In Proxmox we can enable updates via apt without a paid license.

Establish a shell on your Proxmox server. Replace pve with the hostname or IP address of your Proxmox server.

ssh root@pve

I’m going to use vi to edit files, but nano is a better choice if you aren’t familiar with a modal editor like vi. I normally use vim, but only vi is available until you get apt working and have the ability to install it.

Edit your sources.list file.

vi /etc/apt/sources.list

Add this.

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

Edit your pve-enterprise.list file.

vi /etc/apt/sources.list.d/pve-enterprise.list

Comment out the single entry there.

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

Run the following commands.

wget http://download.proxmox.com/debian/proxmox-ve-release-6.x.gpg -O /etc/apt/trusted.gpg.d/proxmox-ve-release-6.x.gpg
sha512sum /etc/apt/trusted.gpg.d/proxmox-ve-release-6.x.gpg
apt update

That’s it. You can update and install what you wish.

apt update
apt install vim curl -y

Perform a distribution upgrade if you wish.

apt dist-upgrade