Any new devices released with Windows 10 on board will need to have a display at least eight inches in size to gain access to the desktop and desktop applications, Joe Belfiore confirmed through Twitter.
Even with Windows 10 unifying the experience across phones, tablets, laptops and desktops, there still has to be a cut-off point for desktop access. It makes no sense to have access to the desktop on a phone, for example, where the display is far too small for it to be usable. Now that the cut-off has been defined, it appears 7-inch tablets have also been deemed too small.
In some cases even eight inch displays are too small to properly use desktop apps, as we've noted previously in our reviews of 8-inch Windows 8 tablets. However, with Windows 10 you'll still be able to purchase devices of this size and run desktop Office, Photoshop and even AutoCAD if you really want to.
It should be noted that the desktop will only be unavailable on devices smaller than eight inches that come with Windows 10 pre-loaded. Existing seven inch tablets with the full, desktop Windows 8.1 experience - such as the $99 HP Stream 7 - will be upgraded to the full, desktop-capable version of Windows 10.
Folks asking about updating 7" *existing* devices to Win10 -- you keep your desktop, you get continuum. Go try it yourself now! :)— joebelfiore (@joebelfiore) January 27, 2015
Windows 10 will be officially released later this year, though if you're curious, you can already check out some of its features through the Windows 10 Preview program.