So if you have been running Zimbra Open Source Edition any decent amount of time, you have probably gotten emails similar to this one about there being an update available.
I’ve worked with many open source Linux based projects before and most come with a fairly simple, built-in, way to apply the latest updates. So after getting that email I logged into the administrator web interface and poked around, looking for a magical “Update” button. Much to my surprise, there was no magical button, so off to Google I went, and after some research, I found that to apply the update I just needed to download it (from the URL provided in the email), unzip, and finally run the install file.
So first off I ran wget on the URL provided, and it turned out that the file was over 500MB! Clearly, a “non-critical” update was not all I was downloading, and after extracting I found that to apply the update you actually download the entire Zimbra install file. Not exactly a quick download and update, but hey it worked and didn’t bitch about any unmet dependencies.
So when you run the installer it detects the older version and asks if you want to update, then it runs through the install/update process which takes about the same amount of time as a new install. The catch is that it will shutdown the services before it starts to make sure that things stay consistent, so if you’re going to update your server make sure to pick an appropriate time as users will not be able to retrieve mail.