[[last-will-and-testament-service]]
= Last Will and Testament Service

The Last Will and Testament Service (LWTS) has an AMQP receiver on the
following control address :

* $mqtt.lwtservice

This receiver is attached with :

* rcv-settle-mode : first (0)
* snd-settle-mode : unsettled (0)

so that it can provide a QoS 1 (AT_LEAST_ONCE) for receiving messages.

It's able to handle following scenarios :

* receiving “will” information for a new connected client (see
“Connection”).
* start publishing “will” due to a brute client disconnection (see
“Disconnection”). The WS acts as an AMQP sender on “will-topic” in order
to publish the “will”. The QoS level specified with sender and receiver
settle modes during the attachment depends on the desired QoS specified
in the "will" message (see "Publish").
* removing “will” information for a specific client (see
“Disconnection”).
* overwriting “will” information for a specific client (it’s something
that we don’t have in the MQTT spec).
