Last week, Microsoft released Windows 10 Insider Preview build 18342 to the Fast ring. Being the following Tuesday, that can only mean one thing: a new SDK Preview with the same build number is available to download.
As usual, Microsoft has not published a blog post just yet, and it likely will do so later on today. There won't be any major front-facing features, as development of Windows 10 19H1 is starting to wind down. Right now, the company is working on finalizing the feature update, so there will be fixes and quality improvements.
You can run this SDK in a production environment, as long as your app still targets a production version of Windows 10 when you submit it to the Microsoft Store. Also, it's only supported by Visual Studio 2017 or higher, and you can only install it on a Windows 10 Insider Preview build.
Update: Three days after the fact, Microsoft has finally published a blog post.