Publish by mosquitto client with QoS higer than 0 not allowed for V5

[Do4bled]

Describe the bug

When trying to publish a message with a higher QoS than 0 using the mosquitto_pub.exe client the client disconnects with the error message "Error: Message QoS not supported on broker, try a lower QoS."
If I remove the -V mqttv5 option from the command parameters the message get published to the broker without any errors. Mosquitto uses the mqttv311 by default.

Which component is your bug related to?

• Server

To Reproduce

Steps to reproduce the behavior:

1. Using this version of MQTTnet 'latest'.
2. Add the below code to a simple C# console application and run it to start the server.
3. Download the latest mosquitto installer and install the product.
4. Navigate to the install dir from a command prompt and find mosquitto_pub.exe
5. use the following parameters (assuming default port and localhost). "mosquitto_pub.exe -t samples/temperature -i "clientid2" -q 2 -d -m "test4" -V mqttv5"
6. See error.
7. Rerun the commando with the "-q" option changed to "-q 1"
8. see the error
9. Rerun the commando with the "-q" option changed to "-q 0"
10. see that the message is accepted by the server
11. Rerun the commando without the "-V mqttv5" with with the "-q" set back to 2
12. see that the message is accepted by the server.

Expected behavior

that regardless of the mqtt version the message must be accepted by the server. especially as mentioned in bug #1425 that QoS is "supported".

Additional context / logging

C:\Program Files\mosquitto>mosquitto_pub.exe -t samples/temperature -i "clientid2" -q 2 -d -m "test4" -V mqttv5
Client clientid2 sending CONNECT
Client clientid2 received CONNACK (0)
Error: Message QoS not supported on broker, try a lower QoS.
Client clientid2 sending DISCONNECT

C:\Program Files\mosquitto>mosquitto_pub.exe -t samples/temperature -i "clientid2" -q 2 -d -m "test4"
Client clientid2 sending CONNECT
Client clientid2 received CONNACK (0)
Client clientid2 sending PUBLISH (d0, q2, r0, m1, 'samples/temperature', ... (5 bytes))
Client clientid2 received PUBREC (Mid: 1)
Client clientid2 sending PUBREL (m1)
Client clientid2 received PUBCOMP (Mid: 1, RC:0)
Client clientid2 sending DISCONNECT

Code example

static void Main(string[] args)
        {
            var mqttFactory = new MqttFactory();

            var options = new MqttServerOptionsBuilder()
                .WithDefaultEndpoint()
                .Build();

            var mqttServer = mqttFactory.CreateMqttServer(options);

            mqttServer.StartAsync();

            while(true)
            {
                Thread.Sleep(TimeSpan.FromSeconds(2));
            }
        }

[chkr1011]

Thanks for reporting the issue. Please test with version 4.0.2.197 from the MyGet feed (see Readme) and let me know if it works now.

[Do4bled]

Hi, I have no idea how to get content from the MyGet feed ( and could not find anything in the readme) but I took the code from the branch that was created for this issue, compiled the server and tested it. the fix works fine, and the behavior is as expected.

[chkr1011]

Thanks for your feedback. The patch will be part of the next release.