Windows Phone
Windows Phone 8 replaces the Windows CE-based architecture used in Windows Phone 7 with the Windows NT kernel found in Windows 8. Windows Phone 7 devices cannot run or update to Windows Phone 8, and new applications compiled specifically for Windows Phone 8 are not made available for Windows Phone 7 devices. Developers can make their apps available on both Windows Phone 7 and Windows Phone 8 devices by targeting both platforms via the proper SDKs in Visual Studio.