I asked a couple of weeks ago, and haven't had any suggestions yet, so I'll ask again (but more clearly): I've upgraded from sendmail and I need some way to support sendmail's user+extra feature. It's a bit like courier's user-extra feature, but of course it uses "+" to separate the components instead of "-". I need to provide backward compatibility for my users. I'm currently doing that by using a .courier-default file, which trims "+extra", but it causes mail to be accepted for any address, even those which obviously don't exist on my system. Is there a better way to provide the backward compatibility that I need?