diff --git a/src/Extension/Extension.php b/src/Extension/Extension.php
index 8635d6799..6ae5947f6 100644
--- a/src/Extension/Extension.php
+++ b/src/Extension/Extension.php
@@ -299,6 +299,8 @@ class Extension implements Arrayable
         if (file_exists($deprecatedFilename)) {
             return $deprecatedFilename;
         }
+
+        return null;
     }
 
     /**