Microsoft shared info that it would offer the Windows 10 upgrade for free even to people with pirated versions of Windows. However, one important new snippet of information is that this will not turn pirated copies into genuine versions of Windows. 

New information today confirms worldwide pirated version can upgrade their old operating system to Windows 10. 

Microsoft has issued the following statement in regard to upgrades for "non-genuine" PCs:

We have always been committed to ensuring that customers have the best Windows experience possible. 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. Non-Genuine Windows is not published by Microsoft. It is not properly licensed, or supported by Microsoft or a trusted partner. 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. According to industry experts, use of pirated software, including Non-Genuine Windows, results in a higher risk of malware, fraud (identity theft, credit card theft, etc), public exposure of your personal information, and a higher risk for poor performance or feature malfunctions.

BTW we forgot to give props to DVHardware for spotting and reporting this one, mentioned and link added - sorry guys ! ;)

Windows 10 will not make pirated copies genuine