It’s fine to tell user that a certain feature has been replaced by something else, but, have you ever thought of redirecting user to the new feature, if they interacted with the old one?
This problem exists for the plugin manager:
Obviously, this is a bad UX case, telling the user the feature has been replaced and tells the user to use the new feature but not redirecting them to the new feature.
So, this button only shows a prompt, pretty useless, eh?
Solution:
When the user clicked on the plus icon, redirect them to the toolbox > plugin category.