As the release date draws near for Microsoft's Windows 10 operating system, new details are emerging every day. From the start, Microsoft has been stressing that when Windows 10 becomes available, current users of Windows 7, Windows 8 and Windows Phone 8.1 will be able to migrate to the new version for free. The caveat, however, is that these users must upgrade within a year of the Windows 10 launch, which is expected sometime this summer.

But the tech giant hasn't yet answered crucial questions, such as "What happens after the first year passes?" and "Will the time frame be extended?"

According to PC World, Microsoft will not extend the time frame to let the one billion-or-so Windows users upgrade to Windows 10. Meanwhile, Neowin quotes Alex Snelson, a Windows product marketing manager for Microsoft in Australia, as stating the following: “Microsoft will offer a free upgrade to Windows 10 for qualified Windows 7, Windows 8 and Windows Phone 8.1 devices in the first year. After the first year, upgrades will be paid via boxed product and VL Upgrades.”

This means that if Windows users fail to upgrade to Windows 10 within the first year, they will have to pay to upgrade -- although Microsoft hasn't yet said what that price will be. In any case, a Windows 10 upgrade won't be entirely free. The free upgrade covers only those PCs using a “legitimately licensed version of Windows 7 or Windows 8.” Any users of pirated versions of Windows will have to shell out cash to get Windows 10.

Neowin says that when Windows 10 launches, there will be paid options for upgrading to the OS specific to consumers who are still stuck with Windows XP or Window Vista. Plus, full copies of the OS will be made available for those users that build their own machines.