Hello all - I am on the "New Teams' version 23217.806.2340.1703.
Prior to this update we were able to @ the members of a private channel to give a notification to all users in that channel. In the latest update for teams (the 2.0 webview) we have somehow lost that functionality.
If you revert back to the old version of teams, it will work and you're able to tag the channel name. With that being said I don't believe that it is a permissions issue , but rather an issue specifically with the new update.
