About changing the license from GPLv3 to AGPLv3

[Matthew Flaschen]

Finjon Kiang wrote:
> "We have got a permission from the author of OpenAccounting to
> increase the license to GPL v.3. OA was discontinued back in 2005. And
> the GPL v3 and AGPL v.3 are compatible, so there should be no problems
> by using the license GNU AGPL v.3 (or later) for FA."
> 
> FrontAccounting was extended by OpenAccounting, and OpenAccounting was
> extended by WebERP. Both WebERP and OpenAccounting were released under
> GPLv2.
> 
> According to the FAQ in gnu.org:
> http://www.gnu.org/licenses/gpl-faq.html#WhatIsCompatible
> 
> In my understanding, the word 'compatible' means the programs which
> released under either GPLv3 or AGPLv3 could put together. It doesn't
> mean anyone could change the licenses of either program between GPLv3
> and AGPLv3.

As always, it's a bit complicated.  GPLv3 says, "Notwithstanding any
other provision of this License, you have permission to link or combine
any covered work with a work licensed under version 3 of the GNU Affero
General Public License into a single combined work, and to convey the
resulting work. The terms of this License will continue to apply to the
part which is the covered work, but the special requirements of the GNU
Affero General Public License, section 13, concerning interaction
through a network will apply to the combination as such."

So they can create a AGPLv3 module and link to the GPLv3 code.  When the
combination is distributed, AGPLv3 requirements apply.  However, the
GPLv3 code (and any modifications clearly within that module) can still
be used alone without AGPLv3 requirements.

It's not allowed to simply apply AGPLv3 requirements to GPLv3-only code.

Matt Flaschen