CalDav Issues: migrating iCal server (10.6) to Calendar (10.9)

Question

We just migrated our 10.6 Server using the migration tool assistant to Mavericks Server. Most of the data migrated smoothly except for the user calendars...
We have all our users running their account as mobile accounts and using the iCal Server service to store their calendars. On our 10.6 server the calendars were store to a specific volume (example: /Volumes/Drobo/iCalServer ). After the migration to Mavericks Server, we activated the Calendar service and then all the calendars for all the users went blank with a default calendar called "calendar"... so it seems we lost all the calendars and events for all the users :-(
How can I restore them? Is there a way to export the calendars from the old server to the new one?
Thank you.

Answer 1

My impression is that the individual users' Calendars are stored in their individual User Directories on the Server.
/Users/short-user_name/Library/Calendars/
The actual filenames are impenetrable -- they look like UUID strings.
I did not copy any calendar data around. But when I did my upgrade, I had to re-specify the calendar accounts
(inside Calendar > Preferences > Accounts for each user)
... before it would agree that there was any valid Calendar data anywhere.