diff --git a/resources/lang/sl_SI/demo.php b/resources/lang/sl_SI/demo.php
index b6d1a61428..e6a07ca5c4 100644
--- a/resources/lang/sl_SI/demo.php
+++ b/resources/lang/sl_SI/demo.php
@@ -1,4 +1,6 @@
 <?php
+declare(strict_types=1);
+
 /**
  * demo.php
  * Copyright (c) 2016 thegrumpydictator@gmail.com