[whpalmer4]

Or simply use the File->Back Up Database... command in OmniFocus to save a copy of your data in some safe place. The paranoid might even zip that up (File->Create Archive... in the Finder) so that there's no chance that the new version of OmniFocus (or whatever program you're upgrading) might spot the old data and helpfully "convert" it for you. Why settle for just suspenders and a belt when you've got duct tape, baling wire and used chewing gum handy? :-)