Please don’t post useless polls, and please don’t demand a fast answer. Please edit your post. You are already using the latest version of IAP which is IAP 4.1.4. That version already uses the latest billing library Google Play Billing Library v3. First step here is to make a full project backup. Then once you’ve installed IAP via Package Manager as you have, then delete the previous asset version. Delete everything under /Assets/Plugins/UnityPurchasing as it’s no longer needed and can cause conflicts. Don’t use Codeless as it needs updating. Instead please consider starting with the Sample IAP Project v3 here Sample IAP Project