I use those steps on LXC virtual in Proxmox:
- Make sure all packages are upgraded:
apt update && apt upgrade - Backup container in Proxmox
- Edit release version:
sed -i'.bak' 's/buster/bullseye/g' /etc/apt/sources.list - Fix security distribution name:
sed -i 's|bullseye/updates|bullseye-security|g' /etc/apt/sources.list - Update other configuration files in
/etc/apt/sources.list.d/appropriately - Update packages index:
apt update - Do minimal system upgrade:
apt upgrade --without-new-pkgs - Do full upgrade:
apt full-upgrade - Restart the system:
reboot