How to Upgrade Debian 10 to Debian 11
One of the advantages of the Debian operating system is easy to upgrade to the newer version.
Login to your Debian 10 server using SSH or console. Install all available software updates with the command
apt update && apt upgrade -y
Remove any unused packages
apt autoremove
Change /etc/apt/sources.list
Make a backup of the file
cp /etc/apt/sources.list ~/
Edit the file /etc/apt/sources.list
In the file, change all “buster” entries to “bullseye”. You can do this manually or using sed command
sed -i 's/buster/bullseye/g' /etc/apt/sources.list
Update System
Update repository cache with
apt update
Upgrade software with
apt upgrade
Do a full-upgrade with
apt full-upgrade
Now reboot system
reboot
After reboot, you need to make sure all services running properly, there is a chance some services won’t work as expected, in that case, you need to debug and fix i.
See Debian