The Meaning of Life, the Universe, and Everything.
It's pretty simple to downgrade if you just download a version changer.
With the one I got, I can change to any version, even the april fools updates and snapshots if I decide to not be lazy and download the new minecraft launcher, with two clicks of my mouse. Yeah, thats right. Just two clicks of my mouse, and I'm at any version I want.
Do version changers not work on most computers or something? :/