Upgrade macOS for Office 365 for Mac or Office 2019 for Mac new updates

PSA:

As of the November 2019 update for Office 365 for Mac or Office 2019 for Mac (build 16.31), macOS 10.13.6 or later is required to receive updates.

https://support.office.com/en-us/article/upgrade-macos-for-office-365-for-mac-or-office-2019-for-mac-new-updates-f18e459c-b164-4dd9-8bfc-effcf64dadd4

Office 2016 will continue to receive monthly security updates on macOS 10.10 and later until October 2020.