Microsoft to launch Windows 8.1 : on October 18 Microsoft has announced that Windows 8.1 will be arriving on October 17th, confirming. For some reason, the company's specified an exact release time of 12.00 am on October 18th in New Zealand, which is 4.00 am PT or 7.00 am ET on October 17th. At that time, the free update will begin rolling out across local Windows Stores, and will be available "at retail and on new devices" from the 18th onwards, depending on your region. Check out our hands-on and subsequent coverage for an idea of what to expect from the update. Windows 8.1 will be offered as a free download to those already using Windows 8, and comes in response to a lukewarm reception to the operating system introduced last year aimed at serving both mobile devices and PCs. A full retail version of Windows 8.1 will also be available on the same date.