MQTT protocol

Specification

The current formal MQTT protocol specification can be found at:

• MQTT v3.1.1 specification

The current MQTT-SN specification from IBM can be found at:

• MQTT-SN v1.2 specification

Clarifications

As questions arise around particular aspects of the specification, we are collecting clarifications:

• Topic Format

• Security considerations

• Are topics dynamic?

• Overlapping topics

• KeepAlive for the client

• Miscellaneous clarifications

• MQTT over Websockets

• Duplicates on QOS 0

• Clarify UTF8 strings

• Will Message UTF8 Support

• ClientID autogeneration

Ideas for future enhancement

Ideas (and reasons for why they may be required) are being collected here:

• ClientID autogeneration

• Topic string enhancement

• Broker auto-discovery

• URL scheme

• Status field for acks

• Add messageid to ping

• Will Message UTF8 Support

• Bridge protocol

• Extended CONNACK codes

• Registered topics like MQTT-SN

• MQTT for Centralised Data Collection

• Time To Live for retained message

Items fixed in the updated OASIS spec

• Extended ClientID

• Short usernames and passwords