Microsoft revealed that Windows 8.1 would be released to the masses on October 18th 2013. Microsoft also revealed that Windows Server 2012 R2 will also be released on the same day.
"I'm excited to announce that, on the same day, eligible customers will be able to download Windows Server 2012 R2 and System Center 2012 R2, as well as the latest update to Windows Intune! We’ll make evaluation versions available through the TechNet Evaluation Center, and these products will be available for new purchases when they hit the price list on November 1st," Microsoft's Brad Anderson stated in an official blog post.