We will be making available a FREE UPGRADE to Win 10 to all devices running Win 8.1. And to all devices running Windows Phone 8.1. And for a year, a FREE UPGRADE from Windows 7.
This is really great news. Free upgrades lead to more people on newer operating systems, which typically leads to more people on newer hardware. I know there are a lot of Windows users out there running Windows 7 on five year old machines. I hope this will bring a huge amount of users up to speed on recent advances, especially on the web browser side of things.