Bootstrap 2.2.2 is going to be the last 2.x release and it's fairly polished to begin with.
There's nothing wrong with intentionally staying behind -- Bootstrap 3.x features will more than likely lean a lot more heavily on CSS3/HTML5.
There's nothing wrong with intentionally staying behind -- Bootstrap 3.x features will more than likely lean a lot more heavily on CSS3/HTML5.
Sure there is an archive somewhere of the old docs but that is a long way from ideal.