Windows RT powered slates to get some features from Windows 10
While the exact features that will be taken from Windows 10 are unknown, an update to Windows RT means that the Microsoft Surface RT and Microsoft Surface 2 will receive these new capabilities. Meanwhile, all of the Surface Pro tablets will receive the Windows 10 update.
The Microsoft Surface Pro 4 will most likely have Windows 10 pre-installed. With the new software expected to launch around late September, not only should we see the Surface Pro 4 hit the market at about the same time, we should also find out which Windows 10 features will be made available to Windows RT.
source: WinSupersite via TechRadar, GSMArena