Thanks a lot. Do you know of any real world mqtt deployments that deploy QoS 1 or 2 with success on non trivial scale? Can you recommend a broker impl. that is well tested in those scenarios?
There are some big players that use MQTT although i am not sure about the QoS levels. I know WhatsApp used MQTT, although i am not sure if they still do it not or what QoS they used. My bet would be they used QoS 1.
There are multiple brokers for MQTT: Mosquitto, HiveMQ (Java), VerneMQ (Erlang), EMQ: the one we used (Erlang) etc. You can find out more brokers that are available as well.
