For Android devices download ColorReader app from Android Play Store here:
https://play.google.com/store/apps/details?id=com.datacolor.colorreader

For iOS devices download ColorReader app from the Apple AppStore here:
https://apps.apple.com/app/id1217566816

Important:

Make sure the on Android as well as on iOS, that the ColorReader app has the permission to access the location services from the OS, as only this will allow the ColorReader app to use the Bluetooth functionality of your mobile phone