If you want to update an old APK that is no longer supported and is not compatible with newer versions of Android, there are several things you can try.
- Change the target SDK version: The first thing to try is to change the target SDK version of the app to a newer version. You can do this by decompiling the APK file, editing the AndroidManifest.xml file, and changing the value of the "targetSdkVersion" attribute to a higher number that is compatible with the Android version you want to run the app on. Keep in mind that this may not always work, as there may be other compatibility issues that prevent the app from running on newer versions of Android.
- Use an emulator: Another option is to use an Android emulator to run the app on your computer. This can be done using tools like Android Studio or Genymotion. Emulators allow you to simulate different versions of Android and test the app to see if it works on newer versions.
- Use a compatibility layer: There are also compatibility layers like "Android Runtime for Chrome" (ARC Welder) or "Anbox" that allow you to run Android apps on non-Android systems like Chrome OS or Linux. These tools can be useful if you want to run an old Android app on a non-Android device.
- Use an app wrapper: Finally, you can use an app wrapper tool like "Expo" or "PhoneGap" to package the old APK as a web-based app that can run on multiple platforms. This can be a good option if you want to make the app available to users on different devices or operating systems.
Keep in mind that these options may not always work, as there may be other compatibility issues or limitations that prevent the app from running on newer versions of Android. It's always a good idea to test the app thoroughly after making any changes or modifications to ensure that it works as expected.