The newer method of connecting to the XC.org Zarafa server is to use the ActiveSync protocol. This method has the added benefit of not requiring a proprietary plugin.
In order to set this up, you can follow the steps to set up a new profile if you already have an Exchange account on your machine. Or, you can skip the new profile instructions and move directly to the new account information if this is a new installation.
1. On your Windows machine, go to Control Panel and select Mail 32-bit.