Sinnoh/Johto/Alola/dungeons when?

                
No ETA. Don't believe it when someone tells you something is "tomorrow", they're memeing.
That said, Sinnoh is coming SOON™ (has been shown on a test server twice already, now the devs are working out the kinks), Johto and dungeons in the distant future after that, gen 6+ regions are not likely to appear.