json_encode(): Invalid UTF-8 sequence in argument
echo json_encode(pack("H*" ,'c32e'));
Seems like the symbol was
Å, but since data consists of surnames that shouldn't be public, only first letter was shown and it was done by just
$lastname, which is wrong for multibyte strings and caused the whole hassle. Changed it to
mb_substr($lastname, 0, 1) - works like a charm.