We recommend that you upgrade older Office clients to a subscription version of the Office client, such as Microsoft 365 Apps for enterprise. Upgrade resources available to administrators Therefore, to provide the best experience with using Microsoft 365 services, we strongly recommend that you move off older Office versions to versions supported for connecting to Microsoft 365 services.

Both of these versions are in extended support until October 14, 2025. This includes Office 2019 and Office 2016 after October 10, 2023.

We won’t take any active measures to block older Office versions from connecting to Microsoft 365 services if they're in extended support and are kept up to date. That's because as we make improvements to Microsoft 365 services, we're not taking into account or testing with these older Office versions.

In addition, over time, these older versions might encounter other unexpected performance or reliability issues while using Microsoft 365 services. In practical terms, what this means is that these older Office versions might not be able to use all the latest functionality and features of Microsoft 365 services. Older Office versions might still be able to connect to Microsoft 365 services, but that connectivity isn't supported. Older Office versions not supported for connecting to Microsoft 365 services Office 2016 is no longer in mainstream support, but we made an exception for it until October 2023, as stated in a September 2018 blog post. As stated in a April 2017 blog post, only perpetual Office versions in mainstream support are supported for connecting to Microsoft 365 services.

Difference between o365 and office 2016