Microsoft is now testing Windows 10 Creators Update build 15063.251 for PC. The new build 15063.251 (rs2_release_svc_escrow.170420-1743) was compiled on April 17, 2017.
Recently, the company also released Redstone 3 Insider Preview build 16179 for PC and mobile build 10.0.15205 feature 2 for mobile devices. Microsoft also confirmed that only selected Windows mobile devices will receive future updates.
Windows 10 version 1703 or Creators Update is now available for everyone on PC. Windows 10 Mobile Creators Update will roll out on April 25.