The setup

I run a Debian Squeeze host that I use to build a multilanguage project (python, java, php...) and generate custom packages (debian and RPM) automatically (through jenkins)

The problem

The target distributions of those Debian packages are Etch, Lenny and Squeeze. But our project has some native dependencies that are available only through the DebianRelease + 1 repository (i.e Lenny + 1 == Squeeze, Squeeze + 1 == Wheezy). We for example, need the jetty packages from Squeeze in Lenny, and the cyrus-imapd-2.4 packages from Wheezy in Squeeze. Some additional info :

• Some package we can simply 'backport by hand' by mirroring the DebianRelease + 1 packages to our own repositories. For instance, the jetty package from Squeeze will run fine on Lenny because it doesn't need an s**tload of additional dependencies

• However we do need to rebuild some packages. For instance, cyrus-imapd-2.4 from Wheezy has a lot of unsatisfied dependencies on Squeeze. So we need to rebuild it in Squeeze and then upload it to our repo.

The question

I need to have a simple way of knowing if they are any updates on those extra packages (both "normal" and "security" updates). I could write a simple script that runs weekly, get some parameters from a file, and generate an update report. Let's say the file looks like this:

jetty:squeeze
cyrus-imapd-2.4:wheezy

The script should run as normal user not to mess up the system apt configuration and issue the appropriate commands to generate that report.

Does Debian has some built-in apt-* commands/options dedicated to that kind of problem I could use to write this script ? If not, can someone think of another clean solution to achieve what I need ?