Those are all firmwares, not DPP as far as i can tell.
It took me abit of googling and a lot of 'stop-being-retarded' to find the newest version.
You go there, you choose your OS and the first thing on the list is DPP 3.11.0.something - that should be the newest version, atleast newer than 3.8.something.
Same page holds the newest EOS utility updates, picture style editors, raw codecs and whatever else canon supplies. If something is missing check the 1dx site, that list was long as ...
Hope I helped, and that i'm correct.