Upgrading from Fedora 9 directly to Fedora 11 using yum is not possible, you must upgrade to Fedora 10 first, then upgrade to Fedora 11. See http://fedoraproject.org/wiki/YumUpgradeFaq for more information. You can also use preupgrade to upgrade directly to Fedora 11 using anaconda, minimizing the system downtime by downloading the packages in advance.

Some modified configuration files will be replaced by their original versions during the upgrade. Your modified versions of these configuration files will be saved as *.rpmsave files in that case.