Pokemon GO update adds improved AR features on iOS devices
The new AR+ technology takes advantage of Apple's ARKit framework. So, players using devices running iOS 11 like the iPhone 6s and newer models will be able to experience the new AR+ in Pokemon GO.
A new awareness meter will now show up next to the Pokemon, and when it's filled, the Pokemon will flee, so keep an eye on that meter. You get one more chance at catching that Pokemon that has just fled by tapping on the tall grass nearby, which might cause him to reappear, but that's not a given.
The Expert Handler bonus awards more XP and Stardust than usual. Overall, if you can catch a Pokemon while in close proximity using AR+, you'll have greater chances of earning better Throw bonuses.
source: Niantic
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