Microsoft is gearing up to add a monthly subscription fee for its Windows 10, but it doesn't apply to consumers — at least not at this point.

Called Windows 10 Enterprise E3, the new monthly subscription tier will apply only to enterprises, not individual consumers who upgraded to Windows 10 on the promise that it's free.

The new tier will cost enterprises $7 per month for each user, bringing Windows 10 in line with Azure and Office 365 as a subscription service.

Microsoft promised time and time again that upgrading to Windows 10 is free, prompting many consumers to take the plunge when otherwise they wouldn't have paid for the upgrade. The news of the monthly subscription service stirred some concerns that Microsoft might be looking to charge customers once that year of free upgrades to Windows 10 ends on July 29, but the company confirmed that it's not the case.

So how does this new enterprise tier affect those who got Windows 10 for free? It doesn't, according to Microsoft.

"This new subscription model is not associated with our current upgrade offering or applicable to the Windows 10 consumer edition," a company spokesperson confirmed for PCWorld.

On the other hand, this only gives assurance that consumers will not be charged for Windows 10 at this point, but offers no guarantees that it will not happen in the future. Microsoft could eventually add Windows 10 monthly subscriptions for consumers as well, but it's highly unlikely that it would push them to all customers who already upgraded because it was free.

Instead, the company could decide to implement a threshold at some point and require a subscription for those who want additional features past that point.

While it's just speculation at this stage, this would make sense considering that Microsoft repeatedly said that Windows 10 is the last version of its OS. This means that it will get various upgrades in the future, but it will not get a successor in the form of a Windows 11.

With no Windows 11 replacement, Windows 10 could require a fee somewhere down the line, when it reaches a more advanced stage.

For now, consumers who want to upgrade to Windows 10 can still take advantage of the free upgrade offer until July 29, and they will not have to pay any fees afterward. Once the free upgrade offer expires, Windows 10 will be available for purchase at $119 for the Home edition and $199 for the Pro.