Did someone actually succeeded in having multicast working on LoPy ? We are using LoPy4 with the LoRaWan compact server (https://github.com/gotthardp/lorawan-server) as network server: the dowlink messages are sent but are never received.
Yes, this is the way I was trying to implement it, without success until I realized there was an error with the device address. So now, it works fine many thanks !
If you setup your devices as class C nodes using ABP to the same DevAddr and keys they will all pick up a message, effectively a multicast solution. We have had other users use this successfully.