I know it's not easy, but a nice option to me would be if the 8.1 docs
page linked to the equivalent page in the other versions. That would
avoid the need to manually edit the URL after a google search.
Oh, and +10 for the "Up" link at the top of the page also.
+1 (!)
This would solve all of the docs problems I mentioned - include a line at the top stating "This is the documentation for version 8.1. Hyperlink:See documentation of current version (8.4)".
And, yes, an "Up" at the top would be super helpful - reduce about 50% of searches.