May 20, 2026
Microsoft is ending support for Exchange Web Services (EWS) in Exchange Online, with full retirement starting October 2026. The article explains why this matters for Microsoft 365 administrators, developers, ISVs, backup vendors, and enterprises still relying on legacy integrations. EWS has been a core API for mailbox access, calendar synchronization, migrations, archiving, and third-party tools for years, but Microsoft is now pushing organizations toward Microsoft Graph as the modern replacement. The article highlights that this is not just a technical API change. Many existing applications, scripts, automation processes, monitoring tools, and enterprise workflows still depend heavily on EWS. Organizations that fail to identify these dependencies early may face outages, broken integrations, compliance risks, or unsupported applications once Microsoft disables the service. A major focus is the migration challenge. While Microsoft Graph offers a modern, secure, and unified API mo…