Hi there!
I am using Wireshark Version 3.0.2 .
I created new protocol dissector and get the same error msg: proto_new there cannot be two protocols with the same name.
I tried with: MQTTPROTO = Proto.new("mqtt_new", "MQ Telemetry Transport New")
and
MQTTPROTO = Proto("mqtt_new", "MQ Telemetry Transport New")
both options throw exception.