diff --git a/Filter/DataHydrator/Locator/DoctrineODM.php b/Filter/DataHydrator/Locator/DoctrineODM.php
index 21547d4..aa7ffe3 100644
--- a/Filter/DataHydrator/Locator/DoctrineODM.php
+++ b/Filter/DataHydrator/Locator/DoctrineODM.php
@@ -13,9 +13,9 @@ class DoctrineODM implements LocatorInterface
     protected $registry;
 
     /**
-     * @param ManagerRegistry $registry registry
+     * @param ?ManagerRegistry $registry registry
      */
-    public function __construct(ManagerRegistry $registry = null)
+    public function __construct(?ManagerRegistry $registry = null)
     {
         $this->registry = $registry;
     }
diff --git a/Filter/DataHydrator/Locator/DoctrineORM.php b/Filter/DataHydrator/Locator/DoctrineORM.php
index 75d50ee..9eb97ed 100644
--- a/Filter/DataHydrator/Locator/DoctrineORM.php
+++ b/Filter/DataHydrator/Locator/DoctrineORM.php
@@ -15,9 +15,9 @@ class DoctrineORM implements LocatorInterface
     protected $registry;
 
     /**
-     * @param ManagerRegistry $registry registry
+     * @param ?ManagerRegistry $registry registry
      */
-    public function __construct(ManagerRegistry $registry = null)
+    public function __construct(?ManagerRegistry $registry = null)
     {
         $this->registry = $registry;
     }