“Because Proton are not accepting contributions, they own all the copyright, so can make the code closed source again if they want to (that wouldn’t affect the already released versions, but future versions)”
They can’t do that actually. They can close the source, yes, but if they do they can’t then release the new closed-source version to the public.
Does the GPL require that source code of modified versions be posted to the public?
The GPL does not require you to release your modified version, or any part of it. You are free to make modifications and use them privately, without ever releasing them. This applies to organizations (including companies), too; an organization can make a modified version and use it internally without ever releasing it outside the organization.
But if you release the modified version to the public in some way, the GPL requires you to make the modified source code available to the program’s users, under the GPL. [Emboldened by me.]
Can the developer of a program who distributed it under the GPL later license it to another party for exclusive use?
No, because the public already has the right to use the program under the GPL, and this right cannot be withdrawn.
“They could likely take down any derivative on iOS, since Apple will always take instruction from the copyright holder, for GPL’d code”
Does the license prohibit this? Definitely. Could they get away with it? Probably. Though I’m uncertain Proton would go that far. I mean, if they wanted to prevent forks, they wouldn’t have released the source, let alone with the GPL3 license, which requires the right to make modifications (as that’s one of the Four Freedoms).
“Since the builds are not reproducible, there’s no guarantee that the binaries they distribute are built from the source code”
Technically true, I suppose, though again why they would do that is beyond me. If they didn’t want forks, they likely wouldn’t have allowed forks.
Again, this is all assuming I’m understanding the GPL FAQ page correctly. If I’m wrong, I would welcome someone smarter than me to correct me. :)
IANAL, but AFAIK that’s incorrect. If you’re the only copyright holder, you can issue multiple licenses for your work. GPL doesn’t allow you to rescind previous issues, so anyone in possession of your GPL code can still modify and release it under the GPL freely. But it doesn’t prevent you from issuing your own work under a different license.
There isn’t usually much economic sense for most applications to do that because anyone can fork the project and distribute it for free. For Proton, since they still hold the server as closed source, they could simply introduce a breaking protocol change and all the forks would be useless.
The way I understand it is that they can relicense it and then publish it if they want, but the GPL would still fully apply to the previous versions.
The first question you cited seems to refer to any different organisation/individual making changes to the source code. And the second seems to refer to revoking the GPL for an already released version, which they would of course not be allowed to do.
This would make sense as ownership of the copyright would supersede a license.
“releasing the modified version to the public” would cover them re-closing the source and then subsequently releasing that newly closed source, so they can’t relicense it and then release the built version of the code.
At least not easily, this is where court history would likely need to be visited because the way it’s worded the interpretability of “modified” in this context would need to be examined.
Not a lawyer but in the scenario where proton closed the source but kept offering the build, even if gpl3 still applies since they’re the only copyright holder (no contributions) it’d only give them grounds to sue themselves?
The GNU licenses are copyright licenses; free licenses in general are based on copyright. In most countries only the copyright holders are legally empowered to act against violations.
They can’t do that actually. They can close the source, yes, but if they do they can’t then release the new closed-source version to the public.
From the GPL FAQ page:
Alternatively:
Does the license prohibit this? Definitely. Could they get away with it? Probably. Though I’m uncertain Proton would go that far. I mean, if they wanted to prevent forks, they wouldn’t have released the source, let alone with the GPL3 license, which requires the right to make modifications (as that’s one of the Four Freedoms).
Technically true, I suppose, though again why they would do that is beyond me. If they didn’t want forks, they likely wouldn’t have allowed forks.
Again, this is all assuming I’m understanding the GPL FAQ page correctly. If I’m wrong, I would welcome someone smarter than me to correct me. :)
IANAL, but AFAIK that’s incorrect. If you’re the only copyright holder, you can issue multiple licenses for your work. GPL doesn’t allow you to rescind previous issues, so anyone in possession of your GPL code can still modify and release it under the GPL freely. But it doesn’t prevent you from issuing your own work under a different license.
There isn’t usually much economic sense for most applications to do that because anyone can fork the project and distribute it for free. For Proton, since they still hold the server as closed source, they could simply introduce a breaking protocol change and all the forks would be useless.
The way I understand it is that they can relicense it and then publish it if they want, but the GPL would still fully apply to the previous versions.
The first question you cited seems to refer to any different organisation/individual making changes to the source code. And the second seems to refer to revoking the GPL for an already released version, which they would of course not be allowed to do.
This would make sense as ownership of the copyright would supersede a license.
“releasing the modified version to the public” would cover them re-closing the source and then subsequently releasing that newly closed source, so they can’t relicense it and then release the built version of the code.
At least not easily, this is where court history would likely need to be visited because the way it’s worded the interpretability of “modified” in this context would need to be examined.
Not a lawyer but in the scenario where proton closed the source but kept offering the build, even if gpl3 still applies since they’re the only copyright holder (no contributions) it’d only give them grounds to sue themselves?
From gnu.org:
Oh, yes but the DRM exemption clause means that you can backwards engineer the changes and continue releasing them under GPL
Edit: as an example we should probably be looking at the duckststion situation evolving right now:
https://vimuser.org/duckstation.html