[kh99]

There's an admincp function that will tell you which files have changed, but you'll need some other program to find which lines have changed. I don't know what to recommend, but it shouldn't be hard to find (I would call it doing a "diff", but I'm sure there are other names).

Is there some reason you want to upgrade step by step? It shouldn't be necessary and it seems like a lot of work (especially if you are going to carry those file changes through each version).

Also I believe there were a number of template changes over those versions, so if you have a custom style you should be ready to make some changes to that.