Slack is getting a new look starting today. The service is rolling out a redesign aimed at helping folks stay focused and get things done by streamlining the interface.
Perhaps the most obvious change is to the sidebar. On the far left, you'll no longer see a tile for each of your workspaces if you're logged in to more than one. Those have been collapsed into a single tile, and Slack is using the freed-up space for new navigation options.