Windows Phone
It was first launched in October 2010 with Windows Phone 7. Windows Phone 8 succeeded it in 2012, replacing the Windows CE-based kernel of Windows Phone 7 with the Windows NT kernel used by the PC versions of Windows (and, in particular, a large amount of internal components from Windows 8). Due to these changes, the OS was incompatible with all existing Windows Phone 7 devices, although it still supported apps originally developed for Windows Phone 7. In 2014, Microsoft released the Windows Phone 8.1 update, which introduced the Cortana virtual assistant, and Windows Runtime platform support to create cross-platform apps between Windows PCs and Windows Phone.
Windows Phone-2