The test demo on README

[xiaowenlong100]

I can't run it well when "ret = client.connect(version=4)" .
"ret = client.connect(version=3)" will be OK.

[gbour]

version=4 enable mqtt 3.1.1 (latest protocol version), while version=3 stick to past 3.1 version.
Which broker are you testing the demo with ? does it support mqtt v3.1.1 ?

[xiaowenlong100]

Thank you .I got a 'emqttd-windows10-v2.1.2.zip' that I download from http://www.emqtt.io/ 。It could support mqtt 3.1.1 since version emqttd-v0.3.1.

[gbour]

yes, Emqtt is supporting Mqtt v3.1.1
Could you try with mosquitto tools (mosquitto_pub & mosquitto_sub) with option --protocol-version mqttv311

Could you also take & send a network trace when using nyamyk demo ?

[tronar]

I bumped in the same issue, seems a bug on the packet length that assumes version 3 ID (3.1, MQIsdp), which is longer than version 4 (3.1.1, MQTT). Solved by toast-uz by changing at line 123 of nyamuk/mqtt_pkt.py from:
self.remaining_length = 12 + payload_len
to:
self.remaining_length = 6 + payload_len + len(getattr(NC, 'PROTOCOL_NAME_{0}'.format(version)))

[elegentFrog]

hello!excuse me，{
connection failed
2019-03-01 17:55:31,601 - test_nyamuk - INFO - Connecting to server ....192.168.8.7
2019-03-01 17:55:31,609 - test_nyamuk - INFO - CONNACK reveived
error： Client([email protected]:38106): Username 'undefined' login failed for password_undefined
}，how do you solve this problem?