diff --git a/.php-cs-fixer.dist.php b/.php-cs-fixer.dist.php
index 8733752..f9d4b7a 100644
--- a/.php-cs-fixer.dist.php
+++ b/.php-cs-fixer.dist.php
@@ -7,7 +7,11 @@
 $config = new PhpCsFixer\Config();
 $config->setRules([
     '@PSR1' => true,
-    '@Symfony' => true
+    '@Symfony' => true,
+    'nullable_type_declaration' => [
+        'syntax' => 'question_mark',
+    ],
+    'nullable_type_declaration_for_default_null_value' => true,
 ]);
 $config->setFinder($finder);
 return $config;
\ No newline at end of file