Microsoft has confirmed once and for all that Windows 9 will be a free software upgrade, it's claimed.

Several reports have gone back and forth in recent months, asserting Microsoft might or might not charge for the upgrade to Windows 9. But now, according to Indonesian news site Detik.com, which was first spotted by BGR, Andreas Diantoro, the president of Microsoft Indonesia, has announced that Windows 9 will be a free upgrade for all Windows 8 users.

Windows 9 is the next version of Windows OS. It is currently also known by the codename Threshold. Microsoft reportedly wants to abandon the Windows 8 brand with Windows 9, mostly because Windows 8 was not well-received by critics and users. It's also assumed that Microsoft decided not to charge for the Windows 9 upgrade in order to entice users who were put off by Windows 8.

It's worth noting too that Microsoft didn't charge for the upgrade to Windows 8.1. That all said, Microsoft has yet to even announce a release date or even key features for Windows 9. The Redmond-based company recently however invited the media to a Windows event scheduled for 30 September. The invites indicated Microsoft will discuss "what's next for Windows and the enterprise".

Microsoft should debut a "Windows Technical Preview" at the event. The preview will not only reveal the next version of Windows but will also allow developers and enterprise customers to prepare for all the coming OS changes. The invitations didn't reveal if Microsoft plans to distribute the Windows Technical Preview during or after the event.

Keep in mind many leaks have suggested Microsoft wants to make a public preview also available in September or early October.

READ: Windows 9 Threshold rumour round-up