Windows 10 'Redstone 5' starts appearing on BuildFeed

Microsoft has apparently started to compile the first 'Redstone 5' (RS 5) builds. Windows build tracker site, BuildFeed, lists the first RS 5 build as 17600.1000 compiled a week ago. The latest build spotted is 17604.1000. These builds will now be part of the 'rs_prerelease' branch and will be flighted soon to Insiders in the Skip Ahead ring. Current 'Redstone 4' (RS 4) builds will release from the 'rs4_release' branch from next month to Fast and Slow Ring Insiders. The new build number was also spotted in language packs available in the Microsoft Store. 

Microsoft is following the same Insider release pattern with RS 5 as it did with RS 4 last year. RS 4 is set for a March 2018 release and will probably sport the version number 1803. While new RS 4 builds have been promising, it is not known which build number will Microsoft sign off internally as the Release to Manufacturing (RTM) candidate for the upcoming release. 

As usual, the initial builds from the RS 5 branch will not have any customer-facing features as the development team carries out code refactoring (restructuring existing code without changing its behavior) in the initial builds. RS 5 is expected to make the Windows shell more modular and should enable new device form factors (read Surface Phone). We could very well see the first glimpses of 'Polaris' — Windows without the traditional Win32 APIs either during RS 5 or beyond. Also, we could see the 'Sets' feature make its way into RS 5 builds down the line. 

Do remember that while anyone can download these Insider builds, they are not meant for use in a production environment as they are unsupported, time-bombed, and can potentially result in data loss. The best way to test them is in a virtual environment or a non-production machine. 

Source(s)