Nike has released a minor update to its GPS-based run tracking app adding improvements to its social media integration and a new auto-calibration feature. Nike+ GPS 3.1.1 now allows users to include their pace in their Facebook and Twitter posts and provides the option to edit Twitter messages before posting. The app now also makes use of Push Notifications for keeping track of ongoing Nike+ Tag games and allows users to link the music play/pause button to start and pause runs. The update also adds an auto-calibration feature to assist users with calibrating their runs to actual distance and improve accuracy. Users can also now register or login using Facebook or Twitter accounts in addition to their Nike+ account. Nike+ GPS is available from the App Store for $2.