Prior to November 1, 2018, California was the only state that did not use either set of professional responsibility rules developed by the American Bar Association. From 2001 to 2014, the Commission for the Revision of the Rules of Professional Conduct of the State Bar of California worked on a comprehensive revision of the California rules that was intended to, among other things, convert them into a heavily modified, localized version of the Model Rules. That is, the result would look like the Model Rules, but with appropriate modifications to preserve the substance of existing California rules that better reflect local laws and customs.