Methods, devices, and computer programs for improving the efficiency of multi-user multimedia messaging services are disclosed. A multimedia message is sent from an originator user device to an originator server and further to one or more recipient servers to which recipient user devices as addressed are associated to. The one or more recipient servers execute a multicast delivery for distributing the multimedia message to the recipient user devices and/or an improved reporting of a transmission state of the multimedia message by receiving status messages from the recipient user devices, each status message comprising an indication of an individual transmission state of the multi media message at one of the recipient user devices, aggregating the indications into a report representing the transmission state of the multimedia message, and sending the report to the originator server.