Ask HN: Is Immutable.js a dead project?

It seems like there's huge interest for this project, with almost 20,000 stars. However, the last stable release was more than a year ago (April 2016). An alpha version was released on March of this year, but it's broken for most users and almost no pull requests have been approved since then. Issues sit idle for months at a time with no response.

Did Facebook give up using this internally for something else?