RE: next emacs version?

[Drew Adams]

> > It's a transient problem that is not worth worrying about. Users who
> > build from development sources will update and rebuild soon anyway.
> 
> Right.  And because of this, I think testing with version< against the
> last officially released version would be good enough.

Actually, this is the test I think is appropriate, where N is the _next_
official release (e.g. "23.2" in the current case):

(if (or (not (fboundp 'version<))
        (version< emacs-version N))
     OLD
  NEW)

24.0.50.1, 23.2, and later will pick up NEW.
23.1 and anything older will pick up OLD.

Testing with `version<' against the _last_ official release won't help, I think.
Maybe you meant `version<='?  E.g.:

(if (version<= emacs-version "23.1") OLD NEW)