In addition to the updates in AppGameKit Classic:

• Fixed: Linux extension is now compiled for the stable ABI and should work on all Python 3 versions.  Tested with Python 3.6 on Ubuntu 18.04 and Python 3.8 on Ubuntu 20.04.
• Changed: InAppPurchaseAddProductID's "consumable" parameter has been changed from a bool to an int and is now called "product_type", but this method doesn't do anything on Windows or Linux anyway.

Note that the name of the .so file used by Linux has changed and the old file (appgamekit/_x64/appgamekit.so) will need to be removed manually.