The latest release of Android Studio, version 3.4 uses the R8 component in the app build process by default. Having built our app with this new tool chain I find that In-App purchases no longer work. We get a FAILED response in onPurchaseResponse. By disabling R8, in-app purchases again work. We would prefer to use the latest tool chain in our builds and disabling R8 is not an acceptable long term solution. R8 does replace the Proguard obfuscation tool so this could be part of the problem.