Ahead of its October 18 schedule, Microsoft began rolling out Windows 8.1 as free-upgrades to current Windows 8 users, through the Windows Store. At your command, the Store app downloads and upgrades the operating system in complete silence, in the background. Windows 8 and Windows 8 Pro users get Windows 8.1 and Windows 8.1 Pro, respectively, as free upgrades. Users coming from older versions have to purchase the upgrade, which is $120 for Windows 8.1, and $200 for Windows 8.1 Pro. Those coming from Windows 7 Ultimate or Windows Vista Ultimate can only upgrade to Windows 8.1 Pro.