This one greatly expands the module variety available to modular fortress owners in champion games. Every module that can be unlocked on a champion now has a mod-fort equivalent (fortress modules only go up to MkIII though). The pre-existing mod-fort modules are still unlocked via their related turret/starship/etc research, but the newly added ones are unlocked when any player-controlled champion in the game has unlocked them.
Speaking of champions, the "you must be within 20000 range of the dying unit to get XP for it" rule has been removed: you still have to be on the same planet, but the fine details don't matter. Hopefully this will reduce the field of OCD behaviors slightly ;) Overall it wasn't a big deal since most XP comes from winning nebulae (and everyone gets that), but it should please some players.
And speaking of modules: AI-controlled Spire Corvettes will now be much scarier because we fixed a bug that was keeping their modules at MkI. Watch out for the high-mark ones.
Speaking of Spire stuff, the Shard-recovery chases in Fallen Spire have been revised again to not be so intense early on (where you don't have very far to go anyway) but still have the full force (or more) of the recent speed increases in the later stages (where you'll be more prepared).
The Ancient Shadows bonus ship far-zoom icons (i.e. the representation you see almost all the time) have been redone by long-time community member HitmanN. Same with the Spire champion far-zoom icons. They look [i]much[/i] better, in my opinion :)
Fixed a basically-since-forever bug where Defender mode would sometimes not launch waves. Perhaps unsurprisingly, it happened when you rolled both AIs as types that don't send waves. Computers think they're cute like that, doing what we say and not what we mean.
Special Forces now "breed" much more slowly, but have a higher possible population (both the rate and the cap scale up during the game with AIP, etc). It's been amusing to see the "intergalactic sentry eye" effect as it's been called, but not actually the intention there ;)
And a few other changes.
Update: 6.004 hotfix to fix bug in the last version that changed the color of your ships in the planetary summary.
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.