A couple of weeks ago I tested my new app airTracker on my iPhones the first one running on iOS5.1 and the second one running on iOS6.1. During the development process the app was named EnvironmentMonitor and was finally changed to airTracker. On iOS5 iPhone everything worked as expected, however on the iOS6 iPhone I did not get any location updates.
My first assumption was that Apple has deprecated some delegate methods. After a quick look into Apple's CLLocationManager documentation my assumption was confirmed, the delegate method locationManager:didUpdateToLocation:fromLocation: was deprecated and locationManager:didUpdateToLocations delegate method should be used instead.
I had been glad already too early. After implementing the new delegate methods my app still did not receive any location updates. The first conspicuous thing came in my mind was the missing notification that asks if the app is allowed to use the location service. This notification is shown if the app is started the first time. So I checked the iOS privacy settings, however I could not find my app's name there. So I wasted some time with deleting and reinstalling the app, I have also tested the the airTracker app on the iPad also running on iOS6 with the same result - no location updates.
So I tried the last thing that came in my mind, I changed the name from EnvironmentApp to TestApp, installed it on the iOS6 iPhone and surprisingly it worked. I do not know why however renaming solved the problem.