thanks for your response! however there is something that i do not understand.For example for IwIP, it has functions such as mqtt_subscribe. Nucleo f446re does not have an inbuilt GSM module right? so im using an external sim800l. how does mqtt_subscribe know which interface to use to send packets? it doesen’t know the AT commands also. so how come people on the ST forums say that it is not dependent on the hardware and that i can use any mqtt client?
