Microsoft is still rolling out fixes for Windows 10 "Redstone 4" to its Insider testers.
On April 10, this month's Patch Tuesday, Microsoft made available to Fast, Slow and Release Preview Ring testers Build 17133.73 of Windows 10 Redstone 4. This is a cumulative update -- KB4100375-- for test build 17133.
The update includes fixes for a PDF security issue in Edge; an issue that prevents IE from identifying custom controls; and a bunch of security updates for IE, Edge, Microsoft Scripting engine, Windows kernel, Microsoft graphics component, Windows Server, Windows cryptography and Windows datacenter networking.There are no new features in 17133.73.
Microsoft officials have said to expect Windows 10 Redstone 4 to start rolling out to mainstream users some time in April, but have not provided a specific release date so far.
Microsoft also released on April 10 new Windows Server test builds to Fast Ring testers. That build, Windows Server 2019 Build 17639, includes both new features and fixes for Server 2019, the coming on-premises and Long Term Servicing Channel (LTSC) release of Windows Server, which is expected to roll out around October 2018. Microsoft is rolling out Build 17639 of Windows Server Semi-Annual Channel release 1809 for Windows Server today, as well.
On the new features list, Build 17639 adds a new role to Windows Server Standard and Datacenter called Storage Migration Service (SMS). Microsoft officials describe SMS as a "job-based orchestration and proxy" that will work with a "Project Honolulu"-based graphical management system to enable migrations of multiple servers simultaneously to new targets running on premises or in Azure.
Today's Server 2019 build also includes several updates to Storage Replica, a feature that Microsoft first introduced in Windows Server 2016 Datacenter Edition. The improvements are around the log system, test failover and support for Windows Server 2019 Standard Edition (not just Datacenter Edition).
Microsoft makes Server 2019 preview available in ISO format in 18 languages. The Semi-Annual 1809 Server build is available as a Server Core Edition in English only in ISO or VHDX format. Information about keys, how to download and known issues are all included in the Windows Server 17639 blog post.
A related aside: Today, April 10, is the last time that Microsoft will provide patches for Windows 10 1607, the "Anniversary Update" version of Windows 10 client. The only exception is for customers running Enterprise or Education versions of the product. They have an additional six months of support. To continue to get patches, non-Enterprise/Education users should upgrade to a more recent version of Windows 10.