**NOTE:** to use groups, at least firmware version `20181224` is required! (available [here](https://github.com/Koenkk/Z-Stack-firmware/tree/dev/coordinator))
Controlling a group is similar to controlling a single device. For example to turn on all devices that are part of group send a MQTT message to `zigbee2mqtt/[GROUP_FRIENDLY_NAME]/set` with payload:
By using the above `add` command above, a device will be added to a group. The device itself is responsible for storing to which groups it belongs. Others, e.g. the coordinator, do not have knowledge to which device a groups belongs.
When using the `set` command, e.g. to turn on all devices in a group, a broadcast request is send to **all* devices in the network. The device itself then determines if it belongs to that group and if it should execute the command.