diff --git a/phpBB/admin/page_header_admin.php b/phpBB/admin/page_header_admin.php
index de37b600f7..7be3e34fff 100644
--- a/phpBB/admin/page_header_admin.php
+++ b/phpBB/admin/page_header_admin.php
@@ -160,11 +160,11 @@ $template->assign_vars(array(
 );
 
 header ("Cache-Control: no-store, no-cache, must-revalidate");
-header ("Cache-Control: pre-check=0, post-check=0, max-age=0");
+header ("Cache-Control: pre-check=0, post-check=0, max-age=0", false);
 header ("Pragma: no-cache");
 header ("Expires: " . gmdate("D, d M Y H:i:s", time()) . " GMT");
 header ("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
 
 $template->pparse("header");
 
-?>
\ No newline at end of file
+?>
diff --git a/phpBB/includes/page_header.php b/phpBB/includes/page_header.php
index 40aa161c5e..1eb6ef5158 100644
--- a/phpBB/includes/page_header.php
+++ b/phpBB/includes/page_header.php
@@ -468,11 +468,11 @@ else
 }
 
 header ("Cache-Control: no-store, no-cache, must-revalidate");
-header ("Cache-Control: pre-check=0, post-check=0, max-age=0");
+header ("Cache-Control: pre-check=0, post-check=0, max-age=0", false);
 header ("Pragma: no-cache");
 header ("Expires: " . gmdate("D, d M Y H:i:s", time()) . " GMT");
 header ("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
 
 $template->pparse("overall_header");
 
-?>
\ No newline at end of file
+?>