Windows 10
Windows 10 technical preview Microsoft

Microsoft is reportedly working on new builds of Windows Phone mobile operating system.

While Microsoft testing the next Windows Phone version itself is not a surprise, what is noteworthy is that according to a Twitter message posted by ex-Microsoft employee, Nawzil, the company is working on three Windows Phone development streams at present, reports WMPU.

The first is for Windows Phone 8.1 Update 1 with build version 8.10.14200. Lumia 930, Lumia 830, Lumia 730 and Lumia 735 are a few of the devices running Windows Phone 8.1 Update.

The second one is Windows Phone 8 Update 2 running build number 8.10.15xxx. The Update 2 or GDR2 is rumoured to pack new features such as a data toggle in the Action Centre, sortable settings, support for new processors and Cortana in Alpha for more regions. The update was expected to hit in October.

Already there is evidence of Cortana in other regions suggesting the release of Update 2 is imminent.

Finally, there is Windows 10 bearing build version 8.15.12434. The Windows Phone operating system is expected to bring API unification with Windows 10 Metro, deliver side-by-side apps for phablets, UI modifications to make it consistent with Windows 10 Metro, such as app groups, Windows Phone for tablets and the full Office Touch for Windows Phone.

Microsoft might show off the Windows 10 for Windows Phone in the first or second quarter of 2015.