Today, while the software will still run, it no longer receives security patches. This makes it a "time capsule" version—perfect for keeping an old MacBook productive, but potentially vulnerable if used for sensitive online work.

Are you looking to this specific version for an older Mac, or are you trying to fix an issue with an existing installation?

: For many, 16.16.9 was the stable midpoint for those with perpetual licenses (one-time purchases) who didn't want to move to the subscription-based Office 365 or the then-new Office 2019.