Mailing the story:

Nobody ever thinks to mention .rpmnew and .rpmsave extensions to new users of Fedora or Red Hat derivatives. Instead, most users suddenly discover that these files are accumulating on their hard drives, or notice a fleeting message on the screen about them during a version upgrade. Many, I suspect, simply leave them alone, uncertain what to do about them. Yet dealing with them is simply a matter of using a few basic commands, and can be a necessity for ensuring trouble-free upgrades in the future.