Thanks for the responses. They seem to all same the same thing: multiple
message id's are not a factor in modern email (if they ever were.) So I'm going
to remove reference to them from the email-arch draft.
Tony Finch wrote:
On Sat, 1 Mar 2008, Dave Crocker wrote:
The email-arch specification notes that Internet standards provide for at most
one Message-ID, but the document asserts that more than one sometimes appear
in a message. I put that in because that's been my impression.
Arnt's comments agree with my experience.
RFC 2822 provides for an additional resent-message-id each time a message