public static function strtoupper($text) {
    if (static::getStatus() == static::STATUS_MULTIBYTE) {
      return mb_strtoupper($text);
    }
    else {
      // Use C-locale for ASCII-only uppercase.
      $text = strtoupper($text);
      // Case flip Latin-1 accented letters.
      $text = preg_replace_callback('/\xC3[\xA0-\xB6\xB8-\xBE]/', '\Drupal\Component\Utility\Unicode::caseFlip', $text);
      return $text;
    }
  }