diff --git a/phpBB/install/database_update.php b/phpBB/install/database_update.php
index b20ca1e4ea..3341c20058 100644
--- a/phpBB/install/database_update.php
+++ b/phpBB/install/database_update.php
@@ -41,6 +41,26 @@ if (!function_exists('phpbb_require_updated'))
 	}
 }
 
+if (!function_exists('phpbb_include_updated'))
+{
+	function phpbb_include_updated($path, $optional = false)
+	{
+		global $phpbb_root_path;
+
+		$new_path = $phpbb_root_path . 'install/update/new/' . $path;
+		$old_path = $phpbb_root_path . $path;
+
+		if (file_exists($new_path))
+		{
+			include($new_path);
+		}
+		else if (!$optional || file_exists($old_path))
+		{
+			include($old_path);
+		}
+	}
+}
+
 function phpbb_end_update($cache, $config)
 {
 	$cache->purge();
@@ -82,19 +102,21 @@ $phpbb_adm_relative_path = (isset($phpbb_adm_relative_path)) ? $phpbb_adm_relati
 $phpbb_admin_path = (defined('PHPBB_ADMIN_PATH')) ? PHPBB_ADMIN_PATH : $phpbb_root_path . $phpbb_adm_relative_path;
 
 // Include files
-require($phpbb_root_path . 'includes/class_loader.' . $phpEx);
+phpbb_require_updated('includes/class_loader.' . $phpEx);
 
-require($phpbb_root_path . 'includes/functions.' . $phpEx);
-require($phpbb_root_path . 'includes/functions_content.' . $phpEx);
-require($phpbb_root_path . 'includes/functions_container.' . $phpEx);
+phpbb_require_updated('includes/functions.' . $phpEx);
+phpbb_require_updated('includes/functions_content.' . $phpEx);
+phpbb_require_updated('includes/functions_container.' . $phpEx);
 
-require($phpbb_root_path . 'includes/constants.' . $phpEx);
-require($phpbb_root_path . 'includes/utf/utf_tools.' . $phpEx);
+phpbb_require_updated('includes/constants.' . $phpEx);
+phpbb_require_updated('includes/utf/utf_tools.' . $phpEx);
 
 // Set PHP error handler to ours
 set_error_handler(defined('PHPBB_MSG_HANDLER') ? PHPBB_MSG_HANDLER : 'msg_handler');
 
 // Setup class loader first
+$phpbb_class_loader_new = new phpbb_class_loader('phpbb_', "{$phpbb_root_path}install/update/new/includes/", $phpEx);
+$phpbb_class_loader_new->register();
 $phpbb_class_loader = new phpbb_class_loader('phpbb_', "{$phpbb_root_path}includes/", $phpEx);
 $phpbb_class_loader->register();