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Re: Overview of copyright issues

From: Hans Aberg
Subject: Re: Overview of copyright issues
Date: Wed, 9 Sep 2009 20:53:21 +0200

On 9 Sep 2009, at 20:30, Joseph Wakeling wrote:

I think that the formulation should be "GPL, v2 or latest", because
otherwise those that want to redistribute the code can choose which
version, which is not the intent - v3 is in fact more restrictive with
respect to tivoization. Only one GPL should be applicable. The
formulation "or later" is probably spilled usage when indicating which
version can be used - then it means one can choose version.

The standard formulation, as advised in the GPL appendix which describes
how to apply the GPL to your programs, is

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

The whole point of this formulation is to give users of the program the
option to choose which version of the license they want to be bound by
if they redistribute or modify the code, and in particular to make it
easy for a project to upgrade the license OR NOT.

You might check with the GNUers if it is the intention. It means that sources can be tivoized, even in the face of the new v3.

This formulation also means that the distribution conditions may change, even though the copyright notice is not changed of a package, when new
version of the GPL are issued. I think that is fully legal.

The problem with your formulation is that it is too restrictive.
Consider this scenario: a program is being distributed as 'GPLv2 or
latest' as you suggest. Someone writes a GPLv3 program which links with
that code (as they are allowed to do at that point).  Now Version 4 of
the GPL is released. Suddenly the person with the second program can no longer keep linking to new releases of the first one, because 'GPLv2 or latest' now means v2 or v4 and neither v2 nor v4 are compatible with v3.

Linking is always allowed if you make sure the interfaces are provided and other linking info is provided - copyright only controls distribution of the parts that makes it creatively unique, and v3 seemed to have changed over v2 to bring that out. There is no legal requirement that the parts should have the same license.

It's a scenario that is completely undesirable. 'or later' basically is about making sure that writers of programs using all future versions of the GPL will have the right to link to or incorporate your code (as well
as being handy if, as a community, you decide you want to upgrade the

But it has the effect that sources that formerly have been OK to distribute may not be so. For example, if they are tivoized, then when the GPL v3 now has arrived, the old sources cannot be tivoized, even if the package itself has not been changed.

On the other hand, the formulation "or later" means that new sources can be tivoized even if the new version v3 has been released, unless they explicitly mention v3.

It is a choice: when a new license is issued, if it is more restrictive, do you want it to apply or not?

I just point this difference out - do what you prefer.


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