This one has some really substantial changes to forcefield balance. First of all, the player forcefields are buffed and increased in ship cap. Then players also get a new line of mark I-III hardened forcefields, which are high-armor but lower-heath alternatives to regular forcefields.
Next, the way that enemy ships collide at the edge of forcefields has been radically changed. This is a complex one to explain, so I'll just point you to the full release notes link above, which does the best job of explaining it. Feedback welcome on this in particular!
Oh, also ion cannons/blasters have been buffed about 4x, and preservation wardens now scale properly in multiplayer.
This is a standard update that you can download through the
in-game updater itself, if you already have 4.000 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 4.000 or later, you can download that here.