Convert GPL to MPL

Chuck Swiger chuck at
Fri Jan 18 18:47:31 UTC 2008

On Jan 18, 2008, at 10:01 AM, Marcel Ferrante wrote:
> Ok, so lets start from begining.
> There is a open source gpl. I take the software and do some  
> modifications.
> I want distribute the code, everthing, but I wanna charge. Wich my  
> options:
> 1. Change the license
> R: I cant ok ?

You can't change the license of the original source code or derivative  

If your changes are additions rather than modifications to the  
existing sources, and are sufficiently distinct that they form a  
clearly separate work, you could license that work under any terms  
which you like, provided you distribute your work separately.  See GPL  
clause 2:

"  2. You may modify your copy or copies of the Program or any portion
of it, thus forming a work based on the Program, and copy and
distribute such modifications or work under the terms of Section 1
above, provided that you also meet all of these conditions:

     a) You must cause the modified files to carry prominent notices
     stating that you changed the files and the date of any change.

     b) You must cause any work that you distribute or publish, that in
     whole or in part contains or is derived from the Program or any
     part thereof, to be licensed as a whole at no charge to all third
     parties under the terms of this License.  [ ... ]"


"These requirements apply to the modified work as a whole.  If
identifiable sections of that work are not derived from the Program,
and can be reasonably considered independent and separate works in
themselves, then this License, and its terms, do not apply to those
sections when you distribute them as separate works.  But when you
distribute the same sections as part of a whole which is a work based
on the Program, the distribution of the whole must be on the terms of
this License, whose permissions for other licensees extend to the
entire whole, and thus to each and every part regardless of who wrote  

> 2. I keep the gpl license but add a annex with new deffinitions. In  
> this deffinitions I add how I am charging  and some restrictions.
> For example:
> The four lays of open source is respected, of course. But I add if  
> the software or some part is used
> for commercial proposits I charge some $X for month or $XXX forever.
> I can do that ?

You're not allowed to change the license of a GPL'ed work.  However,  
you don't have to change the GPL at all if you simply want to charge  
money for the software-- see RedHat and other Linux distributions--  
"You may charge a fee for the physical act of transferring a copy, and  
you may at your option offer warranty protection in exchange for a fee."

All of the above being said, you cannot prevent people who receive a  
GPL'ed work by any means from freely redistributing it to others.  In  
practice, that means people tend to pay for receiving tech support for  
GPL'ed software, but can fairly easily obtain a GPL'ed program free of  

> 3. If I have a open software gpl that charge $Y for commercial use.  
> Can I do a fork of this project that charge nothing ?

The GPL doesn't contain anything related to charging for commercial  
use.  If it is under the GPL, you are welcome to fork the project  
under the same license terms and charge nothing, yes.


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