diff --git a/core/Middleware/TwoFactorMiddleware.php b/core/Middleware/TwoFactorMiddleware.php
index 47b09536acd..45c165d1ba5 100644
--- a/core/Middleware/TwoFactorMiddleware.php
+++ b/core/Middleware/TwoFactorMiddleware.php
@@ -1,4 +1,7 @@
 <?php
+
+declare(strict_types=1);
+
 /**
  * @copyright Copyright (c) 2016, ownCloud, Inc.
  *