Office 365 for Mac drops support for macOS 10.13 High Sierra in November

As we approach the release of macOS 11 Big Sur, Microsoft is preparing to shift its Office 365 support away from another older version of macOS. Specifically, Office 365 apps will no longer support macOS 10.13 High Sierra as of November 10. From that point, only macOS 10.14, 10.15, and 11 will be supported with the Office 365 suite.

In an update to the Office 365 message center (via OnMSFT), Microsoft said:

As of the Microsoft 365 for Mac November 2020 update, macOS 10.14 Mojave or later is required to receive updates to Word, Excel, PowerPoint, Outlook and OneNote. If you continue with an older version of macOS, your Office apps will continue to work but you will no longer receive any updates including security updates.

This move stays in line with Microsoft's practice of supporting the latest three macOS releases with its Office 365 suite. Currently, those include macOS 10.13, 10.14, and 10.15. After the release of macOS 11 Big Sur, the oldest version supported will be 10.14.

As of the release of Big Sur, macOS will support both Intel and ARM-based Macs. Apple is expected to launch Macs sporting its own ARM-based chips later in 2020, and the company says Microsoft's Office apps are already running on ARM-based Macs.