More and more these days I'm having to convert Illustrator CC EPS to CS6 version of Illustrator (or earlier). I'm being extremely stubborn about not upgrading to Creative Cloud - I want to still be able to use my licensed software without paying Adobe hand over fist every month. Anyway, that was my mini rant - back to the matter at hand.
If you have an EPS file that's too new to open in CS6 or earlier, just open it in Acrobat Pro (assuming you have it) and then save it as a PDF file. Now you should be able to open the PDF in older versions of Illustrator. The main problem with this approach is that you will lose any layers from the original file - but it will get you out of a tight spot.
Having tested EPS files, I tried an experiment of my own. I opened a CS6 AI file in Acrobat and saved it as a PDF. I then imported the PDF into Illustrator CS5. After agreeing with the dialogue box warning me that it was created in a newer version, it imported the file (almost) perfectly - but again, without the inclusion of the layers.