Microsoft displayed a chart at today's WinHEC conference in China showing all of the update paths for Windows 10, which confirms that Windows RT devices like the Surface RT and Surface 2 are being denied a way to get the company's next operating system.
In January, a statement from Microsoft indicated that the Surface RT and Surface 2 tablets would receive some sort of update in the future "which will have some of the functionality of Windows 10." However, this new chart from Microsoft shows flat out that Windows RT won't get the full Windows 10 treatment, either via an automatic update or via a manual download of ISO files.
The chart does show that all versions of Windows 7 and Windows 8/8.1 can be updated to Windows 10 via ISO files, and Windows 7 SP1 and Windows 8.1 S14 will have the additional option of getting the download via Windows Update. Smartphones that are still running Windows Phone 8 will have to update to Windows Phone 8.1 in order to download Windows 10 for phones.
Update: Many people are gawking at the 'Windows Mobile 10' mention. This is not a name change. There are different SKUs for Windows 10 so at some place in the backend they do need to be differentiated for hardware manufacturers and partners. However, for consumers, it is just Windows 10. Nothing has changed, there is nothing to see.
Source: Channel 9