Why HHVM Is Dropping PHP Support and What It Means for Developers

Facebook's HHVM team announced they will cease supporting PHP.

HHVM translates PHP to native machine code for speed and supports both PHP and the Hack language. Version 3.30 will be the last release that supports PHP, with key dates:

2018-12-03 (branch cut): PHP code stopped in master and nightly builds.

2018-12-17: Release v3.30.0.

2019-01-28: Release v4.0.0, no longer supports PHP.

2019-11-19: End of support for v3.30.

The HHVM team recommends that projects fully migrate to Hack or the PHP 7 runtime.

They also aim to improve real‑world PHP support, for example by using inout parameters instead of built‑in reference parameters (&$foo), allowing INT64_MAX + 1 === INT64_MIN (excluding floating‑point numbers).

Previously, due to large compatibility issues between PHP 5 and PHP 7, the HHVM team shifted to developing HHVM with Hack to provide a higher‑performance experience.

Hack is built on the PHP ecosystem, but Facebook’s ultimate goal is for Hack to have its own core framework ecosystem.

In 2018 the open‑source roadmap prioritized supporting existing users and reducing the pain of dropping PHP, involving new projects and optimizing existing ones to reach a stable v1.x state.

Current plans

hh‑apidoc: improve usability, integration with existing projects, and documentation readability and format.

hacktest: improve usability, documentation, and serve as a PHPUnit alternative.

hack‑router and hack‑router‑codegen: remove PSR‑7 dependency, adopt modern API design, and improve documentation.

Investigate migration from Composer and Packagist, aiming for a unified package manager for web‑based JS and Hack components.

In 2019 the team hopes to continue this work, expand its scope, and provide more automated migration tools to handle language changes.