Andrew,
Here is the response from the Product Manager:
You can download the 10.5 trial from the Promotional Software Store, accessible from the product web site, www.cisco.com/go/primecollaboration
click on "try Prime Collaboration"
I believe you will be able to backup the 10.0 database and restore it onto the 10.5. If there is any problem with that, the alternative is to discover the publisher(s) again.
Regards,
Jim Whitten, Product Manager
Hope that helps.
Kelli Glass
Moderator for the Cisco Collaboration Community