topic_max_depthsets a global maximum value for topic levels. This protects the broker from clients subscribing to arbitrary deep topic levels.
topic_max_depthis 10. As an example, this value will allow topics like
a/b/c/d/e/f/g/h/i/k, that is 10 levels. A client running into the topic depth limit will be disconnected and an error will be logged.
false) to be removed if they do not reconnect within a certain time frame.
yfor hour, day, week, month, and year; or
0, which means that all valid messages are accepted. MQTT specification imposes a maximum payload size of 268435455 bytes.