license-update: add documentation about PHP license changes

README.rst

@@ -26,6 +26,10 @@ It contains the following items:
 -  `Third-Party code <third-party-code.rst>`_: The circumstances under which the
    PHP project will use PHP code written by third parties in the ecosystem.
 
+-  `PHP License <php-license.rst>`_: Documents the PHP project's adoption of the
+   PHP License, version 4, and the Zend Engine License, version 3, and their
+   deprecation in favor of the Modified BSD License.
+
 ***********************
  Requirements Notation
 ***********************

php-license.rst

@@ -0,0 +1,86 @@
+#################
+ The PHP License
+#################
+
+.. IMPORTANT::
+
+   This is a meta document discussing the PHP license. For the actual PHP
+   license, see `PHP Licensing`_.
+
+On April 4, 2026, the PHP project adopted the `PHP License Update RFC`_, which
+published new versions of the PHP License and the Zend Engine License, both
+based on the `Modified BSD License`_ (SPDX: ``BSD-3-Clause``).
+
+*********
+ Changes
+*********
+
+The PHP Group invoked clause 5 of the PHP License, version 3.01, to publish the
+PHP License, version 4. Zend Technologies invoked clause 4 of the Zend Engine
+License, version 2.00, to publish the Zend Engine License, version 3. Both
+organizations provided formal correspondence consenting to these changes.
+
+The PHP project, the PHP Group, and Zend Technologies have deprecated the PHP
+License and the Zend Engine License to decrease `license proliferation`_. Use of
+these licenses for new projects is discouraged. The Modified BSD License (or
+another compatible license) is recommended instead.
+
+*****************
+ Impact on Users
+*****************
+
+The rights granted to users under the PHP License, version 3.01, and the Zend
+Engine License, version 2.00, do not change under the new license versions.
+
+Maintainers of software licensed under the PHP License, version 3.01, may
+relicense under PHP License, version 4, by exercising the upgrade clause in that
+license. When doing so, use the SPDX identifier ``BSD-3-Clause`` rather than the
+name "PHP License, version 4."
+
+******************************
+ Copyright and License Header
+******************************
+
+New source code files contributed to the PHP project should include the
+following header block. See also the php-src CONTRIBUTING_ document.
+
+.. code::
+
+   /*
+     +----------------------------------------------------------------------+
+     | Copyright © The PHP Group and Contributors.                          |
+     +----------------------------------------------------------------------+
+     | This source file is subject to the Modified BSD License that is      |
+     | bundled with this package in the file LICENSE, and is available      |
+     | through the World Wide Web at <https://www.php.net/license/>.        |
+     |                                                                      |
+     | SPDX-License-Identifier: BSD-3-Clause                                |
+     +----------------------------------------------------------------------+
+     | Author:                                                              |
+     +----------------------------------------------------------------------+
+   */
+
+***********
+ Resources
+***********
+
+-  `PHP License Update RFC`_
+-  `PHP License version 4`_
+-  `PHP Group consent correspondence`_
+-  `Zend Technologies consent letter`_
+
+.. _contributing: https://github.com/ramsey/php-src/blob/master/CONTRIBUTING.md
+
+.. _license proliferation: https://en.wikipedia.org/wiki/License_proliferation
+
+.. _modified bsd license: https://opensource.org/license/bsd-3-clause
+
+.. _php group consent correspondence: php-license/php-group-consent.pdf
+
+.. _php license update rfc: https://wiki.php.net/rfc/php_license_update
+
+.. _php license version 4: php-license/php-license-v4.txt
+
+.. _php licensing: https://www.php.net/license/
+
+.. _zend technologies consent letter: php-license/zend-technologies-consent.pdf

php-license/php-license-v4.txt

@@ -0,0 +1,27 @@
+Copyright © The PHP Group and Contributors.
+Copyright © Zend Technologies Ltd., a subsidiary company of Perforce Software, Inc.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this
+   list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+
+3. Neither the name of the copyright holder nor the names of its
+   contributors may be used to endorse or promote products derived from
+   this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.