Windows 10 is a free upgrade, for a limited time, for qualified Windows 7
and Windows 8.1 devices (including devices that you already own). It is our
intention that most of these devices will qualify, but some hardware/software
requirements apply and feature availability may vary by device. The availability
of Windows 10 upgrade for Windows Phone 8.1 devices may vary by OEM, mobile
operator or carrier. Devices must be connected to the Internet and have Windows
Update enabled. ISP fees may apply. Windows 7 SP1 and Windows 8.1 Update required.
Some editions are excluded: Windows 7 Enterprise, Windows 8/8.1 Enterprise
and Windows RT/RT 8.1. Active Software Assurance customers in volume licensing
have the benefit to upgrade to Windows 10 enterprise offerings outside this
offer. To check for compatibility and other important installation information,
visit your device manufacturers website and the Windows
10 Specifications page.