One of the more puzzling decisions made recently in Pokemon GO was the removal of the game's handy battery saving mode for iOS users. Turns out there was a very good reason for that: It was busted. Niantic have said today, "We had removed this feature as several users were experiencing it to be buggy, but we are fairly confident that a fix for this should roll out within the next several days."
There's also this:
We have been working long hours to fix many other bugs and bring some exciting new features to Pokemon GO in the future. However, next up for us is the continued roll-out of Pokemon GO to more countries around the world.
Like Latin America, which saw the game released there today. Including Brazil, just in time (or just a little too late for some) for the Olympics.