Microsoft confused everyone about its free upgrade plans for Windows 10 last week. While it looked like everyone who tested Windows 10 will get a free copy, the reality is slightly more complex. In an attempt to address some of the confusion Microsoft has created, the software giant has updated its blog post to clarify who gets a free copy of Windows 10. Windows 7 and Windows 8.1 users will obviously get a copy of Windows 10 on July 29th as a free upgrade, but Windows 10 preview users will also get a free upgrade.

Read next: Our Windows 10 review.

The nuance here is that Microsoft will keep fresh copies of Windows 10 activated for testers only if they keep opting-in to future preview updates. So if you’ve clean installed a Windows 10 preview build and upgrade to the final then you don’t have to worry about activation as long as you keep receiving 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," explains Microsoft’s Gabe Aul.

You have to opt-in to future pre-release updates to get Windows 10 for free

If you install a Windows 10 preview copy right now and upgrade to the final release on July 29th and then opt-out of pre-release updates then you won’t be genuine anymore if you didn’t upgrade from a copy of Windows 7 or Windows 8.1. Microsoft says you’ll need to "roll back to your previous OS version or acquire a new Windows 10 license" if you clean installed the Windows 10 preview and opt-out of updates. "If you do not roll back or acquire a new license the build will eventually expire." Microsoft is making it clear that clean installing the Windows 10 preview and upgrading just to get the final bits and opting-out of future updates "is not a path to attain a license for Windows XP or Windows Vista systems."

Still, if you clean install the Windows 10 preview now and continue to opt-in to future updates then you’ll get your free copy of Windows 10, but you’ll have to put up with potential pre-release software bugs and continued updates in the future. Microsoft says Windows 10 is "intended to be installed on Genuine Windows devices," but the Windows Insider program is a clear, if complicated, loop hole if you don’t have a Windows 7 or Windows 8.1 license.

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