From Statistics Canada:
The changes brought to NAICS for the 2017 version were made to account for the changing economies of Canada, the United States and Mexico. The revisions were minor in nature and occurred at the lower levels of the classification.
Among the most notable changes are those relating to oil and gas extraction, telecommunications, and arts and sports.
NAICS is jointly developed by three agencies: Instituto Nacional de Estadística y Geografía, United States Office of Management and Budget, and Statistics Canada. The goal is to provide a consistent framework for the collection, analysis and dissemination of industrial statistics used by policy analysts, academics and researchers, the business community and the public.