diff --git a/src/CsFixerConfig.php b/src/CsFixerConfig.php
index daa3b48..b26c73e 100644
--- a/src/CsFixerConfig.php
+++ b/src/CsFixerConfig.php
@@ -79,6 +79,10 @@ class CsFixerConfig extends Config implements CsFixerConfigInterface
         'no_unused_imports' => true,
         'no_useless_else' => true,
         'no_useless_nullsafe_operator' => true,
+        'nullable_type_declaration' => [
+            'syntax' => 'question_mark',
+        ],
+        'nullable_type_declaration_for_default_null_value' => true,
         'ordered_imports' => ['imports_order' => ['class', 'function', 'const'], 'sort_algorithm' => 'alpha'],
         'php_unit_construct' => ['assertions' => ['assertEquals', 'assertSame', 'assertNotEquals', 'assertNotSame']],
         'php_unit_mock_short_will_return' => true,