Upgrading your operating system to macOS 10.15 or later will allow Office updates to be delivered for your apps. If you continue with an older version of macOS, your Office apps will still work, but you'll no longer receive any updates including security updates.
Starting with the November 2021 update (16.55) macOS 10.15 Catalina or later is required receive updates to Word, Excel, PowerPoint, Outlook and OneNote.
