public static function isBuggyIe()
    {
        if (empty($_SERVER['HTTP_USER_AGENT'])) {
            return false;
        }
        $ua = $_SERVER['HTTP_USER_AGENT'];
        // quick escape for non-IEs
        if (0 !== strpos($ua, 'Mozilla/4.0 (compatible; MSIE ')
            || false !== strpos($ua, 'Opera')) {
            return false;
        }
        // no regex = faaast
        $version = (float)substr($ua, 30);

        return self::$encodeToIe6
            ? ($version < 6 || ($version == 6 && false === strpos($ua, 'SV1')))
            : ($version < 7);
    }