Windows 8.1 (codenamed Blue) is a computer operating system released by Microsoft. First unveiled and released as a public beta in June 2013, it was released to manufacturing on August 27, 2013, and reached general availability on October 17, 2013, almost a year after the retail release of its predecessor. Windows 8.1 is available free of charge for retail copies of Windows 8 and Windows RT users via the Windows Store. In February 2013, ZDNet writer Mary Jo Foley disclosed potential rumors about “Blue”, the codename for a wave of planned updates across several Microsoft products and services, including Windows 8, Windows Phone 8, Outlook.com, and SkyDrive. In particular, the report detailed that Microsoft was planning to shift to a more “continuous” development model, which would see major revisions to its main software platforms released on a consistent yearly cycle to keep up with market demands. Lending credibility to the reports, Foley noted that a Microsoft staff member had listed experience with “Windows Blue” on his LinkedIn profile, and listed it as a separate operating system from 8.