If you see an error message like
src/main.cpp: In function 'void InitMQTT()': /home/uli/.platformio/packages/framework-arduinoespressif32/tools/sdk/esp32/include/esp_event/include/esp_event_base.h:37:32: error: invalid conversion from 'int' to 'esp_mqtt_event_id_t' [-fpermissive] #define ESP_EVENT_ANY_ID -1 /**< register handler for any event id */ src/main.cpp:80:44: note: in expansion of macro 'ESP_EVENT_ANY_ID' esp_mqtt_client_register_event(client, ESP_EVENT_ANY_ID, mqtt_event_handler, client); ^~~~~~~~~~~~~~~~
replace ESP_EVENT_ANY_ID
by MQTT_EVENT_ANY
and recompile. This will fix the issue. Using ESP_EVENT_ANY_ID
was possible in an outdated version of the MQTT library.