Microsoft has released a new insider preview of Windows Server

What’s New
In this preview build we are adding support for Network Policies using Tigera Calico for Windows Containers. The latest Tigera Calico for Windows bits are included in Tigera Essentials — for access to the latest release, contact Tigera by email at contact@tigera.io
We’re releasing the full set of 38 server language packs to Insiders for the first time. Use DISM or LPKSETUP commands to install on Windows Server core. Language packs will only install on a matching build.
We have new innovations in networking that we will announce in the early new year, please stay tuned.
The expiration date for this preview is July 5th, 2019.

  Windows Server vNext Insider Preview Build 18298 released