Errata exists for this version of the document.
The syntax of the MQTT transporting protocol URL used in the Address parameter defined in 6.2.6.3 has the following form:
mqtts://<domain name>[:<port>][/<path>]
The default port is 8883.
The syntax for an MQTT URL over Web Sockets has the following form:
wss://<domain name>[:<port>][/<path>]
The default port is 443.