If you choose (in the AcuRhythm app Settings) to get your current location via GPS (or Network) for the Solar time setting, the current longitude (to 1 decimal places – approx. precision equates to around 11km) is temporarily stored (cached) in the AcuRhythm app users preferences. This is to allow the Solar Time functionality to work in the future if live location data is not available at that time. The cached longitude value is updated each time the AcuRhythm app is run (when the ‘Use GPS setting is selected’).
At no time is any information from the AcuRhythm app transmitted externally from the device.