Annoying. A classic example of a situation that should not be your problem, yet has become your problem. The easiest way to get the job to the online editor is to tell him to upgrade. I know you may feel like you're not in a position to do so, but the onus is on him to be compliant with what other editors are doing. By installing CC2014 he's not overwriting CC. Its a separate application. So he can always go back to CC for other jobs (although why he would beggars belief). And he can just run CC2014 for your job.
Good luck.