The update brings about a bunch of bug fixes, such as fixes to bugs like Scatterbug.
Rock types become more common for a week starting on the 18th of May! Poké Balls are also cheaper, and Buddy Pokémon will give Candy out more frequently for this event.
A shocking bit of information to do with Marshadow has been promised for the next issue of CoroCoro.
It runs in the UK, Spain, Italy and France! For most of those, it starts via store distribution May 5th.