Questions around moving from 2.2.12 to 2.4.12

[Stefan G. Weichinger]

Hello, cyrus-imap-users (and -devs?),

I subscribed to this list today because I am searching for some
information around upgrading/migrating my cyrus-imap-server.

Unfortunately I waited very long, hopefully not too long ...

The old server runs Suse Linux 10.1 with these versions:

# rpm -qa | grep cyrus
cyrus-sasl-2.1.21-3
cyrus-sasl-devel-2.1.21-3
cyrus-imapd-2.2.12-13

I have a few hundred accounts within web-cyradm, which means their
passwords are stored encrypted (so the imapsync-approach is problematic).

My goal is to migrate things over to a newer server running gentoo
linux, the maintained version of cyrus-imapd there is 2.4.12 (the older
2.2.13 from a separate gentoo-overlay didn't compile for me).

Moving the mysql-DB shouldn't be much of a problem, the web-cyradm tool
runs on gentoo already.

So my question is: how to move things in the most stress-free way?

Could I simply copy over /var/spool/imap etc, and start the newer version?

Do I have to somehow convert things? If yes, is it problematic?

I am thinking about just trying it for a test, but I would really feel
much better with some competent feedback from the cyrus-imap-community.

Thanks a lot in advance, Stefan.