As of October 10, 2023, Microsoft is discontinuing its Mainstream support for Office 2016 and Office 2019 versions.
Despite Microsoft not taking any active measures to block 2016 and 2019 Office versions from connecting to Microsoft 365 services (if they are kept up to date), legacy clients may encounter performance, reliability, and connectivity to UTMail+ and M365 services issues (Exchange Online, SharePoint or OneDrive).
| Office version | Mainstream and connectivity to Microsoft 365 services Support End date | Extended Support End date |
| Microsoft 365 Apps | Supported as long as you’re using a supported version. | N/A |
| Office LTSC 2021 | October 13, 2026 | N/A |
| Office 2019 | October 10, 2023 | Oct 14, 2025 |
| Office 2016 | October 10, 2023 | Oct 14, 2025 |
To provide the best experience with using Microsoft 365 services and UTMail+ connectivity, we strongly recommend that you move off older Office versions to a recent and fully supported Microsoft 365 Apps Office Version.
Additional information: