Here are my note from upgrading Fedora 7 to Fedora 8 on a x86_64 system. The existing system is not very customized, but does pull some things from the Livna repo. It runs a nvidia video card and one of the video output is connected to a LCD TV to be used as a secondary monitor.
Following the recommendation of some of the posts online, I first did a yum update on fc7 to make sure I got the latest packages. In hindsight, I'm not sure if this was the best thing to do since it might have pulled a kernel version that is more current then the Fedora 8 version.
Right off the bat, I encountered the Upgrade Hang bug. The fix is listed in the link. When booting from the DVD, at the first menu when it asks you whether you want graphic or text installer, hit "TAB" and append the line to what is shown.
Once it finishes installing, it then reboots.
The video setting changed to using the open source nvidia driver which looks crappy on my monitor, but I figure I can always changes after I get the latest update from Livna.
Just like last time, I did a "yum upgrade" and just like last time it failed due to dependency issues from Livna packages. The upgrade is suppose to recognize third party repos, but never fully does. I had to remove them. vlc and xine to get past the dependency problem.
I noticed that there are a lot of fc7 packages still hanging around. The update didn't have that many new packages (suspicious) and it kept trying to grab the fc7 kernel. I had to reboot the machine before yum started to grab updated Fedora 8 packages. No where did it ever ask me to reboot, so it took a while before I was able to get this to work.
Still, after the update, Livna's Nvidia package still didn't work. Gnome's Display applet didn't show the right monitor or video card and it was missing the native resolution. I was able to select my monitor manually, but it still didn't give me the right resolution option. I finally removed kmod-nvidia so I can re-install it.
Fedora simply wouldn't let me sett the correct resolution even after I rebooted and re-installed kmod-nvidia. This time I first to the Display applet and changed to using the vendor supplied Nvidia driver. Then I used Nividia's (nvidia-settings, and make sure you run it as root or it'll just tell you that you don't have permission) app to change the display settings. Another reboot showed me an login screen that was working, but whenver I log in the resolution messes up. Finally, I just deleted all my Gnome settings and finally got things working! (I should've backed it up since my terminal fonts don't look quite as good now. It's possible I made a change but forgotten about it in the pre-F8 days).
Fedora 8 upgrade leaves a lot of fc7 packages hanging around. Most of them are orphaned packages since they either got moved to another package or no longer maintained in f8. The one remaining is kernel-headers which is fc7 but most of the dependency issues were caused by f8 packages when I tried to remove it or upgrade it. The version of the kernel header is newer then the f8 kernel that is installed... Maybe when the kernel gets above the f7 version on f8 then I'll be able to upgrade it.
Like F7, I faced enough trouble that I wished I didn't try to do an upgrade so soon especially since Fedora 7 was working fine for me. The upgrade process is still not as mature and it probably would've been easier if I just installed a fresh new copy instead of trying to upgrade.