MQTT stands for Message Queuing Telemetry Transport, that is, a message protocol for the transmission of sensor data. It is primarily used for IoT and Industry 4.0 applications and stands out for its ability to cope also with low bandwidths and high latencies. The protocol developed by IBM and released under a free license is used for machine-to-machine communication (M2M) and connected cars, as well as in logistics and home automation, among other applications. Alternatives to MQTT in particular include AMQP (Advanced Message Queuing Protocol) and STOMP (Simple Text Orientated Messaging Protocol).

The new MQTT Version 5 succeeds MQTT Version 3.1.1 and offers a number of new features, notably relating to client/server communication. The exact specifications are listed in a document compiled by the Organization for the Advancement of Structured Information Standards ( OASIS ), which has been working toward standardizing the protocol since 2013. Client implementations of the new version are anticipated for Q2 2018.