I don't have an answer but there's nothing preventing you from converting the Raw files to DNG using the free DNG converter then editing the DNGs in Adobe software.
A Cannon 6D requires ACR 7.3 or greater. So you either have to upgrade to CS6 or convert images to DNG which will work with any version. Download is free and probably latest is 7.4.
Adobe does not update previous versions of ACR and each new PS has a new ACR series. I know this seems unfair, but if you bought a 2009 car and a new radio is introduced for the 2012 version does the dealer replace it?
You might find this thread enlightening:
Additionally, if you can afford that camera, you can afford to upgrade.
Forget about the DNG Converter, you leave a lot of image quality on the table if you stick to an older version of ACR.
Why does Adobe refuse to provide the latest version of Camera Raw (like my Canon 6d) that could be supported in Photoshop CS5 or earlier?
Adobe's policy to to provide free updates (not upgrades) for currently shipping software, which means the current Photoshop CS6 and Camera Raw 7.x. Development on Photoshop CS5.x and Camera Raw 6.x stopped when Photoshop CS6 started shipping. While it may appear on the surface that's it's a ploy to force users to upgrade to the most recent version when getting a new camera, it's really a policy based on the technical issues of trying to provide backwards compatible software for application that are no longer being developed.
Camera Raw is a plug-in for Photoshop and as such, it is dependent on the Photoshop SDK in which it loads...it's also dependent upon the system level APIs being used by the applications. Could Adobe keep upgrading old software? Yes, but it would be a technical nightmare.
Your alternative is simply use the free DNG Converter if you want to use new cameras that weren't in existence when your old software was developed. Pretty simple really and it's not designed as insult to Adobe customers...it's actually an affirmative program to make sure current users are provided support.
The problem of new camera support for old software is really a problem caused primarily by the camera companies spawning off new cameras whose file formats are undocumented and proprietary. If the camera makers adopted a standard file format that could be opened in standard applications (kinda like DNG) then tis problem would be mitigated. You really should place the lion's share of the problem at the feet of the camera companies...
Its like Adobe saying you want a Camera Raw for you Camera then buy CS6 which is insulting to your customers.
Not really. No software company on this planet keeps supporting legacy versions forever and as Jeff said, it's not Adobe's fault that each new camera requires its own version of RAW conversion. And I also agree with station_two: You were able to buy a 2000 bucks camera, probably have tons of lenses and other equipment worth another thousands of bucks and make a fuss over a 200 bucks software upgrade or a 20bucks/ month subscription? Makes no sense.