In any case my observations indicate that Outlook/Exchange 2000 does in fact change the Message-ID whenever a message is edited, both in the case where that message originated via "New Post in This Folder" and was subsequently edited (with the "Revise Contents" command) and also in the case where the message was delivered via SMTP and was later edited (with the "Edit Message" command). And I must interoperate with OE2K. While the Outlook/Exchange Message-IDs are rather lengthy there does not appear to be any information which is common between 2 edited messages, i.e. I can't find an unchanging UID sub-encoded within and it looks like it's just a system or folder-specific GUID value concatenated with an incrementing counter (see examples below).
When OE has edited a message, how can you discover that an edit has taken place? As near as I can tell, the effect of OE's "Edit Message" command must be identical to that of deleting the old message and writing a new one.
--Arnt
