In order to settle the confusion brought about by its earlier statement regarding the Windows 10 upgrade, Microsoft explained the qualifications for getting a free copy of the new operating system.

The confusion began when Microsoft's Gabriel Aul announced Friday that all registered users of the Windows 10 Insiders beta will be able to enjoy a free upgrade of the software's final version upon its release on July 29. Then the blog was later on updated, this time appearing as if only beta testers who will upgrade from Windows 7 or 8 will get the final edition of the software without having to make a purchase.

But in his latest update, Aul finally released a new statement to clear the confusion regarding the free release of the final build called Windows 10 RTM for testers. This time, the Microsoft exec said that only those who installed the original Windows 10 Preview on devices that run the activated versions of Windows 7 or 8.1 can get it for free under the terms and conditions mentioned in the offer.

Based on the terms of the free upgrade, Insider testers must decide to take advantage of the offer within one year from release. Those who choose to upgrade can enjoy using Windows 10 on a specific device for free.

However, Aul reminded the preview testers who choose to discontinue their Windows Insider Program during the official release date of Windows 10 that it is not an option to get a license for the Windows XP and Windows Vista OS.

"If your system upgraded from a Genuine Windows 7 or Windows 8.1 license it will remain activated, but if not, you will be required to roll back to your previous OS version or acquire a new Windows 10 license. If you do not roll back or acquire a new license the build will eventually expire," the Microsoft rep said.

For those who are not qualified to avail the free upgrade, Windows 10 will be available starting July 29 for just $119 for the Home package, while the Window 10 Pro can be purchased for $199.