Currently calls are not enabled for non-admin users. You can change the setting through the system console

[Akito]

Could you please go to the base view (where all the channels are) and take a screenshot of your instance’s About pop-up?

Updating MM docker container

If you are in the default Mattermost view, seeing Teams, Channels, etc., then you click in the top left corner, where it says “Channels”, then you pick “About ”. There it tells you the exact Mattermost version. I guess, upgrading should work the same, as if it weren’t Docker, but you should create a full backup before any upgrade, anyway!