sos2 is on an experimental git branch. It has a few positive changes but also some negative ones. For example it simplifies the way shields and heat works. On the other hand, ship salvaging has to be done by hand and is no longer automatic which REALLY makes the game drag on and on and makes ship combat really really shitty since it takes 1 year just to harvest a ship and profit off of a fight. Also the ship combat has been rebalanced to make it easier for the enemy in ways I don't agree with. I was able to hack most of the stuff I don't like with dnspy but I haven't figured out how to reverse the salvaging yet.

Android Tiers, another important mod doesn't work as well anymore but there's a VE android mod now. I still use Android Tiers just because I don't like mechtech crap and I like the feel of using "alternate" technology. Beyond that, any old 1.3 or 1.2 mod that doesn't work anymore has been replaced with something better anyway.