didUpdateToLocation was deprecated in iOS 6.0

locationManager:didUpdateToLocation:fromLocation: was deprecated in iOS 6.0. It is recommended that locationManager:didUpdateLocations: be used instead.

https://developer.apple.com/library/ios/documentation/CoreLocation/Reference/CLLocationManagerDelegate_Protocol/DeprecationAppendix/AppendixADeprecatedAPI.html#//apple_ref/occ/intfm/CLLocationManagerDelegate/locationManager:didUpdateToLocation:fromLocation: