Codeigniter 3.1.7 valid_email issue

Go to system/library/email.php and replace valid_email()

    public function valid_email($email)
    {
    if (function_exists('idn_to_ascii') && defined('INTL_IDNA_VARIANT_UTS46') && $atpos = strpos($email, '@'))
    {
        $email = self::substr($email, 0, ++$atpos).idn_to_ascii(self::substr($email, $atpos), 0, INTL_IDNA_VARIANT_UTS46);
    }
    return (bool) filter_var($email, FILTER_VALIDATE_EMAIL);
   }

I found discussion of this problem here.

Issue is outdated ICU library (ICU version 4.2.1 was installed)