According to CR, Canon is going to update two new super telephoto prime lenses in 2018. Canon has already updated 4 new super telephoto prime lenses in last several years, first the EF 300mm f/2.8L IS II & EF 400mm f/2.8L IS II came, followed by the EF 500mm f/4L IS II & EF 600mm f/4L IS II a few months later.
At Canon EXPO in New York today, Canon shows off prototype of new EF 600mm f/4L IS DO BR USM lens, Photography Bay had a chance to take several photos of this new lens. Price of release date info is not available yet. Stay tuned for more info.