Hello fellow Zimbra administrators, how are you all doing today?

At my company, we are currently running ZCS N. Edition 6.0.8, on a Ubuntu 8.04 x64 server, and I'm in charge of updating it to the latest version, 7.1.1.

Last time, when we updated Zimbra 5 on 6.06 x32 -> 8.04 x64, I did a clean install of Zimbra 5 on the new server, imported all accounts, input all settings, certificates etc., and then I updated it to Zimbra 6. However, when I created the new Zimbra 5 installation, it did create new Wiki, Ham and Spam accounts, and when I imported the old contacts, it duplicated all these system accounts. It always bothered me a bit, but I never gave it much attention. And, out of curiosity, what is the purpouse of the wiki account?

This time, I'm not upgrading the OS, I'm leaving that for Zimbra 8 since it will no longer support Ubuntu 8.04, however before running Zimbra 7.1.1 upgrade process, I wanted to sort out which accounts are being used so I can deleted the useless ones. Also, when I do upgrade to Zimbra 8, what is the correct procedure to import the user's accounts without importing those system accounts.

Also, are there any additional advices/checks I should do before running the upgrade? I've got ~200 accounts running on the server.

Thank you very much!

Kind regards,
Marcelo.