diff --git a/src/Middleware/HeaderAuthenticationMiddleware.php b/src/Middleware/HeaderAuthenticationMiddleware.php
index d49b36c..7c35d0f 100644
--- a/src/Middleware/HeaderAuthenticationMiddleware.php
+++ b/src/Middleware/HeaderAuthenticationMiddleware.php
@@ -20,7 +20,7 @@ class HeaderAuthenticationMiddleware implements MiddlewareInterface
         protected Authenticate $authorize,
         protected UserInterface $entity,
         protected \Closure $loginFailedResponse,
-        HeaderAuthentication $authenticator = null,
+        ? HeaderAuthentication $authenticator = null,
     ) {
         $this->authenticator = $authenticator ?: new HeaderAuthentication($authorize);
     }
diff --git a/src/Middleware/PostRequestAuthenticationMiddleware.php b/src/Middleware/PostRequestAuthenticationMiddleware.php
index e7c3a45..60d2513 100644
--- a/src/Middleware/PostRequestAuthenticationMiddleware.php
+++ b/src/Middleware/PostRequestAuthenticationMiddleware.php
@@ -19,7 +19,7 @@ class PostRequestAuthenticationMiddleware implements MiddlewareInterface
     public function __construct(
         protected UserInterface     $entity,
         protected \Closure          $loginFailedResponse,
-        PostRequestAuthentication   $authenticator = null,
+        ? PostRequestAuthentication $authenticator = null,
     ) {
         $this->authenticator = $authenticator ?: new PostRequestAuthentication(new Authenticate($entity));
     }