matk

> how to add this to my project? Thank you. Maybe you should wait for this to have a proper review, necessary changes and to be merged.

> Thanks, I made some comments. We upgraded Gradle as well, can you resolve conflicts caused by this when you are at it? @MrStahlfelge This changes in gradle requires Java...

The INAPP purchase is unavailable in older devices. Query products list already generate problems like: Response Code: FEATURE_NOT_SUPPORTED, Debug Message: Client does not support ProductDetails. Not sure how to fix...