问题
I'm integrating in-app billing to my Xamarin.Android application. I tested the API using Google test products (android.test.purchased and others) and it worked just fine. After doing some testing I started receiving the following error on the OnInAppBillingError event.
ERROR: In-app billing version 3 NOT supported for com.example.appname
com.example.appname is the bundle id of my app.
I found this error on the internet (this is the closest match) and the solution is to update Google Play Client. I have the latest possible GPC (version 5.9.12).
The weird thing is that I started receiving this error after some successful tests. And I receive it even when my phone is not connected to the internet. This suggest that the billing SDK is checking for something missing on my phone.
For the first round of tests I used a MotoG 1st Gen running Android 4.4.4, and Google Play Client 5.9.12 (this is the test that first worked and then error started showing). Then I decided to use two more devices and it worked on a Samsung S4 (Android 4.4.2, GPC 5.9.12) and failed again on a Samsung S2 (Android 4.1.2, GPC 5.7.10).
EDIT: After a few days the error started showing on the Samsung S4 (didn't make any changes to the billing code, it just stopped working). I also used a Samsung S5 without luck.
回答1:
I get In-app billing version 3 NOT supported error when the user is not signed into google play. Ensure a user is logged into google play on the device.
回答2:
Try "Clear Data" and then "Force stop" for Google Play app.
来源：https://stackoverflow.com/questions/33180743/in-app-billing-version-3-not-supported-with-up-to-date-play-store