Setting-up Subscription (Annual) in Play Store

I would like to set-up an annual subscription for my app. But it says, I need to "add the BILLING permission to my APK"

How do I do it? Thanks for your help in advance :smiley:

I already added "", but didn't work.


You can buy a billing extension here.

Taifun said I can test it before buying. How do I do that?

I already purchased the extension. It worked. But one more question, what is the Billing Library 2.0?

"Resubscribe is not currently available for your users because your app does not use Billing Library 2.0 in all active APKs."