This one includes some key enhancements to the base game we wanted to get in with enough testing time left before 6.0.
Players have been telling us for a while that the AI's Special Forces units were basically... irrelevant. They used to be far more significant but many changes over the years have resulted in a mechanic that just doesn't make a lot of difference in most games. So we rewired it.
Now the galaxy's AI Special Forces will act as a sort of defensive response force, pushing back whenever you attack a planet the AI cares about (which is not all of them). In testing this produced a pretty cool feeling of maneuver and counter-maneuver, but as always we'll really see if it works out when the players get their hands on it. I think it's a step in the right direction, at least.
Speaking of AI defense, here's another thing the players have been asking for: now each AI planet picks three typs of ships to "focus" on when spawning reinforcements. In one sense this reduces the distinct number of ships you're likely to encounter in large numbers in the midgame (in the early game they still start with the same distribution as before), but actually increases the gameplay variety as each planet's mix will be different.
Mere balance changes seem mundane compared to mechanics changes like the above, but there are some pretty important ones to starships and the triangle: The six "combat" starship lines have been given another balance pass. K costs are now more in line with what you're getting, notably. And the fighter is now faster than the bomber was (and the bomber slightly slower) and has more of a role on the attack due to several guardians being switched to hull types that are vulnerable to the fighter. All in all, none of the balance changes are earthshaking, but they're one more step in the right direction.
The release has a couple bugfixes, as well.
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.