@mdawaffe The recent #11460 merge breaks Calypsoify, giving an error PHP Fatal error: Uncaught Error: Call to undefined function use_block_editor_for_post_type() in /var/www/html/wp-content/plugins/jetpack/modules/calypsoify/class.jetpack-calypsoify.php:335. It looks like this gets triggered by AJAX calls, such as saving drafts. I noticed it by clicking the Preview button.

Steps to reproduce the issue

1. Go to /wp-admin/post-new.php?calypsoify=1.
2. Make an update, and click on Preview.
3. See error both in console and logged server-side.

I thought I could just wrap the instantiation in a ! DOING_AJAX check, but then Calypsoify doesn't seem to load at all (you can tell if you're in the calypsofied version of Gutenberg by the hot pink Publish button; if it's blue, add the ?calypsoify=1 query param to set it).

Can you see a better fix?