PHP Licence v3.01

A fairly permissive open source software licence that is based on but not equivalent to the Apache Software Licence v1.1, it is used primarily with the PHP package itself and by a few open source projects that are related and it is recommended in general that you use the Apache Software Licence v2 rather than the PHP Licence if you are looking for a licence with similar terms and ideas.

Cynically enough the Debian project classifies the PHP Licence as "free software" although it is clearly both GPL incompatible and incompatible with the Debian definition of a "free licence", while software released under the BISS AWT Licence for instance is considered "non-free", this is due to large amount of packages included with Debian that rely on PHP in one way or another especially in the server setup and control domain, and just goes to show that highly principled people never hold themselves to the same principles as they do to others.

Disclaimer

Note that the licence text below is here for reference purposes and unlike other material on the EDM/2 Wiki is not under the Attribution-ShareAlike 3.0 licence and should be treated under its own terms, or if an addition by the combined terms of the addition and the licence that it is an addition to. As it is a licence with fixed terms the text below it should not be modified except for formatting purposes, if a more recent version is published a new page should be created for that licence since software packages that do not get updated will continue to be governed by the terms of the older licence.

Text of licence

-------------------------------------------------------------------- 
                  The PHP License, version 3.01
Copyright (c) 1999 - 2014 The PHP Group. All rights reserved.
-------------------------------------------------------------------- 

Redistribution and use in source and binary forms, with or without
modification, is 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. The name "PHP" must not be used to endorse or promote products
     derived from this software without prior written permission. For
     written permission, please contact group@php.net.
  
  4. Products derived from this software may not be called "PHP", nor
     may "PHP" appear in their name, without prior written permission
     from group@php.net.  You may indicate that your software works in
     conjunction with PHP by saying "Foo for PHP" instead of calling
     it "PHP Foo" or "phpfoo"
 
  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.

  6. Redistributions of any form whatsoever must retain the following
     acknowledgment:
     "This product includes PHP software, freely available from
     <http://www.php.net/software/>".

THIS SOFTWARE IS PROVIDED BY THE PHP DEVELOPMENT TEAM ``AS IS'' AND 
ANY EXPRESSED 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 PHP
DEVELOPMENT TEAM OR ITS 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.

-------------------------------------------------------------------- 

This software consists of voluntary contributions made by many
individuals on behalf of the PHP Group.

The PHP Group can be contacted via Email at group@php.net.

For more information on the PHP Group and the PHP project, 
please see <http://www.php.net>.

PHP includes the Zend Engine, freely available at http://www.zend.com