New patents for supertelephoto optical formulas have appeared at the USPTO.
The range of formulas is quite vast, all the way from a new EF 300mm f/2.8L IS to a new EF 800mm f/5.6L IS design.
We do think there will be some new “big white” lenses announced in the next 12 months, not including the EF 600mm f/4 DO IS. We’ve heard from at least one person that Canon may take the EF 200mm f/2L IS back to its f/1.8 roots. Though the latter hasn’t yet been confirmed.