UPGRADING RASPBERRY PI OS IN PLACE

Doing an in place upgrade is rather simple actually. Edit one file, execute three commands and done!

EDIT THE APT SOURCES FILE

Edit the sources.list file :

sudo nano /etc/apt/sources.list

Then change the line that should be at the top, that reads :

deb http://raspbian.raspberrypi.org/raspbian/ buster main contrib non-free rpi

And change the "buster" part, the Debian release version according to the following:

As of the time of writing this, you would want to use "bullseye".

Execute the following two commands to update the system:

sudo apt update
sudo apt upgrade

When the upgrade command completes, you can then do :

systemctl reboot

Once the Pi is back up and sitting at the login screen/desktop you are golden!