diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 201931ee51..453780df57 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -28,7 +28,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       # without this, setup-node errors on mismatched yarn versions
       - run: corepack enable
@@ -75,7 +75,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       # without this, setup-node errors on mismatched yarn versions
       - run: corepack enable
@@ -121,7 +121,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       # without this, setup-node errors on mismatched yarn versions
       - run: corepack enable
@@ -158,7 +158,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       # without this, setup-node errors on mismatched yarn versions
       - run: corepack enable
@@ -194,7 +194,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       # without this, setup-node errors on mismatched yarn versions
       - run: corepack enable
@@ -230,7 +230,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       # without this, setup-node errors on mismatched yarn versions
       - run: corepack enable
@@ -271,12 +271,15 @@ jobs:
       fail-fast: false
       matrix:
         node-version: [20.x]
-        moddable-version: [5.0.0]
+        # Including one of each category, named release and git ref, to ensure
+        # we support both cases for the duration of the PR that introduces this
+        # CI job.
+        moddable-version: [5.0.0, 1f49b61d52987bce8d430ac2fe1fab5365bc2043]
         platform: [ubuntu-latest]
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       # without this, setup-node errors on mismatched yarn versions
       - run: corepack enable
@@ -295,71 +298,46 @@ jobs:
       - name: Run yarn build
         run: yarn build
 
-      - name: Get XS
+      - name: Choose download or build
+        id: check-release
         run: |
-          wget https://github.com/Moddable-OpenSource/moddable/releases/download/${{ matrix.moddable-version }}/xst-lin64.zip
-          mkdir -p bin
-          unzip xst-lin64.zip -d bin
-          chmod 755 bin/xst
+          if curl -f -s -o /dev/null -I -L https://api.github.com/repos/Moddable-OpenSource/moddable/releases/tags/${{ matrix.moddable-version }}
+          then
+            echo release=download
+          else
+            echo release=build
+          fi >> $GITHUB_OUTPUT
+
+      - name: Download XS
+        if: steps.check-release.outputs.release == 'download'
+        working-directory: ..
+        run: |
+          BINDIR=$GITHUB_WORKSPACE/moddable/build/bin/lin/debug
+          wget "https://github.com/Moddable-OpenSource/moddable/releases/download/${{ matrix.moddable-version }}/xst-lin64.zip"
+          mkdir -p "$BINDIR"
+          unzip xst-lin64.zip -d "$BINDIR"
+          chmod 755 "$BINDIR/xst"
+
+      - name: Checkout XS
+        if: steps.check-release.outputs.release == 'build'
+        uses: actions/checkout@v4
+        with:
+          repository: moddable-OpenSource/moddable
+          ref: ${{ matrix.moddable-version }}
+          path: moddable
 
-      - name: Is this thing on?
+      - name: Build XS
+        if: steps.check-release.outputs.release == 'build'
+        working-directory: moddable/xs/makefiles/lin
         run: |
-          PATH=$PATH:$GITHUB_WORKSPACE/bin
+          make debug MODDABLE=$GITHUB_WORKSPACE/moddable CC='cc "-D__has_builtin(x)=1"' # give the syntax highlighter a hand: '
+
+      - name: Validate XS Build or Download
+        run: |
+          PATH=$PATH:$GITHUB_WORKSPACE/moddable/build/bin/lin/debug
           xst -e true && ! xst -e null.reference
 
       - name: Run XS tests
         run: |
-          PATH=$PATH:$GITHUB_WORKSPACE/bin
+          PATH=$PATH:$GITHUB_WORKSPACE/moddable/build/bin/lin/debug
           yarn lerna run test:xs
-
-  # for testing a version with a particular hash, when pre-built binaries are unavailable
-  # make-and-test-xs:
-  #   name: make-and-test-xs
-  #
-  #   # begin macro
-  #
-  #   runs-on: ${{ matrix.platform }}
-  #   strategy:
-  #     fail-fast: false
-  #     matrix:
-  #       moddable-version: []
-  #       node-version: [20.x]
-  #       platform: [ubuntu-latest]
-  #
-  #   steps:
-  #     - name: Checkout
-  #       uses: actions/checkout@v3
-  #
-  #     # without this, setup-node errors on mismatched yarn versions
-  #     - run: corepack enable
-  #
-  #     - name: Use Node.js ${{ matrix.node-version }}
-  #       uses: actions/setup-node@v3
-  #       with:
-  #         node-version: ${{ matrix.node-version }}
-  #         cache: yarn
-  #
-  #     - name: Install dependencies
-  #       run: yarn install --immutable
-  #
-  #     # end macro
-  #
-  #     - name: Run yarn build
-  #       run: yarn build
-  #
-  #     - name: Clone XS
-  #       run: git clone https://github.com/moddable-OpenSource/moddable --branch "${{ matrix.moddable-version }}" --depth 1
-  #
-  #     - name: Build XS
-  #       working-directory: moddable/xs/makefiles/lin
-  #       run: make debug MODDABLE=$GITHUB_WORKSPACE/moddable CC='cc "-D__has_builtin(x)=1"' # give the syntax highlighter a hand: '
-  #
-  #     - name: Is this thing on?
-  #       run: |
-  #         PATH=$PATH:$GITHUB_WORKSPACE/moddable/build/bin/lin/debug
-  #         xst -e true && ! xst -e null.reference
-  #
-  #     - name: Run XS tests
-  #       run: |
-  #         PATH=$PATH:$GITHUB_WORKSPACE/moddable/build/bin/lin/debug
-  #         yarn lerna run test:xs