Originally Posted by bob
I'd back up my data and reinstall. Anything else would leave you bald, I'm afraid.
This would be exactly my advice as well.
I would not risk upgrading when the number difference between releases is greater than 2, and if the difference is 2 -- I would advise to be prepared for anything. Done properly, in any case that would be probably a long and tiresome process.
I think only the upgrade to the next release is tested at all, and I can confirm that it is handled nowadays quite nicely. On both of my Fedora 13 installations (32 bit and 64 bit), on two different computers, the upgrade to 14 went smoothly (via recommended, so called, 'preupgrade' path).