This is the first time I used PreUpgrade and to my surprise, it was flawless. I was able to upgrade from Fedora 15 to Fedora 17 without any issues. That's one Beefy Miracle!

Steps:
  1. Backup!

  2. Always backup. I used Deja Dup.

  3. Update your packages
  4. $ sudo yum update
  5. Install the preupgrade
  6. $ sudo yum install preupgrade
  7. Run preupgrade
  8. $ sudo preupgrade
    This step will take hours since it will download all packages to update and test your system. While this is running, you can still use your system or even cancel the preupgrade and resume it later.
    Click forward.

    Choose the target release Beefy Miracle.
    Wait.
    Wait still.
    Sleep.

    Wake up! Once upgrade is done click Reboot Now.

  9. Reboot to upgrade

  10. This is when the actual upgrade happens. It will take several minutes to an hour or so depending on your current number of packages installed. At the end, it will also do a cleanup which would also take a few minutes. 
  11. Reboot again

  12. Here you will notice the update to grub2 during boot. Just let it start using the defaults. If you're lucky like me, you will see your newly upgraded Fedora.


There are post-upgrade steps that you'll have to do to cleanup and verify the upgrade.
  1. Cleanup old packages
  2. $ sudo package-cleanup --orphans
    This will list packages that are not supported any more after your upgrade. You may remove these packages. For example, I got a lot of kmod-nvidia packages from my previous release.
    kmod-nvidia-2.6.43.2-6.fc15.x86_64-280.13-4.fc15.3.x86_64
    kmod-nvidia-2.6.43.5-2.fc15.x86_64-280.13-4.fc15.5.x86_64
    kmod-nvidia-2.6.43.8-1.fc15.x86_64-280.13-4.fc15.6.x86_64

    $ sudo yum remove kmod-nvidia-2.6*
  3. Verify that your repos are now F17.
  4. $ sudo yum repolist
  5. Sync packages with the F17 repo
  6. $ sudo yum distro-sync
If you encounter unexpected issues, you can read more here.