Detecting when to use REST from GroupWise client version

This is not quite a REST question but it should be close enough.

For programs supporting both the 2014 REST API, and the old 2012 GroupWise Admin object API, in the absence of 2012 or 2014 being specified at program startup, I'm wanting to detect the GroupWise client version. I can then make the assumption that if its the 2014 client, then we will use the REST API.

I've poked around in the registry and have not found anything which gives the GroupWise client version. Is there anything there that I've overlooked?

Otherwise extracting version info via Win APIs from c:\program files (x86)\Novell\GroupWise\grpwise.exe appears to be a possibility.

Any suggestions appreciated. I'm wanting to improve the decision making when the client for OES Enterprise Server is installed, there is authentication to a tree, and the tree has the 2012 and earlier GroupWise schema extensions in place, but GroupWise has been upgraded to 2014. If the client is 2014, I can then prompt for the Admin Service Address and a username/password.

Thanks, John