Microsoft is now testing Windows 10 build 16252 for PCs. The new Insider build 10.0.16252.1000 (rs_prerelease.170722-1158) was compiled on July 22, 2017.
As a reminder, this is Windows 10 Redstone 4 build. The Fall Creators Update build number is 16252.0 from rs3_release branch. Read more details about Redstone 4 builds here.
Yesterday, Windows Insider team released the Fall Creators Update build 16251.0 and Windows 10 Redstone 4 build 16251.1000 to Fast Ring insiders. The builds were released with new features, bug fixes, and improvements.
The company also recently released Windows 10 Cumulative update KB4025342 build 15063.483 for Creators Update systems, update KB4025339 build 14393.1480 (Anniversary Update) and update KB4025344 build 10586.1007 (Threshold 2).