from 2.2.12 to 2.3.1, mailbox has invalid format

[Nicolas KOWALSKI]

Hello,

I am testing the migration from a 2.2.12 installation, compiled with
the default options (./configure without any option), to a 2.3.1
installation, also compiled with the default options. The databases
used are the default for both. The system is Debian 3.1, using db3 for
the berkeley databases (but this should not matter because we do not
use tls caching or duplicate suppression).

When I start the server using the new binaries, accessing some
mailboxes is not possible, the server sending a "mailbox has invalid
format" error. If I run reconstruct on these mailboxes, everything
runs fine afterwards.

Did I forget something ? Should I run reconstruct unconditionnaly on
all mailboxes to prevent any inconsistencies during upgrades ?

Thanks,
-- 
Nicolas