Moving the discussion over here:

The problem with pinning a range is that I know django-model-utils does not work with Django 1.5 (which is the current target) on less than 1.4.0, so that's a minimum requirement.  I'm happy to add `>=1.4.0,<={{ highest tested }}` once those come out, but I'd much rather run the tests and verify everything works than blindly have different versions being installed.