Microsoft's next major Windows 10 update, Redstone 5, has been in the works for quite some time now. However, the update may finally be close to an official launch, as Microsoft recently published Redstone 5's ISO files, finally allowing users to perform a clean install of the release.
In brief: Microsoft has been issuing test builds of Redstone 5, its next major Windows 10 update, to testers for many months now.