Which AOE game to buy for Voobly?

So I want to play AOE II on Voobly but it's been so long I don't even know which expansion I used to play.

I could get Age of Empires 2:The Age of Conquerors if that's viable or any other expansion too. My goal is to play multiplayer with my SO so I will be installing it on 2 PCs. Looking for the most stable and reliable version.

Thanks!