Microsoft Works to Get Windows 8/RT Users Updated to 8.1
By Paul Thurrott

Why is this needed? You may recall that with Windows 8.1, inexplicably, Microsoft made the update available through the Windows Store. While this update worked fine for many users, some had problems getting the update to install, and if it failed, there's no sure-fire way to get it fixed.

So this update—or this "experiment"—is aimed at fixing the issue and setting up your PC or device so that you can upgrade to Windows 8.1 successfully.