Rh projects are really version specific. Once opened in the highest version, they cannot realistically be worked on in earlier versions.
There are back door ways of opening a higher version in a lower version but any code that is specific to the higher version will give problems. I believe there is up to date version on how to do that on Willam van Weelden's site at http://wvanweelden.eu
If the topics have simple code only, you may be able to import the topic into your version, make the changes and then let your teammate import back but I wouldn't like to be doing that for any significant amount of work and you would have to check carefully each time.
The real answer is to upgrade to Rh2015.
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