Microsoft is warning Office 2016 and 2019 users that they might encounter issues when connecting to Microsoft 365 back-end services starting in October 2023. But they won't be blocked from doing so.

Support for Microsoft Office 2016 and 2019 will end soon. After that, Microsoft will no longer provide security updates or close security gaps. This is what users can do. By Hans-Christian Dirscherl ...

Microsoft also rolled out Office LTSC (Long Term Servicing Channel) 2024 in September 2024, a volume-licensed perpetual Windows and macOS version of Office for commercial and government customers.

Office 2010 for Windows also is no longer supported after October 13, 2020. But Office 2016 and 2019 for Windows still have a few years of supported life left.

That warning comes from Microsoft even though both Office 2016 and Office 2019 will reach their end of "extended support" phases on Oct. 14, 2025.