Microsoft has released the Windows 10 Insider Preview Build 18290 in Fast Ring. This is the 19H1 development branch, which will be released in spring 2019.
The announcement of the Windows 10 Insider Preview Build 18290 was made by Dona Sarkar on Twitter, as well as in the Windows Blog.
— Dona Sarkar @ #ESPC18 (@donasarkar) 28. November 2018
This time Microsoft points out that the Insider Preview has an early expiration date (time bomb). The stuff expires on December 14, 2018 – or in plain language: It doesn’t worth to invest the time to test this build. Details what’s new (nothing really important stuff, that’s badly needed from Windows users), what’s fixed and what’s still broken, may be found at Windows Blog.