nope, not fucking doing it. 
Discussion
Do it to test. I did. You can then revert back
Bro! How do I reverse this???
Go into test flight app and follow your nose
Go test flight app
Click Damus scroll down to see previous builds click what you want then install
Nope.
time to ditch apple and its proprietary totalitarian shit
Nope
Youโll have to eventually. Development is too rapid currently, old versions will probably just suck at some point.
This whole thing has convinced me to move back to android for my next phone.