diff --git a/.github/workflows/test-application.yaml b/.github/workflows/test-application.yaml
index 023c2ec..237879c 100644
--- a/.github/workflows/test-application.yaml
+++ b/.github/workflows/test-application.yaml
@@ -22,12 +22,14 @@ jobs:
                     - php-version: '7.2'
                       dependency-versions: 'lowest'
                       tools: 'composer:v2'
+                      phpunit-config: 'phpunit-9.xml.dist'
                       env:
                           SYMFONY_DEPRECATIONS_HELPER: disabled
 
                     - php-version: '7.4'
                       dependency-versions: 'highest'
                       tools: 'composer:v2'
+                      phpunit-config: 'phpunit-9.xml.dist'
                       env:
                           SYMFONY_DEPRECATIONS_HELPER: disabled
 
@@ -55,6 +57,13 @@ jobs:
                       env:
                           SYMFONY_DEPRECATIONS_HELPER: weak
 
+                    - php-version: '8.4'
+                      dependency-versions: 'highest'
+                      tools: 'composer:v2'
+                      composer-options: '--ignore-platform-reqs'
+                      env:
+                          SYMFONY_DEPRECATIONS_HELPER: weak
+
         services:
             mysql:
                 image: mysql:5.7
@@ -79,20 +88,23 @@ jobs:
               if: ${{ matrix.php-version == '7.2' }}
               run: composer remove phpspec/prophecy-phpunit --no-update --dev
 
-            - name: Remove not required test tooling
-              run: composer remove "*php-cs-fixer*" "*phpstan*" --no-update --dev
+            - name: Remove Lint Tools
+              # These tools are not required to run tests, so we are removing them to improve dependency resolving and
+              # testing lowest versions.
+              run: composer remove "*php-cs-fixer*" "*phpstan*" "*rector*" --dev --no-update
 
             - name: Install composer dependencies
               uses: ramsey/composer-install@v2
               with:
                   dependency-versions: ${{matrix.dependency-versions}}
+                  composer-options: ${{ matrix.composer-options }}
 
             - name: Bootstrap test environment
               run: composer bootstrap-test-environment
               env: ${{ matrix.env }}
 
             - name: Execute test cases
-              run: composer test
+              run: composer test -- --config ${{ matrix.phpunit-config || 'phpunit.xml.dist' }}
               env: ${{ matrix.env }}
 
     lint:
diff --git a/composer.json b/composer.json
index 4a11afa..854b18f 100644
--- a/composer.json
+++ b/composer.json
@@ -27,7 +27,7 @@
         "phpstan/phpstan-doctrine": "^1.0",
         "phpstan/phpstan-phpunit": "^1.0",
         "phpstan/phpstan-symfony": "^1.0",
-        "phpunit/phpunit": "^8.0 ||^9.6",
+        "phpunit/phpunit": "^8.5.39 || ^9.6.20 || ^10.0",
         "symfony/browser-kit": "^4.4 || ^5.4 || ^6.0 || ^7.0",
         "symfony/dotenv": "^4.4 || ^5.4 || ^6.0 || ^7.0",
         "symfony/form": "^4.4 || ^5.4 || ^6.0 || ^7.0",
diff --git a/phpunit-9.xml.dist b/phpunit-9.xml.dist
new file mode 100644
index 0000000..814b795
--- /dev/null
+++ b/phpunit-9.xml.dist
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit colors="true" bootstrap="Tests/bootstrap.php">
+   <testsuites>
+        <testsuite name="Sulu Comment Bundle">
+            <directory>./Tests</directory>
+        </testsuite>
+    </testsuites>
+
+    <filter>
+        <whitelist addUncoveredFilesFromWhitelist="true">
+            <directory>.</directory>
+            <exclude>
+                <directory>Resources/</directory>
+                <directory>Tests/</directory>
+                <directory>vendor/</directory>
+            </exclude>
+        </whitelist>
+    </filter>
+
+    <php>
+        <env name="KERNEL_CLASS" value="Sulu\Bundle\CommentBundle\Tests\Application\Kernel"/>
+        <env name="APP_ENV" value="test" force="true"/>
+    </php>
+</phpunit>
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index e244108..dcad3b6 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -1,23 +1,23 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <phpunit colors="true" bootstrap="Tests/bootstrap.php">
-   <testsuites>
+    <testsuites>
         <testsuite name="Sulu Comment Bundle">
             <directory>./Tests</directory>
         </testsuite>
     </testsuites>
 
-    <filter>
-        <whitelist addUncoveredFilesFromWhitelist="true">
-            <directory>.</directory>
-            <exclude>
-                <directory>Resources/</directory>
-                <directory>Tests/</directory>
-                <directory>vendor/</directory>
-            </exclude>
-        </whitelist>
-    </filter>
-
     <php>
         <env name="KERNEL_CLASS" value="Sulu\Bundle\CommentBundle\Tests\Application\Kernel"/>
     </php>
+
+    <source>
+        <include>
+            <directory>./</directory>
+        </include>
+        <exclude>
+            <directory>Resources/</directory>
+            <directory>Tests/</directory>
+            <directory>vendor/</directory>
+        </exclude>
+    </source>
 </phpunit>