No, there isn't any kind of change log. That would imply we had some sort of organization. I would say the main thing is we threw away the original combat system and instituted a quite different one. The place to start would be the Combat Revisions thread in the Game Chat forum to see how it's different. The other thing you'll need to read is the build table in the Test Server Zabada thread in the Server Notices forum. The charts there outline the changes in shipbuilding costs that aren't reflected in the client.

Unfortunately for us when Apple upgraded the SDK to use Open GL 2 it caused something like a thousand errors to show up when Zark tries to compile the client. Since we want to add a bunch of new feature as well, he's just going to upgrade the whole client rather than try to just fix the Open GL issues. So for now the client is going to remain somewhat out of date.