$cityval = preg_replace('/(\s)+/', ' ', $cityval);
$serial_extra = preg_replace('/(\s)+/', ' ', $serial_extra);
$serial_extra = preg_replace('!s:(\d+):"(.*?)";!e', "'s:'.strlen('$2').':\"$2\";'", $serial_extra);
I was using PHP 5.6 version, once I upgrade it to 7.1 version it shows an error "code deprecated". Please suggest me any better replacement of this code