Hi, When I use pjsip_inv_answer() to create 200 response, I create my own sdp and set origin version to 3429443492. pj_gettimeofday(&tv); call->o_session_version = tv.sec + 2208988800UL; sdp->origin.version = call->o_session_version; but it changed to 3429443493 when remote party got 200 OK response. I try to trace pjsip source code, But I couldn't find where changes has happen. regards, Gang -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.pjsip.org/pipermail/pjsip_lists.pjsip.org/attachments/20080903/7fbaee29/attachment.html