Before performing upgradation All Scalix Services should be stop
And Choose 1st option "Upgrade one or more Scalix components"
Below components are included  Scalix Libical (required for Scalix Server)  Scalix Character Set Detection (required for Scalix Server)  Scalix Server  Scalix DB  Scalix Apache/Tomcat Connector  Scalix Tomcat  Scalix Messaging Services  Scalix Management Agent  Scalix Web Access  Scalix Management Services  Scalix Search and Index Service
in this process will perform the system check again
and some dependencies are required and it will ask for the installation.
Its too easy. All the dependencies get installed without having to manaully install anything(i mean using yum or yast!). And all the old settings (mailnodes etc), mailboxes etc can be retained . Easiest upgrade ever!