The PHP project announced it is moving to a new license.
PHP is a scripting language used for web development. It can be embedded within HTML and used to create dynamic web pages. It is the “P” in the LAMP stack (Linux, Apache, MySQL and PHP)–although some people use the P to refer to Python or PERL. The Zend Engine, the core of PHP.
For years, PHP as a whole has been offered under the PHP License and the Zend Engine License–both permissive licenses. The PHP License is OSI approved, but the Zend Engine License is not. The Zend Engine License has specific naming restrictions related to “Zend” and “Zend Engine,” sometimes referred to as advertising clauses or attribution clauses. Such restrictions were common in early permissive licenses like Apache 1.0, but have since been deprecated by the open source community and do not appear in most recent permissive licenses.
License changes can be a challenge, because unless a project uses a contribution license agreement (CLA), it must get permission from all contributors to change the license for their contributions. In major projects, this has been done a few times, such as the Wikipedia migration and the OpenSSL change, but it’s a big project that can require broad socialization and risk that a contributor will object. These changes usually take place with popular projects whose licenses are outdated, ad hoc, and confusing.
But PHP has found a neat trick to avoid having to get permission from every contributor. Like many open source licenses, the PHP license allows the license steward to issue new versions.
5. The PHP Group may publish revised and/or new versions of the
license from time to time. Each version will be given a
distinguishing version number.
Once covered code has been published under a particular version
of the license, you may always continue to use it under the terms
of that version. You may also choose to use such covered code
under the terms of any subsequent version of the license
published by the PHP Group. No one other than the PHP Group has
the right to modify the terms applicable to covered code created
under this License.
Apparently, PHP, as license steward, is redefining its own license as the BSD license. The announcement says that the BSD License will be adopted as the PHP License v.4 and as the Zend Engine License v. 3.
