How to update debian 6.0 squeeze at CURRENT moment (Sep 2016)

Debian Squeeze has reached EOL, it doesn't receive any security updates, but if you need to update your database and install packages, its repositories can be found on Debian Archive.

You should edit your sources.list as bellow:

deb http://archive.debian.org/debian/ squeeze main non-free contrib

Also you need to comment out all other repositories.

To update run:

apt-get install debian-archive-keyring
apt-get update

debian-archive

As time goes on we will expire the binary packages for old releases. Currently we have binaries for squeeze, lenny, etch, sarge, woody, potato, slink, hamm and bo available, and only source code for the other releases.

If you are using APT the relevant sources.list entries are like:

 deb http://archive.debian.org/debian/ hamm contrib main non-free

or

 deb http://archive.debian.org/debian/ bo bo-unstable contrib main non-free