Since September 2, HHVM (hip hip virtuam machine) has long term support from Facebook team and from the HHVM team. Facebook understands that, in order to reach every corner of PHP programming language, it’s users need to have a commitment, in order to plan their deployments and react to new versions that will bring features like security and stability.

Starting with HHVM 3.3, the HHVM team and the Facebook team will support two source releases at all times, this will be a so-called LTS (long term support).

For these and other reasons, starting with HHVM 3.3, the HHVM team will support two source releases at all times (that we will call LTS, Long-Term Support), separated by roughly 6 months (24 weeks apart to be exact), to have an effective support cycle of nearly a year. As an example, HHVM 3.3, which is scheduled for 11th Sept 2014, will be supported until 3.9 is released (8×6=48 weeks later, about 11 months). Accordingly, 3.6 (hopefully released 24 weeks after 3.3) will be supported for 6 releases (until 3.12 or equivalent sees the light).

Source – HHVM’s Official Blog

Available distributions

HHVM will offer long term support for Debian and Linux soperating systems. They will also offer support for Debian alternatives. But this long term support can be reached only if the distributors of these operating systems will release new security-related fixes in time. Facebook will not support an expired operating system.
HHVM team says on it’s blog that they will try to support other platforms also, such as Fedora. But they also remember that they have limited resources.

What should we expect from these Long term support releases?

The answer is it depends.

said Ender, a Security Engineer from Facebook

It depends on the severity of the problem we want to fix and intrusiveness of the patch to apply. Security issues? Absolutely! Big regressions? Sure, why not, if they don’t imply re-architecting a big chunk of code. Small patches that can drive that version to 100% completeness on some framework? Let’s do it. But observe that the longer an LTS release is out there, the less likely we will be doing major surgery on it. Security fixes will have absolute priority, and the rest of issues will need to be studied by balancing the amount of work patching and testing vs. the benefit and the risk of getting it out of the door. We expect you, the users, to guide us with PRs or features that you would like to have in the current LTS releases.

You can read Ender’s post and also you can add a suggestion or post a question if you follow this link to the HVVM’s blog.

You can find more information about Facebook’s Hack Lang programming language if you follow this link: