For this request of yours for the Geofence feature, the router can only generate an event and with the use of event reporting, you are going to be able to send an SMS or Email notification. For local notification that you are looking for it is not included with the latest firmware available. In short, you may need additional changes in the SDK or additional development. It may be also possible with custom scripting.
If you want to add this feature and you cannot do it on your own, you can contact your sales account manager and request for development.
Hope it helps.
Thank you and have a nice day!