Ron wrote on 09/05/2015 1:34 AM:
If I upgrade from Win8.1 to Win10 and use it for 28 days and then
rollback to 8.1 can I upgrade to Win10 before the 1 year free upgrade
period is up?

Yes.

It would be in your best interest to create a system image (using
Acronis, Macrium, Windows etc.) prior to upgrading to 10 and use that
image to revert to Win8.

Doing the above will allow you to revert back to 8.1 anytime (before or
after July 2016) and if reverted before July 29th, 2016 one can still
upgrade to 10 before July 29, 2016.

The 31 day limit only applies to how long the Win10 GoBack feature is
available for use.


--
...winston
msft mvp windows experience