idn_to_ascii(): INTL_IDNA_VARIANT_2003 is deprecated - php

Question

I am using codeigniter framework for my site, but in form_validation I am getting error I followed this link in stackoverflow but it didn't work for me
followed link:
idn_to_ascii() in 5.2.17
Issue:
code in codeigniter libraries/form_validation.php:
public function valid_email($str)
{
if (function_exists('idn_to_ascii') && preg_match('#\A([^#]+)#(.+)\z#', $str, $matches))
{
$domain = defined('INTL_IDNA_VARIANT_UTS46')
? idn_to_ascii($matches[2], 0, INTL_IDNA_VARIANT_UTS46)
: idn_to_ascii($matches[2]);
if ($domain !== FALSE)
{
$str = $matches[1].'#'.$domain;
}
}
return (bool) filter_var($str, FILTER_VALIDATE_EMAIL);
}

Answer 1

The ideal solution would be to upgrade ICU to its latest version
As this was not possible at my shared server, I resolved that problem, extending the CI email library:
overrules valid_email() function which uses INTL_IDNA_VARIANT_UTS46, which is unfortunately not installed on my server.
PhP 7.2 works with that version, so if you have INTL_IDNA_VARIANT_2003 installed, you get the above deprecated error message.
SOLUTION: you need to go back to valid_email() function from 2.0 version email library:
class MY_Email extends CI_Email {
public function valid_email($address)
{
return ( ! preg_match("/^([a-z0-9\+_\-]+)(\.[a-z0-9\+_\-]+)*#([a-z0-9\-]+\.)+[a-z]{2,6}$/ix", $address)) ? FALSE : TRUE;
}
}
Save this extended Class as MY_email.php in your application/libraries folder. About Extending Native Libraries, the prefix MY_ is configurable.