Thanks for the quick reply, Alex. I will try to provide more context information. The route in question is related to presence. Our usage of t_newtran() is very similar to the following presence examples: https://github.com/kamailio/kamailio/blob/master/test/unit/presence.cfg https://lists.kamailio.org/pipermail/sr-users/2016-April/092544.html https://www.kamailio.org/dokuwiki/doku.php/presence:configuration-file (see route[2]) I believe our config was probably based off one of those. In that context, with reliable transport, is 't_newtran()' useful? Thanks.