Client settings

Client allows us to publish and subscribe to broker and we can read status of the device and send command to the device.

Client ID is a unique name for each individual client. No two client names can be alike.
Keep alive is pinging the device every x seconds.

Clean session is a flag that tells the broker how to handle the session state for a client — especially subscriptions and messages — when it connects or disconnects.

MQTT Version is displaying current MQTT version used in this client/broker communication. (V500, V311, V310 or Unknown).

Birth Message is a special message that a client (often a device or service) sends automatically when it connects to the broker.

For the Birth message we can set a specific topic and different Quality of Service types:
At most once - Low importance; not guaranteed to arrive

At least once - More reliable; might be delivered multiple times
Exactly once - Highest reliability; never duplicated

Birth message retain tells the MQTT broker to store the message and deliver it to new subscribers immediately — even if it was published earlier.

Birth message payload  is the content the client sends to indicate it's alive and ready after connecting. It can be as simple or as detailed as you need, depending on the application.

At most once - Low importance; not guaranteed to arrive

At least once - More reliable; might be delivered multiple times
Exactly once - Highest reliability; never duplicated
Last will message retain will make Broker store the Last Will message. Any new subscribers to the topic immediately receive the message, ensururing offline status is visible even after it’s sent.