Last updated on May 9, 2025  

The system requirements for Microsoft 365 are provided on the page below. Please refer to it for details.

https://support.microsoft.com/ja-jp/topic/%E3%83%93%E3%82%B8%E3%83%8D%E3%82%B9-%E6%95%99%E8%82%B2-%E6%94%BF%E5%BA%9C%E6%A9%9F%E9%96%A2%E5%90%91%E3%81%91%E3%81%AE-microsoft-365-%E3%81%AE%E3%82%B7%E3%82%B9%E3%83%86%E3%83%A0%E8%A6%81%E4%BB%B6-13eda659-3dfc-448e-b2cd-70ebb989be47 

For Windows, most recent PCs generally meet the system requirements for Microsoft 365.

For Mac, Microsoft 365 supports the latest version of macOS and the two preceding versions, for a total of three supported operating systems.
For example, if the latest macOS version is 15, then macOS 15, macOS 14, and macOS 13 meet the system requirements. When macOS 16 is released in the future, macOS 13 will no longer meet the system requirements.

Even if your system met the requirements at the time of installing Microsoft 365, your installed Microsoft 365 will continue to work if a new OS is later released and your current OS no longer meets the system requirements (although operation cannot be guaranteed).
However, please note that if you uninstall Microsoft 365 in an environment where the OS no longer meets the system requirements, you will not be able to reinstall it until you upgrade to an OS that meets the requirements.