Postfix "Security" update in Dapper?

[Scott Kitterman]

I was surprised to find apt-get bringing me a new Postfix version this 
morning:

# apt-get update
...
# apt-get -s upgrade
Reading package lists... Done
Building dependency tree... Done
The following packages will be upgraded:
  postfix
1 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Inst postfix [2.2.10-1] (2.2.10-1ubuntu0.1 Ubuntu:6.06/dapper-security)
Conf postfix (2.2.10-1ubuntu0.1 Ubuntu:6.06/dapper-security)

I am subscribed to ubuntu-security-announce at lists.ubuntu.com and the only 
potentially relevant message I see is:

https://lists.ubuntu.com/archives/ubuntu-security-announce/2006-June/000332.html

The only problem is that I don't have the affected postfix-pgsql installed, so 
I don't know why my Postfix would be "Upgraded".  Additionally, the official 
Postfix version listed at http://packages.ubuntu.com/dapper/mail/postfix 
remains 2.2.10-1.

So, now some questions:

1.  What, if anything, does this change on a system that does not have 
postfix-pgsql installed (and how can I figure this out for myself next time)?

2.  Is this a packaging/dependency bug or is this how it's supposed to work?  
postfix-pgsql depends on postfix, not the other way around.  It doesn't seem 
logical to me that the version of postfix would have to increment because of 
a change in postfix-pgsql.

3.  If one questions the validity of an update, where is the best place to 
look to verify the current version for the release?  I would have thought 
that http://packages.ubuntu.com/dapper/mail/postfix would have been the place 
to check, but it still shows the old version.

I'm somewhat reluctant to apply an update that fixes a problem for a system I 
don't have installed to a correctly functioning system, so I appreciate any 
light that someone can shed on this.

Thanks,

Scott K