So the only difference is they incremented the version number and changed some other numbers, just to make sure that all software will have to be able to handle the numbers changing going forward, so changing them again won't break things?
They're like mold, these middleboxes. Grows easily, doesn't evolve much, likes sitting in the dark, surprisingly hard to kill, and ultimately not very friendly to human life
By exercising the fields early and encrypting anything that's not nailed down, they prevent ossification from taking hold before it becomes a problem