Upgrade bullseye->bookworm

apt update && apt full-upgrade -y

eher unwahrscheinlich, aber checken:

apt-mark showhold
apt-mark unhold [Paketname]

Sicherung und bullseye durch bookworm ersetzen in einem Befehl

sed -i'.BAK' 's/bullseye/bookworm/g' /etc/apt/sources.list

apt update
apt dist-upgrade --fix-missing

nach der installation meckert er irgedwas wegen „non-free-firmware“ – einfach hinten an die urls hängen

nano /etc/apt/sources.list

deb http://security.debian.org/ bookworm-security main contrib non-free non-free-firmware
deb-src http://security.debian.org/ bookworm-security main contrib non-free non-free-firmware
deb http://ftp.uk.debian.org/debian/ bookworm-updates main contrib non-free non-free-firmware
deb-src http://ftp.uk.debian.org/debian/ bookworm-updates main contrib non-free non-free-firmware
deb http://ftp.uk.debian.org/debian/ bookworm main contrib non-free non-free-firmware
deb-src http://ftp.uk.debian.org/debian/ bookworm main contrib non-free non-free-firmware
deb http://ftp.debian.org/debian bookworm-backports main non-free-firmware
## PHP
deb https://packages.sury.org/php/ bookworm main