Hi,
quick suggestion with the upcoming OMEMO Encryption and the general desire to save messages in MAM that do not have a body wouldn't it make sense to add a new message processing hint that asks the server politely to store the message in the archive. (For example named <pretty-please-store xmlns="urn:xmpp:hints" /> ) In contrast to previously discussed rules for MAM storage (save everything type="chat" and everything type="normal" with a body) this probably would not spam the archive as only new clients that actually speak MAM/OMEMO willl add that hint. cheers Daniel