Thank you for your question,
In the current base firmware digital output of the device is controlled by most of the features, but no output control can be set up by "Geofence" exit/entering. We would recommend you to set up "Manual Geofence" generate event option, to "On both" and set up your server that it would send a GPRS command "setdigout" when this event is received, according to preferences.
More on SMS/GPRS commands can be found in our wiki link:
Note, that GPRS commands should be sent using CODEC12 protocol.
More on this can be found in the link:
Hope this helps,