upgrading BerkeleyDB

[Robert Carsey]

I'm sure this has been asked and answered, but the archives seem to be
very slow tonight.

I have a machine running Cyrus 2.1.13 and Berkeley 3.3 (used only for
mailboxes.db and duplicate suppression).

Is it possible to stop the server, install BDB 4.x, compile Cyrus 2.1.14
(with the BDB 4.x libraries), and restart Cyrus?

Obviously, the Cyrus upgrade is very minor and won't present any
problems.  The Berkeley DB upgrade I'm not so sure about.  Will the 4.x
libraries be able to use a 3.3 database?  Will it "upgrade" the
database?  Is it easier (safer?)  to do a dump/load of the database?  If
so, how and why?

I did a quick test and it seems to work, but I'm reluctant to put it
into production until I hear from some other sysadmins.

--Robert