Upgrade from Breezy

Andy stude.list at googlemail.com
Thu Feb 21 16:25:11 UTC 2008

On 21/02/2008, Sam Przyswa <samp at arial-concept.com> wrote:
> I never ask to install Postfix 2.4.5 I just "apt-get dist-upgrade" !

You must have added backports at some point. (you may have forgotten
you have done this).
apt-get goes for the newest version backports was the newest version
and presumably Mailscanner didn't have anything in the dependencies
that said don't use a new version of Postfix.

> Ok but HOW to downgrade safely to the 2.2.10 with the right
>  dependencies ?

First off create a backup of everything.
Avoid doing this on your production machine until you know it works
(if possible).
VMs are useful here ;)
I haven't tested this as I am not on an Ubuntu machine at the moment
(and no longer have dapper anyway).
Record *any* error messages generated, don't ignore them.

If you no longer want to use backports then remove it's entry from
your sources list.

If you don't disable backports you're going to need to tell apt not to
use backports for Postfix.
For this you need to edit:
> /etc/apt/preferences
(if it doesn't exist create it).

Add the following:
> Package: postfix
> Pin: release a=dapper-backports
> Pin-Priority: -10

Now do:
> apt-get update
> apt-get install postfix/dapper-security

Now you should check the postfix version is the one you wanted.

As a final check do an
> apt-get upgrade
to check that it leaves postfix alone (i.e. it doesn't update from backports).
(if it replaces postfix with the new version then something has gone wrong)

By the way is packages.ubuntu.com down?

You may also be interested in Commercial support from Canonical, see:

Let us know if this does/doesn't work.


Computers are like air conditioners.  Both stop working, if you open windows.
                -- Adam Heath

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