Outlook 2013 on Windows 8.1 Zarafa MAPI client issue

I am a huge fan of ClearOS. Have been using it for quite a while now. For one of our customer we have installed clearOS pro and Zarafa small business last year. They were using MS Office 2010. Everything was working flawlessly. We connected each outlook 2010 with Zarafa MAPI client to work as it would with Exchange server.

Recently we upgraded MS Office 2010 to MS Office 2013. The Zarafa client will not install any more. It kept saying issues with Office 2013. I downloaded the very latest Zarafa Client 7.2 from Zarafa Portal but still the same issue.

Anybody got any clue how to setup outlook 2013 to work with Zarafa MAPI?