This is a major release for 1.5.2!
This release adds the advanced age generation systems so that ages now get more things you didn’t write. It also adds the ink mixing mechanics to allow you to craft link panels with special properties. Books are now crafted using link panels.
There were some changes that might require a bit of work to update existing saves or will cause other minor changes. Primarily you’ll need to update your configs and you’ll see some changes in height on some terrain gen. I recommend looking at the change log for exact information.
To recap: there is only one download (found at the bottom of this post); This file is the universal install for client and server; it no longer goes in the jar.
Mystcraft goes in the mods folder.