I was in preview prog and got activated couple of days bef Jul 29. Later I downloaded Official Iso and did clean install. (just skipped prod key prompts) and still showing Activated. (diff key than original Win 8.1 showing) Now i received "Reserved Win 10 - whats next" email. saying Your notification to upgrade could come as soon as a few days or in a few weeks. In the meantime, you can always check your upgrade status in the Get Windows 10 app. . . Huh? What do I do?
Nope. Those are probably just automated emails being sent out, marketing and nothing else. Worry not.
People are receiving these messages even after installing Windows 10. So, I don't think you should worry.