mb_ord() && mb_chr() for php < 7.2

func.php

<?php
if (!function_exists('mb_ord')) {
    function mb_ord($string)
    {
        if (extension_loaded('mbstring') === true) {
            mb_language('Neutral');
            mb_internal_encoding('UTF-8');
            mb_detect_order(array('UTF-8', 'ISO-8859-15', 'ISO-8859-1', 'ASCII'));

            $result = unpack('N', mb_convert_encoding($string, 'UCS-4BE', 'UTF-8'));

            if (is_array($result) === true) {
                return $result[1];
            }
        }

        return ord($string);
    }
}

if (!function_exists('mb_chr')) {
    function mb_html_entity_decode($string)
    {
        if (extension_loaded('mbstring') === true) {
            mb_language('Neutral');
            mb_internal_encoding('UTF-8');
            mb_detect_order(array('UTF-8', 'ISO-8859-15', 'ISO-8859-1', 'ASCII'));

            return mb_convert_encoding($string, 'UTF-8', 'HTML-ENTITIES');
        }

        return html_entity_decode($string, ENT_COMPAT, 'UTF-8');
    }

    function mb_chr($string)
    {
        return mb_html_entity_decode('&#' . intval($string) . ';');
    }
}