Read original post at Rajen Kishna's Technical Tidbits
With Windows Phone 8.1, we now have a range of ways to trigger a background task of our app. Aside from the previously available periodic timer that could trigger a background task, we can now also use raw push notifications, system events, device use triggers and location. The location method is used to trigger a background task using geofence, which we’ll be walking through in this post.