# In Place Upgrade Debian 11 Bullseye to 12 Bookworm

1. Log into the Debian 11 device
2. Run the following commands in a terminal window
   # clean apt cache
   sudo apt clean
   # update apt repositories from bullseye to bookworm
   find /etc/apt -type f -name "*.list" -print0 | xargs -0 sudo sed -i.bak "s/bullseye/bookworm/g"
   # add optional non-free repos
   echo "deb https://deb.debian.org/debian/ bookworm main contrib non-free non-free-firmware" | sudo tee /etc/apt/sources.list
   # update software repositories
   sudo apt update
   # install software updates
   sudo apt dist-upgrade -y
   # remove unnecessary packages
   sudo apt autoremove -y
   # clean apt cache
   sudo apt clean
   # reboot
   sudo reboot now
3. That's it, Debian 11 Bullseye has been updated in place to Debian 12 Bookworm