Upgrading from pre-release to final
Fedora 21 Earlybird FAQ
Q: Can I update the Fedora 21 Alpha/Beta/Snap#/Preview release to the final Fedora 21 release?
A: Yes. A few days before F21 is finally released, at 10am EST, there will be an updated "fedora-release" package which will change your release name from Rawhide to the final Fedora 21 (TBA), and more importantly, change your package repositories from rawhide to stable.
Q: I found a Fedora 21 ISO leak before release day! Is it legit or is it exploited?
A: The only way to know for sure is to verify the leaked SHA1SUM's GPG signature (if available) with the official Fedora GPG key. If you can't, or won't do this, it's safer to just be patient and wait for release day. Also note that even if the early leak does check out, it might not be the FINAL release, as fedora has in the past re-pushed out last-minute final-final releases.
Q: I avoided Fedora 9 because there was no proprietary ATI display driver available. Is this fixed?
A: No. Please contact ATI. There's nothing Fedora can do about a closed-source driver.