Microsoft 365 Apps is supported under the Modern Lifecycle Policy. Therefore, the apps are supported continuously given that customers stay current per the servicing and system requirements. These requirements include using Microsoft 365 Apps on an operating system currently in support.
On January 10, 2023, Windows 8.1 will reach the end of support. Also, on the same day, the three-year Extended Security Updates (ESU) paid program for Windows 7 and Windows Server 2008 R2 ends. While Microsoft 365 Apps is not currently supported on Windows 7 or Windows Server 2008 R2, we committed to provide security updates for the length of these ESU programs.
Therefore, after January 10, 2023, Microsoft 365 Apps running on Windows 7, Windows 8.1, or Windows Server 2008 R2 will stop receiving security updates. Additionally, new installations of Microsoft 365 Apps will be blocked on Windows 8.1 devices. We recommend that customers running these operating systems migrate to a supported OS before January 2023. View the Windows and Office configuration support matrix.
Please remember that using unsupported software may increase an organization’s exposure to security risks or impact its ability to meet compliance obligations.
For additional information refer to:
Source: Act now and keep Microsoft 365 Apps supported after January 10, 2023