* Security - Editing an ACF Field in the Field Group editor can no longer execute a stored XSS vulnerability. Thanks to Duc Luong Tran (janlele91) from Viettel Cyber Security for the responsible disclosure
* Security - Post Type and Taxonomy metabox callbacks no longer have access to any superglobal values, hardening the original fix from 6.3.8 further
* Fix - ACF fields now correctly validate when used in the block editor and attached to the sidebar