source/Core/Email.php
private function idnToAscii($idn)
    {
        if (function_exists('idn_to_ascii')) {
            // for old PHP versions support
            // remove it after the PHP 7.1 support is dropped
            if (defined('INTL_IDNA_VARIANT_UTS46')) {
                return idn_to_ascii($idn, 0, INTL_IDNA_VARIANT_UTS46);
            }

            return idn_to_ascii($idn);
        }

        return $idn;
    }
private function idnToAscii($idn)
    {
        if (function_exists('idn_to_ascii')) {
            // for old PHP versions support
            // remove it after the PHP 7.1 support is dropped
            if (defined('INTL_IDNA_VARIANT_UTS46')) {
                return idn_to_ascii($idn, 0, INTL_IDNA_VARIANT_UTS46);
            }

            return idn_to_ascii($idn);
        }

        return $idn;
    }
private function idnToAscii ( $ idn ) { if ( function_exists ( 'idn_to_ascii' ) ) { // for old PHP versions support // remove it after the PHP 7.1 support is dropped if ( defined ( 'INTL_IDNA_VARIANT_UTS46' ) ) { return idn_to_ascii ( $ idn , 0 , INTL_IDNA_VARIANT_UTS46 ) ; } return idn_to_ascii ( $ idn ) ; } return $ idn ; }
Convert domain name to IDNA ASCII form.

@param string $idn The email address

@return string
Convert domain name to IDNA ASCII form .