Windows 10 version 18247 is an early development version of Redstone 6 which is scheduled for release in the first half of 2019.
This is a very early build and as such its not recommended except for developers who need to test compatibility with Visual Studio etc.
More work on Narrator has been done to fine tune it. This have continued to be a big focus for Microsoft as they want accessibility to be a mainstream feature.
Web view controls have been fixed.
Some problems with the dark mode as the context menu has a thick white border.
Steam had some problems with an update. It eventually updated and restarting it asking for the credentials