I've recently received two messages asking how someone can switch back from DUALHDR to what she/he had before. How can subscribers know what they had before if they've already set the subscription to DUALHDR? (Obviously, if they haven't yet set themselves to DUALHDR, they can do a QUERY WMST-L and find out how their subscription is currently set.) Part of my problem is that I don't know what determines when one uses FULLhdr, FULLBsmtp, IETFhdr, SHORThdr, or SHORTBsmtp. Can someone enlighten me or point me to a relevant, clearly-written document? Many thanks. Joan Korenman, WMST-L Listowner KORENMAN@UMBC Univ. of MD. Baltimore County [log in to unmask] Baltimore, Maryland 21228-5398