For the first time since beginning the development of Redstone 2, the next major update to Windows 10 which is expected in early 2017, Microsoft has moved one of the Fast Ring Insider builds to Slow Ring testers.
Dona Sarkar, head of the Windows Insider Program at Microsoft, announced the availability of Windows 10 Build 14931 for the Slow Ring via Twitter and that began a process which made the ISO image of that build available for download.
However, alongside of Build 14931 Microsoft has also made Windows 10 Build 14393 available for download.
If this build sounds familiar it is the base build for the Windows 10 Anniversary Update that was released on 02 August with KB3176929 that brought the Anniversary Update release to OS Build 14393.10.
If you want to download either one of these builds all you need to do is visit insider.microsoft.com and log in with your Microsoft account which is associated with your Insider account.
You will find Builds 14393 and 14931 Windows 10 Clients (Home and Pro) ISO downloads at https://www.microsoft.com/en-us/software-download/windowsinsiderpreviewiso.
There is also an advanced download option for these builds at https://www.microsoft.com/en-us/software-download/windowsinsiderpreviewadvanced and it provides you access to Builds 14393 and 14931 in a few other versions:
Whichever options you choose to use it is still recommended that you only install the Redstone 2 development build, 14931, on a system that is not your daily driver because it is an early build of the operating system.
Be sure to check out all of our Windows 10 Anniversary Update Coverage.