Understanding the Open Publication License (OPL-1.0) The is an early copyleft free documentation license released on June 8, 1999, by the Open Content Project. Designed specifically for text, books, and educational materials, it predates the widespread adoption of Creative Commons. While largely superseded by modern licensing frameworks, it remains a milestone in open-content history. Quick Reference Summary Description Release Date June 8, 1999 Created By Open Content Project License Type Copyleft / Free Documentation Primary Target Written works, documentation, and textbooks Current Status Deprecated (Replaced by Creative Commons) Core Permissions and Rights
If you have an existing project under OPL-1, you cannot simply "change the license." The license is irrevocable for any code already distributed. However, you have two options: opl-1 license
The is a historical artifact—a well-intentioned but ultimately flawed attempt at defensive copyleft. It succeeds in preventing proprietary lock-in better than the MIT License, but it fails to integrate with the modern open-source ecosystem. Understanding the Open Publication License (OPL-1
The OPL-1 attempted to clarify patent rights in a way that the GPL (at the time) arguably did not. It included an explicit patent license grant. This meant that if the author of the software held patents that were necessary to run the software, the license granted users the right to use those patents. This was a forward-thinking inclusion that eventually became standard in licenses like the Apache 2.0. Quick Reference Summary Description Release Date June 8,
The OPL-1.0 is officially deprecated. The original creators at the Open Content Project closed the project and formally recommended that authors migrate to Creative Commons (CC) licenses.
The software may only be executed or modified if a valid license has been purchased (typically through the Odoo store) or if a separate written agreement exists with the authors.