Hello,
The standard Business Central Item No. field is Code[20], so the maximum is 20 characters, not 19. Your integration partner may have imposed a 19-character restriction on their side, but that is not the native BC limit. The standard field length itself cannot simply be increased through an extension because it is a base application field; if you need identifiers longer than 20 characters, a common option is to use Item References, where Reference No. supports up to 50 characters.
Regards,
Oussama Sabbouh
