If you have decided to connect with MQTT, please use the authentication method username/password. You will receive the necessary MQTT client credentials by e-mail upon request: (Please write us a message to: firstname.lastname@example.org). We support the common version MQTT 3.1.1. as of today.
In case you would prefer to use the slowly rising MQTT 5 already, please check if the client library of your choice sufficiently supports it, and then do not hesitate to contact us. Our experts will see what we can do for you within a feasible time frame, depending on relevant 3rd-party roadmaps and timelines.