Microsoft has announced that Windows 10  will be offered as a free upgrade to Windows 8.1, Windows 8, Windows 7 and Windows Phone.


Limited to the OS’s first year of release, this new strategy appears to be designed  to avoid a repeat of the slow uptake of Windows Vista and Windows 8, giving consumers no excuse not to update to Windows 10

Microsoft made the announcement this morning at an event on its corporate campus outside of Seattle.