3v4l.org

run code in 300+ PHP versions simultaneously
<?php setlocale(LC_ALL, 'en_US.UTF-8'); $str = "u\u0308 a\u0302 a\u0308 o\u0300"; $str = preg_replace('/\\\\u([0-9a-f]+)/i', '&#x$1;', $str); $str = html_entity_decode($str, ENT_QUOTES, 'UTF-8'); var_dump( iconv("UTF-8", "ISO-8859-1//TRANSLIT", $str) );

preferences:
40.77 ms | 402 KiB | 5 Q