If Your Mobile application or Game is using in-app Billing version 2 API then upgrade your code with new in-App Billing version 3 as Google issued following notice to Android developers;
“ Beginning January 2015, we will end support for the In-app Billing Version 2 API. After this date, users will no longer be able to make in-app purchases using your app until you upgrade your app to use the Version 3 API…
We recommend that you migrate your version 2 implementation to version 3 as soon as possible to avoid any disruption to your app monetization for the above apps. For apps in this list that have already been updated, please verify your implementation.
You can review the following resources for more information:
If you have any questions, feel free to contact us using this form. ”
In app-billing version 2 has three product types Managed per user account, unmanaged and subscriptions on the other in-app billing v3 has only two product types Managed in app products and subscriptions.
Unlike Version 3, the Version 2 API is asynchronous and uses service messages sent as broadcast intents, so it is more complicated than Version 3. The In-app Billing Version 3 API makes it easier for you to integrate In-app Billing into your applications. The features in this version include improved synchronous purchase flow, APIs to let you easily track ownership of consumable goods, and local caching of in-app purchase data.
Local Caching is another good feature of in-app billing v3, Google play caches in-app billing information locally on device, now in API version 3 you can query for information more frequently unlike previous version that requires a network connection to Google Play.
You can download in-app billing v3 sample application code from here