We got a problem with updating a wordpress from 5.4.2 to 5.7.x. Some custom fields of custom post type in the admin panel disappear after this update.
We are searching for a developer to fix the problem and explain the error(s).
We already created two environnements; one with wordpress 5.4.2 and one with wordpress 5.7.2. You will have access to both for your development.
You need to be able to fix the problem today.