Microsoft's Windows 10 event is just getting started, and it sounds like the company is eager to make it as easy and cheap as possible for those running older versions of Windows to upgrade. Terry Myerson just announced on stage that, for the first year after Windows 10 launches, any device running Windows 7, Windows 8.1, or Windows Phone 8.1 will be able to upgrade to the latest version of MIcrosoft's OS for free. How exactly this program will work isn't clear just yet it'll certainly be subject to some hardware requirements, particularly for older machines running Windows 7. But a simplified upgrade path will likely do a lot to help Windows 10 adoption rather than dealing with a number of different versions of Windows and different upgrade costs, most consumers will simply take this free update and enjoy running Microsoft's latest.
Beyond this, Myerson shared Microsoft's vision for Windows as a service, not just an operating system. A big part of that is Microsoft's new commitment to keep devices consistently updated throughout the "supported lifetime for the device." It sounds like that means those upgrading from Microsoft's older versions of Windows will consistently receive updates to keep it as up-to-date as possible. Myerson noted that this will let developer "target every single Windows device" when they build apps, anything that makes it easier for developers to reach more users will certainly be appreciated by both the developer community as well as end users.
source news : http://www.theverge.com/2015/1/21/7866679/windows-10-will-be-a-free-upgrade-for-windows-7-and-8-1-users
