Clarification of the behaviour of properties for retained messages

In 1,2 Terminorogy change: Application Message: The data carried by the MQTT protocol across the network for the application. When an Application Message is transported by MQTT it is associated with a Quality of Service (QoS), a collection of Properties, and a Topic Name. to Application Message: The data carried by the MQTT protocol across the network for the application. When an Application Message is transported by MQTT it contains payload data and is associated with a Quality of Service (QoS), a collection of Properties, and a Topic Name. In 3.3.1.3 Retain change If the RETAIN flag is set to 1 in a PUBLISH packet sent by a Client to a Server, the Server MUST replace any existing retained message for this topic and store the Application Message and its QoS [MQTT-3.3.1-5] , so that it can be delivered to future subscribers whose subscriptions match its Topic Name. If the Payload contains zero bytes it is processed normally by the Server but any retained message with the same topic name MUST be removed and any future subscribers for the topic will not receive a retained message [MQTT-3.3.1-6] . A zero length retained message MUST NOT be stored as a retained message on the Server [MQTT-3.3.1-7] . to If the RETAIN flag is set to 1 in a PUBLISH packet sent by a Client to a Server, the Server MUST replace any existing retained message for this topic and store the Application Message [MQTT-3.3.1-5] , so that it can be delivered to future subscribers whose subscriptions match its Topic Name. If the Payload contains zero bytes it is processed normally by the Server but any retained message with the same topic name MUST be removed and any future subscribers for the topic will not receive a retained message [MQTT-3.3.1-6] . A retained message with a Payload containing zero bytes MUST NOT be stored as a retained message on the Server [MQTT-3.3.1-7] .