The 2.1 patch was removed recently because of some balance problems. I sometimes try things to see if it can spice up gameplay and possibly find a better gameplay system, iterate on changes, that sort of thing. I do the same while modelling a unit, try stuff to see if it works. This time, it did not work.
I'm currently trying to implement the good parts of 2.1 with the good parts of 2.0 to move directly into 3.0. We'll see when this is finished.
For a closer look at the updates check out the mods Discord server: Discordapp.com