diff --git a/.github/workflows/ci.js.yml b/.github/workflows/ci.js.yml
index d0c212c..23554df 100644
--- a/.github/workflows/ci.js.yml
+++ b/.github/workflows/ci.js.yml
@@ -14,12 +14,12 @@ jobs:
     steps:
       - uses: actions/checkout@f43a0e5ff2bd294095638e18286ca9a3d1956744
       - name: Use Node.js LTS
-        uses: actions/setup-node@v3
+        uses: actions/setup-node@1e60f620b9541d16bece96c5465dc8ee9832be0b
         with:
           node-version-file: .nvmrc
 
       - name: Install project dependencies
-        run: yarn install --frozen-lockfile
+        run: yarn install --immutable
 
       - name: Run exercism/typescript-test-runner ci precheck (lint code)
         run: bin/lint.sh
@@ -34,12 +34,12 @@ jobs:
     steps:
       - uses: actions/checkout@f43a0e5ff2bd294095638e18286ca9a3d1956744
       - name: Use Node.js ${{ matrix.node-version }}
-        uses: actions/setup-node@v3
+        uses: actions/setup-node@1e60f620b9541d16bece96c5465dc8ee9832be0b
         with:
           node-version: ${{ matrix.node-version }}
 
       - name: Install project dependencies
-        run: yarn install --frozen-lockfile
+        run: yarn install --immutable
 
       - name: Build the test-runner (using Node ${{ matrix.node-version }})
         run: bin/test.sh
diff --git a/.github/workflows/pr.ci.js.yml b/.github/workflows/pr.ci.js.yml
index b44ea98..748b432 100644
--- a/.github/workflows/pr.ci.js.yml
+++ b/.github/workflows/pr.ci.js.yml
@@ -11,15 +11,15 @@ jobs:
 
     steps:
       - name: Checkout PR
-        uses: actions/checkout@f43a0e5ff2bd294095638e18286ca9a3d1956744
+        uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332
 
       - name: Use Node.js LTS
-        uses: actions/setup-node@v3
+        uses: actions/setup-node@1e60f620b9541d16bece96c5465dc8ee9832be0b
         with:
           node-version-file: .nvmrc
 
       - name: Install project dependencies
-        run: yarn install --frozen-lockfile
+        run: yarn install --immutable
 
       - name: Run exercism/javascript ci precheck (lint code)
         run: bin/lint.sh
diff --git a/.github/workflows/verify-code-formatting.yml b/.github/workflows/verify-code-formatting.yml
index f044a72..2b8df6b 100644
--- a/.github/workflows/verify-code-formatting.yml
+++ b/.github/workflows/verify-code-formatting.yml
@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - name: 'Checkout code'
-        uses: actions/checkout@f43a0e5ff2bd294095638e18286ca9a3d1956744
+        uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332
 
       - name: 'Verify formatting of all files'
         run: ./bin/check-formatting.sh