Canon is rumored to be working on a replacement for the twenty years old EF 135mm f/2L ($999 – Amazon | B&H | Adorama) lens.
According to latest Canon Rumors, a replacement for the EF 135mm f/2L telephoto prime lens being in active development, with a possible announcement in 2016.
There are several patents for the 135mm focal length in either f/2 and f/1.8 maximum aperture models. See here and here.
Canon EF 135mm f/2L Lens Replacement Rumors
After 20-years of active life and popularity the old EF 135mm f/2L lens is rumored to be replaced by a new model and could have f/1.8 aperture, however, the image stabilization feature found in the previous patent applications may not be implemented into the design of this lens.