Although Microsoft will let pirates upgrade to Windows 10, the company's not giving them a free pass, the company confirmed today.

Illegal copies of Windows 7, Windows 8 and Windows 8.1 that are upgraded to Windows 10 will continue to be marked as "non-genuine," the Microsoft term for pirated or illegitimate licenses of its operating system.

"With Windows 10, although non-genuine PCs may be able to upgrade to Windows 10, the upgrade will not change the genuine state of the license," a Microsoft spokesperson said in a reply to questions.

"If a device was considered non-genuine or mislicensed prior to the upgrade, that device will continue to be considered non-genuine or mislicensed after the upgrade," the spokesperson added (emphasis added).

That explanation followed an announcement yesterday that Microsoft would offer Windows 10 upgrades to PCs running pirated copies of Windows 7 and later. "Anyone with a qualified device can upgrade to Window 10, including those with pirated copies of Windows," the company said Wednesday.

However, another line in yesterday's announcement -- "We believe customers over time will realize the value of properly licensing Windows and we will make it easy for them to move to legitimate copies" -- implied that the Windows 10 upgrades for pirates would not magically transform the license into a "genuine" state.

Today's clarification meant that Microsoft will not completely cave to piracy, but will continue to prompt users running non-genuine Windows to get legal by paying for a license.

Currently, illegal or illegitimate Windows licenses are marked by a permanent notice that the copy is non-compliant. As another warning, the desktop background also resets to black every 60 minutes.

Those markers were first instituted in a new OS with Windows 7, and were a significant relaxation of the tougher rules in Vista (prior to December 2007) and Windows XP (before August 2008), which had relied on a so-called kill switch that dropped the operating system into "reduced-functionality mode," in which nothing worked except the Internet Explorer browser, and that only for an hour at a time.

Pirates should expect the same behavior from Windows 10 as they have seen in Windows 7 and Windows 8.

Non-genuine Windows also faces other limitations: While critical security updates are offered to pirated copies, optional updates are not.

Depending on how Microsoft handles Windows 10 in a non-genuine state -- and there's no reason to believe it will back off current practice -- it will probably decline to serve pirates new features and improvements on existing features. If it did not do so, pirates would have little motivation to get legal, as they would receive the same unlimited OS refreshes and enhancements as those who paid for their licenses.

It will also not be a surprise if many of those running illegal copies decline to upgrade to Windows 10, and so prove a wrench in Microsoft's plans. Pirates have long avoided Windows Update, even for security patches, for fear of being found out, and their desktops tagged with the notices and black screen.

Windows 10 will launch this summer.