"laws of physics might get in the way" LOL!

Ok, I am probably in the minority here... but I like where BIAB is heading with 2021 update. Before rocks fly in my direction,
I think it is a great idea to have RT's backward compatible. At least one prior version. This alone could save a LOT of nerve cells to some who depend or attached to certain features, etc.

...And they will patiently wait until a stable release candidate is available and have whole trunk of new RTs and other content to keep them occupied till then.