Windows 10 Upgrade Offer is valid for qualified and genuine Windows 7 and Windows 8.1 devices, including devices you already own. Some hardware/software requirements apply and feature availability may vary by device and market. 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. 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 of this offer. To check for compatibility and other important installation information, visit your device manufacturer’s website and the Windows 10 Specifications page.

If you have Windows XP and want Windows 10, you either have to pay for a copy of Windows 7 and install it, or wait till Windows 10 becomes available to purchase in a few months.