(Please refer to the Microsoft support lifecycle site for Office mainstream support dates.)” “Effective October 13th, 2020, Office 365 will only allow Office client connectivity from subscription clients (Office 365 ProPlus) or Office perpetual clients within mainstream support to connect to Office 365 services. It references the updated System Requirements for Office, which states: On Apthe Office Blog wrote an article about Office 365 system requirements changes for Office client connectivity. To give you more time to transition fully to the cloud, we are now modifying that policy and will continue to support Office 2016 connections with the Office 365 services through October 2023.
In February, we announced that starting October 13, 2020, customers will need Office 365 ProPlus or Office 2019 clients in mainstream support to connect to Office 365 services. In addition, we are modifying the Office 365 services system requirements related to service connectivity. Office 2016 connectivity support for Office 365 services
