<irony>But surely everyone knows about the major features added in versions they don't yet have.</irony>
Noone ought to be obliged to know about the major features added in versions they don't yet have.
However my gut tells me that documentation far more often gets added than significantly rewritten.
I agree with that.
OK, you've convinced me (but that doesn't mean I'm going to look for the most out-of-date documentation to link to.)
Ok, you've convinced me that any link to online doc has not a lot of use beyond guiding the user to their local equivalent.
(Update to dehumor and just say what I meant straight)