When Microsoft announced that the Windows 10 will be a free upgrade, many users of the operating system from the Redmond-based firm were excited. But it seems that the company has taken an about face on this statement and has issued a clarification on who is qualified to take advantage of this upgrade at no cost.

Microsoft's General Manager for OSG Data and Fundamentals Team announced via Twitter that he has made clarifications on the previous blog post he put up regarding the upgrade with no cost.

"Hey everyone, I've updated the post from Friday as it wasn't clear enough & caused some confusion, take a look here," wrote Aul alongside a link to the updated post on the company's website.

Based on Microsoft's initial statement, users who are currently using Windows 7.1 and Windows 8 will automatically get a free upgrade to the latest OS. But aside from that option, The Verge reported that other PC users could choose to install the Windows 10 preview (build 10130), register to the Windows Insider program and the final version of the latest OS will also be available at no cost.

However, it seems that there is a fine print to this "free Windows 10" promo that was not made clear in the beginning. The company has since updated its qualifications to give users a clearer understanding of how to avail the latest OS with no charge.

For those who are currently using Windows 7.1 and Windows 8, the update will remain free of charge beginning July 29 when Windows 10 is made available to the public as a downloadable update.

Meanwhile, those who are enrolled at the Windows Insider Program and have installed the preview build of the OS will be able to access it for free if they continue to opt-in future pre-release updates.

"Since we're continuing the Windows Insider Program you'll be able to continue receiving builds and those builds will continue to be activated under the terms of the Windows Insider Program," wrote the statement on the company's official website.

If a Windows XP and Windows Vista user, which has upgraded to the Windows 10 preview decide to opt-out of the pre-release builds after installing the July 29 version of the Windows 10, then Microsoft will require the system to go back to its original OS or purchase a new Windows 10 license.

Those who do not revert back to its previous operating system will see their Windows 10 preview expire.

Pirated copies of Windows 7.1 and Windows 8 will not be eligible for the free upgrade, said another report on The Verge. Although the company originally revealed that it is working on a plan to have Windows 10 as a free upgrade to pirated OS, it has not offered any details on how it will be done.

Windows 10 will be available on July 29.