Francois Normandin

The Server might grant a lower maximum QoS than the subscriber requested. The QoS of Payload Messages sent in response to a Subscription MUST be the minimum of the QoS...

If a Server receives a SUBSCRIBE packet that contains multiple Topic Filters it MUST handle that packet as if it had received a sequence of multiple SUBSCRIBE packets, except that...

The Topic Filters in a SUBSCRIBE packet payload MUST be UTF-8 encoded strings as defined in Section 1.5.3.

If a Server implementation does not authorize a PUBLISH to be performed by a Client; it has no way of informing that Client. It MUST either make a positive acknowledgement,...

The Server MUST deliver the message to the Client respecting the maximum QoS of all the matching subscriptions.

If the RETAIN flag is 0, in a PUBLISH Packet sent by a Client to a Server, the Server MUST NOT store the message and MUST NOT remove or replace...

A zero byte retained message MUST NOT be stored as a retained message on the Server.

A PUBLISH Packet with a RETAIN flag set to 1 and a payload containing zero bytes will be processed as normal by the Server and sent to Clients with a...

It MUST set the RETAIN flag to 0 when a PUBLISH Packet is sent to a Client because it matches an established subscription regardless of how the flag was set...

When sending a PUBLISH Packet to a Client the Server MUST set the RETAIN flag to 1 if a message is sent as a result of a new subscription being...