what does it mean by 'For apps installed on a device running Android 8.0, the value of ANDROID_ID is now scoped per app signing key, as well as per user. ' https://developer.android.com/about/versions/oreo/android-8.0-changes.html.
Is that means if I have two android apps in same device with same signing key and different package name, does those apps get same device ID for specific user?
Is that means if I have two android apps in same device with same signing key and different package name, does those apps get same device ID for specific user?
The answer is yes, but if the app has Google Play App Signing enabled in the Google Developer Console the key will not be the same for the different apps even if you uploaded the APK's releases with the same key.
And my recommendation is to use always separate keys for different apps.