Windows 10 build 17072 is now under testing internally. The new Redstone 4(v1803) Update build 17072 (10.0.17072.1000 rs_prerelease.180104-1429) was compiled on Jan 4, 2018. Windows 10 Mobile build 15254.160 was also compiled on the same day.
Previously, feature-rich Windows 10 build 17063 was released for Fast and Skip ahead insiders. This build includes new features like Timeline, Sets, Cortana improvements and much more.
Yesterday, Microsoft released a bunch of new cumulative updates for Windows 10/7/8 to fix Intel Processors Vulnerability. This new and a huge vulnerability affects pretty much all Intel processors. You can download the updates from here.
A new build is expected to roll out this week on Wednesday or Thursday.