Microsoft has announced that Windows 8.1 will begin rolling out to users worldwide on October 18th at 12am New Zealand time (4am PT on October 17). The update will hit retail channels a day later, with new devices running Windows 8.1 and boxed copies of the software expected to be available.

For everyone currently running Windows 8, Microsoft will be delivering Windows 8.1 as a free update through the Windows Store. As previously reported, the update brings a number of new features and improvements over Windows 8. The Start button will partially return, search and multi-tasking have been greatly enhanced, the Start screen has been improved including new customization options, and the OS has been optimized for smaller tablets.

Microsoft is expected to deliver final Release to Manufacturing (RTM) code to OEMs by the end of August, as recent reports have indicated. Unlike previous years, the RTM code will not be made available to TechNet and MSDN subscribers before the general launch in October. Instead, Microsoft is expected to work on several zero-day patches during the time between RTM and release, fixing minor issues discovered by OEMs.

In the lead up to the Windows 8.1 launch on October 18th, expect to see many new devices emerge from the shadows running the new OS. It's possible that we'll see Microsoft line-up the next-generation Surface launch with the release of Windows 8.1, marking the one year anniversary of both the original Surface RT and Windows 8. Other OEMs are also expected to show off smaller Windows-powered tablets, making use of Microsoft's small-screen optimizations.