History of Microsoft Exchange Server

Source: Wikipedia, the free encyclopedia.

The first release of

client–server mail system with a single database store that also supported X.500 directory services. During its development, Microsoft migrated their own internal email from a Xenix-based system to Exchange Server from April 1993,[3] with all 32,000 Microsoft mailboxes on Exchange by late 1996.[3][4] The directory used by Exchange Server eventually became Microsoft's Active Directory service, an LDAP-compliant directory service. Active Directory was integrated into Windows 2000 as the foundation of Windows domains


Version history

Release name Build version Internal version Release Date Mainstream End Date Extended End Date
Old version, no longer maintained: 4.0 4.0.x 2 April 1996 [5]
Old version, no longer maintained: 5.0 5.0.x 23 May 1997 31 December 2003 10 January 2006
Old version, no longer maintained: 5.5 5.5.x 20 March 1998
Old version, no longer maintained: 2000 6.0.x 29 November 2000 31 December 2005 11 January 2011
Old version, no longer maintained: 2003 6.5.x 28 September 2003 14 April 2009 8 April 2014
Old version, no longer maintained: 2007 8.[0123].x 8.0[0123].x 8 March 2007 10 April 2012 11 April 2017
Old version, no longer maintained: 2010 14.[0123].x 14.0[0123].x 9 November 2009 13 January 2015 13 October 2020
Old version, no longer maintained: 2013 15.0.x 15.00.x 9 January 2013 10 April 2018 11 April 2023
Older version, yet still maintained: 2016 15.1.x 15.01.x 1 October 2015 13 October 2020 14 October 2025
Current stable version: 2019 15.2.x 15.02.x 22 October 2018 9 January 2024
Legend:   Old version   Older version, still maintained   Latest version

Exchange Server 4.0

The first release of Exchange outside of Microsoft was Exchange Server 4.0 in April 1996,[6] with five service packs being released over the next two years.[7]

Exchange Server 5.0

Initial release: May 23, 1997.

Introduced the new Exchange Administrator console, as well as opening up "integrated" access to

Microsoft Exchange Client and version 7.5 of Microsoft Schedule+
to support the new features in the new version of Exchange Server.

Exchange Server 5.0 introduced a number of other new features including a new version of Outlook Web Access with calendar support, support for

v3 clients and the Deleted Item Recovery feature.

Exchange Server 5.5

Initial release: Nov. 5, 1997, released to manufacturing.

The last version of Exchange Server to have a separate directory, SMTP and NNTP services. There was no new version of Exchange Client and Schedule+ for version 5.5, instead version 8.03 of Microsoft Outlook was released to support the new features of Exchange Server 5.5.

It was sold in two editions: Standard and Enterprise. They differ in database store size, mail transport connectors, and clustering capabilities.

Standard Edition
Had the same 16 GB database size limitation as earlier versions of Exchange Server. It included the Site Connector, MS Mail Connector, Internet Mail Service (previously "Internet Mail Connector"), and Internet News Service (previously "Internet News Connector"), as well as software to interoperate with cc:Mail, Lotus Notes and Novell GroupWise.
Enterprise Edition
Had an increased limit of 16 TB (although Microsoft's best practices documentation recommends that the message store not exceed 100 GB). Adds an
PROFS. Introduced two node clustering

Exchange 2000 Server

Codenamed "Platinum", this version overcame many of the limitations of its predecessors. For example, it raised the maximum sizes of databases and increased the number of servers in a cluster from two to four. However, many customers were deterred from upgrading by the requirement for a full Microsoft Active Directory infrastructure to be in place, as unlike Exchange Server 5.5, Exchange 2000 Server had no built-in Directory Service, and had a dependency upon Active Directory. The migration process from Exchange Server 5.5 necessitated having the two systems online at the same time, with user-to-mailbox mapping and a temporary translation process between the two directories. Exchange 2000 Server also added support for

Microsoft Office Live Communications Server

Exchange Server 2003

Codenamed "Titanium", this version can be run on

, although some new features only work with the latter. Like Windows Server 2003, Exchange Server 2003 has many compatibility modes to allow users to slowly migrate to the new system. This is useful in large companies with distributed Exchange Server environments who cannot afford the downtime and expense that comes with a complete migration.

It made the migration from pre-2000 versions of Exchange significantly easier (although still involved the same basic steps), and many users of Exchange Server 5.5 waited for the release of Exchange Server 2003 to upgrade. The upgrade process also required upgrading a company's servers to Windows 2000. Some customers opted to stay on a combination of Exchange Server 5.5 and Windows NT 4.0, both of which are no longer supported by Microsoft.

One of the new features in Exchange Server 2003 is enhanced disaster recovery,

Microsoft Office Live Communications Server, Live Meeting, and SharePoint
as its collaboration software of choice. Exchange Server is now to be simply e-mail and calendaring.

Exchange Server 2003 added several basic filtering methods to Exchange Server. They are not sophisticated enough to eliminate spam, but they can protect against DoS and mailbox flooding attacks. Exchange Server 2000 supported the ability to block a sender's address, or e-mail domain by adding '*@domain.com', which is still supported in Exchange Server 2003.

New features

Added filtering methods in Exchange Server 2003 are:

It is included with both

Windows Small Business Server
2003 Standard and Premium editions.


Standard Edition:

  • Supports up to two storage groups (with one of the storage groups, called the recovery storage group, being reserved for database recovery operations) and a maximum of two databases per storage group.
  • Each database is limited to a maximum size of 16 GB.
  • Beginning with the release of
    Service Pack 2, a maximum database size of 75 GB, but only supports 16 GB by default; larger sized databases have to be updated-in with a registry change.[11]

Enterprise Edition allows a 16 TB maximum database size, and supports up to four storage groups with 5 databases per storage group for a total of 20 databases per server.

Exchange 2003 mainstream support ended on April 14, 2009.[12] Extended support ended on April 8, 2014.[13]

Exchange Server 2007

Released to business customers as part of Microsoft's roll-out wave of new products. It includes new clustering options,

x64 support for greater scalability, voicemail integration, better search and support for Web services, better filtering options, and a new Outlook Web Access interface. Exchange 2007 also dropped support for Exchange 5.5 migrations, routing groups, admin groups, Outlook Mobile Access, X.400, and some API interfaces, amongst other features.[14]

Exchange Server 2007 (v8, code name E12, or with SP1 v8.1) runs only on

x64 versions of Windows Server
. This requirement applies to supported production environments only; a 32-bit trial version is available for download and testing. Hence, companies currently running Exchange Server on 32-bit hardware will be required to replace or migrate hardware if they wish to upgrade to the new version. Companies that are currently running Exchange Server on 64-bit capable hardware are still required to migrate from their existing Exchange 2000/2003 servers to a new 2007 server since in-place upgrades are not supported in 2007.

The first beta of Exchange Server 2007 (then named "Exchange 12" or E12) was released in December 2005 to a very limited number of beta testers. A wider beta was made available via TechNet Plus and MSDN subscriptions in March 2006 according to the Microsoft Exchange team blog.[15] On April 25, 2006, Microsoft announced that the next version of Exchange Server would be called "Exchange Server 2007".

Exchange Server 2007 is an integrated part of the Innovative Communications Alliance products.[16]

New features

  • Protection: Anti-spam, antivirus, compliance, clustering with data replication, improved security and encryption
  • Improved Information Worker Access: Improved calendaring, unified messaging, improved mobility, improved web access
  • Improved IT Experience: 64-bit performance and scalability, command-line shell and simplified GUI, improved deployment, role separation, simplified routing
  • Exchange Management Shell: a new command-line shell and scripting language for system administration (based on PowerShell). Shell users can perform every task that can be performed in the Exchange Server graphical user interface plus additional tasks, and can program often-used or complex tasks into scripts that can be saved, shared, and re-used. The Exchange Management Shell has over 375 unique commands to manage features of Microsoft Exchange Server 2007.[17]
  • "Unified Messaging": Lets users receive voicemail, e-mail, and faxes in their mailboxes, and lets them access their mailboxes from cell phones and other wireless devices. Voice commands can be given to control and listen to e-mail over the phone (and also send some basic messages, like "I'll be late")
  • Increased database maximum size limit: Database size is now limited to 16TB per database[18]
  • Increased maximum storage groups and mail databases per server: 5 each for Standard Edition (from one each in Exchange Server 2003 Standard), and to 50 each for Enterprise Edition (from 4 groups and 20 databases in Exchange Server 2003 Enterprise).
  • Configure Outlook Anywhere: Formerly known as RPC over HTTP provides external access to Microsoft Exchange Server 2007 for users. This also provides external URLs for Exchange services such as the Availability service and offline address book.
  • Room and equipment mailboxes: Finally resources can be properly created and managed, and users in Outlook can easily book them.


Standard edition
Can have 5 databases in up to 5 storage groups. Supports LCR (Local Continuous Replication) and SCR (Standby Continuous Replication).
Enterprise edition
This is extended to 50 databases in up to 50 storage groups. Supports LCR (Local Continuous Replication), SCR (Standby Continuous Replication), SCC (Single Copy Clustering), and CCR (Clustered Continuous Replication).

Exchange Server 2010

Exchange Server 2010 logo

Exchange Server 2010 was

general availability on November 9, 2009.[19] The version jumped from v8.x in Exchange 2007 to v14.x in Exchange 2010 to emphasise the synergy of Exchange Server with the Office suite

New features


Several high-availability options have been consolidated into just one option for Exchange Server 2010 (Mailbox Resiliency), which is now offered in both the Standard and Enterprise editions. The capabilities of Local Continuous Replication, Standby Continuous Replication, and Cluster Continuous Replication are now unified into the Exchange 2010 Mailbox Resiliency capability. These capabilities enable a simplified approach to high availability and disaster recovery. The Standard Edition supports up to 5 databases with each database being limited to a maximum size of 16 TB. While the Enterprise Edition supports up to 100 databases with no size limit.

Storage group is discontinued in Exchange 2010 and onward.

In January 2011, Microsoft Exchange Server 2010 won InfoWorld's 2011 Technology of the Year Award for Best Mail Server.[citation needed]

Exchange Server 2013

Microsoft reached the RTM milestone for Exchange Server 2013 (v15.0) on October 11, 2012.

trial version of this product is available from Microsoft website.[21]

Exchange 2013 represented a major change to the servicing model: instead of large Service Packs and small Update Rollup packages, a new Cumulative Update methodology is used with CU packages being released on a quarterly schedule and any security updates for that CU released on Patch Tuesday (or out-of-band as necessary). Microsoft supported only the "n-1" Cumulative Update release of Exchange Server 2013 and later during mainstream support, and only the final CU once the transition to extended support completed. Despite this, Cumulative Update 4 was rebranded as Service Pack 1 due to significant additional functionality.[22] The 23rd and final Cumulative Update for Exchange 2013 was released on June 18, 2019.[23]

New features

New features include:[24][25][26][27]

  • Offline support in OWA: Emails and actions are automatically synced the next time connectivity is restored.
  • Client connectivity: CAS role is the point of connectivity for all clients in Exchange 2013.
  • Public folders: In 2013, public folders are now part of mailbox databases and high availability is achieved using DAG.
  • Site Mailboxes: Brings Exchange emails and SharePoint documents together.
  • Outlook Web App
    : Offers three different UI layouts optimized for desktop, tablet, and mobile phone browsers.
  • Ability to customize: Outlook and OWA by integrating apps from the Office marketplace. (Yes, this is a reference to the Agaves add-ins that Microsoft and partners would be making available via the new Office Store.) The new "Napa" tools and/or HTML5 are Microsoft's preferred ways for developers to build these.
  • Exchange Administrative Center (EAC): Replacement of the Exchange Management Console by a Web-based Exchange Administrative Center (EAC).
  • Support for up to 8 TB disks: And multiple databases per disk via Data Availability Group (DAG) management.
  • Built in basic anti-malware protection: Ability for administrators to configure and manage settings from inside EAC. (Note: this feature can be turned off, replaced or "paired with premium services such as Exchange Online Protection for layered protection.").
  • New Data Loss Prevention (DLP): Capabilities for identifying and protecting "sensitive data." DLP policies are based on regulatory standards, including PII and PCI. Also: new policy tips in Outlook 2013 can be set to inform users about potential policy violations.
  • In-Place eDiscovery: Can be run across Exchange, SharePoint, and Lync (now Skype for Business) from a single interface.
  • Combine Roles: A reduction in the number of available roles to two: a Client Access Server and a Mailbox Server role.
  • FAST Search: Now integrated into Exchange 2013 managed store to provide a more consistent (across Microsoft servers) indexing and searching experience.
  • Inclusion of a "Managed Store": The name of the rewritten information store processes, which are now written in C#.
  • Replication: Public folders are now stored in mailbox databases and can take advantage of Database Availability Groups for replication and high availability.
  • Data loss prevention: Capabilities that can be integrated into Transport Rules.
  • MAPI over HTTPS: New protocol designed from the ground up to replace Outlook Anywhere. This functionality requires that all Exchange 2013 Servers are running at least Service Pack 1; it is disabled by default in organizations where Exchange Server 2013 has been installed and must be manually enabled once the prerequisites are met.

Removed features

  • MAPI over RPC: All client connectivity to Exchange 2013 and later uses HTTPS, requiring special consideration for coexistence with Exchange 2010/2007.

Exchange Server 2016

On October 1, 2015, Microsoft announced the general availability (GA) of Exchange Server 2016 (v15.1).[28]

New features

  • Combine Roles: A reduction in the number of available roles to two: Mailbox Server and Edge Transport
  • Outlook on the web (formerly Outlook Web App): UI changes
  • Office 365 hybrid: The Hybrid Configuration Wizard (HCW) that was included with Exchange 2013 is moving to become a cloud-based application. When users choose to configure a hybrid deployment in Exchange 2016, they'll be prompted to download and install the wizard as a small app.
  • Messaging policy and compliance: New DLP and Archiving/Retention/eDiscovery features.

For more detail on new features, see the following Microsoft TechNet article: What's new in Exchange 2016

Exchange Server 2019

Exchange Server 2019 (v15.2) was released in October 2018.[29] Unlike other Office Server 2019 products such as SharePoint and Skype for Business, Exchange Server 2019 can only be deployed on Windows Server 2019. One of the key features of the new release is that Exchange Server can be deployed onto Windows Server Core for the first time, additionally Microsoft has retired the unified messaging feature of Exchange, meaning that Skype for Business on-premises customers will have to use alternative solutions for voicemail, such as Azure cloud voicemail. Unified Messaging continues to exist in Exchange Online requiring an Exchange Plan 2 license.

A pre-release was released on 25 July.[30]

New Features

  • Security: support for installing Exchange Server 2019 onto Windows Server Core
  • Performance: supports running Exchange Server with up to 48 processor cores and 256 GB of RAM

Removed features

  • Unified Messaging

For more detail on new features, see the following Microsoft blog article: Exchange Server 2019 Public Preview


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