For this you may use microG. I have it installed for geolocation using Wi-Fi and cellular antennas but never tried to enable the notification service. I would

For this you may use microG. I have it installed for geolocation using Wi-Fi and cellular antennas but never tried to enable the notification service. I would actually be interested in being able to choose the server used for this service, and would enable it without hesitation if I could use my own server for instance.