Since 2009 we are developing a fork of a CMS that was started in 1999 as commercial project, but released 2009 additionally under GPL. The original programmer sold copyright, code, name and website in 2012 to a new owner (who is now using the name and website because they have a high google pagerank).

Should our copyright notice be:

@copyright 1999-2009 name of original programmer
@copyright 2009-2014 our names


@copyright 1999-2009 name of new copyright owner
@copyright 2009-2014 our names

  • 1
    I guess your fork is derived from the GPL version and released under GPL as well?
    – Doc Brown
    Commented Nov 5, 2014 at 12:02
  • Yes, our version is based on the 2009 version which was at the time available under commercial licence and linkware. On 1.1.2010 it was additionally released under GPL.
    – svasti
    Commented Nov 7, 2014 at 23:42

3 Answers 3


This is venturing close to a request for legal advice, which we can't give. If you want to be really sure what is legally correct, consult a real lawyer.

The way that copyright statements are generally used is that the initial copyright statement indicates who owned the copyright at the time that a work was created, with a year of creation.
If the work is subsequently modified by the same copyright holder, then the list of years in the copyright statement can be extended to include the year of the modification.
If the work is modified by someone else (person, corporation, etc.) who can claim copyright on the modifications, then a new copyright line is added with the name of the copyright holder for the modifications and the year of change.

The basic principle is that you don't modify copyright statements, except to add additional years of modification to your copyright statement.

When forking a repository, you should leave the original copyrights intact and only add your copyright if and when you make changes to a file.
Thus, if you originally forked in 2010 and have not taken over new material from the original repository and only made a change in 2013, the copyright should look like:

@copyright 1999-2010 name of original programmer
@copyright 2013 your names

In most copyright licenses it is not a strict requirement, but it is usually appreciated if you explicitly state which project you forked from and to change references to the project name to the name of your fork in files you changed to avoid confusion with the original if the file is seen in isolation.


I emailed the FSF licensing lab, and here is the response I received (NB: it was from a licensing volunteer, not from a lawyer, and does not constitute legal advice):

Your obligations under sections 4 and 5 of the GPLv3 are to maintain the existing copyright notices. It has never been a requirement of the GPL to research, affirm or update the copyright headers for modifications to a work for which you are not the copyright holder.

Even if the copyright headers haven't been updated, the current copyright holders would be able to legally enforce the terms of the license by proving that they got the relevant copyrights from the original holders. In addition, the original owners may have a reciprocal license agreement with the current copyright holders which permit them to further distribute the software in certain ways, so you can't know for sure that removing their copyright notice is the right thing even if there is a new copyright holder.

(Bold emphasis mine.)

Therefore, you should keep the licenses intact, as you received them. It appears that your first option is correct:

@copyright 1999-2009 name of original programmer
@copyright 2009-2014 our names

assuming that the software you received had the original header:

@copyright 1999-2009 name of original programmer

Assumed your current version is based on the newest 2014 version from the new owner (with some additional contributions from yourself), you should copy the original copyright notice from this version and add a notice that the additional contributions are yours.

For example: I guess in the original version of 2014 there is something like:

@copyright 1999-2012 name of original programmer
@copyright 2012-2014 name of new copyright owner

then your new copyright notice should be something along the line of this:

This file is part of Fork XYZ
@copyright 2009 your name

This file incorporates work covered by the following copyright and permission notice:   
@copyright 1999-2012 name of original programmer
@copyright 2012-2014 name of new copyright owner

(this is no legal advice, and IANAL.) See this former SO post for a more contrived example.

  • The 1999 code (on which our version is based) was already a bit out of date at the time and has not been developed further. The new owner however aquired the right to change all copyright notices. He actually is now presenting a fork of our verion as the "original". The old code is still available on his website with the notice "development abandoned"
    – svasti
    Commented Nov 7, 2014 at 23:56

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