Access the console through the web interface, User: root and make a copy of the pve-enterprise.list sources file, like so:

cd /etc/apt/sources.list.d/

cp pve-enterprise.list pve-no-subscription.list

Ok, so now we have a copy of the original file. If we ever purchase a subscription later and want to use the enterprise repositories, we will be able to revert what we’ve done very easily. For now, edit the original file and edit its one line and replace it with the following code.

# deb https://enterprise.proxmox.com/debian/pve bullseye pve-enterprise

Save and close the file.

Next, open the copied file, pve-no-subscription.list.

nano pve-no-subscription.list

Now change the pve-no-subscription.list with the following lines.

deb http://ftp.debian.org/debian bullseye main contrib
deb http://ftp.debian.org/debian bullseye-updates main contrib

# PVE pve-no-subscription repository provided by proxmox.com,
# NOT recommended for production use
deb http://download.proxmox.com/debian/pve bullseye pve-no-subscription

# security updates
deb http://security.debian.org/debian-security bullseye-security main contrib

Save and close the file. Now, update the package lists:

apt update

And when that’s done, run software upgrades!

apt dist-upgrade

Note: Always run dist-upgrade, not just “apt-get upgrade.” Dist-upgrade ensures that all the packages and their dependencies are updated. If you just run “apt-get upgrade” things may break.

That’s it, now you have installed Proxmox and updated it to the latest version. Now you can deploy your virtual machines directly from the web interface https://ip:8006.