Microsoft has rolled out new preview bases of Windows Server 2019 and Windows Server 1809, which includes some new features.
Windows Server Build 17723 adds new embedded features to more easily deploy Kubernetes orchestration tool for containers on Windows Server. Among the new capabilities are container planning, health monitoring, networking, service discovery, the ability to add / remove container instances to match the demand and more.
31. July blog posts about 17723 outline a significant number of known issues with this building, which testers should consider before distribution.
On July 31, Microsoft also released testers ISOs of one of the latest Windows 10 Insider Preview Redstone 5 builds. ISO for Windows 10 Build 17713 can be downloaded from here.
Microsoft is expected to roll out Windows Server 2019, which it has designated as a long-term service channel release, and Windows Server 1809 this fall, probably around October 2018.