It turns out that upgrading Feng Office is actually very simple. I had installed Feng Office Community Edition version 1.7.4 recently and a few days ago found out that version 1.7.5 had been released.
It is advisable to backup your current installation before upgrading.
Log in to Feng Office as Admin and then click the Administration link:
Click the Upgrade button:
Click Start automatic upgrade:
Wait a couple of minutes and then log back in to your new version of Feng Office.