The app from the Google Play Store or Apple Appstore have in-app purchases.
I don't believe the non-Google .apk or windows versions have a payment system.
@aenadin there is no version for the new season yet, this is still work in progress. Just the server alredy knows about it and thus the client displays that it isn't prepared for the next season yet (which is technically correct, but a bit confusing).
Can you provide more details what error you encounter in developer's inn?
@andy oh i just solved my problem, i just reinstall the game through playstore, and purchased the item, uninstall it again and reinstalled again through the latest apk i just downloaded here,