Google Play In-app Billing API version is less than 3

Question

I just started beta testing the 2.0 update to the billing library for the Play Store and a lot of my users are getting this error Google Play In-app Billing API version is

Answer 1

It was normal, because at that moment it is not connected to any Google account.

So make sure you have an emulator with Google Play services.

-> Go to Google Play and enter your account credentials. After you close and reopen the app.