diff --git a/phpBB/install/install_install.php b/phpBB/install/install_install.php
index 61491d7b2b..1881c9042f 100644
--- a/phpBB/install/install_install.php
+++ b/phpBB/install/install_install.php
@@ -1140,7 +1140,7 @@ class install_install extends module
 
 		// HTTP_HOST is having the correct browser url in most cases...
 		$server_name = (!empty($_SERVER['HTTP_HOST'])) ? strtolower($_SERVER['HTTP_HOST']) : ((!empty($_SERVER['SERVER_NAME'])) ? $_SERVER['SERVER_NAME'] : getenv('SERVER_NAME'));
-		$referer = (!empty($_SERVER['HTTP_REFERRER'])) ? strtolower($_SERVER['HTTP_REFERRER']) : getenv('HTTP_REFERRER');
+		$referer = (!empty($_SERVER['HTTP_REFERER'])) ? strtolower($_SERVER['HTTP_REFERER']) : getenv('HTTP_REFERER');
 
 		// HTTP HOST can carry a port number...
 		if (strpos($server_name, ':') !== false)