Greetings, This question reminded of of a blog entry. http://blog.l2c2.co.in/index.php/2016/09/12/down-the-rabbit-hole-making-cardnumber-field-in-koha-longer-than-16-characters-limit/ It also reminded me of a bugzilla entry. https://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=15690 I think perhaps another patch might be in order as well. GPML, Mark Tompsett