A technician adjusts a spotlight at the exhibition stand of Microsoft in preparation for the CeBIT computer fair in the northern German town of Hanover March 12, 2007. Reuters/Christian Charisus

Microsoft is practically giving away Windows 10 to PC users on release date no matter what previous versions of the operating system that the machines are running on. But the free offer comes with a definition pre-condition – be a Windows Insider first.

Previously, the July 29 free Windows 10 download was only for current users of Windows 7, 8 and 8.1 but in a new blog post Microsoft discussed the likelihood of Windows XP and Vista users accessing the same privilege. Their free ticket will come via the Windows Insider Program, which is a community of software testers running the beta builds of the soon-to-arrive OS.

Technically, PCs that run on any Windows version are qualified to participate on the Windows Insider Program provided these machines have the hardware credentials set by Microsoft. And to actually get Windows 10, these devices will need to install the latest beta build of the operating system weeks or days before July 29, according to WinBeta.

The latest version, the same report said, currently stands at Beta Build 10130, which according to Microsoft is pretty much the final cut of Windows 10. There will be betas to follow but these are mostly for bug fixes and performance or stability concerns.

So Build 10130 is the gateway to a free Windows 10 copy that Microsoft said will be usable even after a clean install, which likely is the route to be taken by quite a handful of Windows Insiders following the official rollout.

The software giant also reminded that Insiders need to connect their PCs to a registered Microsoft Account or MSA to get hold of the free offer and “in order to continue receiving new Windows 10 Insider Preview builds (both Fast and Slow rings) from Windows Update.”

“Connecting your MSA also allows seamless access to Windows Insider-only functionality in the Windows Feedback app and Insider Hub too,” Microsoft’s Gabe Aul said in a Windows blog post.

Aul revealed too that Windows Insider participants will be given the option to leave the program, start over for clean Windows 10 install and keep the software as promised. But he noted that staying put will mean direct and quick access to the “the latest Windows fixes, features, and updates and give us feedback.”

As mentioned, the fun starts on July 29 that is set as Windows 10 release date, at least for desktop and tablet users who plan to grab the free upgrade. The retail selling is expected to follow soon while Windows 10 Mobile will only be available around December 2015.

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