Just point the QR code to the actual .apk and let the user download it and manually install it. It is not possible for the user to read the QR and then automatically install the application. This is not how OTA or updates work. Even when you perform the actual OTA update for Android, for example, you must confirm that you need to complete the action.
Even if there is a way to achieve this, it doesnβt stop anyone from simply pulling out the .apk from their phone and looking at it or redesigning it.
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