diff --git a/.github/workflows/cs.yml b/.github/workflows/cs.yml
index 3cdb247..9a5aec4 100644
--- a/.github/workflows/cs.yml
+++ b/.github/workflows/cs.yml
@@ -34,7 +34,7 @@ jobs:
       # Install dependencies and handle caching in one go.
       # @link https://github.com/marketplace/actions/install-php-dependencies-with-composer
       - name: Install Composer dependencies
-        uses: "ramsey/composer-install@3cf229dc2919194e9e36783941438d17239e8520" # 3.1.1
+        uses: "ramsey/composer-install@65e4f84970763564f46a70b8a54b90d033b3bdda" # 4.0.0
         with:
           # Bust the cache at least once a month - output format: YYYY-MM.
           custom-cache-suffix: $(date -u "+%Y-%m")
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index bfafb94..e640d6d 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -55,7 +55,7 @@ jobs:
       # Install dependencies and handle caching in one go.
       # @link https://github.com/marketplace/actions/install-php-dependencies-with-composer
       - name: Install Composer dependencies
-        uses: "ramsey/composer-install@3cf229dc2919194e9e36783941438d17239e8520" # 3.1.1
+        uses: "ramsey/composer-install@65e4f84970763564f46a70b8a54b90d033b3bdda" # 4.0.0
         with:
           # For PHP "nightly", we need to install with ignore platform reqs as not all dependencies may allow it yet.
           composer-options: ${{ matrix.php == '8.6' && '--ignore-platform-req=php+' || '' }}