Hi, I'm trying to implement MQTT using LWIP and got such a mistake.
MQTT_CONNECT RETURN -1. Publish Err: -11
According to this link https://www.vtscada.com/help/Content/D_Tags/D_MQTT_ErrMsg.htm
I have "Connection Refused: Unacceptable Protocol Version".
I checked my version of MQTT And got result mosquitto_sub --help. Mosquitto_sub Version 2.0.11 And they say https://debian.pkgs.org/11/debian-main-arm64/mosquitto_2.0.11-1_arm64.deb.html ... This is a Message Broker That Supports Version 3.1 and 3.1.1 of the MQTT ...
Install MQTT version 3.1.1 does not seem possible!
Could someone to tell me, what I do wrong?
PS I'm use STM32F407VG + LAN8720, web-server working well, see my screens.
