A communication network messaging server (1, 100) and user devices (2, 102) have control channels (10, 21, 110) to send and receive control data. The server sends to an originating device control data indicating recipient availability, status, and/or presence prior to the originating device sending a message. The server control channel (110) includes a multiplexer (104) for streaming between a user message channel and the control channel and maintains device registration data, status data, presence data, and user group management data. The server (100) enables end user initiated availability, status, and/or presence updates to be shared with the messaging network and with recipient devices via said control channel.