Out with the old, and in with the new. Microsoft yesterday stopped providing Windows 7 Professional and Windows 8.1 licenses to original equipment manufacturers (OEMs), including its PC partners and systems builders. This means that, as of today, the only way you can buy a computer running Windows 7 or Windows 8.1 is if you can still find one in stock.

Two years ago, Microsoft stopped selling Windows 7 Home Basic, Windows 7 Home Premium, and Windows 7 Ultimate licenses to OEMs. Now Windows 7 Professional and Windows 8.1 are also out of the picture, leaving Windows 10 as the only remaining option, assuming you want a PC with a Microsoft operating system.

This is Microsoft’s way of slowly phasing out old operating systems. The Windows Lifecycle chart for sales doesn’t have an end date for Windows 10, since that operating system doesn’t have a successor.

It’s also worth noting that Mainstream Support for Windows 7 ended on January 13, 2015. Mainstream Support includes free incident support, warranty claims, fixes for non-security bugs as well as security bugs, plus design changes and feature requests. Extended Support consists solely of security updates.

As you can see, Mainstream Support for Windows 8.1 will end on January 9, 2018, while Windows 10 will still get it until October 13, 2020. But the latest and greatest operating system from Microsoft is unique: Windows 10 is a service, meaning it was built in a very different way than its predecessors, so it can be regularly updated with not just fixes but new features too.

The most recent significant update is the Windows 10 Anniversary Update, released in August 2016. Its successor, the Windows 10 Creators Update, is slated to arrive in “early 2017.”

In short, there simply isn’t a good reason to seek out a PC running Windows 7 or Windows 8.1 today. Buying a Windows 10 computer means you will be getting not just support for years to come, but also new features and improvements for free.