diff --git a/Models/Media.php b/Models/Media.php
index 21fa91e..ea868b9 100755
--- a/Models/Media.php
+++ b/Models/Media.php
@@ -311,11 +311,11 @@ class Media implements \JsonSerializable
     }
 
     /**
-     * @return \DateTime
+     * @return \DateTimeImmutable
      *
      * @since 1.0.0
      */
-    public function getCreatedAt() : \DateTimeInterface
+    public function getCreatedAt() : \DateTimeImmutable
     {
         return $this->createdAt;
     }