Microsoft to End Exchange 2016 and 2019 Security Updates, Pushing Move to Subscription Edition

Microsoft said Extended Security Updates for Exchange Server 2016 and Exchange Server 2019 will end in October 2026, closing the final support path for organizations still running those on-premises versions. The company had already ended mainstream support for both products on October 14, 2025, after which they stopped receiving regular security updates, bug fixes, technical support, and time zone updates; the current Period 2 ESU offering followed a six-month extension and Microsoft said it will not be extended again.

Microsoft is directing affected customers to move to Exchange Server Subscription Edition (SE), now the only supported on-premises Exchange release, or migrate to Exchange Online or Microsoft 365. Organizations running Exchange Server 2019 CU15 can transition to Exchange Server SE through an in-place cumulative update without a new license key, while older deployments require legacy migration, and the guidance applies across on-premises, hybrid, and management-tools-only Exchange environments.