The recent version of the Zarafa SPK (0.5.5) for Synology NAS is now available through the Synology Package Center or the community Hub.
This version is compatible to the newly released firmware DSM5. It contains Zarafa 7.1.8 / Webapp 1.5 and Fetchmail 6.3.26 along with the Web Adminstration GUI which integrates seamless in the Synology DSM Interface.
The Upgrade is quite easy:
Detailed Releasenotes could be found on the community hub page and installation instructions with some screenshots could be found in the wiki.