HHVM 4.133 is released! HHVM 4.128–4.131 remain supported, as do the 4.102 and 4.128 LTS releases. HHVM 4.132 was skipped due to issues with the nightly builds.


  • dynamic values can now be used as container keys. The containers will then be inferred to be keyed by arraykeys, so can not be used as T<int, _> or T<string, _>.
  • if a debugger is attached, the JIT will never be used, and the JIT will never be disabled in the middle of a request for the debugger. This improves debugger reliability.
  • fixed order-dependent autoloader issues for enum classes including other enum classes.
  • when a static property is used as an instance property, the error message now correctly says ‘static property’ instead of ‘static method’.
  • fixed Str\format() accidentally using the request locale.
  • fixed hackfmt adding unwanted blank lines to the top of files.
  • updated build environment to OCaml 4.12 and Rust/Cargo v2021.10.21.

Breaking Changes

  • hash comments are no longer supported, and are a parse error. Use // comments instead.
  • Files without a .php, .hack, .hackpartial, or .hhi extension will now be consistently parsed as if they were .hack files.
    • previous behavior was context-dependent.
    • this change includes both files with other extensions, and files with no extension.
    • this may break legacy extensions such as .hck and .hh, as <?hh tokens are banned in .hack files.
  • it is now an error to call parent::__construct() from a trait, unless the parent has <<__ConsistentConstruct>>.
  • it is now an error for a constructor to read properties defined by a parent class before calling parent::__construct().
  • updated Thrift and mcrouter versions to v2021.11.18; supporting libraries and tools may need an update if you are using these extensions.

Future Changes

  • .php files remain deprecated, and support may be removed in a future release; .hack is strongly recommended instead
  • .hackpartial and .php files with <?hh // partial remain deprecated, and support will likely be removed in a future release. .hack is strongly recommended instead.