Upcoming Pokemon Shuffle content preview

The Japanese Pokemon Fan magazine has revealed some of the content and updates coming to Pokemon Shuffle in the future (thanks to Serebii for the translation). This should also apply to Western versions of the game.

50 new main stages will be added on July 26th – Mega Tyranitar will be the 50th and final of these stages. Starting on the 26th as well, checking in will net you several items, including Skill Swappers and Raise Max Levels. Hoopa and Hoopa Unbound special stages will also appear on the 26th.

Several reruns of past special stages are also planned: Zygarde 10% will run from July 26th till August 9th;  Ash-Greninja will run from August 2nd till August 16th and Mew will be available again on August 9th.

Source