> But I don't think > we should discount the existence of the former category. Deploying > to production on an older release of $system than you develop on > is hardly an unusual scenario.
That's probably true, but making dev, test, and production boxes similar is generally good practice and users can do as much or as little of it as they find they need in order to avoid getting burned. They can't do anything about behavior changes we inject into minor releases.
+1; this doesn't seem clear-cut and important enough to deviate from the (for me) preferable position of leaving well-enough-alone in the back branches.