Step zero - change you /etc/apt/sources to new release First the list of available packages for the new release needs to be fetched.

 aptitude update

Before any change try dry run

 aptitude -y -s -f --with-recommends dist-upgrade

Now you have a chance to eliminate problematic packages, especially when you don't need them.

 EXAMPLE: aptitude remove libldap2

Then upgrade packaging system

 aptitude upgrade

Finaly upgrade the whole distribution

 aptitude dist-upgrade

• http://www.debian.org/releases/stable/amd64/release-notes/ Upgrade Debian amd64