This is just a quick sketch of an idea. The server, when delivering to a client, generally knows when the client has received it. For those old-fashioned people still using TCP+SM, the SM </a> will do the trick nicely. For modern people using QUIC, we can detect the receipt via QUIC acks. In either case, the server could send a requested XEP-0184 receipt on behalf of the client. Clients would need to opt in, and there's some security issues around what the server should be responding for (roster vs non-roster, MUC, etc). But, it'd save a considerable amount of traffic which - I think, anyway - is tautological. I think there might be some edge-cases around delivery failures of ack packets, but maybe not? Or maybe the edge cases exist anyway with XEP-0184? Explaining why this won't work would be very welcome, I've not tried anything along these lines yet and it may be that the edge cases are too complicated to deal with. Dave.