diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 7e6eda9..76ea4e7 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -75,8 +75,8 @@ jobs:
                     vendor/bin/contao-console lint:twig contao/templates
                     vendor/bin/contao-console lint:yaml config
 
-    phpunit:
-        name: PHP ${{ matrix.php }}
+    phpunit_c51:
+        name: PHP ${{ matrix.php }} Contao 5.1
         runs-on: ubuntu-latest
         strategy:
             fail-fast: false
@@ -96,7 +96,65 @@ jobs:
                 uses: actions/checkout@v4
 
             -   name: Install the dependencies
-                run: composer install --no-interaction --no-progress
+                run: |
+                    composer require contao/core-bundle "5.1.*"
+                    composer install --no-interaction --no-progress
+
+            -   name: Run the unit tests
+                run: vendor/bin/phpunit --colors=always
+
+    phpunit_c52:
+        name: PHP ${{ matrix.php }} Contao 5.2
+        runs-on: ubuntu-latest
+        strategy:
+            fail-fast: false
+            matrix:
+                php: [ 8.1, 8.2, 8.3 ]
+        steps:
+            -   name: Setup PHP
+                uses: shivammathur/setup-php@v2
+                with:
+                    php-version: ${{ matrix.php }}
+                    extensions: dom, fileinfo, filter, gd, hash, intl, json, mbstring, mysqli, pcre, pdo_mysql, zlib
+                    coverage: xdebug
+                env:
+                    COMPOSER_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+            -   name: Checkout
+                uses: actions/checkout@v4
+
+            -   name: Install the dependencies
+                run: |
+                    composer require contao/core-bundle "5.2.*"
+                    composer install --no-interaction --no-progress
+
+            -   name: Run the unit tests
+                run: vendor/bin/phpunit --colors=always
+
+    phpunit_c53:
+        name: PHP ${{ matrix.php }} Contao 5.3
+        runs-on: ubuntu-latest
+        strategy:
+            fail-fast: false
+            matrix:
+                php: [ 8.1, 8.2, 8.3 ]
+        steps:
+            -   name: Setup PHP
+                uses: shivammathur/setup-php@v2
+                with:
+                    php-version: ${{ matrix.php }}
+                    extensions: dom, fileinfo, filter, gd, hash, intl, json, mbstring, mysqli, pcre, pdo_mysql, zlib
+                    coverage: xdebug
+                env:
+                    COMPOSER_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+            -   name: Checkout
+                uses: actions/checkout@v4
+
+            -   name: Install the dependencies
+                run: |
+                    composer require contao/core-bundle "5.3.*"
+                    composer install --no-interaction --no-progress
 
             -   name: Run the unit tests
                 run: vendor/bin/phpunit --colors=always
@@ -151,7 +209,7 @@ jobs:
 
             -   name: Install the dependencies
                 run: |
-                    composer require contao/core-bundle "^4.13"
+                    composer require contao/core-bundle "5.4.*"
                     composer install --no-interaction --no-progress
 
             -   name: Run the unit tests
diff --git a/phpstan.neon b/phpstan.neon
index ddec0eb..a60268a 100644
--- a/phpstan.neon
+++ b/phpstan.neon
@@ -17,8 +17,5 @@ parameters:
         - Contao\Form
         - Contao\Widget
 
-    ignoreErrors:
-      - '#Constant VERSION not found.#'
-
     excludePaths:
         - %currentWorkingDirectory%/src/Resources/*