Microsoft leaker Walking Cat has just linked to the ISO and EXE files for the Windows 10 build 17134.12 SDK. Microsoft has yet to announce the release of this build, but it lines up perfectly with last week's release of the latest consumer-facing Windows Insider build 17134.5, which Microsoft usually recommends for use with SDKs.
3:51 PM ET Update: Microsoft has officially announced the SDK for the Windows 10 April 2018 Update. Our original article still stands below.
As always, these files are meant to be used by developers for building Windows 10 Apps. The Windows SDK for Windows 10 contains headers, libraries, and tools needed to create apps that run on Windows. We last saw an official SDK release one month ago, with Build 17125, so this might as well be the final Redstone 4 SDK, just in time for the official release of the Windows 10 April 2018 Update.
If you so happen to be a Windows 10 developer eager to get on the latest build, these links will be for you. It will be interesting to see if Microsoft will announce this SDK soon, especially since the company has already been working to add new API updates and additions with each build.