From the "It's NOT dead, Jim" department — the Nethack site has a new announcement up:
April 3, 2015 Announcement
As a rule, the DevTeam does not volunteer information or comment on our plans or schedules. However, at this time we'd like to make an exception to that rule and provide a brief update on what's been happening:
As just about everybody knows, an incident occurred about six months ago with respect to an unauthorized distribution of the NetHack source code in a very unfinished state. Since then, the team has been working on several initiatives. Despite a lot of opinions to the contrary, we aren't dead and we haven't given up on the game.
Over the past months we've added some members of the greater NetHack development community to the team. Specifically; Sean Hunt, Derek S. Ray and Pasi Kallinen are now members of the Team and have been actively helping develop the next release with selected inclusions from some of the NetHack community code bases.
We've also made a significant time investment in upgrades to our underlying development infrastructure, which will be rolled out with the next release. Many thanks to Keni who's been instrumental in making sure the underlying foundations that allow the team to do what it does are there.
Now for the inevitable question: When will the next release happen?
In that respect I'm going to have to fall back on the usual answer - we don't advertise our release dates. To do so would break a long-standing NetHack tradition, but there is a more important reason. Given the amount of time since the previous release, and considering what's been integrated into it, knocking the bugs out of it may not be as easy an exercise as in the past so we're loath to commit to a date and have something throw us off.
For the DevTeam
I still really wish Nethack development was more open, but it's good to hear that the project is alive and kicking and that eventually there will be a new release. And having some major changes to keep the game fresh is very welcome, too (not that it isn't a great game, but changing/reworking the game in major ways is a Nethack tradition in itself).