So have a lot of other people that don't know how to work with version control.
Since you seem to insinuate that 1) all of us don't know about this 2) you know everything about this I'll 'splain some things to you.
I was involved with Crytek and their Cryengine II, our mod was the first to be recognized and supported by Crytek. You might remember who they are, FarCry and it's iterations. We had full on support from the devs. So yeah, I fully understand how different versions can break existing or future bits of software. We dealt with that all the time.