A few tweaks, specifically to an annoying issue where AI units could "appear" on your planets as reinforcements in cases when they should not be.
This is a standard update that you can download through the
in-game updater itself, if you already have 3.701 or later. When you
launch the game, you'll see the notice of the update having been found
if you're connected to the Internet at the time. If you don't have
3.701 or later, you can download the windows installer for 3.711, or the OSX installer for 3.712. Once you do an in-game update, they'll both be on the latest version, despite starting at slightly different versions.