PHP 4 end of life announcement
Today it is exactly three years ago since PHP 5 has been released. In those three years it has seen many improvements over PHP 4. PHP 5 is fast, stable & production-ready and as PHP 6 is on the way, PHP 4 will be discontinued.
Context & Ripple Effects
Three years to the day after PHP 5 shipped, the PHP project is retiring its predecessor: the announcement marks exactly that anniversary and frames PHP 5 as fast, stable and production-ready, with the project's own follow-up commentary landing the next day. The stated trigger is forward-looking — PHP 6 is on the way, and carrying two legacy majors into that transition is what the core team is refusing to do.
First-order effects
- Hosting providers and the large installed base of PHP 4 applications lose a supported runtime, forcing a migration decision onto every site still pinned to the old major version.
- PHP 5 becomes the unambiguous default target for new deployments, ending the three-year window in which developers could justify staying on PHP 4.
Second-order effects
- Shared-hosting operators have to run dual stacks or force upgrades, and application vendors whose products were written against PHP 4's object model face rework to stay sellable on PHP 5 hosts.
- The security-patch burden shifts: unmigrated PHP 4 installs become a standing vulnerability surface that no upstream fix will reach.
Third-order effects
- If the pattern holds, fixed end-of-life dates tied to successor releases become the norm for open-source web infrastructure, replacing the de facto 'supported forever' expectation that had let PHP 4 linger for years.
- A precedent like this pressures adjacent layers of the LAMP stack — the same discipline later shows up in debates over when browsers and servers retire old majors.
The trend: Open-source web platforms are moving from indefinite legacy support to scheduled end-of-life cycles, with each successor major version setting the retirement clock for its predecessor.