Release notes here!
The main player-facing changes here are the rebalancing of fuel and power.
Fuel costs have been halved so that your fleet size is not almost always capped by Fuel, but sometimes by Science.
Power costs themselves are unchanged, but spending science on power-consuming units now gives you a galaxy-wide +% boost to power production. So if you have Planet A which naturally produces 1000 power, and Planet B which naturally produces 1500 power, spending 1000 science on turret techs increases Planet A’s power output by 100 and Planet B’s by 150. This allows you to invest in “thicker” defense rather than only in more diverse defense.
More changes are needed in both areas, of course. Please let us know what you think.
On the non-player-facing side, there’s the huge addition of letting modders attach custom data to the xml records that form the meat of the game definitions. So you can add custom external constants, or custom fields to map types or AI types or ship types or whatever. These use a namespace system similar to the External Data you can attach to in-game objects, so that different mods don’t stomp on each other.