Hi folks, when doing outgoing calls via the FritxBox and having session timers active, we observe that the call is ended by pjsip. We have a 300 s expiry time in the invite and the FritxBox answers the call with a 600 s interval and the uas as refresher. Pjsip stays with the 300s and drops the call before the FritxBox can update. I Pjsip, this is built in by purpose, in sip_timer.c is a comment: /* Update SE. Session-Expires in response cannot be lower than Min-SE. * Session-Expires in response can only be equal or lower than in * request. */ In rfc4028, I can only find that a proxy must not extend the expiry time, is this valid for a PBX as well? So who is wrong? The FritxBox or Pjsip? Mit freundlichen Grüßen / Best regards Dr.-Ing. Andreas Ahland SELECTRIC Nachrichten-Systeme GmbH CTO / Technischer Leiter Haferlandweg 18 48155 Münster tel ) +49 251 6183-196 fax ) +49 251 6183-197 [Anmeldung Newsletter]<https://www.selectric.de/shop/customer/account/create/> Sitz der Gesellschaft (Company Premises): Muenster | Registergericht (Register Court): Amtsgericht Muenster | HRB-Nr. 1264 Geschaeftsfuehrer (General Managers): Michael Heussner, Hendrik Pieper