Microsoft has officially announced that Exchange Server Subscription Edition (SE), the next version of Exchange Server, will be released in the third quarter of 2025. This version represents a shift to a subscription-based model, aligning more closely with other Microsoft products like SharePoint Server Subscription Edition. Exchange Server SE will be available for download through the Microsoft 365 Admin Center, replacing the Microsoft Volume License Service Center as the main distribution channel. The licensing for Exchange Server SE requires subscription licenses or active Software Assurance for both server and user licenses, with a free Hybrid server license available through the Hybrid Configuration Wizard.
Key Features and Changes in Exchange Server SE
Exchange Server SE will largely use the same code as Exchange Server 2019 CU15 but will introduce several changes:
- Security and Authentication Updates: Exchange Server SE will support Kerberos for server-to-server communication, replacing the older NTLMv2 protocol. The release will also feature an updated Visual C++ redistributable version and introduce REST-based Admin APIs, with plans to deprecate Remote PowerShell in future cumulative updates.
- Deprecation of Older Features: Microsoft plans to discontinue features like Outlook Anywhere (RPC over HTTP) and Unified Communications Managed API (UCMA) 4.0. Exchange Server SE will also no longer support coexistence with earlier versions of Exchange, promoting compatibility only with supported versions like Exchange Server 2019.
- Upgrade Paths: Customers using Exchange Server 2019 can perform an in-place upgrade to Exchange Server SE, which will be similar to installing a cumulative update. For those still using Exchange Server 2016, an upgrade to Exchange Server 2019 is required before moving to SE.
Licensing and Support
Exchange Server SE adopts a subscription-based licensing model similar to that used by other Microsoft on-premises subscription products. This model requires either a subscription or active Software Assurance, eliminating the perpetual licenses used in previous versions. Microsoft will continue to provide cumulative updates (CU) for Exchange Server SE, with the first one expected in October 2025, following a biannual release cadence.
Supported Platforms and Clients
Exchange Server SE will be compatible with Windows Server 2025, and it will also continue to support environments at the Windows Server 2012 R2 forest functional level or later. This version will support multiple Microsoft clients, including Outlook 2021, Outlook 2019, Microsoft 365 Apps for enterprise, and various versions of Outlook for mobile devices. Compatibility requirements are largely similar to those for Exchange Server 2019.
Upgrade Path
The two main upgrade paths for Exchange Server SE are:
- In-Place Upgrade: This path allows a direct upgrade from Exchange Server 2019 CU15 to Exchange SE. It is intended to be as seamless as applying a cumulative update.
- Legacy Upgrade: For organizations running Exchange Server 2016, the path involves a legacy upgrade to Exchange Server 2019, followed by an in-place upgrade to SE.
Differences from Older Versions
Compared to Exchange Server 2019, the primary difference with Exchange Server SE lies in its licensing model and focus on improved security and management features rather than adding new user-facing features. Exchange Server SE will continue to improve upon security measures, such as modernizing authentication protocols and retiring outdated protocols, but it will not introduce a wide array of new features, as the focus has shifted to making on-premises versions more secure and easier to manage.
For more detailed information, you can visit Microsoft’s official Tech Community Hub and Microsoft Learn.