Questions about upgrading to Exchange Server Subscription Edition (SE) and current licensing availability

Hi @김정연

Thank you for posting your question in Microsoft Q&A. 

We understand that you're planning an upgrade for your customer's on-premises environment and would like to clarify licensing availability and the upgrade roadmap. We glad to assist you this part.  

For your concerns: 

1.Can we upgrade directly from Exchange Server 2016 to Exchange Server SE, or must we first upgrade to Exchange Server 2019 (CU15) before moving to SE? 

Unfortunately, you cannot perform a direct in-place upgrade from Exchange Server 2016 to Exchange Server SE (SE). Exchange Server 2016 requires a legacy upgrade process, which involves deploying new servers running a supported version (Exchange Server 2019 CU15 or directly Exchange SE RTM), moving mailboxes and resources, and then decommissioning the old servers. This is due to architectural differences and coexistence limitations between major versions. 

Therefore, you could consider update your customer Exchange 2016 to CU23 (if not already applied) to ensure compatibility. Then, perform a legacy upgrade to Exchange Server 2019 CU15 on new hardware/OS. Once on 2019 CU15, you can do an in-place upgrade to SE RTM (which is essentially CU15 + a hotfix, new EULA, and build number). Alternatively, you can legacy upgrade directly to SE RTM from Exchange 2016 CU23, but this skips the interim 2019 step and may require more testing for stability. 

You can refer via: Upgrading to Exchange Server Subscription Edition (SE) | Microsoft Learn 

2.We noticed that there is currently no Exchange Server SE SKU or pricing information in the EA, CSP, or MPSA price lists. When will it be officially added to the Volume Licensing Price List? 

Currently, Exchange Server Subscription Edition (SE) is not listed as a standalone SKU, as it is provided as a free upgrade entitlement rather than a separate purchase. 

Exchange SE reached general availability on July 1, 2025, and was fully integrated into the Volume Licensing Price Lists for EA, MPSA, and Open Value programs starting August 2025. Any price lists published before that date would not include SE, as it was still in pre-release. 

In the Cloud Solution Provider (CSP) program, Exchange SE is not offered as a standalone SKU. However, on-premises rights are granted through qualifying Microsoft 365 E3/E5 subscriptions. 

Effective August 1, 2025, Microsoft implemented pricing adjustments, including increases of 10% for server licenses, 15% for Core CAL Suites, and 20% for Enterprise CAL Suites. Exact pricing may vary depending on your agreement and region, so we recommend reviewing the updated price lists through your Microsoft partner or the Volume Licensing Service Center (VLSC).  

3.For existing Exchange Server 2019 customers, is Software Assurance (SA) required to upgrade to SE? Or will SE be offered as a new subscription license regardless of SA coverage? 

Yes, SA is required to remain compliant when upgrading to Exchange SE. If your Exchange 2019 licenses were purchased without SA, you cannot retroactively add SA. In that case, you must purchase new subscription licenses for Exchange SE. 

4.If our customer is running Exchange 2016 on Windows Server 2012 R2, what is the recommended upgrade path considering both products are EOS? 

Firstly, you could start by applying CU23 to Exchange 2016 for stability, then migrate Active Directory to Windows Server 2022 or 2025 (deploy new domain controllers, transfer FSMO roles, and demote old ones, do not in-place upgrade the OS with Exchange installed, as it's unsupported and risks corruption). Extend the AD schema using the /PrepareSchema command from the Exchange 2019 or SE setup media on your Schema Master DC. 

Next, install Exchange 2019 CU15 (or SE RTM) on new hardware in the existing organization for coexistence, migrate mailboxes in batches for minimal downtime, handle public folders if in use, and verify mail flow. Finally, uninstall the 2016 servers and perform the in-place SE upgrade if using the 2019 interim. This full refresh addresses both EOS issues and positions you for future updates, aim to complete by early 2026 before SE CU1 limits coexistence further. 

5. Are there any important considerations or prerequisites when upgrading to Exchange SE (e.g., AD schema updates, hybrid configuration, DAG membership, Edge server sync, or coexistence restrictions)? 

Begin with AD schema preparation, run Setup.exe /PrepareSchema /IAcceptExchangeServerLicenseTerms on the Schema Master (requires Schema Admins and Enterprise Admins permissions, Forest/Domain Functional Level must be 2012 R2 or higher).  

For hybrid setups with Microsoft 365, re-run the Hybrid Configuration Wizard post-upgrade to refresh OAuth, free/busy sharing, and mail flow connectors, ensuring Azure AD Connect is at v2.1+ and all servers use SSL certificates from the same CA with matching subjects.  

DAG membership is fully supported with no changes, validate quorum and replication health before migrations, and test failovers.  

Edge Transport sync works as before, re-subscribe Edges to SE Mailbox servers after upgrade.  

Coexistence restrictions tighten post-SE CU1 (no more with 2016/2019), and there's no replication to Exchange Online, hybrid is purely for management.  

Other essentials include Windows Server 2019+ (2022/2025 preferred), 128GB RAM minimum for Mailbox roles, .NET 4.8+, and enabling hardened TLS defaults (1.2/1.3 only). Test in a lab, phase out legacy protocols like NTLM, and confirm third-party tools (e.g., backups) compatibility to avoid disruptions. 

References: 

Prepare Active Directory and domains for Exchange Server, Active Directory Exchange Server, Exchang… 

I hope this helps.

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