MicrosoftJohn Joseph In my experience though, MS support doesn't want to scroll up the thread and just says that 3PIP support has "some functionality limitations" which apparently includes Call Queues with Direct Routing. I guess it would be much easier if Call Queues were explicitly listed in the top post.
Another thing I want to mention is that there is a peculiarity with SfB phone certification. We've got Yealink T48G/S phones, which are Skype for business certified phones. Or, as it turns out, they WERE when we bought them.
Check this out:
https://docs.microsoft.com/en-us/skypeforbusiness/certification/devices-ip-phones - no Yealink T4x phones, only newer T5x that are Teams compatible.
http://web.archive.org/web/20190329220750/https://docs.microsoft.com/en-us/skypeforbusiness/certification/devices-ip-phones - there they are, along with some older Audiocodes devices & others. This is the same article in March 2019.
As one would expect,, MS support links the current article and says "your phones are not supported".
All of this, IMO, completely contradicts that whole idea that "you can just upgrade to Teams and continue using your 3PIP phones you've made an investment in never knowing that SfB is being retired so suddenly".
