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Guide to Exchange Server Editions and Licensing

Microsoft Exchange Server is email and personal information management software that runs on Windows Server. It provides a collaboration environment for secure messaging inside and outside a charity or an organization. It also supports group scheduling capabilities, discussion groups, team folders, mobile and web access, and a host of other features.

You can use this guide to find the Microsoft Exchange Server edition and licenses appropriate to your organization's needs.



Standard and Enterprise Editions

Microsoft Exchange Server is offered in both Standard and Enterprise editions.

In the 2016 version, the only significant difference between the Standard and Enterprise products is the number of mailbox databases each edition allows. The Standard edition allows up to 5 mailbox databases, while the Enterprise edition allows up to 50. Thus, you should request the Enterprise edition if your charity or organization is fairly large.

Other product functionality depends on whether you request Enterprise client access licenses (CALs) in addition to Standard CALs. Both Standard and Enterprise CALs can be used with either server edition, but the Enterprise CALs can be used only in conjunction with Standard CALs to access certain Exchange Server features. For more information, see the Licensing section below.

Both editions of Exchange Server 2016 require 64-bit (x64) hardware (Intel EM64T or AMD64), which makes more efficient use of memory and storage than 32-bit hardware. 



Below are some of the major licensing requirements for Microsoft Exchange Server:

  • For each server software license you assign, you may run, at any one time, one instance of the server software in one physical or virtual operating system environment on the licensed server.
  • You may run or otherwise use any number of instances of the Exchange Management Tools software in physical or virtual operating system environments on any number of devices. You may use those instances only with the server software. Use of any instance with the server software may be direct, indirect, or through other additional software.

Microsoft Exchange Server is a server application, not a server operating system, so it must be used along with a server operating system. For each instance of Exchange Server, you must also have a Windows Server license.


Client Access Licenses (CALs)

An Exchange Server device or user CAL is required for each device or user accessing or using the server software. Microsoft offers both Standard and Enterprise user and device CALs for Exchange Server through TechSoup. However, you do not need CALs for:

  • Up to two devices or users to access the server software only to administer those instances
  • Any user or device that accesses your instances of the server software without being directly or indirectly authenticated by Active Directory

Standard CALs

For both the Standard and Enterprise editions of Exchange Server, the Standard device or user CALs authorize one user or device to access Exchange Server.

Enterprise CALs

Enterprise CALs are also available for use with both versions of Exchange Server. Enterprise CALs can be used only in conjunction with Standard CALs to access certain Exchange Server features. These features include integrated archiving, in-place hold, data loss prevention, and unified messaging features. For a complete list, see the Exchange Server Licensing page

Enterprise CALs do not need to be requested for users or devices that do not need to access these additional features.

Windows Server CALs Required

Additionally, a Windows Server CAL is required for each Exchange Server user or device CAL in all scenarios.



For help in upgrading from Exchange Server 2013 to Exchange Server 2016, you can use Microsoft's web-based Deployment Assistant.

You can use Software Assurance to upgrade Exchange Server and associated licenses to any version released during the two years your Software Assurance is in effect. The actual upgrade does not have to take place within those two years. You can upgrade at any time in the future, as long as Microsoft still makes the new version available to users. You cannot, however, upgrade to versions that Microsoft releases after your Software Assurance expires.

CALs obtained through TechSoup will work with the new version since they have their own Software Assurance.

For more information, see Volume Licensing Service Center – Software Assurance Benefits.



You can downgrade Exchange Server to any version that Microsoft continues to make available at its Volume Licensing Service Center website on your organization's Licensed Downloads page. Downgrading does not depend on Software Assurance; it is a benefit of Volume Licensing.

CALs obtained through TechSoup will work with the downgraded version.


Exchange Server Products Available Through TechSoup

Find all Exchange Server donations available through TechSoup here >>