Historically, I've always upgraded my hardware and software together. In short, since I've always had new hardware I've always installed the latest distribution version from scratch. This time, however, I don't need to upgrade my hardware but I do want to upgrade my distribution to one that is still supported, i.e. receives security updates, etc. Currently, I run Postfix and Cyrus-IMAP on a Fedora 8 server. I'm considering upgrading to the new Fedora 11 (when released). I know how to set up Postfix and Cyrus-IMAP and I have good backups of all the configuration data and the actual mail so I'm not overly concerned about losing anything or getting myself into a situation that I can't get out of. What I don't have a lot of experience with is during the install process choosing the "Upgrade" option instead of the "New Install" option. My concern is that an upgrade may screw up anything from SELinux to apache (I run squirrelmail also) to who knows what in such a subtle way that I don't realize it for some time, e.g. security holes, etc. Does anyone have experience using the upgrade option and if so what do I need to be especially aware of?
This server actually provides a couple of different services but the mail service is the critical one.