Understanding Open Source & GPL

When distributing software under any license always seek
appropriate legal council.
The following information has been well researched and is
imparted here for the benefit of informational
understanding on the subject.

Open source software is software whose source code is
available for reuse, modification or enhancement by
anyone.
Source code is the programming language that the
software (program/app) was written in.
Most computer users never get to see source code for the
software they use.

Some software licenses prohibit viewing, modification
and/or redistribution of source code by anyone other
than the ‘owner’ who created it.
aka. ‘proprietary’ or ‘closed source’ software.
Open source allows authors to make its source code
available to anyone under the terms granted in a special
license.
The most popular open source license being used is GPL.
Find more at the Open Source Initiative

• Better control over software execution
• Better security & stability
• Ability to learn & study by viewing code written by
others
• Ability to engage with community by sharing code and
development collaboration
• Ability to repurpose software into doing something it
wasn’t initially intended to do

GNU General Public License, aka GNU GLP or simply just
GPL
• Most widely used “free software license”
• Guarantees end users (individuals, orgs, companies)
– Freedom to use
– Freedom to study
– Freedom to share (copy)
– Freedom to modify

A common misconception is that
“free” GPL software relates to cost.
“Free” is aligned with “freedom to”
i.e. usage & rights, not cost.
“Free as in free speech, not
free beer”

Yes, of course!
However…
As long as the software retains its original GPL license.

The GNU project itself states the following..
"encourages people who redistribute free software to
charge as much as they wish or can... You can charge
nothing, a penny, a dollar, or a billion dollars. It's up to
you, and the marketplace.“
This covers executable code (binaries) not source code.

If you are planning on selling a binary (runnable/working)
copy of a GPL software program…
• You must also include its source code
• Or a formal written offer, valid for 3 years, to provide
the source code or access to it, to whoever possesses
the binary copy.

GPL is “Copyleft” software, a play on Copyright.
Uses the practice of copyright law to offer the right to
• Distribute copies
• Distribute modified versions
AND here’s the important part…
“requiring that the same rights be preserved in modified
versions of the work”
Once GPL – forever GPL

You are free to do what you like with GPL software…
…as long as it stays under GPL license
• For personal use
• For private use
• For commercial use
• For whatever
Once GPL – forever GPL

Licenses are legal copyright entities. They…
• Impose conditions on use
• Impose conditions on reuse
• Impose conditions on redistribution
• Impose conditions on attribution
– You may have the right to redistribute
– You may not claim that you are the original author

Copyright and licenses don’t regulate “identity”-related
issues outside the source code. e.g.
• Company Names
• Logos
• Other copyrighted branding & trademarks
These are separate legal entities covered by Trademark
law.

You obtain some of my original GPL written software.
Yes, you can sell the software and keep all the money for
yourself without giving any of it to me.
You cannot however,
• Say or imply that it is your original work
• Use my company name, logo or trademarks on it
• Imply that we are partners, or that I am in any way
responsible for support or refunds, in any situation

Doesn’t necessarily mean it’s an illegal act.
It means that those issues outside the scope of the
software license and may be dealt with separately and/or
legally.
e.g. Under the “Apache license”*, you must obtain ower
permission before using their trademarks and logos.
*Apache license is another type of “free software” license similar to GPL

Version 1 – 1989
• Freedom to share and modify. GNU project original.
Version 2 – 1991
• “Liberty or Death" clause. If anyone imposes
restrictions on GPL. They can’t distribute under GPL.
Version 3 – 2007 (current)
• Addresses software patents, Digital Rights
Management (DRM)and internationalisation.

Add two elements to each source file or package of your
software
1. A copyright notice
e.g. Copyright Zero Point Development.
2. A statement of copying permission, saying that the
program is distributed under the terms of the
GNU General Public License v3

For a single file program:
Copyright Zero Point Development.
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 3 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
details.
You should have received a copy of the GNU General Public License along with
this program. If not, see <http://www.gnu.org/licenses/>.

For a multi-file programs:
Copyright Zero Point Development.
This file is part of Pooky.
Pooky 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 3 of the License, or (at your option) any later version.
Pooky is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
details.
You should have received a copy of the GNU General Public License along with
this program. If not, see <http://www.gnu.org/licenses/>.

The WordPress “core”
• The WordPress “program” is licensed under GPL
• Includes many other external libraries which may hold
their own GPL license
Themes & Plugins
• Considered separate entities (outside the core)
• These can be licensed under GPL

Themes
• In the style.css in root folder. Comment at top of file.
• e.g. TwentySixteen (on GitHub)
License: GNU General Public License v2 or later
License URI: http://www.gnu.org/licenses/gpl-2.0.html
Plugins
• In the readme.txt (readme.md) and in the plugin
bootstrap (PHP loader file). Comment at top of file.
• e.g. Akismet (on GitHub)
License: GPLv2 or later

Two sites caused a stir in GPL/Premium add-ons in 2013;
WP Avengers (ceased Dec 2014) and GPL Club (active).
Both took (bought) premium WooCommerce themes and
plugins and offered them for lower prices than the
original.
This is legal under GPL but is it ethical or moral to do so?
That’s something for you to decide!

Possible negatives
• GPL Club specifies that support is only provided by
original product authors. This is probably in violation
with GPL and certainly not “in the spirit” of GPL.
• WP Avengers offer paid access to a forum for “premium
support” but customers complained about timely and
lack of responses.
• Support is always best handled by the program authors
who maintain existing and release new versions.

There are many models for selling under GPL.
It is common now to pay for support and updates
How would the premium add-on market react if all GPL
software was available for free (no cost)?
We can’t answer that question but perhaps somebody
will write a presentation about it when it happens.

Visit gnu.org
https://www.gnu.org/licenses/quick-guide-gplv3.html

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[7] synopse.info
[26] gnu.org
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 20+ years in IT: Dev & SysOps
 WordPress Developer since 2008
 Plugins, APIs, Security & Systems Integrations
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zeropointdevelopment.com
@DeveloperWil
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Understanding Open Source & GPL

Understanding Open Source & GPL

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