If you've wanted to use activity-tracking wearables that pair with your phone, you've typically had to use Android or iOS. Windows Phone has some third-party apps that can fill in, but they're imperfect at best. As of today, though, an official solution is at hand -- Fitbit has released its own Windows Phone 8.1 app. You can now sync trackers like the Flex, One and Zip to your Microsoft-powered device to get real-time step and sleep monitoring, complete with a step counter on your home screen if you set up the Live Tile. Other Fitbit fundamentals are also here, including food logging, leaderboards and messaging.