diff --git a/Build/phpstan/phpstan.neon b/Build/phpstan/phpstan.neon
index a7cb2c90c..b609d1c3f 100644
--- a/Build/phpstan/phpstan.neon
+++ b/Build/phpstan/phpstan.neon
@@ -63,3 +63,23 @@ parameters:
     -
       message: '#^Call to static method PHPUnit\\Framework\\Assert\:\:assertInstanceOf\(\) .* will always evaluate to#'
       path: '../../Tests/'
+
+  ergebnis:
+    declareStrictTypes:
+      enabled: false
+    final:
+      enabled: false
+    finalInAbstractClass:
+      enabled: false
+    noExtends:
+      enabled: false
+    noIsset:
+      enabled: false
+    noNullableReturnTypeDeclaration:
+      enabled: false
+    noParameterWithContainerTypeDeclaration:
+      enabled: false
+    noParameterWithNullableTypeDeclaration:
+      enabled: false
+    noParameterWithNullDefaultValue:
+      enabled: false
diff --git a/composer.json b/composer.json
index c00cefd2c..7d5f445a8 100644
--- a/composer.json
+++ b/composer.json
@@ -48,6 +48,7 @@
 	},
 	"require-dev": {
 		"ergebnis/composer-normalize": "2.50.0",
+		"ergebnis/phpstan-rules": "2.5.2 || 2.13.1",
 		"friendsofphp/php-cs-fixer": "3.94.2",
 		"helmich/typo3-typoscript-lint": "3.3.0",
 		"icanhazstring/composer-unused": "0.8.11 || 0.9.6",