diff --git a/src/Users/EloquentUser.php b/src/Users/EloquentUser.php
index a3375b1a..ed4880da 100644
--- a/src/Users/EloquentUser.php
+++ b/src/Users/EloquentUser.php
@@ -246,7 +246,7 @@ public function generatePersistenceCode(): string
     /**
      * {@inheritdoc}
      */
-    public function getUserId(): int
+    public function getUserId()
     {
         return $this->getKey();
     }
diff --git a/src/Users/UserInterface.php b/src/Users/UserInterface.php
index ba5b17d7..6b431de0 100644
--- a/src/Users/UserInterface.php
+++ b/src/Users/UserInterface.php
@@ -25,9 +25,9 @@ interface UserInterface
     /**
      * Returns the user primary key.
      *
-     * @return int
+     * @return int|string
      */
-    public function getUserId(): int;
+    public function getUserId();
 
     /**
      * Returns the user login.