Questions

1. What does QoS stand for?
2. Why are we using QoS 1 instead of QoS 0 or QoS 2?
3. How can messages be sent to the MQTT server besides using the Mosquitto command-line tool?
4. What is a client ID?
5. Can there be multiple loop and setup functions in one sketch?
6. Try using one of the Android or iOS app presented in Chapter 3, Getting Started with MQTT, to publish messages to our channel.
7. Try using your own login data of the shiftr.io server instead of the public try/try login.