@mywonder: The child theme will never be updated, which is a good thing. Updating means deleting and re-uploading, and we don’t want to delete your custom code in the child theme.
You can compare the version numbers with the latest posts here: https://generatepress.com/category/development/
Using a child theme only means you can add custom functions and CSS and it won’t be lost when you update. You can still use GP to customize your site 🙂