCH.txt"; then
+                  opamrun option --switch "$do_setenv_SWITCH" setenv+="DiskuvOCamlDeploymentId = \"setup-dkml-switch-$do_setenv_SWITCH\""
+              fi
+            fi
             case "${dkml_host_abi}" in
             windows_*)
                 if ! grep -q '\(^|\[\)DiskuvOCamlMSYS2Dir ' ".ci/sd4/setenv.$do_setenv_SWITCH.txt"; then
@@ -1431,6 +1487,7 @@ runs:
                     opamrun option --switch "$do_setenv_SWITCH" setenv+="DiskuvOCamlMSYS2Dir = \"$MSYS2_DIR_NATIVE_ESCAPED\""
                 fi
             esac
+            section_end "setenv-$do_setenv_SWITCH"
         }
         if [ "${SECONDARY_SWITCH:-}" = "true" ]; then
             do_setenv two
@@ -1446,7 +1503,9 @@ runs:
             opamrun upgrade --switch "$do_install_compiler_NAME" --yes dkml-base-compiler conf-dkml-cross-toolchain ${ocaml_options:-}
             section_end "install-compiler-$do_install_compiler_NAME"
         }
-        do_install_compiler dkml
+        if ! [ "${PRIMARY_SWITCH_SKIP_INSTALL:-}" = "true" ]; then
+            do_install_compiler dkml
+        fi
         if [ "${SECONDARY_SWITCH:-}" = "true" ]; then
             do_install_compiler two
         fi
@@ -1652,7 +1711,7 @@ runs:
         }
 
         # Locate Visual Studio (Windows)
-        if ("${env:vsstudio_dir}" -eq "" -and (!(Test-Path -Path .ci/sd4/vsenv${ExportExt}))) {
+        if ("${env:vsstudio_dir}" -eq "" -and (!(Test-Path -Path .ci/sd4/vsenv${ExportExt}) -or !(Test-Path -Path .ci/sd4/vsenv.ps1))) {
             $env:PSModulePath += "$([System.IO.Path]::PathSeparator).ci\sd4\g\dkml-runtime-distribution\src\windows"
             Import-Module Machine
 
@@ -1667,6 +1726,12 @@ runs:
             Write-Output "${ExportSN}VS_WINSDKVER=${ExportSV}$($VisualStudioProps.WinSdkVer)${ExportEV}" >> .ci/sd4/vsenv${ExportExt}
             Write-Output "${ExportSN}VS_MSVSPREFERENCE=${ExportSV}$($VisualStudioProps.MsvsPreference)${ExportEV}" >> .ci/sd4/vsenv${ExportExt}
             Write-Output "${ExportSN}VS_CMAKEGENERATOR=${ExportSV}$($VisualStudioProps.CMakeGenerator)${ExportEV}" >> .ci/sd4/vsenv${ExportExt}
+
+            Write-Output "`$env:VS_DIR='$($VisualStudioProps.InstallPath)'" > .ci/sd4/vsenv.ps1
+            Write-Output "`$env:VS_VCVARSVER='$($VisualStudioProps.VcVarsVer)'" >> .ci/sd4/vsenv.ps1
+            Write-Output "`$env:VS_WINSDKVER='$($VisualStudioProps.WinSdkVer)'" >> .ci/sd4/vsenv.ps1
+            Write-Output "`$env:VS_MSVSPREFERENCE='$($VisualStudioProps.MsvsPreference)'" >> .ci/sd4/vsenv.ps1
+            Write-Output "`$env:VS_CMAKEGENERATOR='$($VisualStudioProps.CMakeGenerator)'" >> .ci/sd4/vsenv.ps1
         }
 
         # Link to hardcoded Visual Studio (Windows)
@@ -1676,6 +1741,12 @@ runs:
             Write-Output "${ExportSN}VS_WINSDKVER=${ExportSV}${env:vsstudio_winsdkver}${ExportEV}" >> .ci/sd4/vsenv${ExportExt}
             Write-Output "${ExportSN}VS_MSVSPREFERENCE=${ExportSV}${env:vsstudio_msvspreference}${ExportEV}" >> .ci/sd4/vsenv${ExportExt}
             Write-Output "${ExportSN}VS_CMAKEGENERATOR=${ExportSV}${env:vsstudio_cmakegenerator}${ExportEV}" >> .ci/sd4/vsenv${ExportExt}
+
+            Write-Output "`$env:VS_DIR='${env:vsstudio_dir}'" > .ci/sd4/vsenv.ps1
+            Write-Output "`$env:VS_VCVARSVER='${env:vsstudio_vcvarsver}'" >> .ci/sd4/vsenv.ps1
+            Write-Output "`$env:VS_WINSDKVER='${env:vsstudio_winsdkver}'" >> .ci/sd4/vsenv.ps1
+            Write-Output "`$env:VS_MSVSPREFERENCE='${env:vsstudio_msvspreference}'" >> .ci/sd4/vsenv.ps1
+            Write-Output "`$env:VS_CMAKEGENERATOR='${env:vsstudio_cmakegenerator}'" >> .ci/sd4/vsenv.ps1
         }
 
         '@
@@ -1689,6 +1760,8 @@ runs:
         REM need a native compiler will fail without the MSVC compiler in the
         REM PATH. There isn't a `with-dkml.exe` alternative available at
         REM this stage of the GitHub workflow.
+        SET VSCMD_DEBUG=2
+        SET VSCMD_SKIP_SENDTELEMETRY=1
         call "%VS_DIR%\Common7\Tools\VsDevCmd.bat" -no_logo -host_arch=%vsstudio_hostarch% -arch=%vsstudio_arch% -vcvars_ver=%VS_VCVARSVER% -winsdk=%VS_WINSDKVER%
         if %ERRORLEVEL% neq 0 (
             echo.
@@ -1712,7 +1785,7 @@ runs:
         REM (For some reason no shell commands can happen after the last msys2 -c in GitHub Actions
         REM so split into multiple steps!
         '@
-        Set-Content -Path ".ci\sd4\get-msvcpath-into-msys2.cmd" -Encoding Default -Value $Content
+        Set-Content -Path ".ci\sd4\get-msvcpath-into-msys2.bat" -Encoding Default -Value $Content
 
     - name: Prepare cache keys
       # An undocumented bug with GitHub Actions is that a space in the key
@@ -1721,7 +1794,7 @@ runs:
       shell: bash
       run: |
         set -x
-        echo '317446-${{ inputs.FDOPEN_OPAMEXE_BOOTSTRAP }}-${{ steps.full_matrix_vars.outputs.dkml_host_abi }}-${{ steps.full_matrix_vars.outputs.opam_abi }}-${{ steps.full_matrix_vars.outputs.bootstrap_opam_version }}' > .ci/sd4/cachekey.opam.binaries
+        echo '069b66-${{ inputs.FDOPEN_OPAMEXE_BOOTSTRAP }}-${{ steps.full_matrix_vars.outputs.dkml_host_abi }}-${{ steps.full_matrix_vars.outputs.opam_abi }}-${{ steps.full_matrix_vars.outputs.bootstrap_opam_version }}' > .ci/sd4/cachekey.opam.binaries
         echo '${{ steps.full_matrix_vars.outputs.abi_pattern }}-${{ steps.full_matrix_vars.outputs.vsstudio_arch }}-${{ steps.full_matrix_vars.outputs.vsstudio_hostarch }}-${{ steps.full_matrix_vars.outputs.vsstudio_dir }}-${{ steps.full_matrix_vars.outputs.vsstudio_vcvarsver }}-${{ steps.full_matrix_vars.outputs.vsstudio_winsdkver }}-${{ steps.full_matrix_vars.outputs.vsstudio_msvspreference }}-${{ steps.full_matrix_vars.outputs.vsstudio_cmakegenerator }}' > .ci/sd4/cachekey.vsstudio
         echo '${{ inputs.OCAML_COMPILER }}-${{ inputs.DISKUV_OPAM_REPOSITORY }}-${{ inputs.DKML_COMPILER }}-${{ inputs.CONF_DKML_CROSS_TOOLCHAIN }}' > .ci/sd4/cachekey.ci.inputs
 
@@ -1793,7 +1866,7 @@ runs:
     - name: Capture Visual Studio compiler environment (1/2) (Windows)
       shell: cmd
       run: |
-        call .ci\sd4\get-msvcpath-into-msys2.cmd
+        call .ci\sd4\get-msvcpath-into-msys2.bat
 
     - name: Capture Visual Studio compiler environment (2/2) (Windows)
       shell: msys2 {0}
@@ -1820,24 +1893,29 @@ runs:
         VERBOSE:                          "${{ inputs.VERBOSE }}"
 
         # autogen from global_env_vars.
-        DEFAULT_DKML_COMPILER: '4.12.1-v1.0.2'
-        PIN_BASE: 'v0.14.3'
-        PIN_BIGSTRINGAF: '0.8.0'
-        PIN_CORE_KERNEL: 'v0.14.2'
-        PIN_CTYPES_FOREIGN: '0.19.2-windowssupport-r4'
-        PIN_CTYPES: '0.19.2-windowssupport-r4'
+        DEFAULT_DKML_COMPILER: '4.14.0-v1.1.0-prerel15'
+        PIN_ALCOTEST: '1.6.0'
+        PIN_ALCOTEST_ASYNC: '1.6.0'
+        PIN_ALCOTEST_JS: '1.6.0'
+        PIN_ALCOTEST_LWT: '1.6.0'
+        PIN_ALCOTEST_MIRAGE: '1.6.0'
+        PIN_BASE: 'v0.15.1'
+        PIN_BASE_BIGSTRING: 'v0.15.0'
+        PIN_BIGSTRINGAF: '0.9.0+msvc'
+        PIN_CORE: 'v0.15.1'
+        PIN_CORE_KERNEL: 'v0.15.0'
+        PIN_CTYPES_FOREIGN: '0.19.2-windowssupport-r5'
+        PIN_CTYPES: '0.19.2-windowssupport-r5'
         PIN_CURLY: '0.2.1-windows-env_r2'
-        PIN_DIGESTIF: '1.0.1'
-        PIN_DUNE: '2.9.3+shim.1.0.2~r0'
-        PIN_DUNE_CONFIGURATOR: '2.9.3'
-        PIN_DKML_APPS: '1.0.1'
+        PIN_DKML_APPS: '1.2.0~prerel8'
+        PIN_DKML_EXE: '1.2.0~prerel8'
+        PIN_DUNE: '3.6.2'
+        PIN_FEATHER: '0.3.0'
         PIN_OCAMLBUILD: '0.14.0'
         PIN_OCAMLFIND: '1.9.1'
         PIN_OCP_INDENT: '1.8.2-windowssupport'
-        PIN_PPX_EXPECT: 'v0.14.1'
-        PIN_PTIME: '0.8.6-msvcsupport'
-        PIN_TIME_NOW: 'v0.14.0'
-        PIN_WITH_DKML: '1.0.1'
+        PIN_PPX_EXPECT: 'v0.15.1'
+        PIN_WITH_DKML: '1.2.0~prerel8'
       run: |
         sh .ci/sd4/run-setup-dkml.sh GITHUB_WORKSPACE "$GITHUB_WORKSPACE"
 
@@ -1857,7 +1935,7 @@ runs:
         if [ -x /usr/bin/cygpath ]; then opamrunabs=$(/usr/bin/cygpath -aw "$opamrunabs"); fi
         echo "$opamrunabs" >> $GITHUB_PATH
 
-        #   Special case: GITHUB_PATH does not influence msys2.CMD of msys2/setup-msys2@v2, so place in real MSYS2 PATH
+        #   Special case: GITHUB_PATH does not influence msys2.bat of msys2/setup-msys2@v2, so place in real MSYS2 PATH
         if [ -n "${MSYSTEM:-}" ]; then
           install -d /usr/local/bin
           install -v .ci/sd4/opamrun/opamrun /usr/local/bin/opamrun
diff --git a/ci/setup-dkml/pc/setup-dkml-windows_x86.ps1 b/ci/setup-dkml/pc/setup-dkml-windows_x86.ps1
index 5d22ef9cf23..09c2c15686a 100644
--- a/ci/setup-dkml/pc/setup-dkml-windows_x86.ps1
+++ b/ci/setup-dkml/pc/setup-dkml-windows_x86.ps1
@@ -25,6 +25,9 @@ Input variable. -DKML_COMPILER takes priority. If -DKML_COMPILER is not set and
 .PARAMETER DKML_COMPILER
 Input variable. Unspecified or blank is the latest from the default branch (main) of dkml-compiler. @repository@ is the latest from Opam.
 
+.PARAMETER PRIMARY_SWITCH_SKIP_INSTALL
+Input variable. If true no dkml-base-compiler will be installed in the 'dkml' switch.
+
 .PARAMETER SECONDARY_SWITCH
 Input variable. If true then the secondary switch named 'two' is created, in addition to the always-present 'dkml' switch. 
 
@@ -34,16 +37,41 @@ Input variable. Unspecified or blank is the latest from the default branch (main
 .PARAMETER DISKUV_OPAM_REPOSITORY
 Input variable. Defaults to the value of -DEFAULT_DISKUV_OPAM_REPOSITORY_TAG (see below)
 
+.PARAMETER DKML_HOME
+Input variables. If specified then DiskuvOCamlHome, DiskuvOCamlBinaryPaths and DiskuvOCamlDeploymentId will be set, in addition to the always-present DiskuvOCamlVarsVersion, DiskuvOCamlVersion
+and DiskuvOCamlMSYS2Dir.
+
 # autogen from global_env_vars.
 .PARAMETER DEFAULT_DKML_COMPILER
 Environment variable.
 
+.PARAMETER PIN_ALCOTEST
+Environment variable.
+
+.PARAMETER PIN_ALCOTEST_ASYNC
+Environment variable.
+
+.PARAMETER PIN_ALCOTEST_JS
+Environment variable.
+
+.PARAMETER PIN_ALCOTEST_LWT
+Environment variable.
+
+.PARAMETER PIN_ALCOTEST_MIRAGE
+Environment variable.
+
 .PARAMETER PIN_BASE
 Environment variable.
 
+.PARAMETER PIN_BASE_BIGSTRING
+Environment variable.
+
 .PARAMETER PIN_BIGSTRINGAF
 Environment variable.
 
+.PARAMETER PIN_CORE
+Environment variable.
+
 .PARAMETER PIN_CORE_KERNEL
 Environment variable.
 
@@ -56,16 +84,16 @@ Environment variable.
 .PARAMETER PIN_CURLY
 Environment variable.
 
-.PARAMETER PIN_DIGESTIF
+.PARAMETER PIN_DKML_APPS
 Environment variable.
 
-.PARAMETER PIN_DUNE
+.PARAMETER PIN_DKML_EXE
 Environment variable.
 
-.PARAMETER PIN_DUNE_CONFIGURATOR
+.PARAMETER PIN_DUNE
 Environment variable.
 
-.PARAMETER PIN_DKML_APPS
+.PARAMETER PIN_FEATHER
 Environment variable.
 
 .PARAMETER PIN_OCAMLBUILD
@@ -80,12 +108,6 @@ Environment variable.
 .PARAMETER PIN_PPX_EXPECT
 Environment variable.
 
-.PARAMETER PIN_PTIME
-Environment variable.
-
-.PARAMETER PIN_TIME_NOW
-Environment variable.
-
 .PARAMETER PIN_WITH_DKML
 Environment variable.
 
@@ -112,13 +134,19 @@ param (
   $DKML_COMPILER = "",
   [Parameter()]
   [string]
+  $PRIMARY_SWITCH_SKIP_INSTALL = "false",
+  [Parameter()]
+  [string]
   $SECONDARY_SWITCH = "false",
   [Parameter()]
   [string]
   $CONF_DKML_CROSS_TOOLCHAIN = "@repository@",
   [Parameter()]
   [string]
-  $DISKUV_OPAM_REPOSITORY = ""
+  $DISKUV_OPAM_REPOSITORY = "",
+  [Parameter()]
+  [string]
+  $DKML_HOME = ""
 
   # Conflicts with automatic variable $Verbose
   # [Parameter()]
@@ -127,24 +155,29 @@ param (
     
   # Environment variables (can be overridden on command line)
   # autogen from global_env_vars.
-  ,[Parameter()] [string] $DEFAULT_DKML_COMPILER = "4.12.1-v1.0.2"
-  ,[Parameter()] [string] $PIN_BASE = "v0.14.3"
-  ,[Parameter()] [string] $PIN_BIGSTRINGAF = "0.8.0"
-  ,[Parameter()] [string] $PIN_CORE_KERNEL = "v0.14.2"
-  ,[Parameter()] [string] $PIN_CTYPES_FOREIGN = "0.19.2-windowssupport-r4"
-  ,[Parameter()] [string] $PIN_CTYPES = "0.19.2-windowssupport-r4"
+  ,[Parameter()] [string] $DEFAULT_DKML_COMPILER = "4.14.0-v1.1.0-prerel15"
+  ,[Parameter()] [string] $PIN_ALCOTEST = "1.6.0"
+  ,[Parameter()] [string] $PIN_ALCOTEST_ASYNC = "1.6.0"
+  ,[Parameter()] [string] $PIN_ALCOTEST_JS = "1.6.0"
+  ,[Parameter()] [string] $PIN_ALCOTEST_LWT = "1.6.0"
+  ,[Parameter()] [string] $PIN_ALCOTEST_MIRAGE = "1.6.0"
+  ,[Parameter()] [string] $PIN_BASE = "v0.15.1"
+  ,[Parameter()] [string] $PIN_BASE_BIGSTRING = "v0.15.0"
+  ,[Parameter()] [string] $PIN_BIGSTRINGAF = "0.9.0+msvc"
+  ,[Parameter()] [string] $PIN_CORE = "v0.15.1"
+  ,[Parameter()] [string] $PIN_CORE_KERNEL = "v0.15.0"
+  ,[Parameter()] [string] $PIN_CTYPES_FOREIGN = "0.19.2-windowssupport-r5"
+  ,[Parameter()] [string] $PIN_CTYPES = "0.19.2-windowssupport-r5"
   ,[Parameter()] [string] $PIN_CURLY = "0.2.1-windows-env_r2"
-  ,[Parameter()] [string] $PIN_DIGESTIF = "1.0.1"
-  ,[Parameter()] [string] $PIN_DUNE = "2.9.3+shim.1.0.2~r0"
-  ,[Parameter()] [string] $PIN_DUNE_CONFIGURATOR = "2.9.3"
-  ,[Parameter()] [string] $PIN_DKML_APPS = "1.0.1"
+  ,[Parameter()] [string] $PIN_DKML_APPS = "1.2.0~prerel8"
+  ,[Parameter()] [string] $PIN_DKML_EXE = "1.2.0~prerel8"
+  ,[Parameter()] [string] $PIN_DUNE = "3.6.2"
+  ,[Parameter()] [string] $PIN_FEATHER = "0.3.0"
   ,[Parameter()] [string] $PIN_OCAMLBUILD = "0.14.0"
   ,[Parameter()] [string] $PIN_OCAMLFIND = "1.9.1"
   ,[Parameter()] [string] $PIN_OCP_INDENT = "1.8.2-windowssupport"
-  ,[Parameter()] [string] $PIN_PPX_EXPECT = "v0.14.1"
-  ,[Parameter()] [string] $PIN_PTIME = "0.8.6-msvcsupport"
-  ,[Parameter()] [string] $PIN_TIME_NOW = "v0.14.0"
-  ,[Parameter()] [string] $PIN_WITH_DKML = "1.0.1"
+  ,[Parameter()] [string] $PIN_PPX_EXPECT = "v0.15.1"
+  ,[Parameter()] [string] $PIN_WITH_DKML = "1.2.0~prerel8"
 )
 
 $ErrorActionPreference = "Stop"
@@ -166,9 +199,11 @@ $env:FDOPEN_OPAMEXE_BOOTSTRAP = $FDOPEN_OPAMEXE_BOOTSTRAP
 $env:CACHE_PREFIX = $CACHE_PREFIX
 $env:OCAML_COMPILER = $OCAML_COMPILER
 $env:DKML_COMPILER = $DKML_COMPILER
+$env:PRIMARY_SWITCH_SKIP_INSTALL = $PRIMARY_SWITCH_SKIP_INSTALL
 $env:SECONDARY_SWITCH = $SECONDARY_SWITCH
 $env:CONF_DKML_CROSS_TOOLCHAIN = $CONF_DKML_CROSS_TOOLCHAIN
 $env:DISKUV_OPAM_REPOSITORY = $DISKUV_OPAM_REPOSITORY
+$env:DKML_HOME = $DKML_HOME
 
 # Set matrix variables
 # autogen from pc_vars. only windows_x86
@@ -178,7 +213,7 @@ $env:abi_pattern = "win32-windows_x86"
 $env:msys2_system = "MINGW32"
 $env:msys2_packages = "mingw-w64-i686-pkg-config"
 $env:exe_ext = ".exe"
-$env:bootstrap_opam_version = "2.2.0-dkml20220801T155940Z"
+$env:bootstrap_opam_version = "2.2.0-alpha-20221104"
 $env:opam_abi = "windows_x86"
 $env:dkml_host_abi = "windows_x86"
 $env:opam_root = "${env:PC_PROJECT_DIR}/.ci/o"
@@ -190,22 +225,27 @@ $env:ocaml_options = "ocaml-option-32bit"
 # Set environment variables
 # autogen from global_env_vars.
 $env:DEFAULT_DKML_COMPILER = $DEFAULT_DKML_COMPILER
+$env:PIN_ALCOTEST = $PIN_ALCOTEST
+$env:PIN_ALCOTEST_ASYNC = $PIN_ALCOTEST_ASYNC
+$env:PIN_ALCOTEST_JS = $PIN_ALCOTEST_JS
+$env:PIN_ALCOTEST_LWT = $PIN_ALCOTEST_LWT
+$env:PIN_ALCOTEST_MIRAGE = $PIN_ALCOTEST_MIRAGE
 $env:PIN_BASE = $PIN_BASE
+$env:PIN_BASE_BIGSTRING = $PIN_BASE_BIGSTRING
 $env:PIN_BIGSTRINGAF = $PIN_BIGSTRINGAF
+$env:PIN_CORE = $PIN_CORE
 $env:PIN_CORE_KERNEL = $PIN_CORE_KERNEL
 $env:PIN_CTYPES_FOREIGN = $PIN_CTYPES_FOREIGN
 $env:PIN_CTYPES = $PIN_CTYPES
 $env:PIN_CURLY = $PIN_CURLY
-$env:PIN_DIGESTIF = $PIN_DIGESTIF
-$env:PIN_DUNE = $PIN_DUNE
-$env:PIN_DUNE_CONFIGURATOR = $PIN_DUNE_CONFIGURATOR
 $env:PIN_DKML_APPS = $PIN_DKML_APPS
+$env:PIN_DKML_EXE = $PIN_DKML_EXE
+$env:PIN_DUNE = $PIN_DUNE
+$env:PIN_FEATHER = $PIN_FEATHER
 $env:PIN_OCAMLBUILD = $PIN_OCAMLBUILD
 $env:PIN_OCAMLFIND = $PIN_OCAMLFIND
 $env:PIN_OCP_INDENT = $PIN_OCP_INDENT
 $env:PIN_PPX_EXPECT = $PIN_PPX_EXPECT
-$env:PIN_PTIME = $PIN_PTIME
-$env:PIN_TIME_NOW = $PIN_TIME_NOW
 $env:PIN_WITH_DKML = $PIN_WITH_DKML
 
 # https://patchwork.kernel.org/project/qemu-devel/patch/20211215073402.144286-17-thuth@redhat.com/
@@ -412,6 +452,10 @@ shift
 setup_WORKSPACE=$1
 shift
 
+if [ -x /usr/bin/cygpath ]; then
+    setup_WORKSPACE=$(/usr/bin/cygpath -au "$setup_WORKSPACE")
+fi
+
 # ------------------------ Functions ------------------------
 
 # shellcheck source=./common-values.sh
@@ -483,6 +527,10 @@ install -d .ci/sd4/g
 
 # dkml-runtime-distribution
 
+#   For 'Diagnose Visual Studio environment variables (Windows)' we need dkml-runtime-distribution
+#   so that 'Import-Module Machine' and 'Get-VSSetupInstance' can be run.
+#   The version doesn't matter too much, as long as it has a functioning Get-VSSetupInstance.
+#   commit 1a3ec82dd851751a95e6a4797387a8163c51520e = tag v0.4.0-prerel20
 case "$dkml_host_abi" in
 windows_*)
     section_begin checkout-dkml-runtime-distribution 'Checkout dkml-runtime-distribution'
@@ -503,18 +551,19 @@ set -euf
 # Constants
 SHA512_DEVNULL='cf83e1357eefb8bdf1542850d66d8007d620e4050b5715dc83f4a921d36ce9ce47d0d13c5d85f2b0ff8318d2877eec2f63b931bd47417a81a538327af927da3e'
 #   Edited by https://gitlab.com/diskuv/diskuv-ocaml/contributors/release.sh
-DEFAULT_DISKUV_OPAM_REPOSITORY_TAG=cc9518fa5630bfbe24d4c5e0e2cc29af513037ce
+DEFAULT_DISKUV_OPAM_REPOSITORY_TAG=638195f6db6f54f121a7211515f26d946494eb95
 # Constants
-#   Should be edited by release.sh, but ...
-#   Can't be 1.0.0 or later until https://github.com/ocaml/opam-repository/pull/21704 ocaml-option-32bit
-#   can come back in.
-DKML_VERSION=0.4.0
+DKML_VERSION=1.2.0-prerel8
 
 setup_WORKSPACE_VARNAME=$1
 shift
 setup_WORKSPACE=$1
 shift
 
+if [ -x /usr/bin/cygpath ]; then
+    setup_WORKSPACE=$(/usr/bin/cygpath -au "$setup_WORKSPACE")
+fi
+
 # ------------------ Variables and functions ------------------------
 
 # shellcheck source=./common-values.sh
@@ -574,8 +623,10 @@ DISKUV_OPAM_REPOSITORY=${DISKUV_OPAM_REPOSITORY:-}
 DKML_COMPILER=${DKML_COMPILER:-}
 OCAML_COMPILER=${OCAML_COMPILER:-}
 CONF_DKML_CROSS_TOOLCHAIN=${CONF_DKML_CROSS_TOOLCHAIN:-}
+PRIMARY_SWITCH_SKIP_INSTALL=${PRIMARY_SWITCH_SKIP_INSTALL:-}
 SECONDARY_SWITCH=${SECONDARY_SWITCH:-}
 MANYLINUX=${MANYLINUX:-}
+DKML_HOME=${DKML_HOME:-}
 VERBOSE=${VERBOSE:-}
 .
 -------------------
@@ -607,22 +658,27 @@ ocaml_options=${ocaml_options:-}
 ----
 Pins
 ----
+PIN_ALCOTEST=${PIN_ALCOTEST}
+PIN_ALCOTEST_ASYNC=${PIN_ALCOTEST_ASYNC}
+PIN_ALCOTEST_JS=${PIN_ALCOTEST_JS}
+PIN_ALCOTEST_LWT=${PIN_ALCOTEST_LWT}
+PIN_ALCOTEST_MIRAGE=${PIN_ALCOTEST_MIRAGE}
 PIN_BASE=${PIN_BASE}
+PIN_BASE_BIGSTRING=${PIN_BASE_BIGSTRING}
 PIN_BIGSTRINGAF=${PIN_BIGSTRINGAF}
+PIN_CORE=${PIN_CORE}
 PIN_CORE_KERNEL=${PIN_CORE_KERNEL}
-PIN_CTYPES=${PIN_CTYPES}
 PIN_CTYPES_FOREIGN=${PIN_CTYPES_FOREIGN}
+PIN_CTYPES=${PIN_CTYPES}
 PIN_CURLY=${PIN_CURLY}
-PIN_DIGESTIF=${PIN_DIGESTIF}
 PIN_DKML_APPS=${PIN_DKML_APPS}
+PIN_DKML_EXE=${PIN_DKML_EXE}
 PIN_DUNE=${PIN_DUNE}
-PIN_DUNE_CONFIGURATOR=${PIN_DUNE_CONFIGURATOR}
+PIN_FEATHER=${PIN_FEATHER}
 PIN_OCAMLBUILD=${PIN_OCAMLBUILD}
 PIN_OCAMLFIND=${PIN_OCAMLFIND}
 PIN_OCP_INDENT=${PIN_OCP_INDENT}
 PIN_PPX_EXPECT=${PIN_PPX_EXPECT}
-PIN_PTIME=${PIN_PTIME}
-PIN_TIME_NOW=${PIN_TIME_NOW}
 PIN_WITH_DKML=${PIN_WITH_DKML}
 .
 "
@@ -966,6 +1022,7 @@ EOF
 
     # ---------------
     # Create Opam troubleshooting script
+    #   Dump logs modified within the last 4 hours
     # ---------------
 
     cat >.ci/sd4/troubleshoot-opam.sh <<EOF
@@ -973,8 +1030,13 @@ EOF
 set -euf
 OPAMROOT=\$1
 shift
+if find . -maxdepth 0 -mmin -240 2>/dev/null >/dev/null; then
+    FINDARGS="-mmin -240" # is -mmin supported? BSD (incl. macOS), MSYS2, GNU
+else
+    FINDARGS="-mtime -1" # use 1 day instead. Solaris
+fi
 printf "\n\n========= [START OF TROUBLESHOOTING] ===========\n\n" >&2
-find "\$OPAMROOT"/log -mindepth 1 -maxdepth 1 -name "*.out" ! -name "log-*.out" ! -name "ocaml-variants-*.out" | while read -r dump_on_error_LOG; do
+find "\$OPAMROOT"/log -mindepth 1 -maxdepth 1 \$FINDARGS -name "*.out" ! -name "log-*.out" ! -name "ocaml-variants-*.out" | while read -r dump_on_error_LOG; do
     dump_on_error_BLOG=\$(basename "\$dump_on_error_LOG")
     printf "\n\n========= [TROUBLESHOOTING] %s ===========\n\n" "\$dump_on_error_BLOG" >&2
     awk -v BLOG="\$dump_on_error_BLOG" '{print "[" BLOG "]", \$0}' "\$dump_on_error_LOG" >&2
@@ -1379,6 +1441,7 @@ do_pins() {
         # Validate OCAML_COMPILER (OCAML_COMPILER specified)
         case "${OCAML_COMPILER:-}" in
         4.12.1) true ;;
+        4.14.0) true ;;
         *)
             echo "OCAML_COMPILER version ${OCAML_COMPILER:-} is not supported" >&2
             exit 109
@@ -1429,22 +1492,31 @@ do_pins() {
     # - ppx_expect; only patch is for v0.14.1. Need to upstream fix the problem.
     # - base; patches for v0.14.1/2/3. Need to upstream fix the problem.
     section_begin "opam-pins-$do_pins_NAME" "Opam pins for $do_pins_NAME switch"
+    opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version alcotest "${PIN_ALCOTEST}"
+    opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version alcotest-async "${PIN_ALCOTEST_ASYNC}"
+    opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version alcotest-js "${PIN_ALCOTEST_JS}"
+    opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version alcotest-lwt "${PIN_ALCOTEST_LWT}"
+    opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version alcotest-mirage "${PIN_ALCOTEST_MIRAGE}"
     opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version base "${PIN_BASE}"
+    opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version base_bigstring "${PIN_BASE_BIGSTRING}"
     opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version bigstringaf "${PIN_BIGSTRINGAF}"
+    opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version core "${PIN_CORE}"
     opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version core_kernel "${PIN_CORE_KERNEL}"
     opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version ctypes "${PIN_CTYPES}"
     opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version ctypes-foreign "${PIN_CTYPES_FOREIGN}"
     opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version curly "${PIN_CURLY}"
-    opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version digestif "${PIN_DIGESTIF}"
+    opamrun pin remove --switch "$do_pins_NAME"  --yes --no-action digestif # this used to be pinned, so any cached opamroot needs it unpinned
     opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version dkml-apps "${PIN_DKML_APPS}"
+    opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version dkml-exe "${PIN_DKML_EXE}"
     opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version dune "${PIN_DUNE}"
-    opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version dune-configurator "${PIN_DUNE_CONFIGURATOR}"
+    opamrun pin remove --switch "$do_pins_NAME"  --yes --no-action dune-configurator # this used to be pinned, so any cached opamroot needs it unpinned
+    opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version feather "${PIN_FEATHER}"
     opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version ocamlbuild "${PIN_OCAMLBUILD}"
     opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version ocamlfind "${PIN_OCAMLFIND}"
     opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version ocp-indent "${PIN_OCP_INDENT}"
     opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version ppx_expect "${PIN_PPX_EXPECT}"
-    opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version ptime "${PIN_PTIME}"
-    opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version time_now "${PIN_TIME_NOW}"
+    opamrun pin remove --switch "$do_pins_NAME"  --yes --no-action ptime # this used to be pinned, so any cached opamroot needs it unpinned
+    opamrun pin remove --switch "$do_pins_NAME"  --yes --no-action time_now # this used to be pinned, so any cached opamroot needs it unpinned
     opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version with-dkml "${PIN_WITH_DKML}"
     section_end "opam-pins-$do_pins_NAME"
 }
@@ -1535,6 +1607,7 @@ do_use_vsstudio dkml
 do_setenv() {
     do_setenv_SWITCH=$1
     shift
+    section_begin "setenv-$do_setenv_SWITCH" "Set opam option for $do_setenv_SWITCH switch"
     opamrun option --switch "$do_setenv_SWITCH" setenv > ".ci/sd4/setenv.$do_setenv_SWITCH.txt"
     if ! grep -q '\(^|\[\)DiskuvOCamlVarsVersion ' ".ci/sd4/setenv.$do_setenv_SWITCH.txt"; then
         opamrun option --switch "$do_setenv_SWITCH" setenv+='DiskuvOCamlVarsVersion = "2"'
@@ -1542,6 +1615,25 @@ do_setenv() {
     if ! grep -q '\(^|\[\)DiskuvOCamlVersion ' ".ci/sd4/setenv.$do_setenv_SWITCH.txt"; then
         opamrun option --switch "$do_setenv_SWITCH" setenv+="DiskuvOCamlVersion = \"$DKML_VERSION\""
     fi
+    if [ "$do_setenv_SWITCH" = dkml ] && [ -n "${DKML_HOME:-}" ]; then
+      do_setenv_DKMLHOME_ESCAPED="$DKML_HOME"
+      do_setenv_USRBIN_ESCAPED="$DKML_HOME/usr/bin"
+      do_setenv_BIN_ESCAPED="$DKML_HOME/bin"
+      if [ -x /usr/bin/cygpath ]; then
+        do_setenv_DKMLHOME_ESCAPED=$(/usr/bin/cygpath -aw "$do_setenv_DKMLHOME_ESCAPED" | sed 's/\\/\\\\/g')
+        do_setenv_USRBIN_ESCAPED=$(/usr/bin/cygpath -aw "$do_setenv_USRBIN_ESCAPED" | sed 's/\\/\\\\/g')
+        do_setenv_BIN_ESCAPED=$(/usr/bin/cygpath -aw "$do_setenv_BIN_ESCAPED" | sed 's/\\/\\\\/g')
+      fi
+      if ! grep -q '\(^|\[\)DiskuvOCamlHome ' ".ci/sd4/setenv.$do_setenv_SWITCH.txt"; then
+          opamrun option --switch "$do_setenv_SWITCH" setenv+="DiskuvOCamlHome = \"$do_setenv_DKMLHOME_ESCAPED\""
+      fi
+      if ! grep -q '\(^|\[\)DiskuvOCamlBinaryPaths ' ".ci/sd4/setenv.$do_setenv_SWITCH.txt"; then
+          opamrun option --switch "$do_setenv_SWITCH" setenv+="DiskuvOCamlBinaryPaths = \"$do_setenv_USRBIN_ESCAPED;$do_setenv_BIN_ESCAPED\""
+      fi
+      if ! grep -q '\(^|\[\)DiskuvOCamlDeploymentId ' ".ci/sd4/setenv.$do_setenv_SWITCH.txt"; then
+          opamrun option --switch "$do_setenv_SWITCH" setenv+="DiskuvOCamlDeploymentId = \"setup-dkml-switch-$do_setenv_SWITCH\""
+      fi
+    fi
     case "${dkml_host_abi}" in
     windows_*)
         if ! grep -q '\(^|\[\)DiskuvOCamlMSYS2Dir ' ".ci/sd4/setenv.$do_setenv_SWITCH.txt"; then
@@ -1556,6 +1648,7 @@ do_setenv() {
             opamrun option --switch "$do_setenv_SWITCH" setenv+="DiskuvOCamlMSYS2Dir = \"$MSYS2_DIR_NATIVE_ESCAPED\""
         fi
     esac
+    section_end "setenv-$do_setenv_SWITCH"
 }
 if [ "${SECONDARY_SWITCH:-}" = "true" ]; then
     do_setenv two
@@ -1571,7 +1664,9 @@ do_install_compiler() {
     opamrun upgrade --switch "$do_install_compiler_NAME" --yes dkml-base-compiler conf-dkml-cross-toolchain ${ocaml_options:-}
     section_end "install-compiler-$do_install_compiler_NAME"
 }
-do_install_compiler dkml
+if ! [ "${PRIMARY_SWITCH_SKIP_INSTALL:-}" = "true" ]; then
+    do_install_compiler dkml
+fi
 if [ "${SECONDARY_SWITCH:-}" = "true" ]; then
     do_install_compiler two
 fi
@@ -1658,7 +1753,7 @@ if (("${env:GITLAB_CI}" -eq "true") -or ("${env:PC_CI}" -eq "true")) {
 }
 
 # Locate Visual Studio (Windows)
-if ("${env:vsstudio_dir}" -eq "" -and (!(Test-Path -Path .ci/sd4/vsenv${ExportExt}))) {
+if ("${env:vsstudio_dir}" -eq "" -and (!(Test-Path -Path .ci/sd4/vsenv${ExportExt}) -or !(Test-Path -Path .ci/sd4/vsenv.ps1))) {
     $env:PSModulePath += "$([System.IO.Path]::PathSeparator).ci\sd4\g\dkml-runtime-distribution\src\windows"
     Import-Module Machine
 
@@ -1673,6 +1768,12 @@ if ("${env:vsstudio_dir}" -eq "" -and (!(Test-Path -Path .ci/sd4/vsenv${ExportEx
     Write-Output "${ExportSN}VS_WINSDKVER=${ExportSV}$($VisualStudioProps.WinSdkVer)${ExportEV}" >> .ci/sd4/vsenv${ExportExt}
     Write-Output "${ExportSN}VS_MSVSPREFERENCE=${ExportSV}$($VisualStudioProps.MsvsPreference)${ExportEV}" >> .ci/sd4/vsenv${ExportExt}
     Write-Output "${ExportSN}VS_CMAKEGENERATOR=${ExportSV}$($VisualStudioProps.CMakeGenerator)${ExportEV}" >> .ci/sd4/vsenv${ExportExt}
+
+    Write-Output "`$env:VS_DIR='$($VisualStudioProps.InstallPath)'" > .ci/sd4/vsenv.ps1
+    Write-Output "`$env:VS_VCVARSVER='$($VisualStudioProps.VcVarsVer)'" >> .ci/sd4/vsenv.ps1
+    Write-Output "`$env:VS_WINSDKVER='$($VisualStudioProps.WinSdkVer)'" >> .ci/sd4/vsenv.ps1
+    Write-Output "`$env:VS_MSVSPREFERENCE='$($VisualStudioProps.MsvsPreference)'" >> .ci/sd4/vsenv.ps1
+    Write-Output "`$env:VS_CMAKEGENERATOR='$($VisualStudioProps.CMakeGenerator)'" >> .ci/sd4/vsenv.ps1
 }
 
 # Link to hardcoded Visual Studio (Windows)
@@ -1682,6 +1783,12 @@ if ("${env:vsstudio_dir}" -ne "") {
     Write-Output "${ExportSN}VS_WINSDKVER=${ExportSV}${env:vsstudio_winsdkver}${ExportEV}" >> .ci/sd4/vsenv${ExportExt}
     Write-Output "${ExportSN}VS_MSVSPREFERENCE=${ExportSV}${env:vsstudio_msvspreference}${ExportEV}" >> .ci/sd4/vsenv${ExportExt}
     Write-Output "${ExportSN}VS_CMAKEGENERATOR=${ExportSV}${env:vsstudio_cmakegenerator}${ExportEV}" >> .ci/sd4/vsenv${ExportExt}
+
+    Write-Output "`$env:VS_DIR='${env:vsstudio_dir}'" > .ci/sd4/vsenv.ps1
+    Write-Output "`$env:VS_VCVARSVER='${env:vsstudio_vcvarsver}'" >> .ci/sd4/vsenv.ps1
+    Write-Output "`$env:VS_WINSDKVER='${env:vsstudio_winsdkver}'" >> .ci/sd4/vsenv.ps1
+    Write-Output "`$env:VS_MSVSPREFERENCE='${env:vsstudio_msvspreference}'" >> .ci/sd4/vsenv.ps1
+    Write-Output "`$env:VS_CMAKEGENERATOR='${env:vsstudio_cmakegenerator}'" >> .ci/sd4/vsenv.ps1
 }
 
 '@
@@ -1696,6 +1803,8 @@ REM packages (ocamlbuild, etc.) which
 REM need a native compiler will fail without the MSVC compiler in the
 REM PATH. There isn't a `with-dkml.exe` alternative available at
 REM this stage of the GitHub workflow.
+SET VSCMD_DEBUG=2
+SET VSCMD_SKIP_SENDTELEMETRY=1
 call "%VS_DIR%\Common7\Tools\VsDevCmd.bat" -no_logo -host_arch=%vsstudio_hostarch% -arch=%vsstudio_arch% -vcvars_ver=%VS_VCVARSVER% -winsdk=%VS_WINSDKVER%
 if %ERRORLEVEL% neq 0 (
     echo.
@@ -1716,7 +1825,7 @@ REM * We can't use `bash -lc` directly to query for all MSVC environment variabl
 REM   because it stomps over the PATH. So we are inside a Batch script to do the query.
 msys64\usr\bin\bash -lc "set | grep -v '^PATH=' | awk -f .ci/sd4/msvcenv.awk > .ci/sd4/msvcenv"
 '@
-Set-Content -Path ".ci\sd4\get-msvcpath-into-msys2.cmd" -Encoding Default -Value $Content
+Set-Content -Path ".ci\sd4\get-msvcpath-into-msys2.bat" -Encoding Default -Value $Content
 
 msys64\usr\bin\bash -lc "sh .ci/sd4/run-checkout-code.sh PC_PROJECT_DIR '${env:PC_PROJECT_DIR}'"
 if ($LASTEXITCODE -ne 0) {
@@ -1743,9 +1852,11 @@ If ( "${env:VERBOSE}" -eq "true" ) {
 .ci\sd4\config-vsstudio.ps1
 msys64\usr\bin\bash -lc "dos2unix .ci/sd4/vsenv.sh"
 Get-Content .ci/sd4/vsenv.sh
+Get-Content .ci/sd4/vsenv.ps1
 
 # Capture Visual Studio compiler environment
-msys64\usr\bin\bash -lc ". .ci/sd4/vsenv.sh && cmd /c '.ci\sd4\get-msvcpath-into-msys2.cmd'"
+& .ci\sd4\vsenv.ps1
+& .ci\sd4\get-msvcpath-into-msys2.bat
 msys64\usr\bin\bash -lc "cat .ci/sd4/msvcpath | tr -d '\r' | cygpath --path -f - | awk -f .ci/sd4/msvcpath.awk >> .ci/sd4/msvcenv"    
 msys64\usr\bin\bash -lc "tail -n100 .ci/sd4/msvcpath .ci/sd4/msvcenv"
 
@@ -1770,6 +1881,6 @@ To continue your testing, run in PowerShell:
 Now you can use 'opamrun' to do opam commands like:
 
   msys64\usr\bin\bash -lc 'PATH="`$PWD/.ci/sd4/opamrun:`$PATH"; opamrun install XYZ.opam'
-  msys64\usr\bin\bash -lc 'PATH="`$PWD/.ci/sd4/opamrun:`$PATH"; opamrun -it exec -- bash'
-  msys64\usr\bin\bash -lc 'PATH="`$PWD/.ci/sd4/opamrun:`$PATH"; opamrun exec -- sh ci/build-test.sh'
+  msys64\usr\bin\bash -lc 'PATH="`$PWD/.ci/sd4/opamrun:`$PATH"; opamrun exec -- bash'
+  msys64\usr\bin\bash -lc 'sh ci/build-test.sh'
 "@
diff --git a/ci/setup-dkml/pc/setup-dkml-windows_x86_64.ps1 b/ci/setup-dkml/pc/setup-dkml-windows_x86_64.ps1
index 9018e591042..9064ad291b6 100644
--- a/ci/setup-dkml/pc/setup-dkml-windows_x86_64.ps1
+++ b/ci/setup-dkml/pc/setup-dkml-windows_x86_64.ps1
@@ -25,6 +25,9 @@ Input variable. -DKML_COMPILER takes priority. If -DKML_COMPILER is not set and
 .PARAMETER DKML_COMPILER
 Input variable. Unspecified or blank is the latest from the default branch (main) of dkml-compiler. @repository@ is the latest from Opam.
 
+.PARAMETER PRIMARY_SWITCH_SKIP_INSTALL
+Input variable. If true no dkml-base-compiler will be installed in the 'dkml' switch.
+
 .PARAMETER SECONDARY_SWITCH
 Input variable. If true then the secondary switch named 'two' is created, in addition to the always-present 'dkml' switch. 
 
@@ -34,16 +37,41 @@ Input variable. Unspecified or blank is the latest from the default branch (main
 .PARAMETER DISKUV_OPAM_REPOSITORY
 Input variable. Defaults to the value of -DEFAULT_DISKUV_OPAM_REPOSITORY_TAG (see below)
 
+.PARAMETER DKML_HOME
+Input variables. If specified then DiskuvOCamlHome, DiskuvOCamlBinaryPaths and DiskuvOCamlDeploymentId will be set, in addition to the always-present DiskuvOCamlVarsVersion, DiskuvOCamlVersion
+and DiskuvOCamlMSYS2Dir.
+
 # autogen from global_env_vars.
 .PARAMETER DEFAULT_DKML_COMPILER
 Environment variable.
 
+.PARAMETER PIN_ALCOTEST
+Environment variable.
+
+.PARAMETER PIN_ALCOTEST_ASYNC
+Environment variable.
+
+.PARAMETER PIN_ALCOTEST_JS
+Environment variable.
+
+.PARAMETER PIN_ALCOTEST_LWT
+Environment variable.
+
+.PARAMETER PIN_ALCOTEST_MIRAGE
+Environment variable.
+
 .PARAMETER PIN_BASE
 Environment variable.
 
+.PARAMETER PIN_BASE_BIGSTRING
+Environment variable.
+
 .PARAMETER PIN_BIGSTRINGAF
 Environment variable.
 
+.PARAMETER PIN_CORE
+Environment variable.
+
 .PARAMETER PIN_CORE_KERNEL
 Environment variable.
 
@@ -56,16 +84,16 @@ Environment variable.
 .PARAMETER PIN_CURLY
 Environment variable.
 
-.PARAMETER PIN_DIGESTIF
+.PARAMETER PIN_DKML_APPS
 Environment variable.
 
-.PARAMETER PIN_DUNE
+.PARAMETER PIN_DKML_EXE
 Environment variable.
 
-.PARAMETER PIN_DUNE_CONFIGURATOR
+.PARAMETER PIN_DUNE
 Environment variable.
 
-.PARAMETER PIN_DKML_APPS
+.PARAMETER PIN_FEATHER
 Environment variable.
 
 .PARAMETER PIN_OCAMLBUILD
@@ -80,12 +108,6 @@ Environment variable.
 .PARAMETER PIN_PPX_EXPECT
 Environment variable.
 
-.PARAMETER PIN_PTIME
-Environment variable.
-
-.PARAMETER PIN_TIME_NOW
-Environment variable.
-
 .PARAMETER PIN_WITH_DKML
 Environment variable.
 
@@ -112,13 +134,19 @@ param (
   $DKML_COMPILER = "",
   [Parameter()]
   [string]
+  $PRIMARY_SWITCH_SKIP_INSTALL = "false",
+  [Parameter()]
+  [string]
   $SECONDARY_SWITCH = "false",
   [Parameter()]
   [string]
   $CONF_DKML_CROSS_TOOLCHAIN = "@repository@",
   [Parameter()]
   [string]
-  $DISKUV_OPAM_REPOSITORY = ""
+  $DISKUV_OPAM_REPOSITORY = "",
+  [Parameter()]
+  [string]
+  $DKML_HOME = ""
 
   # Conflicts with automatic variable $Verbose
   # [Parameter()]
@@ -127,24 +155,29 @@ param (
     
   # Environment variables (can be overridden on command line)
   # autogen from global_env_vars.
-  ,[Parameter()] [string] $DEFAULT_DKML_COMPILER = "4.12.1-v1.0.2"
-  ,[Parameter()] [string] $PIN_BASE = "v0.14.3"
-  ,[Parameter()] [string] $PIN_BIGSTRINGAF = "0.8.0"
-  ,[Parameter()] [string] $PIN_CORE_KERNEL = "v0.14.2"
-  ,[Parameter()] [string] $PIN_CTYPES_FOREIGN = "0.19.2-windowssupport-r4"
-  ,[Parameter()] [string] $PIN_CTYPES = "0.19.2-windowssupport-r4"
+  ,[Parameter()] [string] $DEFAULT_DKML_COMPILER = "4.14.0-v1.1.0-prerel15"
+  ,[Parameter()] [string] $PIN_ALCOTEST = "1.6.0"
+  ,[Parameter()] [string] $PIN_ALCOTEST_ASYNC = "1.6.0"
+  ,[Parameter()] [string] $PIN_ALCOTEST_JS = "1.6.0"
+  ,[Parameter()] [string] $PIN_ALCOTEST_LWT = "1.6.0"
+  ,[Parameter()] [string] $PIN_ALCOTEST_MIRAGE = "1.6.0"
+  ,[Parameter()] [string] $PIN_BASE = "v0.15.1"
+  ,[Parameter()] [string] $PIN_BASE_BIGSTRING = "v0.15.0"
+  ,[Parameter()] [string] $PIN_BIGSTRINGAF = "0.9.0+msvc"
+  ,[Parameter()] [string] $PIN_CORE = "v0.15.1"
+  ,[Parameter()] [string] $PIN_CORE_KERNEL = "v0.15.0"
+  ,[Parameter()] [string] $PIN_CTYPES_FOREIGN = "0.19.2-windowssupport-r5"
+  ,[Parameter()] [string] $PIN_CTYPES = "0.19.2-windowssupport-r5"
   ,[Parameter()] [string] $PIN_CURLY = "0.2.1-windows-env_r2"
-  ,[Parameter()] [string] $PIN_DIGESTIF = "1.0.1"
-  ,[Parameter()] [string] $PIN_DUNE = "2.9.3+shim.1.0.2~r0"
-  ,[Parameter()] [string] $PIN_DUNE_CONFIGURATOR = "2.9.3"
-  ,[Parameter()] [string] $PIN_DKML_APPS = "1.0.1"
+  ,[Parameter()] [string] $PIN_DKML_APPS = "1.2.0~prerel8"
+  ,[Parameter()] [string] $PIN_DKML_EXE = "1.2.0~prerel8"
+  ,[Parameter()] [string] $PIN_DUNE = "3.6.2"
+  ,[Parameter()] [string] $PIN_FEATHER = "0.3.0"
   ,[Parameter()] [string] $PIN_OCAMLBUILD = "0.14.0"
   ,[Parameter()] [string] $PIN_OCAMLFIND = "1.9.1"
   ,[Parameter()] [string] $PIN_OCP_INDENT = "1.8.2-windowssupport"
-  ,[Parameter()] [string] $PIN_PPX_EXPECT = "v0.14.1"
-  ,[Parameter()] [string] $PIN_PTIME = "0.8.6-msvcsupport"
-  ,[Parameter()] [string] $PIN_TIME_NOW = "v0.14.0"
-  ,[Parameter()] [string] $PIN_WITH_DKML = "1.0.1"
+  ,[Parameter()] [string] $PIN_PPX_EXPECT = "v0.15.1"
+  ,[Parameter()] [string] $PIN_WITH_DKML = "1.2.0~prerel8"
 )
 
 $ErrorActionPreference = "Stop"
@@ -166,9 +199,11 @@ $env:FDOPEN_OPAMEXE_BOOTSTRAP = $FDOPEN_OPAMEXE_BOOTSTRAP
 $env:CACHE_PREFIX = $CACHE_PREFIX
 $env:OCAML_COMPILER = $OCAML_COMPILER
 $env:DKML_COMPILER = $DKML_COMPILER
+$env:PRIMARY_SWITCH_SKIP_INSTALL = $PRIMARY_SWITCH_SKIP_INSTALL
 $env:SECONDARY_SWITCH = $SECONDARY_SWITCH
 $env:CONF_DKML_CROSS_TOOLCHAIN = $CONF_DKML_CROSS_TOOLCHAIN
 $env:DISKUV_OPAM_REPOSITORY = $DISKUV_OPAM_REPOSITORY
+$env:DKML_HOME = $DKML_HOME
 
 # Set matrix variables
 # autogen from pc_vars. only windows_x86_64
@@ -178,7 +213,7 @@ $env:abi_pattern = "win32-windows_x86_64"
 $env:msys2_system = "CLANG64"
 $env:msys2_packages = "mingw-w64-clang-x86_64-pkg-config"
 $env:exe_ext = ".exe"
-$env:bootstrap_opam_version = "2.2.0-dkml20220801T155940Z"
+$env:bootstrap_opam_version = "2.2.0-alpha-20221104"
 $env:opam_abi = "windows_x86_64"
 $env:dkml_host_abi = "windows_x86_64"
 $env:opam_root = "${env:PC_PROJECT_DIR}/.ci/o"
@@ -189,22 +224,27 @@ $env:vsstudio_arch = "x64"
 # Set environment variables
 # autogen from global_env_vars.
 $env:DEFAULT_DKML_COMPILER = $DEFAULT_DKML_COMPILER
+$env:PIN_ALCOTEST = $PIN_ALCOTEST
+$env:PIN_ALCOTEST_ASYNC = $PIN_ALCOTEST_ASYNC
+$env:PIN_ALCOTEST_JS = $PIN_ALCOTEST_JS
+$env:PIN_ALCOTEST_LWT = $PIN_ALCOTEST_LWT
+$env:PIN_ALCOTEST_MIRAGE = $PIN_ALCOTEST_MIRAGE
 $env:PIN_BASE = $PIN_BASE
+$env:PIN_BASE_BIGSTRING = $PIN_BASE_BIGSTRING
 $env:PIN_BIGSTRINGAF = $PIN_BIGSTRINGAF
+$env:PIN_CORE = $PIN_CORE
 $env:PIN_CORE_KERNEL = $PIN_CORE_KERNEL
 $env:PIN_CTYPES_FOREIGN = $PIN_CTYPES_FOREIGN
 $env:PIN_CTYPES = $PIN_CTYPES
 $env:PIN_CURLY = $PIN_CURLY
-$env:PIN_DIGESTIF = $PIN_DIGESTIF
-$env:PIN_DUNE = $PIN_DUNE
-$env:PIN_DUNE_CONFIGURATOR = $PIN_DUNE_CONFIGURATOR
 $env:PIN_DKML_APPS = $PIN_DKML_APPS
+$env:PIN_DKML_EXE = $PIN_DKML_EXE
+$env:PIN_DUNE = $PIN_DUNE
+$env:PIN_FEATHER = $PIN_FEATHER
 $env:PIN_OCAMLBUILD = $PIN_OCAMLBUILD
 $env:PIN_OCAMLFIND = $PIN_OCAMLFIND
 $env:PIN_OCP_INDENT = $PIN_OCP_INDENT
 $env:PIN_PPX_EXPECT = $PIN_PPX_EXPECT
-$env:PIN_PTIME = $PIN_PTIME
-$env:PIN_TIME_NOW = $PIN_TIME_NOW
 $env:PIN_WITH_DKML = $PIN_WITH_DKML
 
 # https://patchwork.kernel.org/project/qemu-devel/patch/20211215073402.144286-17-thuth@redhat.com/
@@ -411,6 +451,10 @@ shift
 setup_WORKSPACE=$1
 shift
 
+if [ -x /usr/bin/cygpath ]; then
+    setup_WORKSPACE=$(/usr/bin/cygpath -au "$setup_WORKSPACE")
+fi
+
 # ------------------------ Functions ------------------------
 
 # shellcheck source=./common-values.sh
@@ -482,6 +526,10 @@ install -d .ci/sd4/g
 
 # dkml-runtime-distribution
 
+#   For 'Diagnose Visual Studio environment variables (Windows)' we need dkml-runtime-distribution
+#   so that 'Import-Module Machine' and 'Get-VSSetupInstance' can be run.
+#   The version doesn't matter too much, as long as it has a functioning Get-VSSetupInstance.
+#   commit 1a3ec82dd851751a95e6a4797387a8163c51520e = tag v0.4.0-prerel20
 case "$dkml_host_abi" in
 windows_*)
     section_begin checkout-dkml-runtime-distribution 'Checkout dkml-runtime-distribution'
@@ -502,18 +550,19 @@ set -euf
 # Constants
 SHA512_DEVNULL='cf83e1357eefb8bdf1542850d66d8007d620e4050b5715dc83f4a921d36ce9ce47d0d13c5d85f2b0ff8318d2877eec2f63b931bd47417a81a538327af927da3e'
 #   Edited by https://gitlab.com/diskuv/diskuv-ocaml/contributors/release.sh
-DEFAULT_DISKUV_OPAM_REPOSITORY_TAG=cc9518fa5630bfbe24d4c5e0e2cc29af513037ce
+DEFAULT_DISKUV_OPAM_REPOSITORY_TAG=638195f6db6f54f121a7211515f26d946494eb95
 # Constants
-#   Should be edited by release.sh, but ...
-#   Can't be 1.0.0 or later until https://github.com/ocaml/opam-repository/pull/21704 ocaml-option-32bit
-#   can come back in.
-DKML_VERSION=0.4.0
+DKML_VERSION=1.2.0-prerel8
 
 setup_WORKSPACE_VARNAME=$1
 shift
 setup_WORKSPACE=$1
 shift
 
+if [ -x /usr/bin/cygpath ]; then
+    setup_WORKSPACE=$(/usr/bin/cygpath -au "$setup_WORKSPACE")
+fi
+
 # ------------------ Variables and functions ------------------------
 
 # shellcheck source=./common-values.sh
@@ -573,8 +622,10 @@ DISKUV_OPAM_REPOSITORY=${DISKUV_OPAM_REPOSITORY:-}
 DKML_COMPILER=${DKML_COMPILER:-}
 OCAML_COMPILER=${OCAML_COMPILER:-}
 CONF_DKML_CROSS_TOOLCHAIN=${CONF_DKML_CROSS_TOOLCHAIN:-}
+PRIMARY_SWITCH_SKIP_INSTALL=${PRIMARY_SWITCH_SKIP_INSTALL:-}
 SECONDARY_SWITCH=${SECONDARY_SWITCH:-}
 MANYLINUX=${MANYLINUX:-}
+DKML_HOME=${DKML_HOME:-}
 VERBOSE=${VERBOSE:-}
 .
 -------------------
@@ -606,22 +657,27 @@ ocaml_options=${ocaml_options:-}
 ----
 Pins
 ----
+PIN_ALCOTEST=${PIN_ALCOTEST}
+PIN_ALCOTEST_ASYNC=${PIN_ALCOTEST_ASYNC}
+PIN_ALCOTEST_JS=${PIN_ALCOTEST_JS}
+PIN_ALCOTEST_LWT=${PIN_ALCOTEST_LWT}
+PIN_ALCOTEST_MIRAGE=${PIN_ALCOTEST_MIRAGE}
 PIN_BASE=${PIN_BASE}
+PIN_BASE_BIGSTRING=${PIN_BASE_BIGSTRING}
 PIN_BIGSTRINGAF=${PIN_BIGSTRINGAF}
+PIN_CORE=${PIN_CORE}
 PIN_CORE_KERNEL=${PIN_CORE_KERNEL}
-PIN_CTYPES=${PIN_CTYPES}
 PIN_CTYPES_FOREIGN=${PIN_CTYPES_FOREIGN}
+PIN_CTYPES=${PIN_CTYPES}
 PIN_CURLY=${PIN_CURLY}
-PIN_DIGESTIF=${PIN_DIGESTIF}
 PIN_DKML_APPS=${PIN_DKML_APPS}
+PIN_DKML_EXE=${PIN_DKML_EXE}
 PIN_DUNE=${PIN_DUNE}
-PIN_DUNE_CONFIGURATOR=${PIN_DUNE_CONFIGURATOR}
+PIN_FEATHER=${PIN_FEATHER}
 PIN_OCAMLBUILD=${PIN_OCAMLBUILD}
 PIN_OCAMLFIND=${PIN_OCAMLFIND}
 PIN_OCP_INDENT=${PIN_OCP_INDENT}
 PIN_PPX_EXPECT=${PIN_PPX_EXPECT}
-PIN_PTIME=${PIN_PTIME}
-PIN_TIME_NOW=${PIN_TIME_NOW}
 PIN_WITH_DKML=${PIN_WITH_DKML}
 .
 "
@@ -965,6 +1021,7 @@ EOF
 
     # ---------------
     # Create Opam troubleshooting script
+    #   Dump logs modified within the last 4 hours
     # ---------------
 
     cat >.ci/sd4/troubleshoot-opam.sh <<EOF
@@ -972,8 +1029,13 @@ EOF
 set -euf
 OPAMROOT=\$1
 shift
+if find . -maxdepth 0 -mmin -240 2>/dev/null >/dev/null; then
+    FINDARGS="-mmin -240" # is -mmin supported? BSD (incl. macOS), MSYS2, GNU
+else
+    FINDARGS="-mtime -1" # use 1 day instead. Solaris
+fi
 printf "\n\n========= [START OF TROUBLESHOOTING] ===========\n\n" >&2
-find "\$OPAMROOT"/log -mindepth 1 -maxdepth 1 -name "*.out" ! -name "log-*.out" ! -name "ocaml-variants-*.out" | while read -r dump_on_error_LOG; do
+find "\$OPAMROOT"/log -mindepth 1 -maxdepth 1 \$FINDARGS -name "*.out" ! -name "log-*.out" ! -name "ocaml-variants-*.out" | while read -r dump_on_error_LOG; do
     dump_on_error_BLOG=\$(basename "\$dump_on_error_LOG")
     printf "\n\n========= [TROUBLESHOOTING] %s ===========\n\n" "\$dump_on_error_BLOG" >&2
     awk -v BLOG="\$dump_on_error_BLOG" '{print "[" BLOG "]", \$0}' "\$dump_on_error_LOG" >&2
@@ -1378,6 +1440,7 @@ do_pins() {
         # Validate OCAML_COMPILER (OCAML_COMPILER specified)
         case "${OCAML_COMPILER:-}" in
         4.12.1) true ;;
+        4.14.0) true ;;
         *)
             echo "OCAML_COMPILER version ${OCAML_COMPILER:-} is not supported" >&2
             exit 109
@@ -1428,22 +1491,31 @@ do_pins() {
     # - ppx_expect; only patch is for v0.14.1. Need to upstream fix the problem.
     # - base; patches for v0.14.1/2/3. Need to upstream fix the problem.
     section_begin "opam-pins-$do_pins_NAME" "Opam pins for $do_pins_NAME switch"
+    opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version alcotest "${PIN_ALCOTEST}"
+    opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version alcotest-async "${PIN_ALCOTEST_ASYNC}"
+    opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version alcotest-js "${PIN_ALCOTEST_JS}"
+    opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version alcotest-lwt "${PIN_ALCOTEST_LWT}"
+    opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version alcotest-mirage "${PIN_ALCOTEST_MIRAGE}"
     opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version base "${PIN_BASE}"
+    opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version base_bigstring "${PIN_BASE_BIGSTRING}"
     opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version bigstringaf "${PIN_BIGSTRINGAF}"
+    opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version core "${PIN_CORE}"
     opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version core_kernel "${PIN_CORE_KERNEL}"
     opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version ctypes "${PIN_CTYPES}"
     opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version ctypes-foreign "${PIN_CTYPES_FOREIGN}"
     opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version curly "${PIN_CURLY}"
-    opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version digestif "${PIN_DIGESTIF}"
+    opamrun pin remove --switch "$do_pins_NAME"  --yes --no-action digestif # this used to be pinned, so any cached opamroot needs it unpinned
     opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version dkml-apps "${PIN_DKML_APPS}"
+    opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version dkml-exe "${PIN_DKML_EXE}"
     opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version dune "${PIN_DUNE}"
-    opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version dune-configurator "${PIN_DUNE_CONFIGURATOR}"
+    opamrun pin remove --switch "$do_pins_NAME"  --yes --no-action dune-configurator # this used to be pinned, so any cached opamroot needs it unpinned
+    opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version feather "${PIN_FEATHER}"
     opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version ocamlbuild "${PIN_OCAMLBUILD}"
     opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version ocamlfind "${PIN_OCAMLFIND}"
     opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version ocp-indent "${PIN_OCP_INDENT}"
     opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version ppx_expect "${PIN_PPX_EXPECT}"
-    opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version ptime "${PIN_PTIME}"
-    opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version time_now "${PIN_TIME_NOW}"
+    opamrun pin remove --switch "$do_pins_NAME"  --yes --no-action ptime # this used to be pinned, so any cached opamroot needs it unpinned
+    opamrun pin remove --switch "$do_pins_NAME"  --yes --no-action time_now # this used to be pinned, so any cached opamroot needs it unpinned
     opamrun pin add --switch "$do_pins_NAME"  --yes --no-action -k version with-dkml "${PIN_WITH_DKML}"
     section_end "opam-pins-$do_pins_NAME"
 }
@@ -1534,6 +1606,7 @@ do_use_vsstudio dkml
 do_setenv() {
     do_setenv_SWITCH=$1
     shift
+    section_begin "setenv-$do_setenv_SWITCH" "Set opam option for $do_setenv_SWITCH switch"
     opamrun option --switch "$do_setenv_SWITCH" setenv > ".ci/sd4/setenv.$do_setenv_SWITCH.txt"
     if ! grep -q '\(^|\[\)DiskuvOCamlVarsVersion ' ".ci/sd4/setenv.$do_setenv_SWITCH.txt"; then
         opamrun option --switch "$do_setenv_SWITCH" setenv+='DiskuvOCamlVarsVersion = "2"'
@@ -1541,6 +1614,25 @@ do_setenv() {
     if ! grep -q '\(^|\[\)DiskuvOCamlVersion ' ".ci/sd4/setenv.$do_setenv_SWITCH.txt"; then
         opamrun option --switch "$do_setenv_SWITCH" setenv+="DiskuvOCamlVersion = \"$DKML_VERSION\""
     fi
+    if [ "$do_setenv_SWITCH" = dkml ] && [ -n "${DKML_HOME:-}" ]; then
+      do_setenv_DKMLHOME_ESCAPED="$DKML_HOME"
+      do_setenv_USRBIN_ESCAPED="$DKML_HOME/usr/bin"
+      do_setenv_BIN_ESCAPED="$DKML_HOME/bin"
+      if [ -x /usr/bin/cygpath ]; then
+        do_setenv_DKMLHOME_ESCAPED=$(/usr/bin/cygpath -aw "$do_setenv_DKMLHOME_ESCAPED" | sed 's/\\/\\\\/g')
+        do_setenv_USRBIN_ESCAPED=$(/usr/bin/cygpath -aw "$do_setenv_USRBIN_ESCAPED" | sed 's/\\/\\\\/g')
+        do_setenv_BIN_ESCAPED=$(/usr/bin/cygpath -aw "$do_setenv_BIN_ESCAPED" | sed 's/\\/\\\\/g')
+      fi
+      if ! grep -q '\(^|\[\)DiskuvOCamlHome ' ".ci/sd4/setenv.$do_setenv_SWITCH.txt"; then
+          opamrun option --switch "$do_setenv_SWITCH" setenv+="DiskuvOCamlHome = \"$do_setenv_DKMLHOME_ESCAPED\""
+      fi
+      if ! grep -q '\(^|\[\)DiskuvOCamlBinaryPaths ' ".ci/sd4/setenv.$do_setenv_SWITCH.txt"; then
+          opamrun option --switch "$do_setenv_SWITCH" setenv+="DiskuvOCamlBinaryPaths = \"$do_setenv_USRBIN_ESCAPED;$do_setenv_BIN_ESCAPED\""
+      fi
+      if ! grep -q '\(^|\[\)DiskuvOCamlDeploymentId ' ".ci/sd4/setenv.$do_setenv_SWITCH.txt"; then
+          opamrun option --switch "$do_setenv_SWITCH" setenv+="DiskuvOCamlDeploymentId = \"setup-dkml-switch-$do_setenv_SWITCH\""
+      fi
+    fi
     case "${dkml_host_abi}" in
     windows_*)
         if ! grep -q '\(^|\[\)DiskuvOCamlMSYS2Dir ' ".ci/sd4/setenv.$do_setenv_SWITCH.txt"; then
@@ -1555,6 +1647,7 @@ do_setenv() {
             opamrun option --switch "$do_setenv_SWITCH" setenv+="DiskuvOCamlMSYS2Dir = \"$MSYS2_DIR_NATIVE_ESCAPED\""
         fi
     esac
+    section_end "setenv-$do_setenv_SWITCH"
 }
 if [ "${SECONDARY_SWITCH:-}" = "true" ]; then
     do_setenv two
@@ -1570,7 +1663,9 @@ do_install_compiler() {
     opamrun upgrade --switch "$do_install_compiler_NAME" --yes dkml-base-compiler conf-dkml-cross-toolchain ${ocaml_options:-}
     section_end "install-compiler-$do_install_compiler_NAME"
 }
-do_install_compiler dkml
+if ! [ "${PRIMARY_SWITCH_SKIP_INSTALL:-}" = "true" ]; then
+    do_install_compiler dkml
+fi
 if [ "${SECONDARY_SWITCH:-}" = "true" ]; then
     do_install_compiler two
 fi
@@ -1657,7 +1752,7 @@ if (("${env:GITLAB_CI}" -eq "true") -or ("${env:PC_CI}" -eq "true")) {
 }
 
 # Locate Visual Studio (Windows)
-if ("${env:vsstudio_dir}" -eq "" -and (!(Test-Path -Path .ci/sd4/vsenv${ExportExt}))) {
+if ("${env:vsstudio_dir}" -eq "" -and (!(Test-Path -Path .ci/sd4/vsenv${ExportExt}) -or !(Test-Path -Path .ci/sd4/vsenv.ps1))) {
     $env:PSModulePath += "$([System.IO.Path]::PathSeparator).ci\sd4\g\dkml-runtime-distribution\src\windows"
     Import-Module Machine
 
@@ -1672,6 +1767,12 @@ if ("${env:vsstudio_dir}" -eq "" -and (!(Test-Path -Path .ci/sd4/vsenv${ExportEx
     Write-Output "${ExportSN}VS_WINSDKVER=${ExportSV}$($VisualStudioProps.WinSdkVer)${ExportEV}" >> .ci/sd4/vsenv${ExportExt}
     Write-Output "${ExportSN}VS_MSVSPREFERENCE=${ExportSV}$($VisualStudioProps.MsvsPreference)${ExportEV}" >> .ci/sd4/vsenv${ExportExt}
     Write-Output "${ExportSN}VS_CMAKEGENERATOR=${ExportSV}$($VisualStudioProps.CMakeGenerator)${ExportEV}" >> .ci/sd4/vsenv${ExportExt}
+
+    Write-Output "`$env:VS_DIR='$($VisualStudioProps.InstallPath)'" > .ci/sd4/vsenv.ps1
+    Write-Output "`$env:VS_VCVARSVER='$($VisualStudioProps.VcVarsVer)'" >> .ci/sd4/vsenv.ps1
+    Write-Output "`$env:VS_WINSDKVER='$($VisualStudioProps.WinSdkVer)'" >> .ci/sd4/vsenv.ps1
+    Write-Output "`$env:VS_MSVSPREFERENCE='$($VisualStudioProps.MsvsPreference)'" >> .ci/sd4/vsenv.ps1
+    Write-Output "`$env:VS_CMAKEGENERATOR='$($VisualStudioProps.CMakeGenerator)'" >> .ci/sd4/vsenv.ps1
 }
 
 # Link to hardcoded Visual Studio (Windows)
@@ -1681,6 +1782,12 @@ if ("${env:vsstudio_dir}" -ne "") {
     Write-Output "${ExportSN}VS_WINSDKVER=${ExportSV}${env:vsstudio_winsdkver}${ExportEV}" >> .ci/sd4/vsenv${ExportExt}
     Write-Output "${ExportSN}VS_MSVSPREFERENCE=${ExportSV}${env:vsstudio_msvspreference}${ExportEV}" >> .ci/sd4/vsenv${ExportExt}
     Write-Output "${ExportSN}VS_CMAKEGENERATOR=${ExportSV}${env:vsstudio_cmakegenerator}${ExportEV}" >> .ci/sd4/vsenv${ExportExt}
+
+    Write-Output "`$env:VS_DIR='${env:vsstudio_dir}'" > .ci/sd4/vsenv.ps1
+    Write-Output "`$env:VS_VCVARSVER='${env:vsstudio_vcvarsver}'" >> .ci/sd4/vsenv.ps1
+    Write-Output "`$env:VS_WINSDKVER='${env:vsstudio_winsdkver}'" >> .ci/sd4/vsenv.ps1
+    Write-Output "`$env:VS_MSVSPREFERENCE='${env:vsstudio_msvspreference}'" >> .ci/sd4/vsenv.ps1
+    Write-Output "`$env:VS_CMAKEGENERATOR='${env:vsstudio_cmakegenerator}'" >> .ci/sd4/vsenv.ps1
 }
 
 '@
@@ -1695,6 +1802,8 @@ REM packages (ocamlbuild, etc.) which
 REM need a native compiler will fail without the MSVC compiler in the
 REM PATH. There isn't a `with-dkml.exe` alternative available at
 REM this stage of the GitHub workflow.
+SET VSCMD_DEBUG=2
+SET VSCMD_SKIP_SENDTELEMETRY=1
 call "%VS_DIR%\Common7\Tools\VsDevCmd.bat" -no_logo -host_arch=%vsstudio_hostarch% -arch=%vsstudio_arch% -vcvars_ver=%VS_VCVARSVER% -winsdk=%VS_WINSDKVER%
 if %ERRORLEVEL% neq 0 (
     echo.
@@ -1715,7 +1824,7 @@ REM * We can't use `bash -lc` directly to query for all MSVC environment variabl
 REM   because it stomps over the PATH. So we are inside a Batch script to do the query.
 msys64\usr\bin\bash -lc "set | grep -v '^PATH=' | awk -f .ci/sd4/msvcenv.awk > .ci/sd4/msvcenv"
 '@
-Set-Content -Path ".ci\sd4\get-msvcpath-into-msys2.cmd" -Encoding Default -Value $Content
+Set-Content -Path ".ci\sd4\get-msvcpath-into-msys2.bat" -Encoding Default -Value $Content
 
 msys64\usr\bin\bash -lc "sh .ci/sd4/run-checkout-code.sh PC_PROJECT_DIR '${env:PC_PROJECT_DIR}'"
 if ($LASTEXITCODE -ne 0) {
@@ -1742,9 +1851,11 @@ If ( "${env:VERBOSE}" -eq "true" ) {
 .ci\sd4\config-vsstudio.ps1
 msys64\usr\bin\bash -lc "dos2unix .ci/sd4/vsenv.sh"
 Get-Content .ci/sd4/vsenv.sh
+Get-Content .ci/sd4/vsenv.ps1
 
 # Capture Visual Studio compiler environment
-msys64\usr\bin\bash -lc ". .ci/sd4/vsenv.sh && cmd /c '.ci\sd4\get-msvcpath-into-msys2.cmd'"
+& .ci\sd4\vsenv.ps1
+& .ci\sd4\get-msvcpath-into-msys2.bat
 msys64\usr\bin\bash -lc "cat .ci/sd4/msvcpath | tr -d '\r' | cygpath --path -f - | awk -f .ci/sd4/msvcpath.awk >> .ci/sd4/msvcenv"    
 msys64\usr\bin\bash -lc "tail -n100 .ci/sd4/msvcpath .ci/sd4/msvcenv"
 
@@ -1769,6 +1880,6 @@ To continue your testing, run in PowerShell:
 Now you can use 'opamrun' to do opam commands like:
 
   msys64\usr\bin\bash -lc 'PATH="`$PWD/.ci/sd4/opamrun:`$PATH"; opamrun install XYZ.opam'
-  msys64\usr\bin\bash -lc 'PATH="`$PWD/.ci/sd4/opamrun:`$PATH"; opamrun -it exec -- bash'
-  msys64\usr\bin\bash -lc 'PATH="`$PWD/.ci/sd4/opamrun:`$PATH"; opamrun exec -- sh ci/build-test.sh'
+  msys64\usr\bin\bash -lc 'PATH="`$PWD/.ci/sd4/opamrun:`$PATH"; opamrun exec -- bash'
+  msys64\usr\bin\bash -lc 'sh ci/build-test.sh'
 "@