A few changes in Adafruit_MQTT.h and .cpp that allow connecting to any MQTT broker without knowing in advance what protocol version it uses.
The original used a hard-coded
#define MQTT_PROTOCOL_LEVEL
of either 3 or 4 to distinguish between the two protocol versions. In this version, mqtt_protocol_level is a member variable, and the protocol version is determined in the same (kludgy) way that Paho does it -- try to connect with it set to 4, then switch to 3 if that fails.
But this should be transparent to the calling code, aside from taking a tiny bit longer.
A few changes in Adafruit_MQTT.h and .cpp that allow connecting to any MQTT broker without knowing in advance what protocol version it uses.
The original used a hard-coded
#define MQTT_PROTOCOL_LEVELof either 3 or 4 to distinguish between the two protocol versions. In this version, mqtt_protocol_level is a member variable, and the protocol version is determined in the same (kludgy) way that Paho does it -- try to connect with it set to 4, then switch to 3 if that fails.But this should be transparent to the calling code, aside from taking a tiny bit longer.