PHP Retires Its 23-Year-Old Custom License and Adopts BSD 3-Clause Starting With PHP 8.6
After a six-month community process and unanimous vote, the PHP Group has retired the PHP License 3.01 and Zend Engine License in favor of the widely recognized BSD 3-Clause.
Editor's Note ·
- Correction:
- The article states that The Build noted, "the transition eliminates licensing complexity for downstream packagers who previously had to manage compatibility calculations against a proprietary license used nowhere else in the industry." This is a paraphrase, not a verbatim quote. The Build (Christophe Pettus) actually wrote that "downstream packagers have spent two decades doing license-compatibility math against a license that almost nobody else uses" and that PHP "removed an entire category of licensing question from their packagers' lives." The substance is accurate; the wording in quote marks is the article's paraphrase of those passages.
Overview
The PHP Group has officially retired the PHP License 3.01 and the Zend Engine License, replacing both with the BSD 3-Clause license for PHP 8.6 and all future releases. PHP release manager Ben Ramsey submitted the notice on behalf of the PHP Group to the Open Source Initiative’s license-review mailing list on May 7, 2026, marking the end of a custom licensing structure that had governed one of the web’s most widely deployed programming languages since 1998.
What Changed
Since PHP 4, the project operated under a dual-license arrangement. As Christophe Pettus described in The Build, “The bulk of the source — the runtime, extensions, the interpreter scaffolding — lives under the PHP License v3.01. The Zend/ directory lives under the Zend Engine License v2.0.”
The Zend Engine License carried a particular problem: Pettus noted that “PHP, the canonical implementation of one of the most-deployed languages on the planet, has been shipping a substantial chunk of its own source code under a license that is not, by the OSI’s own definition, open source.”
The PHP License version 4, which took effect starting with PHP 8.6, resolves this by removing clauses 4, 5, and 6 from the prior version. According to the official PHP license FAQ, “The PHP License, version 4 removes clauses 4, 5, and 6 of the PHP License, version 3.01. This makes it effectively identical to the Modified BSD License (BSD-3-Clause).”
As Ramsey summarized in his personal blog: the change gives PHP “The actual BSD-3-Clause license, with its SPDX identifier, recognized by the OSI, the FSF, and every major piece of licensing tooling.”
Why the Old License Was a Problem
The PHP Group’s official FAQ explains that while the OSI approved PHP License versions 3.0 and 3.01 through its legacy process, “the licenses were not compatible with the GPL. Additionally, clauses 4 and 6 were challenging or impossible to enforce, and various readings and interpretations sometimes caused confusion among distributors.”
The GPL-incompatibility created friction for Linux distributions and enterprise environments. As FOSS Force reported, the old licenses created ambiguity for distributions like Debian, which patch and redistribute PHP. The Zend Engine License was never OSI-approved.
For downstream packagers, The Build noted, “the transition eliminates licensing complexity for downstream packagers who previously had to manage compatibility calculations against a proprietary license used nowhere else in the industry.”
Ramsey put the practical effect plainly in a statement quoted by Copahost: “Strip away the PHP Group-specific and Zend-specific clauses from both licenses, and what remains is effectively BSD 3-Clause anyway.”
A Multi-Year Process
The licensing change did not happen quickly. Ramsey opened the RFC on the PHP internals mailing list on July 10, 2025, with a minimum six-month discussion period, according to the RFC thread.
As LWN.net reported, “Getting here required more than writing an RFC. The PHP License gives the PHP Group the authority to change it, which meant tracking down each of the original PHP Group members and getting their written consent.”
The original PHP Group members whose consent was obtained include Thies, Stig, Shane, Andi, Rasmus, Sam, Sascha, Zeev, Jim, and Andrei, according to Ramsey’s blog. Alongside the PHP Group consent, Perforce Software — the current owner of Zend Technologies — provided formal approval. Legal counsel Pamela Chestek of Chestek Legal reviewed the proposal. After six months of community discussion, the vote passed unanimously.
The vote on php.internals closed on April 4, 2026, per The Build. Ramsey then submitted the voluntary retirement notice to the Open Source Initiative on May 7, 2026, as reported by FOSS Force.
What This Means for the PHP Ecosystem
PHP is the server-side scripting language underlying a significant portion of the web. WordPress, which Copahost notes runs approximately 43% of all websites, is built on PHP. An estimated 75% of server-side web applications involve PHP, according to Copahost.
The license change applies to PHP 8.6 and later; existing PHP 8.x releases are unaffected retroactively. The PHP License and Zend Engine License are now classified as deprecated and legacy. The official PHP guidance states that while projects can still use the old licenses, “they are not recommended for use in new projects.”
Not all PHP subdirectories moved to BSD-3-Clause. Components with existing BSD-2-Clause coverage — including TSRM and FPM — retain their current licenses, according to the RFC thread, to avoid the burden of obtaining contributor re-approval.
What We Don’t Know
The RFC and announcement do not specify a release date for PHP 8.6. The community discussion also addressed, but did not finalize, plans for adding SPDX identifier headers across the PHP codebase; Jakub Zelenka requested that work proceed via a separate follow-up pull request, per the RFC thread. How quickly downstream projects and Linux distributions will update their packaging metadata to reflect the BSD-3-Clause designation has not been publicly discussed.