With the general availability (GA) of Windows 10 set on July 29th, 2015, it’s said that Microsoft Operating Systems Group (OSD) has completed the selection and sign off of Windows 10 Gold Master RTM build, signifying that the development process of current stage of Windows 10, codenamed Threshold, has come to an end. And, the development plan for the next minor update release, codenamed Redstone, has also begun, with several builds from TH2 branch compiled. Redstone is expected to arrive end 2015 or in 2016.
The full build string of Windows 10 gold RTM is said to be 10.0.10240.16384 or 10240.16384.150709-1700 or 10.0.10240.16384.th1.150709-1700 indicating the build was compiled at July 9, 2015.
Since then, no new builds has been compiled on the TH1 or fbl_impressive branch. All new builds has the number starting from 10500 and has branch name starting from th2.
In addition, Windows 10 Assessment and Deployment Kit (ADK) which was recently released has the PE with version number 10.0.10240.16384, further cementing the view that build 10240 is indeed the RTM version.
For Windows Insiders, Microsoft has also silently changed the flighting branch name from fbl_impressive to TH1 in HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WindowsSelfHost\Applicability registry key. As Microsoft has announced that they’re suspending Windows 10 Insider preview builds and next build offered to Windows Insiders will be using production servers, which means the TH1 branch would be the Windows 10 RTM, or at least RTM candidate if Microsoft decided to let Windows Insiders try out another build.
However, the build number for Windows 10 RTM has still changed if there is major issue, bug or problem found in the OS. If other minor issues or bugs are found, Microsoft is expected to fix them with ZDP (Zero-Day Patch), with code-freeze on July 27th, 2015, which is also the date Windows 10 RTM setup installer is uploaded to Windows Store. There won’t be change in build number or version number for patches through ZDP. It works this way because Microsoft OEM partners require manufacturing and logistics lead time to be able to put PCs and tablets running Windows 10 on the retail shelves on the same day with Windows 10 release. In fact, it’s rumored that Microsoft has released Windows 10 Build 10240 to OEM manufacturers on July 15th, 2015.
Update: Windows 10 Build 10240 has been released to Windows Insiders, confirming that it’s indeed the RTM final release.