The version banner appears for any signed-in admin-panel user (the same check the have_admin() permission itself starts from), but only one acceptance per account is needed: once anyone clicks Accept <version> Update & Terms, the banner disappears for everyone, because the accepted version, the accepting user and the date are all saved account-wide (resellerId 0), not per user. This is different from the separate Updated Terms & Conditions pop-up, which is recorded per user in its own table and must be acknowledged by each admin individually.