Upgrading and migrating from 2.0.16 to 2.1.9

[Ken Causey]

I'm retiring a server that is currently running Cyrus IMAPD 2.0.16 and
would like to replace it with a Debian server that would be running
2.1.9.  I need to move all existing data (mailboxes, etc.) from the
2.0.16 to the 2.1.9 server.  I tried the stupid way which is to simple
move the files but Cyrus clearly wasn't happy with that.  Can someone
please point me at information on upgrading a migrating between these
two versions?

Ken Causey
ken at ineffable.com