diff --git a/Models/Client.php b/Models/Client.php
index 23b5ed9..cb57485 100644
--- a/Models/Client.php
+++ b/Models/Client.php
@@ -299,11 +299,11 @@ class Client
     /**
      * Get created at date time
      *
-     * @return \DateTime
+     * @return \DateTimeImmutable
      *
      * @since 1.0.0
      */
-    public function getCreatedAt() : \DateTimeInterface
+    public function getCreatedAt() : \DateTimeImmutable
     {
         return $this->createdAt;
     }