Hey Gareth
Babak's right -It's not as tough as the 7 to 8 was for so many people.
But - there are things to think about. Be sure to visit
WebFOCUS Upgrade Resource Center you'll need to scroll down to the 8.0->8203 section.
I'll tell you at the moment, in 8203, parts are not super staightforward. Some of the doc is missing descriptions (they're working on it).
Generally, you have a couple of ways to go at it, but an 'in place' update is supposed to work for you (I think).
Besides the changes in the repository, there's also new and /or different configuration files that point to the reposistory (among other settings).
So the first step you'll probably see is to update the configuration files first, then you'll cut the repository updater loose to update your repository tables.
Do make sure to get a backup of your existing repository and all it's configuration files for good measure before you start.
I just did a single tier 8105m to split tier 8203 a couple of weeks ago. We haven't really tested much yet so I can't tell you much about that part. I can say it looks pretty good.
I also hear that 8204 will have smoother / easier upgrade tools. So that might be something to wait on.
Toby