"Coming soon", scheduled "Release: February 2017". "Keep your eye on the News section here" including peer user posts on the Forum. I'm sure there'll be various upgrade offers. If you have "Use Net Notify" ticked in your app's Preferences, General, you'll probably be informed. I'm not so sure you'll get an email. When it's available, check https://support2.magix.com/customer/vegas/upgrade but that may not always have the best offer.
And it is not a Sony/SCS product any more. It's owned and (hopefully) developed by MAGIX. These Forums are also provided by Magix.
I'm not aware of a public beta or similar. It's likely that after the release there will be the 30-day free trial. Some users tend to regard the first builds of any new software version as de facto beta versions. I understand the current dev team appreciates the forum feedback on the issues that the users encounter.