Upgrading OS in LXC Container

Backup the container

Debian 11 (bullseye) -> 12 (bookworm)

Follow these steps:

Start with:

apt-get update
apt-get upgrade
apt-get full-upgrade

Then replace references to bullseye with bookworm:

• edit /etc/apt/sources.list. bookworm sources.list.
• edit files in /etc/apt/sources.list

Then:

apt-get clean
apt-get update
apt-get upgrade
apt-get full-upgrade
apt-get autoremove

If apt update results in

W: https://foo/bar: Key is stored in legacy trusted.gpg keyring (/etc/apt/trusted.gpg), see the DEPRECATION section in apt-key(8) for details.

Try:

mv /etc/apt/trusted.gpg /etc/apt/trusted.gpg.d/