The recent changes to libjitsi, jitsi and jitsi-videobridge break the
compatibility of opus. An "old" version of Jitsi (build 4810 or older)
will not be able to establish a call *using opus* with a "new" version
of Jitsi. Calls will not fail, because another codec will be
automatically chosen (except in very rare configurations in which opus
is the only mutually supported codec)
Conferences mixed by Jitsi should also work in this way -- with another
codec automatically being chosen when necessary.
The changes were necessary in order to be compliant with the
specification of the rtp payload format for opus, which requires use
of 2 channels.
The situation with videobrdige conferences is a bit more complicated. If
you are running an old version of jitsi-videobridge, there are some
situations in which calls will have no audio or not all participants
will have audio.
Newer versions of videobridge are able to handle all configurations of
"old"/"new" clients, sometimes falling back to another codec.
Therefore it is advisable to upgrade videobridge deployments to build 41