Server: User: Password: ClientId: Clean session: TCP WS Use TLS Connect Disconnect Topic: Payload: Text Base64 Retain: QoS: 0 (At most once) 1 (At least once) 2 (Exactly once) Publish Topic: QoS: 0 (At most once) 1 (At least once) 2 (Exactly once) Received messages: Add received messages to list Subscribe Unsubscribe Clear received messages Port: Persist retained messages in JSON format Clear previously retained messages on startup Start Stop Clear