HTC has something big in the works it seems. We'll wager that it's a phone, or something like a phone, but you never know. 
Whatever it turns out to be, it will be shown off on January 12th. Exactly where and when hasn't been disclosed.
Here's what HTC have revealed so far;
Hello,

HTC wanted to share the date of our next big announcement… 01.12.2017! ...More info to come soon...
What's interesting is the timing of the news especially as CES is coming soon. It wraps up in Las Vegas on Sunday, January 8th - but has been attracting less and less mobile hardware over the last few years. 
The main event for the first half of the year is Mobile World Congress in Barcelona, which doesn't kick off until late February. Of course, larger mobile manufacturers are now often opting to host their own press events outside the usual show venues. Such would seem to be the case here.
HTC's current head honcho phone, the 10, isn't due for a replacement until the second quarter of 2017 at the earliest, what this means is that the new announcement might be a phone that is NOT a flagship and is a mid-range phone i which case the whole thing would be a tad pointless. But we'll just have to wait and see how things pan out and hope for the best.