Problems with Fedora 9 and above and KDE. 
PROBLEM
When initially logging in to the new Fedora 9 following the upgrade, KDE 4.0 GUI started but all my settings were gone.  Except for my documents that I had in various places, the settings and configuration like KDE themes I had installed earlier, were now gone.  After [...]

The Fedora 8 to Fedora 9 upgrade follows the general procedure outlined on the very first Fedora Core upgrade page:
RedHat Fedora: Fedora Core 1 to Fedora Core 2 Upgrade .  If you have not already upgraded to F8 please visit  RedHat Fedora: Fedora 7 to Fedora 8 upgrade. page first before going up to [...]

The Fedora 7 to Fedora 8 upgrade follows the general procedure outlined on the first Fedora Core upgrade page: RedHat Fedora: Fedora Core 1 to Fedora Core 2 Upgrade .  If you have not already upgraded to F7 please visit  RedHat Fedora: Fedora Core 6 to Fedora 7 upgrade. page first before going up [...]

The Fedora Core 6 to Fedora 7 upgrade follows the general procedure outlined on the first Fedora Core upgrade page: RedHat Fedora: Fedora Core 1 to Fedora Core 2 Upgrade .  If you have not already upgraded to FC6 please visit  RedHat Fedora: Fedora Core 5 to Fedora Core 6 upgrade. page first before [...]

The Fedora Core 5 to Fedora Core 6 upgrade follows the general procedure outlined on the first Fedora Core upgrade page: RedHat Fedora: Fedora Core 1 to Fedora Core 2 Upgrade .  If you have not already upgraded to FC5 please visit  RedHat Fedora: Fedora Core 4 to Fedora Core 5 upgrade. page [...]

The upgrade here really hasn’t changed from the previous ones all that much and the Fedora Core 4 to Fedora Core 5 upgrade is nearly identical to the first upgrade outlined in: RedHat Fedora: Fedora Core 1 to Fedora Core 2 Upgrade .  If you have not already upgraded to FC4 please visit RedHat [...]

The procedure for this upgrade follows the same steps outlined in: RedHat Fedora: Fedora Core 1 to Fedora Core 2 Upgrade with the exception of the below step.  If you have not already upgraded to FC3 please visit RedHat Fedora: Fedora Core 2 to Fedora Core 3 upgrade. page first before going up to [...]

Now that you are at Fedora Core 2 you can jump to Fedora Core 3 as the next step.  For those of you who have been using Fedora Core 2 and have not read Fedora Core 1 to Fedora Core 2 Upgrade please take a look.  The procedures here are identical except for some [...]

For those of you still stuck in the old archeic version of Fedora Core 4 or older, perhaps because you have lot’s of files stored and documents and do not wish to reinstall the entire OS: it may be time to consider an upgrade.  Thankfully there is a way to do this from Fedora [...]

If you have MailScanner running in the background, one issue you can run into is duplicate emails.  Try the below to see if it fixes your issue:
PROBLEM
Receiving duplicate or repeating e-mails in your inbox.
SOLUTION