updated core to 8.6.1 via composer

core/includes/theme.maintenance.inc

@@ -5,7 +5,6 @@
  * Theming for maintenance pages.
  */
 
-use Drupal\Component\Utility\Unicode;
 use Drupal\Core\Site\Settings;
 
 /**
@@ -29,7 +28,6 @@ function _drupal_maintenance_theme() {
   require_once __DIR__ . '/file.inc';
   require_once __DIR__ . '/module.inc';
   require_once __DIR__ . '/database.inc';
-  Unicode::check();
 
   // Install and update pages are treated differently to prevent theming overrides.
   if (defined('MAINTENANCE_MODE') && (MAINTENANCE_MODE == 'install' || MAINTENANCE_MODE == 'update')) {