Hi Mikael,
It is in our roadmap, but unfortunately we have other higher priority tasks for Datafari before writing this document. We have an automatic procedure for the Enterprise Edition, not yet for the Community Edition, sorry for that.
* First save somewhere safe your Solr index, the Solr config files, and use the admin ui to backup your MCF configs.
* Second, uninstall your Datafari 4.2.
* Third, install your Datafari 4.3
* Last, push back your saved data (Solr index, Solr config and MCF configs)
Regards,
Cedric