HHVM 4.77 is released! This release marks the end of support for 4.71; HHVM 4.72–4.76 remain supported, as do the 4.32 and 4.56 LTS releases.


  • Removed redundant typechecker error 4164 (“Properties cannot be declared final”). The same issue is already reported as a parsing error (1002).
  • Improved IDE support: The “rename” operation now also supports type aliases.

Breaking Changes

  • The Xbox extension no longer supports inter-process communication (local or remote). It can still be used for in-process parallelism (xbox_task_* functions). Removed built-in functions:
    • xbox_send_message
    • xbox_post_message
    • xbox_get_thread_timeout
    • xbox_set_thread_timeout
    • xbox_schedule_thread_reset
    • xbox_get_thread_time
  • A constant can no longer be used as a shape key if its type is an opaque type alias (a newtype not from the same file). This makes it more consistent with how opaque type aliases can be used in other contexts.