You can run Proxmox for free with all features because of the copy-left license AGLP3.
You pay for support tickets (zero or more). Are you a lawyer? I guess I'm a nerd and I pay for free software (for a much as I feel I can afford), to keep it free.
The thing with license vs subscription is not really how it is simplified on the forum, license is the right to use e.g. a product or access content, quite often perpetually (even e.g. e-books would be licensed to you on an e-reader "kind of" forever, i.e. they are NOT irrevocable and they can pull your purchases off your device).
Subscription simply implies (in this context) a recurrent payment (for anything, really). Nowadays, everyone really likes to sell you a subscription, the whole SaaS is a
subscription licensing model - so it is perfectly normal that one and the other are used interchangeably.
The license (to use) PVE (the software) is indeed the GPL one. The subscription happens to be for support (not that it would be impossible, but I can't quite imagine profitable business offering a one-off payment for perpetual support), but the Community one is not really payment for any support, it's a mere LICENSE to access the select repo, a recurrent one, hence it is a
subscription license. As are effectively all the other subscriptions, since they contain the license to access the repo. Note they could still be considered all licenses even if all they granted was "just" the right to make use of the support, but you would casually just refer to them as "support subscriptions".
Also note how the whole Agreement [1] is phrased: "
(Re-)Distributing Software packages received under this Subscription Agreement to a third party or using any of the subscription services for the benefit of a third party is a material breach of the agreement. Even though the open-source license applicable to individual software packages may give you the right to distribute those packages (this limitation is not intended to interfere with your rights under those individual licenses)"
EDIT: Since I expect to end up being taken apart here after the past day, let me support myself [2] ...
license, n. (15c) 1. A permission, usu. revocable, to commit some act that would otherwise be unlawful; esp., an agreement
open-source license. A license that allows open-source software users to copy, distribute, or modify the source code, and publicly distribute derived works based upon the source code. - Open-source licenses usu. do not require royalty or other fees on distribution. The license typically requires a user who redistributes original or modified software that was received under an open-source license to provide the original license terms, including all disclaimers, to all future users, and to distribute the source code with any machine-executable software. It is unclear who has the right or power to enforce the terms of an open-source license. Sometimes termed general public license.
proprietary license. A license that restricts a software user's ability to copy, distribute, or modify the software.
subscription, n. (15c) 3. An oral or a written agreement to contribute a sum of money or property, gratuitously or with consideration, to a specific person or for a specific purpose. Also termed subscription contract.
subscription list. An enumeration of subscribers to an agreement, periodical, or service.
And yes, these things matter [3].
[1]
https://www.proxmox.com/images/download/pve/agreements/Proxmox_VE-Subscription-Agreement_V4.3.pdf
[2]
Black’s Law Dictionary 1002,1564 (9th ed. 2009)
[3] https://www.dlapiper.com/en/insight...rench-court-awards-damages-for-gpl-violations