diff --git a/.php-cs-fixer.php b/.php-cs-fixer.php
index 1aaac2d..223eac5 100644
--- a/.php-cs-fixer.php
+++ b/.php-cs-fixer.php
@@ -24,6 +24,7 @@
         'no_superfluous_phpdoc_tags' => true,
         'no_trailing_comma_in_singleline' => true,
         'no_unused_imports' => true,
+        'nullable_type_declaration_for_default_null_value' => true,
         'ordered_imports' => ['imports_order' => ['class', 'function', 'const'], 'sort_algorithm' => 'alpha'],
         'phpdoc_add_missing_param_annotation' => ['only_untyped' => true],
         'phpdoc_align' => ['align' => 'left'],
diff --git a/composer.json b/composer.json
index b052dc5..4421983 100644
--- a/composer.json
+++ b/composer.json
@@ -27,12 +27,12 @@
     "php": "^8.1"
   },
   "require-dev": {
-    "friendsofphp/php-cs-fixer": "^3.51.0",
-    "phpstan/phpstan": "^1.10.59",
+    "friendsofphp/php-cs-fixer": "^3.52.1",
+    "phpstan/phpstan": "^1.10.64",
     "phpstan/phpstan-strict-rules": "^1.5.2",
     "phpstan/phpstan-phpunit": "^1.3.16",
     "phpstan/phpstan-deprecation-rules": "^1.1.4",
-    "phpunit/phpunit": "^10.5.11",
+    "phpunit/phpunit": "^10.5.15",
     "symfony/var-dumper": "^6.4.4"
   },
   "autoload": {
diff --git a/src/Enum/JavaScriptConverter.php b/src/Enum/JavaScriptConverter.php
index bb6bf61..2311464 100644
--- a/src/Enum/JavaScriptConverter.php
+++ b/src/Enum/JavaScriptConverter.php
@@ -39,7 +39,7 @@ public static function new(): self
         );
     }
 
-    public function propertyNameCase(Closure $casing = null): self
+    public function propertyNameCase(?Closure $casing = null): self
     {
         return new self(
             $this->useSymbol,
diff --git a/src/Error/Cloak.php b/src/Error/Cloak.php
index b4d6367..dc32113 100644
--- a/src/Error/Cloak.php
+++ b/src/Error/Cloak.php
@@ -103,7 +103,7 @@ public function __invoke(mixed ...$arguments): mixed
     /**
      * @throws ErrorException
      */
-    protected function errorHandler(int $errno, string $errstr, string $errfile = null, int $errline = null): bool
+    protected function errorHandler(int $errno, string $errstr, ?string $errfile = null, ?int $errline = null): bool
     {
         if (ReportingLevel::fromEnv()->doesNotContain($errno)) {
             return false;