Description:
Windows Phone 8.1 is an iteration of the Windows Phone line of Microsoft mobile OS.
Website:
http://www.windowsphone.com/en-us/features-8-1

Detailed Description

Update

Windows Phone 8.1 brings a number of updates to Microsoft’s mobile platform, including an improved more customizable home screen, Wi-Fi tools to preserve cellular data, and, most importantly, Cortana, a audio virtual assistant.