Licenses April 2018
PHP 4, PHP 5 and PHP 7 are distributed under the PHP License v3.01, copyright (c) the PHP Group.
This is an Open Source license, certified by the Open Source Initiative.
The PHP license is a BSD-style license which does not have the "copyleft" restrictions associated with GPL.
Some files have been contributed under other (compatible) licenses and carry additional requirements and copyright information.
This is indicated in the license + copyright comment block at the top of the source file.
Open source software is freely available for anyone, including source code. The license grants everyone permission to adapt or improve the source code, for example to fix errors, to make a more efficient implementation or to add completely new functionality. The software may also be copied and distributed freely, even in modified form.
MySQL Commercial License for OEMs, ISVs and VARs
Oracle provides its MySQL database server and MySQL Client Libraries under a dual license model designed to meet the development and distribution needs of both commercial distributors (such as OEMs, ISVs and VARs) and open source projects.
For OEMs, ISVs, VARs and Other Distributors of Commercial Applications:
OEMs (Original Equipment Manufacturers), ISVs (Independent Software Vendors), VARs (Value Added Resellers) and other distributors that combine and distribute commercially licensed software with MySQL software and do not wish to distribute the source code for the commercially licensed software under version 2 of the GNU General Public License (the "GPL") must enter into a commercial license agreement with Oracle.
For Open Source Projects and Other Developers of Open Source Applications:
For developers of Free Open Source Software ("FOSS") applications under the GPL that want to combine and distribute those FOSS applications with MySQL software, Oracle’s MySQL open source software licensed under the GPL is the best option.
For developers and distributors of open source software under a FOSS license other than the GPL, Oracle makes its GPL-licensed MySQL Client Libraries available under a FOSS Exception that enables use of the those MySQL Client Libraries under certain conditions without causing the entire derivative work to be subject to the GPL.
However, open source software is not public domain. The software is protected by copyright and one must accept the license terms before the software may be modified and distributed. With open sour