Microsoft is reportedly testing versions of Windows Phone 8.1 internally. A report by Windows Phone Central cites an app developer named Tom Myles who has spotted an unrevealed Windows Phone OS version 8.10.12166 on his server logs. The developer claims that his app Love Wallpaper HD has been installed on phones running various Windows Phones OS versions 8.10.12073.0, 8.10.12086.0, 8.10.12100.0 and 8.10.12102.0.
The highest version of Windows Phone that is available right now is 8.0.10328.78 and a higher version being spotted hints that Microsoft might be testing the all new Windows Phone 8.1 internally. Presently, it is not known what improvements can be expected from the next version of Windows Phone.
Microsoft is also expected to release the GDR3 update for Windows Phone 8 this year that will enable support for quad-core processors and full-HD displays on the Windows Phone platform. The Windows Phone GDR3 update is expected to bring an additional column of Live Tiles on the Start screen, rotation lock, minor UI tweaks and a new Driving Mode option. It is not clear if the company will be pushing out the GDR3 update prior to the update Windows Phone 8.1.
A recent report indicated that Microsoft is close to achieving its August target for releasing Windows 8.1 to manufacturing.