Microsoft announced on August 27 that Windows 8.1 and Windows RT 8.1 have been released to manufacturing (RTM'd) and are now being delivered to its OEM partners.

Company officials also confirmed, as I blogged earlier this month, that there will be no early access to the Windows 8.1 RTM bits by subscribers to MSDN, TechNet and its volume-license customers. They will have to wait for Windows 8.1's launch, October 18, to get the gold code.
Put down the pitchforks -- at least for a minute -- and consider this:
Microsoft confirms Windows 8.1 RTM; no early access to final bits | ZDNet