Over the last few months we’ve received a few mentions of a replacement for the EF 135mm f/2L being in active development, with a possible announcement in 2016. A couple of the mentions have said the lens could possibly be an f/1.8, as opposed to a straight f/2 replacement of this classic Canon lens. There have been no mention of the lens getting IS, which I’d wager is the case.
The current EF 135mm f/2L was announced almost 20 years ago and could definitely use some modernization in build and optics.
We do think we’ll see an updated 50mm lens, either the f/1.4 or f/1.2L before we see any other high performance prime getting a refresh.