A. 1. Check for app updates: Go to the App Store and see if there is an update for Planimeter Pro that addresses compatibility issues with the latest iOS version. 2. Reinstall the app: Delete Planimeter Pro and reinstall it from the App Store. This can sometimes resolve compatibility issues by ensuring you have the latest version.

B. 3. Use an older iOS version: If possible, consider downgrading to a previous iOS version that is known to work well with Planimeter Pro.