Windows 10 will stay genuine, so users can install the preview right now and simply upgrade to the final bits for no charge. Gabe Aul from Microsoft confirmed the plans on Twitter as part of a new blog post detailing some new changes to the way the company tests Windows 10.

Microsoft clarified that the free offer to upgrade to Windows 10 will not apply to Non-Genuine Windows devices. The company has offered free Windows 10 upgrade for genuine Windows 7, Windows 8.1 customers.

Once a customer upgrades, he or she will continue to receive ongoing Windows innovation and security updates for free, for the supported lifetime of that device.

These customers purchased their Genuine Windows license from our valued OEM partners, which ensures Windows is properly installed, licensed, and not tampered with. Windows 10 offers our customers an even more secure and modern experience.

Bringing all of our customers to Windows 10 improves the ecosystem for developers which makes Windows better for all of our customers.

Non-Genuine Windows has a high risk of malware, fraud, public exposure of your personal information, and a higher risk for poor performance or feature malfunctions. Non-Genuine Windows is not supported by Microsoft or a trusted partner.