Android 10 migrate-data-for-scoped-storage

https://developer.android.com/about/versions/11/privacy/storage#migrate-data-for-scoped-storage

Scoped storage enforcement

Apps that run on Android 11 but target Android 10 (API level 29) can still request the requestLegacyExternalStorage attribute. This flag allows apps to temporarily opt out of the changes associated with scoped storage, such as granting access to different directories and different types of media files. After you update your app to target Android 11, the system ignores the requestLegacyExternalStorage flag. Maintain compatibility with Android 10

If your app opts out of scoped storage when running on Android 10 devices, it's recommended that you continue to set requestLegacyExternalStorage to true in your app's manifest file. That way, your app can continue to behave as expected on devices that run Android 10. Migrate data to directories that are visible when using scoped storage If your app uses the legacy storage model and previously targeted Android 10 or lower, you might be storing data in a directory that your app cannot access when the scoped storage model is enabled. Before you target Android 11, migrate data to a directory that's compatible with scoped storage.