Well they have been taunting us with the release of new districts since they started taking other cities away from us! So it's about time, and with any record of how long it takes from teaser to release we are looking at a few weeks here, so don't get your hopes up to quickly!
Hopefully they are actually working on re-releasing the previously locked districts as well, or get them out of the menu so they stop taunting us with their grayed out appearance! But since they are still there that makes me believe they will do something, even if it does take them a while.
But onto the new districts, be prepared for them to be a hefty set of jobs. As fore-casted by the steep curve set forth by the already released chapters. By the time you get to the final sets in ruby mastery be prepared to spend upwards of 1,000 energy points per job. I don't feel that it would be to far of a stretch to see some really difficult jobs to master. But the payoffs should be equally rewarding.
So in preparation for the upcoming release I suggest you start racking up some 2x Mastery boosts and put some skill points towards energy and don't be caught off guard when it happens!