https://www.theregister.co.uk/2019/12/17/windows_10_insider/

Mixed news for Windows Insiders today as the window for jumping to the Slow Ring slammed shut amid promises of minty fresh code for those on Fast (but don't ask for which version of Windows, m'kay?)

Build 19536 of Windows 10 arrived for those brave souls on the Fast Ring last night, as the Windows Insider team offered up an almost-apology for the confusion over how things have worked over previous years and, er, obscured things just a little bit more. Because, hey, its Windows.