Transitioning L2jMobius code license from GPLv3 to MIT

[Mobius]

I have a significant announcement to make about the L2jMobius project's future.
After giving it some thought, I've decided that a gradual switch from the GPLv3 license to the MIT license would be best for the project and our community.

Anyone may use, alter, and distribute the code under the more liberal terms of the MIT license, even in proprietary software, provided that due credit is provided.
With this change, we hope to provide developers more freedom to utilize and expand on our work without being constrained by the GPLv3 license.

My Personal Commitment
I'll start this process by moving my own contributions from the GPLv3 to the MIT license.
This will be a gradual transition, where we will legally "free" the project class by class.
I kindly ask everyone who has contributed code to L2jMobius to join me in this endeavor by transferring ownership of their own works to MIT.

With this adaptation, L2jMobius will become the first project in the L2j project line to be truly open-source.
This is a big step toward full open-source freedom since it guarantees that anyone can use our code freely without being constrained by copyleft agreements.

It's Within Our Rights
It's crucial to remember that, as the project lead, I have complete authority to make this modification. I encourage people to do the same, as I am able to relicense my own efforts.
Recently, there has been unwarranted friction in the community due to misunderstandings regarding the true meaning of the GPLv3 license and its history and intent.
These problems have been exacerbated by the widespread misconception that the GPLv3 was never meant to be anything other than what it is.

I will also update previous contributions to the MIT license made by L2jMobius members who have since departed the project.
In the spirit of good faith and true open-source collaboration, their agreement will be assumed unless they later express any objections.
Additionally, any code that has been substantially reworked, with changes exceeding 70%, or adapted either fixed from an inoperable state, will also be transitioned.
Should any of these previous contributors object to this modification, they ought to get in touch with me directly to discuss it.

Next Steps for Contributors
If you have contributed code to the project, I kindly ask that you:

• Review your contributions.
• Update the license of your code from GPLv3 to MIT, ensuring that the necessary attribution is preserved.
• Notify me or the team so we can track this transition and reflect it in the repository.

We acknowledge that some of you might be worried or have questions,
and I'm available to talk about this with anyone who needs additional information about the procedure or the effects of this change.
Although we are not hurrying this change, we are dedicated to making sure that L2jMobius develops in a way that more closely conforms to the ideals of genuine open-source software.

Why Make This Change?
The MIT license offers:

• Freedom of use: Developers can use the code in both open-source and proprietary applications (like your own game).
• Less legal complexity: The MIT license is short, simple, and less restrictive, making it easier for people to adopt and contribute to the project.
• A wider audience: We believe this change will attract more developers to the project, as they will have the freedom to use and modify the code without legal barriers.

Related Discussion
As some of you may know, before branching out as L2jMobius, I contributed to L2jServer under the name Pandragon.
This topic was first raised in a discussion on the L2jServer forum by me under the name Pandragon in this post six years ago,
where the challenges and limitations of the GPLv3 license were discussed in detail. However, the L2jServer lead was opposed to such a change.


Since L2jMobius is now the initial endeavor to be truly open source, we are grateful for everyone's contributions to the project thus far and look forward to this new chapter in its progress.
Please don't hesitate to contact us with any questions, and we appreciate your participation in this amazing journey.


The New MIT License
For your reference, here is the updated license header that will be included in our source files.

Code: [Select]

/*
 * Copyright (c) 2013 L2jMobius
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
 * IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
Please note: The copyright year remains 2013 in the new MIT license.
This is essential for maintaining the legal continuity and validity of the original software.
Copyright law generally requires that the year reflects when the work was first published or created
and altering it could create legal ambiguities or invalidate claims of ownership over the code.

By keeping the original date intact, we ensure that the history of the project is preserved, while still allowing us to move forward under the new MIT license.
This way, both past and future contributions are clearly tied to their original legal context, ensuring the project’s continuity without disruption.


Preserve Your Code by Transitioning to MIT
Members who wish to give their permission to transition their past contributions from GPLv3 to MIT and be remembered for doing so,
ensuring their code is not eventually deleted or replaced, please use this topic: Request for Member Agreement to Transition Code Licensing from GPLv3 to MIT

[Mobius]

The Ship of Theseus and Clean-Room Engineering

In software development, preserving a project’s functionality while transforming its underlying codebase presents unique challenges.
Concepts like the "Ship of Theseus" and reverse engineering practices provide helpful frameworks for projects
seeking to gradually update or replace code, whether for licensing transitions, improvements, or compatibility.

This topic aims to explain how these ideas can guide a methodical and legally sound transformation of code within open-source projects,
like L2jMobius, while maintaining functionality and respecting original contributions.


The Ship of Theseus Paradox: What Is It?
The Ship of Theseus is a philosophical paradox about identity and transformation.
It asks whether an object that has had all its parts replaced remains fundamentally the same object.
In the classic example, Theseus' ship, over time, has each of its planks replaced one by one. When all the planks are eventually replaced, is it still the same ship?

In software, the Ship of Theseus applies to projects undergoing systematic code replacement, where functionality and purpose remain constant, but the underlying code changes over time.
This is particularly relevant when reworking or re-licensing software, as each piece of code can be individually re-implemented until the project’s original source code is entirely replaced.


Ship of Theseus in L2jMobius
For L2jMobius, we’re using the Ship of Theseus as a guide to gradually transition from GPLv3 to MIT licensing by re-implementing classes one by one under the new license.
Over time, this will result in a project where all code has transitioned to the MIT license without losing its core functionality or requiring a total rewrite.


Reverse Engineering: Clean-Room and Black-Box Practices
Reverse engineering in software is the process of analyzing and reconstructing code to understand how it works and create functionally similar implementations.
When applied to open-source projects, reverse engineering can be a solution for building clean, legally compliant code that preserves existing functionality without copying original code.

There are two primary reverse engineering methods often used in projects with legal or compatibility requirements:

• Clean-Room Engineering: In this approach, one team documents the functionality of a component in detail
  (without using or copying the original code) and a separate team uses this specification to write new code.
  This method ensures that the new code is legally distinct from the original, providing a “clean” replacement.
• Black-Box Analysis: Black-box engineering focuses on observing inputs and outputs without accessing the original code.
  Developers analyze how a component behaves in different situations and write new code that mimics this behavior.
  This method is useful for projects that need to replicate specific features while avoiding code duplication.

Clean-Room Approach in L2jMobius
For L2jMobius, we’re employing a clean-room engineering approach, where specifications for each GPLv3-licensed class are documented, and new MIT-licensed code is implemented based on these specs.
This process involves documenting each class’s purpose, methods, and functionality before writing a new, independent implementation.

Why Use These Approaches?
The Ship of Theseus and reverse engineering methods provide a pathway for projects looking to re-implement code without infringing on original licenses or compromising functionality.
Here are the key benefits:

• License Transition: By re-implementing code under a new license, projects can transition to the more flexible licensing model (MIT), providing greater freedom for developers and users.
• Legal Compliance: Clean-room and black-box engineering ensure the new code is distinct from the original, allowing to maintain legal compliance when re-implementing proprietary or restrictive code.
• Modular Updates: Following a Ship of Theseus approach allows for gradual, modular updates rather than a complete overhaul.
  This means the project can remain functional and up-to-date without pausing development for a large-scale rewrite.

How L2jMobius Will Use These Principles
To transition L2jMobius from GPLv3 to MIT:

• Clean Documentation: We’ll create detailed specifications for each existing class. These specs will describe the functionality without copying any original code.
• New Implementations: Based on these specs, we’ll implement new MIT-licensed classes, gradually replacing the original GPLv3-licensed classes.
• Testing and Integration: Each new implementation will be rigorously tested to ensure it integrates seamlessly with the rest of the codebase, preserving the original functionality.

In time, L2jMobius will have transitioned fully to an MIT license, with each original GPLv3 component replaced by a functionally equivalent, legally distinct implementation.
This transformation not only adheres to open-source principles but also enhances the project's flexibility and appeal to a broader developer community.

We hope this approach resonates with our community and invites both continued participation and support.
Feel free to reach out if you’d like to learn more or get involved in this transformative journey!