I’m confused - is this a repeat or just a different version of the same question?
And this:
can’t be correct as the Lorank8 uses the Poly Packet Forwarder which uses UDP not MQTT - although it’s “open source” the code isn’t actually shared so it’s hard to be definitive.
And if you subscribe to the ‘up’ topic, you get uplinks sent from the device, that’s one way only, what are you hoping to do by sending a message to that topic?