For decades, PHP has utilized custom licenses: the PHP License for the core language and a separate Zend Engine License for the sources found within the Zend directory. Wondering why? Here’s the answer.
Back in the day, the idea was that the Zend Engine could be unbundled and used independently. However, after 25 years of tight integration within the same repository, that separation is no longer practical.
At the same time, these separate licenses have long been sources of ambiguity due to specific clauses and their incompatibility with widely recognized licenses, such as the GPL. Moreover, while the PHP License previously gained Open Source Initiative approval, this was more a matter of legacy use rather than an explicit endorsement of its content.
This brings us to the news that came a few days ago from the PHP camp: Ben Ramsey, a prominent figure in the PHP community, introduced a new RFC proposing a significant update to the PHP License and the Zend Engine License. The goal? To adopt the widely respected Modified BSD License, also known as the 3-clause BSD License, for both PHP and its underlying Zend Engine starting with PHP 9.0.
To clarify, the Modified BSD License is officially approved by both the Open Source Initiative and the Free Software Foundation, ensuring that it aligns with current open-source standards and maintains compatibility with GPL software.
So, what’s the plan? The RFC, currently under discussion, proposes adopting the Modified BSD License as the PHP License, version 4, and the Zend Engine License, version 3. This license, known for its simplicity and permissiveness, is both OSI-approved and GPL-compatible, ticking all the right boxes for open source enthusiasts.
It allows developers to use, modify, and distribute the software with minimal restrictions, provided they include the copyright notice and disclaimer.
By stripping away PHP-specific and Zend-specific terms from the existing licenses, the proposal ensures that the rights granted to contributors and users remain unchanged while aligning PHP with a globally recognized standard.
To make this happen, the PHP project plans to collaborate with the PHP Group and Perforce Software (the current owner of Zend Technologies) to adopt the Modified BSD License.
The existing PHP License and Zend Engine License would be deprecated, and their use in new projects would be strongly discouraged. The LICENSE file in the PHP software would be updated to reflect the new terms, and file headers across PHP and Zend Engine source files would be revised to align with the Modified BSD License.
For now, the RFC is still under discussion, and the PHP community is actively weighing in on it. If it moves forward, the changes would likely debut with PHP 9.0. As always, we’ll keep you in the loop with any updates. In the meantime, you can check out the proposal here.
