Microsoft has announced that Windows 10 will be a free upgrade to current users of Windows 7 and 8.1. This offer will be extended for one year after Windows 10 launches. Once you’ve taken advantage of this free upgrade, you will continue to get free upgrades for the lifetime of the device on which Windows 10 is installed.
So, if you are one of those XP holdouts, this may be the greatest incentive yet to upgrade to Windows 8.1, guaranteeing you’ll get Windows 10 when it comes out. There is no free upgrade for Windows XP users.