If I'm an existing customer, how do I go about updating an existing Zulu installation with the latest upgrade?

Haven't found any procedure on the website that refers to that. By upgrade, I mean the newest version that supports Google Calendar as well as the past feature set.

Don't want to blow away anything critical in a mis-guided attempt to remain current;)

Had been looking for "upgrade" on the Seed Code website. Actual citation is under "new version" heading within the online documentation section of the Seed Code website.

One needs to do 2 things.

First, download the full, current installer from URL:
www.seedcode.com/downloads/downloads.php

Second, follow the instructions for applying that new installer that are posted at this URL:

http://www.seedcode.com/pmwiki/pmwiki.p ... NewVersion