Microsoft is currently pushing build 10240 of Windows 10 to both users of the ‘slow ring’ and ‘fast ring’ of its Insiders program. Microsoft hasn’t officially confirmed build 10240 is the Release to Manufacturing (RTM) version of the operating system.
However, this build is the first Windows 10 version that doesn’t show a watermark on the desktop. This indicates the build is ready to be released. Sources of Microsoft Insiders previously already stated build 10240 is the RTM version of Windows 10. Microsoft sends RTM builds to hardware manufacturers so they can install it on new devices.
There are no major innovations in the build that can only be obtained through Windows Update. Microsoft has also stated that within a week the Preview label of its Office 2016 applications will be removed.
Windows 10 will be released in about 2 weeks. From then users can upgrade to the OS for free. New devices with Windows 10 will likely become available several weeks later.