Attached are the relevant URL aliases.
When I initially saw the issue I thought it was a matter of a change to the way the docs are built, not old vs new documentation. That makes the list I've attached a little tricky to maintain. Of course within emacs is the best way for a user to reach the documentation, but maybe a different approach for the web would be appropriate. Some ideas:
Versioned folders living side-by-side. That's done in some other projects like Django, CommonMark, Bootstrap. A script could go into files from the last version and indicate that these are docs for an older version of Org.
Keep aliasing. Require an alias added each time is removed or is renamed. The script here would be a check between versions. Seems like more friction both in creating the check and in requiring the aliases, though big rearranges don't seem to be the norm so perhaps it's not so bad.
Just leave it. The easy option!
Maybe there are others.
At any rate, thanks for your help.
Ori
org-documentation-url-aliases.el