12.1 isn’t out. Maybe in 9 months? Maybe early next year? 
By 12.1, I know you actually mean 12.0.10, since 12.1 isn’t coming out for a long time, or maybe never, who knows PG’s future release plans? Not trying to give you a hard time or be a smart-a$$ about the version number BTW, but I do wonder why so many people in this forum get the version numbers wrong when they post threads? It doesn’t help with search results, since in the future, if there ever is a Wavelab 12.1, this thread will show up, when you meant 12.0.10. So actually for this reason, just for my future self, I’m posting a response so that when I do a search for 12.1 next year, and this thread pops up, it will be clear you’re actually referring to 12.0.10.
And BTW, for those that want to complain about my version nit-picking, Steinberg’s numbering system is pretty consistent, the little minor updates/bugfixes and hotfixes are X.X.XX (with two decimal points), and larger updates are X.X – if you look back through the version history even just of WL11, you will find 11.0.10, 11.0.20, etc., for minor updates/bugfixes, and then later on, many months later, there were also 11.1 and 11.2 for larger updates. They were completely different levels of updates though, and actually 11.2 was a very big deal since it introduced the new Steinberg licensing system. 11.2 was quite a difference from 11.0.20… but back then some people might have pulled up confusing searches for 11.2 which were mislabeled threads referring to 11.0.20. For some reason in this forum, people just keep getting these version numbers wrong. Maybe that’s something Steinberg can reconsider in their version numbering system, oh well. But it is what it is.
Anyway, about the lack of announcement, I’m curious too. My speculation is that it is a very minor update that addresses only a couple of issues and it seemed like it was mentioned in this forum here and there. Or maybe they forgot to mention it and it just fell through the cracks. Or maybe they just posted the download file early and haven’t officially announced it yet here, which maybe they’ll do today. Who knows. But it’s a valid question.
Cheers and have a great day. (And no offense about the version number thing.)