- Log into the Debian 10 device
- Run the following commands in a terminal window
# clean apt cache
sudo apt clean
# update apt repositories to bullseye
find /etc/apt -type f -name "*.list" -print0 | xargs -0 sudo sed -i.bak "s/buster\/updates/bullseye-security/g;s/buster/bullseye/g"
# update software repositories
sudo apt update
# install software updates
sudo apt dist-upgrade -y
# clean apt cache
sudo apt clean
# reboot
sudo reboot now - That's it, Debian 10 Buster has been updated in place to Debian 11 Bullseye