--- a/wp/wp-includes/vars.php	Tue Dec 15 15:52:01 2020 +0100
+++ b/wp/wp-includes/vars.php	Wed Sep 21 18:19:35 2022 +0200
@@ -134,7 +134,7 @@
  *
  * @global bool $is_iis7
  */
-$is_iis7 = $is_IIS && intval( substr( $_SERVER['SERVER_SOFTWARE'], strpos( $_SERVER['SERVER_SOFTWARE'], 'Microsoft-IIS/' ) + 14 ) ) >= 7;
+$is_iis7 = $is_IIS && (int) substr( $_SERVER['SERVER_SOFTWARE'], strpos( $_SERVER['SERVER_SOFTWARE'], 'Microsoft-IIS/' ) + 14 ) >= 7;
 
 /**
  * Test if the current browser runs on a mobile device (smart phone, tablet, etc.)