The developers of the PHP programming language plan to transition the PHP interpreter and the Zend Engine from the PHP License and Zend Engine License to a 3-clause BSD license (BSD-3). Switching to the BSD-3 license will simplify licensing terms, unify the licenses for PHP and the Zend Engine, ensure compatibility with GPL, and resolve long-standing issues while preserving all rights for users and developers. The license change is intended to take place in the release of PHP 9.0, which may be formed next year. All members of the PHP Group have approved the license change, and this proposal is currently open for public discussion.
The BSD-3 license is compatible with GPL and is widely recognized in the community, unlike the previously used licenses. The PHP License is approved by the Open Source Initiative (OSI), but is deemed incompatible with GPL by the Software Freedom Conservancy due to a clause that prohibits using the term PHP to promote derivative products without obtaining written permission. Debian developers criticized the PHP License for its association with PHP Group products.
Initially, the PHP 1.x and 2.x branches were supplied under the GPLv2 license, but the PHP 3 branch transitioned to a dual license model — PHP License and GPL. In PHP 4, the license was changed again — the main code was distributed solely under the PHP License, while the Zend Engine, which serves as the core interpreter for PHP, was placed in a 'Zend/' subdirectory under a separate Zend Engine License. The Zend Engine License, like the PHP License, contains restrictions regarding the use of the term Zend in derivative products, but additionally requires acknowledgment of the engine's use in promotional materials.
After the transition to the new license, the copyright of all development participants will be retained, and user rights will remain unchanged. The new license imposes no additional restrictions and does not undermine existing rights regarding the use, modification, and distribution of the product. The PHP and Zend licenses are based on the text of the 4-clause BSD license, and transitioning to the BSD-3 license will only involve removing clauses defining requirements related to using the 'PHP' brand, as well as eliminating the condition mandating acknowledgment of the use of the free PHP project in derivative products.
The transition to the BSD-3 license requires approval from Perforce Software, which owns Zend Technologies. It is noted that the issue of switching licenses has already been informally agreed upon with Perforce, and only an official legally significant written confirmation remains to be obtained. Moreover, the license change will not require separate consent from each developer, as the PHP and Zend license texts define the authority allowing the PHP Group to amend the license and release new versions. The process of transitioning to the new license will be framed as an update of the code to PHP License v4 and Zend Engine License v3, the texts of which will match those of the BSD-3 license.
Source: opennet.ru
