diff --git a/phpBB/includes/page_header.php b/phpBB/includes/page_header.php
index 3b03050c95..cf1c2e6704 100644
--- a/phpBB/includes/page_header.php
+++ b/phpBB/includes/page_header.php
@@ -466,7 +466,7 @@ else
 
 // Work around for "current" Apache 2 + PHP module which seems to not
 // cope with private cache control setting
-if (!empty($HTTP_SERVER_VARS['SERVER_SOFTWARE']) && strstr($HTTP_SERVER_VARS['SERVER_SOFTWARE'], 'Apache/2'))
+if (!empty($_SERVER['SERVER_SOFTWARE']) && strstr($_SERVER['SERVER_SOFTWARE'], 'Apache/2'))
 {
 	header ('Cache-Control: no-cache, pre-check=0, post-check=0, max-age=0');
 }