Almost every camera model’s raw file is different. There is a file that can be updated, but sometimes Adobe decides you have to move forward and they don’t put the necessary stuff in the older files, for your new camera.
Getting the latest version will solve your problem with the 5D Mk III. I’m still using Photoshop CS5 and have a working update file for my 5D Mk III. It also works with CS6 and CC.