Debian Reference
Chapter 5 - Upgrading a distribution to testing

Official release notes for upgrading are located at http://www.debian.org/releases/stable/releasenotes and http://www.debian.org/releases/testing/releasenotes (work in progress).

The process for upgrading a system to testing/unstable flavors is:

• upgrade the APT system to the Woody version if your system is Potato, since Potato's APT did not have the features described in the Woody apt_preferences(5) manpage.

• modify your /etc/apt/sources.list and /etc/apt/preferences files, to include references to the "testing" section of the repositories you use. If you wish you can add references to the "unstable" section, too.

• update your package lists, and install any packages that are now upgradeable.

5.1 Transition of APT to the Woody version

Network upgrade of the APT system and some core packages to the Woody versions can be done as follows after including stable sources in the /etc/apt/sources.list if you still run Potato.

     # apt-get update
     # apt-get install libc6 perl libdb2 debconf
     # apt-get install apt apt-utils dselect dpkg

5.2 Transition preparation (stable to testing)

Tracking the testing flavor of Debian has a side effect of providing very slow security fixes. So be warned.

Network upgrade to testing can be done as follows (run the script go-woody to do this in one command):

Empty the existing sources.list file:

     # cd /etc/apt
     # cp -f sources.list sources.old 
     # :>sources.list

Get a clean list of repositories, for stable:

     # cd /
     # apt-setup noprobe 
         ... select repositories, accessed with HTTP or FTP methods

Add the testing section to this new list. The deb-src lines are commented out.

     # cd /etc/apt
     # grep -e "^deb " sources.list  >sources.deb
     # grep -e "^deb-" sources.list  >sources.src
     # sed -e "s/stable/testing/"  sources.deb \
          >>sources.list
     # sed -e "s/stable/testing/" sources.src | \
          sed -e "s/^deb-/#deb-/"  >>sources.list
     
     # apt-get update
     # apt-get install apt apt-utils
     # cat >preferences <<EOF
      Package: *
      Pin: release a=testing
      Pin-Priority: 600
      
      Package: *
      Pin: release a=unstable
      Pin-Priority: 50
     
      EOF

Optionally, add the "unstable" section of the archives.

     # sed -e "s/stable/unstable/" sources.deb \
          >>sources.list
     # sed -e "s/stable/unstable/" sources.src | \
          sed -e "s/^deb-/#deb-/"  >>sources.list

See Basics of Debian package management, Section 6.2 for the art of tuning /etc/apt/sources.list and /etc/apt/preferences.

Now you can update and upgrade, using one of the methods in the next section.

5.3 Upgrade the Debian system

After properly setting up /etc/apt/sources.list and /etc/apt/preferences files, the system can be upgraded to testing. See Debian package management, Chapter 6 for the basics, and see APT upgrade troubleshooting, Section 6.3.2 if you encounter problems.

5.3.1 Best upgrade practice using dselect

If a system has many packages which include -dev packages, etc., the following method using dselect is recommended for fine-grained package control.

     # dselect update  # always do this before upgrade
     # dselect select  # select additional packages

All your current packages will be selected when dselect starts. dselect may prompt you with additional packages based on depends, suggests, and recommends. If you do not want to add any packages, just type Q to exit dselect again.

     # dselect install

You will have to answer some package configuration questions during this part of the process, so have your notes ready and allow some time for this part. See dselect, Section 6.2.3.

Use dselect. It always works :)

5.3.2 Deprecated upgrade practice using apt-get

The use of apt-get described below is widespread but it is not recommended for system upgrades. If you need to upgrade without dselect after Woody, consider aptitude and other options.

If a system does not have many packages or the Debian archive did not have major changes, the following may be sufficient (sometimes).

     # apt-get update # always do this before upgrade
      ... to upgrade the system with "depends" selections: 
     # apt-get upgrade                     # always do this before upgrade
      ... to upgrade the whole system with "depends" selections: 
     # apt-get -u dist-upgrade
      ... or to upgrade and stay with current dselect settings (new, better):
     # apt-get -u dselect-upgrade         # use dselect setup result

Since this upgrade method uses apt-get, its handling of recommends and suggests is limited. See Package dependencies, Section 2.2.8.

Debian Reference