We do send emails (a lot of them, in waves). If you did not get one a number of things could have happened:
- The email got caught in your spam filter (or the spam filter of your organization email server)
- We have an old or incorrect email for you
- You may have indicated in the past you prefer not to receive email from us
In case of 2 or 3, I would suggest contacting our Customer Service and they should be able to update or correct information.
Since do send email in waves it is possible you may yet receive an email.
The official announcementfor a new version is typically made on the company blog page:
https://blog.wolfram.com/2020/03/18/in-less-than-a-year-so-much-new-launching-version-12-1-of-wolfram-language-mathematica/
This announcement is typically cross-posted to social media as well, including Facebook, Twitter, and (I think) LinkedIn.