Seeking comments/suggestions from the community on a particular Freeswitch (FS)  behavior observed. 

We see that  if there is a SIP reINVITE message (in-dialogue) from far end switch coming to FS, it responds back with the last negotiated codec  in the  SDP  offer as opposed to forming a brand new SDP offer with all the supported codecs listed. 

Now according to my understanding, It is recommended (not mandated) that the SIP entity should respond to  a SIP reINVITE w/o SDP with all the Codecs it can support and not just respoind with narrowed down list of codecs (as negotiated in previous SDP offer/answer exchange).

This allows the far side a way to re-negotiate the codec from scratch mid dialogue if there is a need (for example call getting transferred to new SIP UA)

Any configuration option that can influence this behavior?

Regards

Arslan