5 ms·

I'm sure it even matters. GPL is copyleft. Doesn't that mean that they can not relicense the same or derived work under a more restrictive license?

rcfox 13y ago
No, that means you can't relicence it. The copyright owners aren't affected by the license and may do as they please.
_delirium 13y ago
Not being able to relicense under a more restrictive license is actually the main element of copyleft. With an MIT or BSD licensed work, you can add more restrictive conditions, e.g. make a derived work proprietary, or add a "noncommercial use only" clause to your derived work, or whatever else you want. But with a GPL-licensed work, you cannot add additional conditions to the derived work, i.e. you must give all downstream reusers the same permissions you received. That's what's sometimes referred to as the "viral" property. Unless, as here, you are the owner of the copyrights, in which case you can apply any license you want to the work.
- dragonwriter 13y ago
  > Not being able to relicense under a more restrictive license is actually the main element of copyleft. Not being able to relicense under a license not acceptable to the authors of the particular copyleft license at issue is a main element of copyleft, but copyleft licenses often allow redistributing under more restrictive licenses that remain acceptable to the copyleft license author (e.g., the FSF encourages the use of "or any later version" language in GPL licenses, and GPLv3 is in many respects more restrictive than GPLv2; further, GPLv3 allows relicensing with specified kinds of additional terms that may in some ways be more restrictive.)
  - foobarbazqux 13y ago
    Some more examples: the LGPL is copyleft and you can convert it to the GPL. Sometimes the GPL comes with a special exception, which can also be removed. AGPLv3 is more restrictive than GPLv3, and again you can convert GPLv3 to AGPLv3. If you consider what developers are allowed to do with a piece of software, the main element of copyleft is actually not being able to relicense under a less restrictive license on the spectrum of FOSS licenses. The least restrictive "license" of all is no license, no copyright, i.e. public domain (in the US). Because you can convert MIT/BSD to a closed source license, but you cannot convert GPL to a closed source license, in this sense the GPL is more restrictive than MIT/BSD. You can convert MIT/BSD to GPL (less to more) but not GPL to MIT/BSD (more to less). I understand that closed source licenses are the most restrictive of all, this is just an alternative perspective on software freedom with regard to developers.

rcfox 13y ago

No, that means you can't relicence it. The copyright owners aren't affected by the license and may do as they please.

_delirium 13y ago

Not being able to relicense under a more restrictive license is actually the main element of copyleft. With an MIT or BSD licensed work, you can add more restrictive conditions, e.g. make a derived work proprietary, or add a "noncommercial use only" clause to your derived work, or whatever else you want. But with a GPL-licensed work, you cannot add additional conditions to the derived work, i.e. you must give all downstream reusers the same permissions you received. That's what's sometimes referred to as the "viral" property. Unless, as here, you are the owner of the copyrights, in which case you can apply any license you want to the work.

dragonwriter 13y ago
> Not being able to relicense under a more restrictive license is actually the main element of copyleft. Not being able to relicense under a license not acceptable to the authors of the particular copyleft license at issue is a main element of copyleft, but copyleft licenses often allow redistributing under more restrictive licenses that remain acceptable to the copyleft license author (e.g., the FSF encourages the use of "or any later version" language in GPL licenses, and GPLv3 is in many respects more restrictive than GPLv2; further, GPLv3 allows relicensing with specified kinds of additional terms that may in some ways be more restrictive.)
- foobarbazqux 13y ago
  Some more examples: the LGPL is copyleft and you can convert it to the GPL. Sometimes the GPL comes with a special exception, which can also be removed. AGPLv3 is more restrictive than GPLv3, and again you can convert GPLv3 to AGPLv3. If you consider what developers are allowed to do with a piece of software, the main element of copyleft is actually not being able to relicense under a less restrictive license on the spectrum of FOSS licenses. The least restrictive "license" of all is no license, no copyright, i.e. public domain (in the US). Because you can convert MIT/BSD to a closed source license, but you cannot convert GPL to a closed source license, in this sense the GPL is more restrictive than MIT/BSD. You can convert MIT/BSD to GPL (less to more) but not GPL to MIT/BSD (more to less). I understand that closed source licenses are the most restrictive of all, this is just an alternative perspective on software freedom with regard to developers.