The latest Zone is saying "COMING SOON". What does this mean?

At this stage, you will have completed all of the available Zones that there are to play at this time.

No further progress can be made until we release a new Zone via an update.

In the meantime, you are able to go back and play every previous Zone by tapping the white arrows to the sides of the Zone name in the top-right corner. You can also play other modes like PvP and Events.