Hello, the server cannot increase it if the phone puts a value lower than you want. You can send a response telling the client that the interval is too short, specifying also the minimum value. I don't recall exactly the header names right now, but should be easy to search in rfc3261. Of course, if you just want to increase it in Kamailio side, that is possible, but the phone might not expect it. You can change the Expires header (or parameter for contact), then do msg_apply_changes() and then handle the register/presence requests as usual. Cheers, Daniel On 05/02/16 12:37, kssyrr wrote: -- Daniel-Constantin Mierla http://twitter.com/#!/miconda - http://www.linkedin.com/in/miconda Book: SIP Routing With Kamailio - http://www.asipto.com http://miconda.eu