Upgrade Debian

Currently most relevant upgrade is Bookworm to Trixie

The main aproach is being cautios, and considering if the install is pure Debian, or there are special things added.

Otherwise the quick and dirty route is:

Check for obsolete packages

apt list '~o'

And remove if they are not essential:

apt purge '~o'

Find and cleanup leftover configurations

find /etc -name '*.dpkg-*' -o -name '*.ucf-*' -o -name '*.merge-error'

Final checks

Check that GPG is installed:

apt install gpgv

Check packages:

dpkg --audit

Update package lists

Change bookworm to trixie in all of:

/etc/apt/sources.list.d/*

Unless there is a good reason not to.

Update, and watch out for failures:

apt update

Prepare upgrade

It is recommended to record a script:

script -t 2>~/upgrade-trixie-1.time -a ~/upgrade-trixie-1.script

Increment the number every time, so they do not get overridden.

Check that there is enough free space:

apt -o APT::Get::Trivial-Only=true full-upgrade

It will fail with:

E: You don't have enough free space in /var/cache/apt/archives/.

The upgrade

First one without installing new packages:

apt upgrade --without-new-pkgs

If that all looks good, go for full upgrade:

apt full-upgrade

When confident and ready, do a reboot!

Cleanup after

Check all app’s are still present. Some times files can be removed from /etc/apt/sources.list.d/ and then the app’s are removed. Fear not mostly it is easy to re-install.

Some configurations are left unchanged (you are asked during full-upgrade), and a .ucf-dist, .dpkg-old and dpkg-bak files for the new config are written instead.

So after the upgrade, find all those:

find /etc -name '*.dpkg-*' -o -name '*.ucf-*' -o -name '*.merge-error'

And decide how to bring your old config up-to-date with the new. Usually manual diff’ing and bringing over new stuff.

OLD!!! Bullseye to Bookworm

Old upgrade was Bullseye to Bookworm