This feature is still in the backlog.
-WarrenSergio Hernandez commented
We want this change implemented too and would be happily use a different default tab than "Conversations", it is not very user-friendly having that one for all Teams and all Channels.
27 votesSergio Hernandez commented
It is not working for us either in the desktop nor the browser versions and it is a very used feature.
Due to a priority shift this request has slipped to the backlog. I hate to bring bad news. I will continue to provide the feature team your feedback and votes.
Hopefully this will move back up in the queue soon.
Sorry for the delay on an update on this one! I’m hunting down the status for you and will update once I have it.
Also, if you are interested in participating in testing or surveys for this, just tweet me at @skprufo.
This is in the works! Fill out this survey if you want to influence the feature: https://microsoft.qualtrics.com/jfe/form/SV_esTxHdABLQxKLvn