Starting 16.3.3 Administrators can now control which users can access Classic PPM by using the Actions workspace. You can disable the Classic PPM Access action to restrict all Clarity users from accessing Classic PPM, including administrators. The information is also documented under section Disable Classic PPM for Users
Clarity 16.3.3 onwards
With this enhancements
Customer should reduce its reliance on channels back to Classic PPM. This enhancement aims to eliminate users' need to access Classic Clarity. Outside of the need to access the Classic administration area (which should only be for admin users) if a customer still needs to access Clarity particularly the functional side, please raise it via enhancement using Product Management Office hours.