Microsoft confirmed that it will not offer extended support for Exchange Server 2013 after April 11.
It encourages customers to move to Exchange Online to benefit from cloud-driven performance and security updates. Microsoft also continues to support Exchange Server 2019 for customers with on-premises requirements.
According to an announcement, after April 11 Microsoft will no longer offer technical support for problems that may occur, bug fixes for issues that may impact the stability and usability of the server, security fixes for newly-discovered vulnerabilities or time zone updates.
Last year, the company developed an end of support roadmap to help prepare Exchange 2013 customers for the cut-off date. Those options include migrating to Microsoft 365 or upgrading on-premises Exchange servers to more updated 2019 version.
“We strongly believe that you get the best value and user experience by migrating fully to Microsoft 365. But we understand that some organizations need to keep some Exchange servers on-premises,” the road map states. “This might be because of regulatory requirements, to guarantee data isn’t stored in a foreign datacenter, because you have unique settings or requirements that can’t be met in the cloud, or because you need Exchange to manage cloud mailboxes because you still use Active Directory on-premises.”
Very likely the unpatched systems remaining in the wild because their operators lacked the visibility into those deployments or organizational capability to patch them. In a broader sense, this is an issue of lifecycle management.