Microsoft preparing closure of EWS
Microsoft is preparing to retire Exchange Web Services (EWS) from Microsoft 365 and Exchange Online, marking the end of a technology that has powered email integrations and automation for nearly two decades. The company has now put firm dates on the transition, giving organizations a limited window to move to newer APIs.
Starting in October 2026, EWS will switch off by default in Exchange Online. Admins will still have the option to turn it back on for a while, but this is only meant as a temporary safety net. The real cutoff arrives on April 1, 2027, when EWS will stop working in Microsoft’s cloud services entirely. Microsoft has been clear that this deadline will not move.
The change only affects cloud environments. If you’re running Exchange on-premises, EWS will continue to function. The retirement is part of Microsoft’s wider push to move customers toward modern authentication methods and newer interfaces like Microsoft Graph.
One interesting part of the transition is something Microsoft calls “scream tests.” These are short, planned outages where EWS is briefly disabled. The goal is simple: if something suddenly stops working, you’ve just discovered a dependency that needs to be replaced before the final shutdown.
Microsoft says the move is mainly about security and reliability. EWS was designed in a very different era of IT, and maintaining it alongside modern cloud security standards has become increasingly difficult.
To avoid surprises, Microsoft plans to send regular reminders through the Message Center. But the key takeaway is simple: if your environment still depends on EWS in the cloud, the time to plan migration is now, not next year.
