Default Hivemq QOS value is 1?
While HiveMQ does support all MQTT QoS levels, it’s not accurate to say that the “default” QoS is 1. The default QoS for publishing messages is 0 unless specified otherwise by the client. The QoS for receiving messages depends on what the client specifies when it subscribes to a topic.
I’d highly recommend revisiting our “MQTT Essentials” series as suggested previously.
Diego from HiveMQ Team