With both Exchange 2016 and 2019 going out of support in October 2025, we have heard from some of our customers that they have started their migrations to Exchange Subscription Edition (SE) but might...
Updated Jul 15, 2025
Version 1.0
Blog Post
We’re in the process of moving all user mailboxes to Exchange Online (included with Microsoft 365 Business Premium). As part of the required hybrid setup, we're following the supported upgrade path to Exchange Server Subscription Edition (SE).
Once all mailboxes are in the cloud, our intention is to use Exchange SE purely as a management server — to manage mail-related attributes for users via AD, keep things supported, and maintain hybrid connectivity.
Given this scenario:
All mailboxes will reside in Exchange Online
Exchange SE will be used for management purposes only
Do we still need to license Client Access Licences (CALs) for users, or is CAL licensing not required in this management-only configuration?
Licensing for Exchange Server SE is the same as Exchange Server 2019. See https://www.microsoft.com/microsoft-365/exchange/microsoft-exchange-server-licensing-licensing-overview for details on the licensing model used by Exchange Server 2019.
For Exchange Server SE, in addition to purchasing the required Server licenses and CALs, customers must also maintain an active subscription. This means purchasing either:
- Cloud subscription licenses for all users and devices that access Exchange Server SE (for example, Microsoft 365 E3 or E5 licenses); or
- Exchange Server SE Server licenses and CALs with https://www.microsoft.com/licensing/licensing-programs/software-assurance-default (SA).
Other cloud subscription licenses besides Microsoft 365 E3/E5 also satisfy, but we’re calling E3/E5 out because they include Extended Use Rights that provide an unlimited number of Office Server licenses at no additional charge (see the https://www.microsoft.com/licensing/terms/productoffering/Microsoft365/EAEAS for full details).
If you don't buy cloud subscription licenses, then Server licenses and CALs you buy must have Software Assurance.
To summarize your licensing options (choose one):
- Qualifying cloud subscription licenses for users (for example, Microsoft 365 E3/E5) If you go this route, all users that access Exchange Server SE must have an E3 or E5 license.
- License (Server and CALs) + SA for Exchange Server 2016/2019 Maintain SA for usage rights and access Exchange Server SE and updates.
- License (Server and CALs) + SA for Exchange Server SE (once released) Maintain SA for Exchange Server SE for usage rights and access to updates.
Sorry - late to this. Business Premium no longer includes CAL entitlement. M365 E3 and E5 do. I'd recommend checking out m365maps.com for any questions regarding sub features
As far as I read the product terms of Exchange Server SE, M365 Business Premium USL includes a Exchange Server SE CAL.
https://www.microsoft.com/licensing/terms/productoffering/ExchangeServer/MCA
