The clock has just ticked over 4am in Redmond, Washington, and that means Microsoft has begun the rollout of Windows 8.1 around the globe. The update is free to download for all Windows 8 users, so head in to the Windows Store app to find out how to upgrade.

For those who haven't yet upgraded to Windows 8, starting on October 18th you'll be able to pick up a full copy of Windows 8.1 from your favorite retailer. New hardware packing Windows 8.1 will also be available starting October 18th, in case you'd like new hardware to go with your software upgrade.

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.

If you've managed to install Windows 8.1 already, or you've been using it since it was available on MSDN/TechNet, tell us your thoughts on the OS in the comments below. Also, don't forget to read Julio's thoughts on what Microsoft got right in Windows 8.1, and what's still missing.