Elliot, I don't have practical experience with most of this, but for OpenSRF, at least, you should just be able to install the newer version over top of the old. In other words, I'm not aware of any upgrade-specific steps that don't happen with a normal installation. Hopefully me chiming in here will refocus the eyeballs of other folks and they'll weigh in.
My advice would be to change as few things at one time as possible. If you don't need to upgrade Postgres, for example, then delay the upgrade. I think you should also go through a test upgrade if possible, using a virtual machine, before messing with a production system. Install a matching version in a VM, put some data into it (a user, a bib, an item, a circ, a bill, and a hold, or use the stock test data if available with your version), take a snapshot of the virtual image, and then try the upgrade. If necessary, restore from the snapshot to start over until you get the process down. -- Jason
