We've known for sometime now that Windows 8.1 build 9600 had been compiled, but we were all unsure whether or not said build was the final RTM. Today, The Verge is reporting that Windows 8.1 has indeed reached RTM, confirming recent speculation.
Build 9600 was compiled on the 21st of August 2013, more so, OEM's have had access to said build for sometime now. It's rather surprising that the final RTM hasn't leaked yet. Windows 8.1 is right on track for it's October 18 launch. We recently learned that OEM's will be allowed to start selling their Windows 8.1 inventory as soon as they receive it, which will likely be way before October 18.
Windows 8.1 will launch for all Windows 8 users as a free update on October 17, and will launch as a standalone OS on October 18 for users who wish to upgrade from other operating systems. Stay tuned at WinBeta for more on the Windows 8.1 RTM.
Microsoft recently revealed that Windows 8.1 would be hitting stores on October 18, 2013. Those who wish to upgrade via the Windows Store can snag the update one day early. Windows 8.1 is an update and not an upgrade, and it will be free for users running Windows 8.