Yeah, I remember being disappointed about the Mozilla chairman's announcement[1] that Thunderbird "not a priority" and they were essentially giving up on it. (I don't personally use Thunderbird, but we have a lot of Windows users at work who do).

So this bubbly and optimistic-sounding blog post confused me a little. But then I looked next at the previous entry in this blog[2] and it states that at the end of 2014 they reorganized and elected new leadership to take over from the Mozilla people who weren't working on it any more.

So apparently there are at least some people actively working on it again, and they are hoping for financial sponsorship to cover a full-time developer.

If it works out, then actually it seems like Mozilla's handling of the problem ('we have a standards-based IMAP email client with millions of users, but nobody -- including the team in charge of it -- wants to work on it any more') was pretty good. They did keep the project on life support with security updates, for a little over two years, until they found some people that did want to work on it.

[1]: https://blog.lizardwrangler.com/2012/07/06/thunderbird-stabi...

[2]: https://blog.mozilla.org/thunderbird/2014/11/thunderbird-reo...