Exchange Server 2019 to Subscription Edition (SE) Licensing and Migration Guidance

Note: licensing can be region-specific and subject to Microsoft’s current terms, so always validate with your Microsoft licensing partner or representative.

Key concepts to keep in mind

• Software Assurance (SA) is commonly used to enable upgrade rights within a licensing program and to access certain benefits (like license mobility across virtualization, support). For on-prem Exchange, SA isn’t a hard technical prerequisite to run Exchange, but it affects upgrade rights and certain migration options when moving to newer licensing models.
• Exchange Server SE requires purchasing SE licenses for the server (and associated CALs) instead of traditional perpetual licenses. SE editions are typically tied to the subscription model with monthly/annual payments.
• CALs generally need to be purchased or migrated as part of the SE licensing model. Legacy CALs (from pre-SE SKUs) do not automatically convert to SE CALs; you usually need appropriate SE CALs if you’re moving to SE.
• Migration path: moving from on-prem Exchange 2019 (perpetual license, no SA) to SE usually involves purchasing SE server licenses and SE CALs for the covered users, and ensuring you’re compliant with virtualization/hosted deployment rights.

Detailed guidance by topic

1. Software Assurance (SA) requirement for ongoing compliance and support

• Technical impact: SA is not strictly required to run Exchange Server 2019 itself. You can operate an on-prem Exchange 2019 deployment without SA.
• Support impact: Without SA, you may not be eligible for upgrade rights, certain support benefits, or predictable access to newer licensing scenarios (e.g., streamlined migration paths to SE via partner programs). Most standard support remains, but some benefits (and any future upgrade rights) may be limited.
• Practical stance: If your goal is a smooth, predictable migration to SE and you want cooperative upgrade rights with Microsoft, consider obtaining SA on your existing licenses as part of the transition plan. If you’re confident in a direct SE migration and can work with a partner to license correctly, you can proceed without SA—but you’ll want to confirm any constraints with your licensing partner.

1. Standalone SA purchase for existing 2019 licenses

• Is it possible to purchase SA now? In many licensing programs, you can add SA to existing perpetual licenses, but this depends on region and the specific agreement you have with Microsoft or your licensing reseller.
• Does it have to be a new license with SA? Not necessarily; you often can add SA to existing licenses (or convert to an SA-enabled agreement) if your plan and partner support it.
• Practical action: Engage directly with your CSP/licensing partner to confirm:
  • Whether your 2019 Exchange licenses can be covered by SA retroactively.
  • What the cost/term would be and how it interacts with the SE transition timeline.
  • Any minimum terms or renewal prerequisites tied to SA.

1. CAL migration: compatibility of existing CALs with SE

• Typical reality: SE licensing generally requires SE CALs (per-user or per-device) for the covered users/devices. Legacy CALs (perpetual CALs from pre-SE) do not automatically convert to SE CALs.
• Do old CALs become obsolete? In practice, you would need to purchase SE CALs for the SE deployment. Your existing CALs would not directly convert to SE CALs; you would license the SE environment with SE CALs.
• Practical implications:
  • If you stay on-prem with SE servers, budget for SE CALs for all users/devices that will access Exchange in SE.
  • If you’re planning to maintain some legacy perpetual CALs in other contexts, ensure you’re compliant with any licensing terms and note that SE generally requires SE CALs for the deployment scope.

1. Recommended migration path (budget-conscious)

Option A: Purchase SA for existing Exchange 2019 licenses, then migrate to SE

• Pros:
  • Maintains a continuity plan, potentially easier upgrade/migration rights with Microsoft.
  • SA can provide upgrade paths and visibility into eligibility for SE.
  • If your partner supports it, you may reuse some agreed-upon license constructs during migration.
• Cons:
  • Additional SA cost upfront.
  • Migration still requires purchasing SE server licenses and SE CALs for the SE deployment; you cannot reuse 2019 CALs as SE CALs.
• Suggested approach:
  • First verify with your licensing partner the feasibility and cost of adding SA to your existing licenses.
  • Then plan the SE migration with the partner, ensuring you procure SE server licenses and SE CALs for all users/devices covered by the SE deployment.