Microsoft MVP, Microsoft Support Visiting Expert,
Microsoft steams ahead with Windows 10 development, build 9855 recently compiledIt's only been four days since the Windows 10 Technical Preview was released to the public, however that doesn't mean the build that was issued with the Technical Preview is new. Windows 10 build 9841 was compiled on September 12, which was around three weeks ago. That's ancient in development time, so it's no surprise that build 9855 was recently compiled.
Thanks to the "preview builds" ability (which doesn't currently work) in the Windows 10 Technical Preview, users who are using the Technical Preview have managed to see some more recent builds of Windows 10. According to logs that appear when the operating system is attempting to connect to the update server, the operating system is seeing builds as new as a few days ago. Build 9855 was compiled on October 2nd, just two days ago.