diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 4ef98d0..7a81e19 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -45,7 +45,12 @@ jobs:
       - name: Install dependencies
         run: |
           composer remove --dev phpstan/phpstan
-          composer require --dev -W "phpunit/phpunit:^9"
+          # PHPUnit 9 for 8.0 and 8.1
+          if [ "${{ matrix.php-version }}" == "8.0" ] || [ "${{ matrix.php-version }}" == "8.1" ]; then composer require --dev -W "phpunit/phpunit:^9.6.34"; fi
+          # PHPUnit 11 for 8.2
+          if [ "${{ matrix.php-version }}" == "8.2" ]; then composer require --dev -W "phpunit/phpunit:^11.5.55"; fi
+          # PHPUnit 12 for 8.3 8.4 and 8.5
+          if [ "${{ matrix.php-version }}" == "8.3" ] || [ "${{ matrix.php-version }}" == "8.4" ] || [ "${{ matrix.php-version }}" == "8.5" ]; then composer require --dev -W "phpunit/phpunit:^12.5.14"; fi
           composer install --prefer-dist --no-progress --no-interaction --no-scripts
           mkdir -p build/logs
 
diff --git a/composer.json b/composer.json
index fefe9f2..df5fe4f 100644
--- a/composer.json
+++ b/composer.json
@@ -32,8 +32,8 @@
     "firebase/php-jwt": "^7.0"
   },
   "require-dev": {
-    "phpunit/phpunit": "^4.0|^5.0|^6.0|^7.0|^8.0|^9.0",
-    "yoast/phpunit-polyfills": "^1.0",
+    "phpunit/phpunit": "^9.6.34|^10.5.64|^11.5.55|^12.5.14",
+    "yoast/phpunit-polyfills": "^4.0",
     "phpstan/phpstan": "^1.4"
   },
   "autoload": {