Further to the changes made in https://github.com/kamailio/kamailio/issues/1720 I am opening a new ticket regarding https://github.com/kamailio/kamailio/issues/1720#issuecomment-638158699 It is my understanding that 1xx replies do not require a Contact header, but commit https://github.com/kamailio/kamailio/commit/3b586d554740ae578283024c1508e91… specifically excludes 183 replies from passing without a Contact header. This is causing us some issues and I am wondering why 183 is set to require the Contact header. Thanks -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://github.com/kamailio/kamailio/issues/2344