diff --git a/src/Model.php b/src/Model.php
index fddaaca..5fa19b2 100644
--- a/src/Model.php
+++ b/src/Model.php
@@ -773,7 +773,7 @@ public function fromJson($value, $asObject = false)
      * @param  array|null  $except
      * @return \Jenssegers\Model\Model
      */
-    public function replicate(array $except = null)
+    public function replicate(?array $except = null)
     {
         $except = $except ?: [];