PHP 7.2
iconv('UTF-8', 'ASCII//TRANSLIT', 'é@ùµ$`à');
// "e@uu$`a"
iconv('UTF-8', 'ASCII//IGNORE', 'é@ùµ$`à');
// "@$`"
iconv('UTF-8', 'ASCII//TRANSLIT//IGNORE', 'é@ùµ$`à');
// "e@uu$`a"
PHP 7.4
iconv('UTF-8', 'ASCII//TRANSLIT', 'é@ùµ$`à');
// PHP Notice: iconv(): Detected an illegal character
iconv('UTF-8', 'ASCII//IGNORE', 'é@ùµ$`à');
// "@$`"
iconv('UTF-8', 'ASCII//TRANSLIT//IGNORE', 'é@ùµ$`à');
// "e@u$`a"
iconv('UTF-8', 'ASCII//TRANSLIT//IGNORE', Transliterator::create('Any-Latin; NFD; [:Nonspacing Mark:] Remove; NFC')->transliterate('é@ùµ$`à'))
// "e@uu$`a" -> same as PHP 7.2