Make a list of the systems current packages for later reference:

rpm -qa --qf '%{NAME}\n' | sort | uniq > ~/new-pkgnames.txt

Make a backup of any system configuration data (as root):

tar czf ~/etc-`date +%F`.tar.gz /etc


yum clean all

Make sure the new repo files isn’t placed as .rpmnew files, perhaps by

mv /etc/yum.repos.d/fedora-updates.repo.rpmnew /etc/yum.repos.d/fedora-updates.repo
mv /etc/yum.repos.d/fedora.repo.rpmnew /etc/yum.repos.d/fedora.repo

Also make sure that all the 3rd party repos you normally use point to the repository for the new Fedora release.

Next the upgrade.
Make sure you are in runlevel 3

telinit 3

Run the following command to update the yum repo on your box:

rpm -Uhv rpm -Uvh rpm -Uvh http://mirror.anl.gov/pub/fedora/linux/releases/8/Everything/i386/os/Packages/fedora-release-8-3.noarch.rpm http://mirror.anl.gov/pub/fedora/linux/releases/8/Everything/i386/os/Packages/fedora-release-notes-8.0.0-3.noarch.rpm

yum might complain about conflicts or requirements. That is probably because you have used non-standard repositories or installed non-standard packages manually. Try to guess which packages cause the problem (or at least is a part of the dependency chain) – uninstall them and try again. Remember to install the packages again if they are essential.

Tip: Find and review “lost” packages.
You can find orphaned packages (ie packages not in the repositories anymore) after the upgrade with the tool package-cleanup from the yum-utils package

yum install yum-utils; package-cleanup --orphansIt's often helpful to run this command before the update, too. For packages with a failing "%postun" script the old package will remain partly installed. Remove it with rpm -e package-name-and-version

yum clean all
yum upgrade

yum groupupdate Base

yum grouplist

package-cleanup --orphans