Maybe a bit offtopic, but I can't find a rtpengine mailinglist and know the Sipwise guys are reading this list.
Since upgrading to 4.2.x and rtpengine instead of rtpproxy I'm seeing problems with calls being terminated by upstream provider after a bit more than 5m. The INVITE process looks okay, the only difference with before as far as I can see is the rtcp attribute in the SDP body.
According to http://kamailio.org/docs/modules/4.2.x/modules/rtpengine.html#rtpengine.f.rt... and https://github.com/sipwise/rtpengine rtcp offering can be disabled. But neither rtcp-mux-demux nor rtcp-mux-accept have any impact on the adding of the a=rtcp:port attribute in SDP.
rtpengine_manage("trust-address replace-origin replace-session-connection rtcp-mux-accept ICE=remove"); or rtpengine_manage("trust-address replace-origin replace-session-connection rtcp-mux-demux ICE=remove");
have no effect op the INVITE to the upstream.
kamailio: 4.2.5 rtpengine: 4.1.0.0+0~mr4.1.0.0