You can use this app to test whether the IP67/IP68 water-resistance seals on your phone are still intact by using the barometer built into it. Keep your phone away from liquids as the seals can become compromised with drops and aging.
The app cannot be supported if your phone does not have a built-in barometer. Apps cannot install hardware that is physically missing from the phone, so this app requires the phone to come with a barometer.