Since it has not yet been released to the public you won't get any answers about how it goes except for the beta testers. General release was scheduled for next week (7/29) but has been postponed for a few days, anyway, and would already be downloaded to your computer before they would advise you that you can upgrade now. Apparently that process may spread out over days or weeks, but once you have signed up for it, the actual installation is something you control, and it can be done for up to a year after they tell you you can do it. Not all computers can be upgraded, but by selecting yes to their invitation they will check your system for compatibility and if it passes, give you a reservation. Operating systems other than Win7, and Win8.1 are not eligible, and they must be up-to-date at that.
