Google announced the closer of the preview of Google Apps Marketplace billing feature for new developers, as they will be launching a significant update later this year.
"For the next version, we are working on making the billing features both easier to integrate with and easier for customers to use.
Additional changes will enable us to innovate faster with expanded country support, payment options, and other exciting features due later on. Version 2 of the licensing API will continue to be supported throughout these changes," Google said.
Developers using the preview implementation can continue to do so until the new version is available and customers are transitioned. Those just getting started with the Marketplace are encouraged to use their own payment solution until the new version is available.
If you have any questions, you can post in the Google Apps Marketplace API forum.