Please provide a snippet of the part of the specification which we violate if possible: XEP-0334, Section 4.2: "A message containing a <no-store/> hint should not be stored by a server either permanently (as above) or temporarily, e.g. for later delivery to an offline client" Please provide a link to the specification: https://xmpp.org/extensions/xep-0334.html#no-store mod_mam and mod_carbons respect hints listed in this spec, but mod_offline does not, meaning a message sent with the <no-store/> hint is still stored on the server. Possible fix: In plugins/mod_offline.lua, a check similar to the other two modules could be placed before offline_messages:append() stores the message. Possible code, in the "message/offline/handle" hook: + if stanza:get_child("no-store", "urn:xmpp:hints") then + module:log("debug", "[[Useful debug statement?]]: %s", stanza:top_tag()); + return true; -- (Not sure what this should return) + end