This App is designed for the Windows Phone 8.1 Developer Preview. It makes use of the Nokia Sensor Core SDK (Beta) and the underlying Sensor Core Platform. The Sensor Core Platform is currently only supported on the following Phones: Lumia 630, Lumia 635, Lumia 930, Lumia 1520 (With Cyan Update) and the Icon (with Cyan Update) If you have one of these Devices you can Track your Steps. Using the Settings Page you can define an amount of steps that you would like to walk per day. Using the Gauge on the Main Page you can easily see how you are doing.