Windows 10 will run on both smartphones and tablets

Windows 10 product key for the smartphone is being tested internally, is expected to have a preview in January or February 2015.
No wonder Microsoft is working on some updates for Windows Phone. While waiting for Microsoft office 2013 product key to release these updates, the Twitter account @Nawzil has publicized a series of related information. Nawzil is an old Microsoft office 2016 product key employee and has made many accurate predictions related to Microsoft products. So, this is a very reliable source.
According to @Nawzil, Microsoft is currently working on 3 updates. The first is the Windows Phone 8.1 GDR 1 update (build code 8.10.14200). This update has been released for participants in the Developer Preview. And it will soon be widely available to other Windows Phone users.

@Nawzil's share on Twitter.

The second update is GDR 2 / Update 2 (build code 8.10.15XXX) for Windows Phone 8.1. This update will be released soon for all users who are members of the Microsoft App Developer Program. This update is expected to bring many more convenient settings on the Action Center, compatible with the new processor and updated Cortana virtual assistant. Previously, GDR 2 / Update 2 was expected to appear in October 2014, but so far no official information.
Best of all, according to @Nawzil, Windows 10 for smartphones are being tested internally. Windows 10 (build code 8.15.12434) for smartphones is expected to be launched by Microsoft in January or February 2015. However, it will not be released for all devices soon. Immediately, but just a Developer Preview.
This is not to be taken lightly, because in the launch of Windows 10 for the PC, Microsoft has announced that it is building a single integrated Windows platform. In addition, Microsoft claims that applications written by developers will be compatible with multiple devices.
This means that computers, tablets, and smartphones will run the same Windows platform with the same code, which is probably Windows 10 product key.