I have not used that specific combination, but I have had different versions of Adobe programs installed before... as far as I know, each version is a separate install in a separate folder
Thanks John. That's what I was guessing, but I thought I'd ask before I made the jump.
I suppose the interoperability of the creative output files are more the issue of backward compatibility. I would assume that I couldn't open a .PSD file created in CC, in my old version of PS CS4 (not that I could think of a reason why I would), but I would certainly be creating TIF, PNG & JPG output in PS CC for use in my legacy versions of InDesign and Dreamweaver, but I can't see a reason that those standard file formats would be an issue.
Again, thanks for the feedback.
I only use/edit JPG as provided by my digital camera, so can't comment on PSD... the only think I do know about backward compatibility is that PROJECT files in newer versions of Premiere Pro will generally not open in earlier versions, which is because newer versions have new features that do not exist in earlier programs
If you maximize compatibility, you will at least be able to open the image composite in an older version. You may also be able to access features that have not changed significantly or are not new. For example, you can probably expect that an image mask, or a cloned layer, or such features, will be openable in an earlier version such as CS4. But if you have done a perspective warp or used smart objects, those features won't be editable in CS4.