I tried several invalid ISBNs, but all pass the validation in v3.0.3.
$isbn = new \Isbn\Isbn();
var_dump($isbn->validation->isbn('7640108702869'));
var_dump($isbn->validation->isbn('5055300330994'));
var_dump($isbn->validation->isbn('5017239196706'));
var_dump($isbn->validation->isbn('0090204645565'));
var_dump($isbn->validation->isbn('4013594529877'));
show 5x true.
I tried several invalid ISBNs, but all pass the validation in v3.0.3.
show 5x true.