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I'm trying to install an unsigned APK on my Android device, but I keep getting the INSTALL_FAILED_UPDATE_INCOMPATIBLE error. The previous version of the app was also unsigned, and I'm trying to install a new version that is also unsigned.

I understand that this error usually occurs when the signatures of the installed app and the new APK do not match. However, since both the installed app and the new APK are unsigned, I'm not sure why I'm getting this error.

I know that one solution is to uninstall the current app and then install the new APK, but I want to avoid this because it would erase the user data and app settings. Is there any other way to solve this problem without uninstalling the current app?

sabreyto
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  • Unsigned APK files can not be installed, thus the installed app has to be signed with a signature key. – Robert Jul 06 '23 at 08:11

1 Answers1

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Unsigned APK files can not be installed, thus the installed app has to be signed with a signature key, may be just with a debug key.

  1. Extract the installed APK file to investigate it's signature. You can extract the APK files using adb. Alternatively you can use an app like Amaze which allows to extract App APK files in it's integrated "App Manager".

  2. Analyze the APK signature details using apksigner tool from Android SDK

If you can identify the used signature key and still has access to the private key you can sign your update APK using the same key.

If you don't have the key and the phone the app is installed to is not rooted then things are getting complicated. If the app allows back and the installed Android version is older than Android 12 you may be able to backup the user data using adb backup ..., uninstall the app install the new app with the new signature and then adb restore ... the backup data.

Robert
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