Upgrade 2.2 -> 2.4

[Henrique de Moraes Holschuh]

On Tue, 29 Mar 2011, Ondřej Surý wrote:
> I have just tested the upgrade from 2.2 to 2.4 on my server and it's
> still quite complicated even when the spool is empty :-(.
> 
> We need to work on that since almost all cyrus-*-2.2 packages were
> left in the Install/Conf-files state and purging them removed some
> files from -2.4 packages.
> 
> I'll try to do more serious testing, but it seems that we will need to
> upgrade scripts in 2.2 as well.

Actually, I think we have some outstanding nastyness in 2.2 with
security implications that deserves a look as well, but I have not found
time to work on that at all.  It is all in the BTS.

It is possible to use preinst to safeguard against installing without the
unfixed 2.2 packages, and avoiding data loss is a damn good reason to do
that.  OTOH, if all that happens is a broken package that --reinstall
can fix, we can probably document that in {NEWS,README}.Debian, plus the
upgrading docs.

-- 
  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh