Canon RF 400mm f/2.8L DO Lens

Canon recently has filed two new diffractive optics lenses in Japan. These two lenses are 300mm f/2.8 DO & 400mm f/2.8 DO. According to patents, these two lenses are probably RF mount lenses. We may see these lenses announced in 2020 with EOS R verison EOS-1D X Mark II.