Thanks for asking, this is important.
We will publish a prolonged preview version today, without an expiry date. We prefer to call it a preview because we discovered a few cosmetic issues when making the release builds, but from a functionality perspective 12.8.r1 will be fully complete, there are no known bugs related to running calculations. The remaining issues are just some glitches in VNL on particular platforms, and optimizing the license checkout time. So if you are hooked on 12.8, go get it (http://quantumwise.com/publications/news-archive/188
), but if you are still on 12.2, you can perhaps wait 1-2 weeks for 12.8.0.