diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index c3fb64c..79fc5e4 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -14,18 +14,30 @@ jobs:
 
     strategy:
       matrix:
-        php: [8.0, 8.1, 8.2, 8.3, 8.4]
+        php: [8.0, 8.1, 8.2, 8.3, 8.4, 8.5]
 
     steps:
     - name: Checkout code
-      uses: actions/checkout@v4
+      uses: actions/checkout@v6
 
-    - name: Setup PHP
+    - name: Setup PHP != 8.5
+      if: ${{ matrix.php != '8.5' }}
       uses: shivammathur/setup-php@v2
       with:
         php-version: ${{ matrix.php }}
         coverage: none
 
+    - name: Setup PHP 8.5
+      if: ${{ matrix.php == '8.5' }}
+      uses: shivammathur/setup-php@v2
+      with:
+        php-version: ${{ matrix.php }}
+        coverage: none
+        # this ini directive seems to be off by default in PHP 8.5
+        # see https://github.com/php/php-src/issues/20279
+        # enable it because codeception relies on it.
+        ini-values: register_argc_argv=1
+
     - name: Validate composer.json and composer.lock
       run: composer validate