Here is my experience of updating a machine from F-11 to F-13, on 2010-05-30, with plain yum over ssh. I got all the info. from "yum history", and had a little help from "distro-sync" which is only in rawhide's yum atm.
The "simple" start.
First off I updated yum to the latest from rawhide "yum-3.2.27-13.fc14.noarch". Then I updated to the new release via. "yum --releasever=13 update fedora-release". Then I ran my first "yum distro-sync" to do the update, and hit depsolving problems.
The first problem was that libgnomedb-1:3.99.7-3.fc11.x86_64 had to be removed, as it didn't exist anymore in F-13 and was depending on things that needed to be upgraded. Then I had a similar problem with a bunch fc8 packages, that were also depending on things that were going away:
Erase chkfontpath-1.10.1-2.fc8.x86_64 Erase fonts-arabic-2.1-2.fc8.noarch Erase fonts-bengali-2.1.5-3.fc8.noarch Erase fonts-gujarati-2.1.5-3.fc8.noarch Erase fonts-hebrew-0.101-2.fc8.noarch Erase fonts-hindi-2.1.5-3.fc8.noarch Erase fonts-kannada-2.1.5-3.fc8.noarch Erase fonts-malayalam-2.1.5-3.fc8.noarch Erase fonts-oriya-2.1.5-3.fc8.noarch Erase fonts-punjabi-2.1.5-3.fc8.noarch Erase fonts-sinhala-0.2.2-3.fc8.noarch Erase fonts-tamil-2.1.5-3.fc8.noarch Erase fonts-telugu-2.1.5-3.fc8.noarch Erase system-config-soundcard-2.0.6-11.fc8.noarch
Finally I had to erase cryptsetup-luks-1.0.6-7.fc11.i586, because that had stopped being multilib. and didn't have obsoletes. All of these were relatively painless, esp. with the new code in yum which tries to explain depsolving problems.
Then I ran distro-sync (excluding yum), and let it do it's thing. This is a new command in yum, and means you don't have to worry about bugs in NEVR packaging (because it will downgrade packages to the latest available). These are the packages it "fixed" for me:
Downgrade compat-db45-4.5.20-2.fc13.x86_64 Downgraded 4.5.20-5.fc10.x86_64 Downgrade nss-softokn-freebl-3.12.4-19.fc13.x86_64 Downgraded 3.12.6-1.2.fc11.x86_64 Downgrade preupgrade-1.1.4-1.fc13.noarch Downgraded 1.1.5-1.fc11.noarch
The compat-db45 is esp. amusing, as that had probably been broken all through fc11.