The mqtt-client adapter seems not to work with a mqtt v3 broker

[pzystorm]

Describe the bug
For me it is not possible to connect the mqtt-client adapter to my current mosquitto broker. It is a version 3 broker so I select the mqtt version 3 in the adapter settings.

# mosquitto -h
mosquitto is an MQTT v3.1 broker.

IP, port and firewall are not an issue. I did some tests with nc on the iobroker instance and it told me the port is open. Other applications are also very fine with the setup.

To Reproduce
Steps to reproduce the behavior:

1. Install the mqtt-client adapter v1.6.3
2. Go to the adapter settings and insert IP / Port (1883) and select mqtt version 3
3. Save and restart the adapter
4. The adapter will be yellow, not green

Expected behavior
The adapter should switch to green state.

Screenshots & Logfiles

Versions:

• Adapter version: v1.6.3
• JS-Controller version: 4.0.23
• Node version: v14.20.1
• Operating system: Synology DSM 6 --> Docker (Docker version 18.09.8, build bfed4f5) --> Debian 11 Image with iobroker

[pzystorm]

Damn... solved :)

Can you implement that? Maybe the possibility to switch between protocol version 4 and 3 is not enough in the adapter settings of iobroker. Maybe a selector for the mqtt broker version?