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Update the device to a newer OS version:
If the affected device supports newer software, update to iOS 16 (or iPadOS 16) or later. This resolves the language discrepancy issue.
Upgrade the device if updates are unavailable:
If the affected device cannot run newer iOS or iPadOS versions, consider upgrading to a newer device to eliminate the problem.
Use alternative authentication methods:
As an alternative, users can switch to other supported Duo authentication methods instead of Duo Mobile.
Use the app in German or other presenting language
Use the familiar colours, symbols, and button locations to accept/deny pushes and otherwise use the app.
By addressing this bug through a software update or device upgrade, users can restore consistent language settings within Duo Mobile.