Yep.... there is a ton of posts around the web with respect to that particular question. Some of it, speculation and conjecture but things do look promising.
Just for the sake of clarity.... "Windows 8" in not included as a route to an upgrade. Microsoft has pretty much divorced itself from that OS.
My concern is with the Windows 10 Insider Preview (Clean Install From ISO, no previous Operating System ever present on hard disk).
If in that situation, we get a free upgrade on July 29th to the GA release of Windows 10 Pro, are we at that point committing to remaining an "Windows Insider" and if so......
Is that "forever"?