[Paul R.]

Support for Windows 7 ended on January 14, 2020. Even though Windows 7 is no longer supported, we've decided to continue to provide you with security updates for Microsoft 365 for the next 3 years, until January 2023.

https://support.microsoft.com/en-us/office/windows-7-end-of-support-and-office-78f20fab-b57b-44d7-8368-06a8493f3cb9

[dayglored]

> Even though Windows 7 is no longer supported, we've decided to continue to provide you with security updates for Microsoft 365 for the next 3 years, until January 2023.

As you're aware, the operating system "Windows 7" and the application suite "Microsoft 365" (nee "Office 365") are completely separate entities. Of course there's nothing stopping a software vendor from continuing to support their application on OSes that are past EOL. But that is entirely different from offering support for the OS.

That said, if you had deep pockets and a large Volume License contract with Microsoft, you could continue to get security updates for Win7 past the Jan 2020 EOL date, but that option was only available to very large corporate accounts, and was extremely costly.