What is Rs1 and Rs2?
Rs1 > Redstone 1 > Windows 10 Redstone 1 (RS1) is the second major update to 
the Microsoft Windows 10 operating system.
Rs2 > Redstone 2 > Codename "Redstone 2" is the third major update to 
Windows 10 and the second of the 3 major updates planned under the Redstone 
codenames.
RS3 > Redstone 3 >Windows 10 "Redstone 3", is the fourth major update to 
Windows 10 and the third of the four major updates planned under the 
Redstone codenames. The first preview was released to Insiders on April 7, 
2017.