Microsoft has officially released the revamped version of its latest Windows operating system.
Windows 8.1 is now available as a free update for owners of a Windows 8 device in more than 230 markets.
It comes after last year's release of Windows 8, Microsoft's attempt to create an operating system which worked just as well on smartphones and tablets as on laptops and desktops.
Windows 8 has failed to take off though, with many users expressing frustration at the new look system, which includes a touch-screen, tiled interface.
Microsoft has since struggled with sales of Windows 8 devices and some in the industry have even blamed the company for falling global PC shipments.