Hi,
It is indeed free, open-source software, licensed under AGPLv3
We offer subscriptions [1], which grant access to the enterprise repository, but you are free to use the no-subscription repository at no cost. The difference here is that the enterprise repository is stable and heavily tested, thus suited to production environments, while the no-subscription repository receives the latest updates that have not had the chance to be vetted as heavily.
To set up with the no subscription repository, simply follow the installation instructions [2]. After the system is set up, remove the enterprise repository with
rm /etc/apt/sources.list.d/pmg-enterprise.list
, and add the no-subscription repo with
echo "deb http://download.proxmox.com/debian/pmg buster pmg-no-subscription" >> /etc/apt/sources.list.d/pmg-no-sub.list
.
Feel free to get in touch, in case you want to find out more about the benefits of a subscription
[1]
https://proxmox.com/en/proxmox-mail-gateway/pricing
[2]
https://pmg.proxmox.com/pmg-docs/pmg-admin-guide.html#_installation