This tip is if you work with
Core Location and wants to continue receiving location updates while the app is suspended.
You need to add the
UIBackgroundModes key with value
location to the app's
Info.plist. In addition, — this is easy to miss because it was only added in iOS 9 — you want to set
allowsBackgroundLocationUpdates property to
true. In addition to getting updates while the app is suspended, if the app is killed and the device crosses the
CLRegion you are monitoring, the app will be automatically launched. So this property is also useful for toggling that behavior.