configlet sync helps tracks to stay up-to-date with changes in problem-specifications. configlet info reports on missing exercises and quirks in concept usage. But I did not find a command to see exercises that a track has implemented but are now deprecated in problem-specifications.
I suggest adding such a list to configlet info, if maintainers prefer being informed only. If deprecating by command is preferred, I suggest adding the list / update action to configlet sync.