As a site with a large number (almost 200) of group/department admins, the recent pop-up informing EVERYONE about a Mandatory API upgrade caused a number of questions to our main admin team. Since I assume you don't create sandboxes for just any admin user, can't you limit this to Main Admins? After all, you know who's logging in. While I appreciate the effort to communicate changes (especially mandatory ones), this message only serves to create confusion for those of us who aren't using your API.