Hi,
I hope this hits the right people (looking at some archives it seems to be, despite the list being mainly for MM3). Apologies if you consider it just noise.
I have a patch for Mailman 2.1.23 for MIME munging when there are no headers or footers. There is code to prevent this from happening but it wasn't happening for us.
The problem we saw occurred when a meeting request was created in Outlook and a mailing list was added as an invited recipient. Mailman would place MIME sections in a multipart which Outlook didn't recognice as a meeting request.
This patch simply allows whitespace-only headers and footers to be considered 'empty' so that the MIME structure is not altered in such cases. I suspect just testing for a single newline character would be enough, but I like to wear a belt and braces.
Iain