diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 33b2cac..1437237 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -37,7 +37,7 @@ 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@a8d0d959dab41457692a5e2041bd9b757a119e3f" # 3.2.1
+      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+' || '' }}