Click the menu icon in the top left of the upgrade reservation thing, then pick Check your PC. On my VERY new Sony VAIO Flip 15, which came with Windows 8, I get the message "These devices aren't fully compatible with Windows 10" -> Intel(R) HD Graphics Family -> You'll experience problems with your display.
So what does this mean? If I let the upgrade happen on July 29, my screen goes black after that? How can such a new video "card" be unsupported? (It's the built-in display on the Core i7-4500U this thing has). Is it because I also have the Nvidia GeForce GT 735M on here, with that GPU-switching technology (Optimus?) that so many new laptops have now?