We are going to be upgrading our ZCS 6.0.7 server running on Ubuntu 8.04 LTS 32-bit to 8.04 LTS 64-bit and ultimately to 10.04 LTS 64-bit.
I have found, and intend on using, the Wiki article on "Network Edition: Moving from 32-bit to 64-bit Server"
However some questions need to be resolved:
1. How do you move the existing Spamassassin training over to the new server?
2. Is there a CLI command that will provide a listing of the current configuration including administrative passwords in readable English from the 32-bit server?
3. From your vast knowledge of all things Zimbra; what other "gotcha's" have you run into?