Well it's partly because steam hasn't updated the builds that I uploaded. Additionally, while I uploaded updated builds to steam mainly to let people know that the latest builds would be on itch. Clearly steam just ignored those builds. That irritating.
So basically what you have is very old at this point. I guess I'll sum up what the latest updates do... Improved economy and balance, but also mechanisms to support a very advanced economy. Vastly improved single player and coop experience (Scavengers). Scavs are now quite fun to play against and it's not so samey from game to game anymore.
Improved lobby. Skylobby supports self hosting games, it also supports direct hosting where your friends can connect directly to you instead of using the central server (this is a big feature, I'm a fan of having a centralized server but I'm a bigger fan of not needing that centralized server for multiplayer)(ports must be forwarded).
Development on Evo is effectively concluded. The game is in an excellent place now. It was always a platform where I tried interesting ideas that I had. I am now in the process of building a new game, not to supplant Evo, but more along traditional RTS lines. It's a safe bet that if you like Evo you'll probably like my new game too. New game is mainly focused on single player and coop (although multiplayer PvP is 100% doable). I'm roughly 50% done with it so maybe I'll have a beta ready in 3 months or so. I'll make an announcement of sorts when the time comes.
In the meantime, delete Evo on steam, and download it from itch (I would recommend using the itch client. It's very nice and will keep it updated). I will be sending out Evo updates as is needed to make sure it keeps running smoothly, and I'll generally keep the lobby on par with the latest releases.