The Catechism of the Council of Trent put is this way:
But, lest the people, aware of the abrogation of the Mosaic Law, may imagine that the precepts of the Decalogue are no longer obligatory, it should be taught that when God gave the Law to Moses, He did not so much establish a new code, as render more luminous that divine light by which the depraved morals and long continued perversity of man had at that time almost obscured. It is most certain that we are not bound to obey the Commandments because they were delivered by Moses, but because they are implanted in the hearts of all, and have been explained and confirmed by Christ our Lord.
Seventh day sabbath keeping is not a moral law.