It would be helpful to know when you have finished testing GeneratePress and its child themes against the latest update to WordPress core, so we know when it is safe to update our individual WP cores and not have to worry about GP compatibility with the latest WP update.
Perhaps you could push out a mass email to your email user list, or at least post such an alert on the GP website and GP Facebook page. Just something simple like “GP version x.x.x and child themes have been tested and are compatible with WP version x.x.x”.
My suggestions is not related with this thread. May be you know, may be not for this site: http://themecheck.org. Our lovely theme have 97% score. If you can fix this 3 Warnings, you can use this badge on the Generatepress home page.
No reference to custom header was found in the theme.: This is because we have a custom header/logo option in the Customizer instead (much better).
No reference to custom background was found in the theme.: This option is handled by our Backgrounds add-on, which has WAY more functionality than the default WP background option. Although I might add this anyways for free users.
No reference to add_editor_style() was found in the theme.: I’ll be adding this shortly 🙂