Attribute android:allowBackup is deprecated from Android 12 and higher

[madmiraal]

To ensure data privacy, we need to disable automatic backups. This is done by setting the android:allowBackup <application> manifest attribute to false:

MyPeriodDataIsMine/app/src/main/AndroidManifest.xml

Line 6 in 92f34bc

android:allowBackup="false"

However this setting has been deprecated and needs to be updated:

The attribute android:allowBackup is deprecated from Android 12 and higher and may be removed in future versions. Consider adding the attribute android:dataExtractionRules specifying an @xml resource which configures cloud backups and device transfers on Android 12 and higher.

Furthermore:

If your app is running on a device with Android 12 or higher and your app targets Android 12 (API level 31) or higher, you cannot disable device-to-device migration of your app's files. In this case, the system automatically allows this functionality.

However, you can still disable cloud-based backup and restore of your app's files by setting this attribute to false, even if your app targets Android 12 (API level 31) or higher.

Although we probably do want to allow a user to migrate their data to a new device, we need to ensure that the current setting doesn't allow an unauthorised user to extract and view the private data just by physically connecting another device.