​Microsoft has reminded admins that Exchange 2016 and Exchange 2019 will reach the end of extended support in October and shared guidance for those who need to decommission outdated servers.
Exchange 2016 reached its mainstream end date in October 2020, while Exchange 2019 reached the end of mainstream support on January 9, 2024.
“On October 14, 2025, 9 months from today, Exchange Server 2016 and Exchange Server 2019 reach end of support,” the Exchange Team said.
“Customer installations of Exchange 2016 and Exchange 2019 will of course continue to run after October 14, 2025; however, due to the upcoming end of support date and potential future security risks, we strongly recommend customers act now.”
After October 14, 2025, Microsoft will no longer provide technical support for problems with Exchange 2016 or Exchange 2019, including technical support and bug fixes for newly discovered issues that may impact server usability and stability.
The company will also stop issuing time zone updates and security fixes for discovered vulnerabilities that may make the server vulnerable to security breaches.
Upgrade to Exchange Online or Exchange Server SE
Microsoft advises admins to migrate to Exchange Online (available as an Office 365 subscription or a stand-alone service) or prepare to upgrade to Exchange Server Subscription Edition (SE) when it rolls out in early H2 of CY2025.
Admins can perform an in-place upgrade from Exchange Server 2019 to Exchange Server SE, identical to installing a Cumulative Update (CU).
“To enable quick and easy in-place upgrades from Exchange Server 2019, we have purposely either pulled new features forward into Exchange Server 2019 CU15 or pushed them to Exchange Server SE CU1 or later, leaving the Exchange SE RTM to be a branding update that introduces new lifecycle and support policies,” the Exchange Team said in September when it provided more information on Exchange Server SE upgrades.
“By moving to Exchange Server SE RTM, your servers are on the supported path to Exchange SE CU1. Once Exchange SE CU1 is released, all older versions will be out of support.”
Redmond’s documentation site provides detailed guidance for global admins on Microsoft 365 migration and helps them decide on the Exchange Online migration path.