@scalz but why do you need this on an already working node? Mysensors has backward compatibility so far. Do you expect any improvements from updated sensor libraries for a working node? In this case, you of course would need proper FOTA.
I don't think that a major fw release (MySensors in this case) always guarantees full backward compatibility.
Perhaps not for a sensor lib (but who knows), still, if not for any core updates, do you expect any improvements from updated MySensors lib for a working node/network? If no, then you don't need fota
app settings != app/fw update