Microsoft's new universal apps will be able to function across all Windows devices--including the Xbox One.
The company announced the new app framework during its Build 2014 conference in San Francisco, showing off the latest updates to Windows Phone and Windows 8.1.
Microsoft says it will provide tools for developers to tweak the UI and features to whatever platform the application is running on. This includes developers being able to incorporate Kinect support when porting to Xbox One, for instance
Despite the new universal applications being able to run on all platforms, Microsoft adds that developers will be able to charge users to access the apps on each platform--you could theoretically have to pay twice if you want it to run on Xbox One and PC, then. But it is also possible for developers to sell an application once and allow it to run on every Windows platform.
Microsoft adds that apps which use the cloud to sync information should also be able to carry that across platforms.
Elsewhere in Microsoft's Build 2014 conference, the company announced that Cortana really is its digital assistant for Windows Phone 8.1, and that the Start Menu is coming back to Windows.