differences for character class \w in php 8.3 and php 8.4 due to https://php.watch/versions/8.4/pcre2-regexp-syntax-changes

phpregextest.php

<?php

$s = "ΟδόςÏ Í J J̈";
foreach (preg_split("//u",$s,-1,PREG_SPLIT_NO_EMPTY) as $c) {
    printf(
        "%s U+%04X => %s (\w=%s)\n",
        $c,
        \IntlChar::ord($c),
        preg_match("/^[\w\s\-,.\x{00C0}-\x{017F}]$/u",$c) ? "MATCH" : "NO",
        preg_match("/^\w$/u",$c) ? "Y" : "N"
    );
}