On Mon, 17 Nov 1997, Chris Newman wrote:
Here's an example extension action that raises an interesting question:
The action is called "denyMDN". Based on: draft-ietf-receipt-mdn-06.txt
If the message has a "Disposition-Notification-To" header which matches
the envelope sender, then this will send an "automatic-ation",
"MDN-sent-automatically", "denied" MDN notification and remove the
"Disposition-Notification-To" header from the message.
The interesting question is: are Sieve scripts allowed to edit the headers
of a message?
Sure, why not?
The only problem I can see is that in IMAP messages are essentially
immutable so that once the delivery agent had written to the message store,
it's never gonna change.