Well, I finally did it. After putting it off for far too long, I've upgraded bob from RHEL3 to RHEL4. RHEL was the only non MS option when we got the server so thats what we went with, unlike debian, upgrades (non security related updates) are not forthcoming, RHEL does major releases that contain the upgrades, but you can't just chose to install postgresql 8 or a 2.6 kernel, you have to upgrade your installation. Redhat recommend you wipe your drive and start again. This isn't really an option when the device is several thousand miles away and your backups have to travel over a home ADSL line.

So I did some research, and found that it is in theory possible to upgrade using the up2date command. It comes with a disclaimer, that it might all go wrong, and then your on your own.

Back in may last year I started this thread [1] to sound out others who might have tried, and got a responce.