To ensure a safe transition, Microsoft will provide security updates for M365 on Windows 10 through October 10, 2028 through the standard update channel.
In another post, Microsoft stressed:
We recommend users upgrade to Windows 11 to avoid performance risks. However, users who find it difficult to upgrade due to Windows 11's strict system requirements can continue to use M365 until 2028.
Extending M365 support on Windows 10 to 2028 is considered a reasonable step from Microsoft, giving many individuals and businesses more time to convert and upgrade their systems, especially when many computers do not meet the hardware requirements of Windows 11. However, the company still encourages early upgrades to take advantage of optimal features and security.
Note: