History of Microsoft Exchange Server
The first release of Microsoft Exchange Server was version 4.0 in April 1996, when it was sold as an upgrade to Microsoft Mail 3.5. Before that, Microsoft Mail v2.0 was replaced in 1991 by "Microsoft Mail for PC Networks v2.1", based on Network Courier from its acquisition of Consumers Software.
Background
heavily used Xenix-based email on its MS-Net internal network, with users sending 60,000 megabytes of messages weekly by 1987. When its Information Technology Group began dogfooding plans to migrate to the company's own Exchange Server in April 1993, Microsoft was using 160 Xenix mail servers; users telneted into them to access email with the exception of the Microsoft Mail team, which used that software as client. The system handled 650,000-750,000 messages daily, 4.5GB total or about 30-35 per user, 10-15% to or from outside the company.ITG created an entirely new based client–server mail system with a single database store that also supported directory services. All 32,000 Microsoft mailboxes were on Exchange 4.0 by April 1996, just before the company shipped 4.0 to customers. 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.
Versions
Version history
| Release name | Build version | Internal version | Release Date | Mainstream End Date | Extended End Date |
| 4.0 | 4.0.x | Rowspan=5 | 2 April 1996 | ||
| 5.0 | 5.0.x | 23 May 1997 | 31 December 2003 | 10 January 2006 | - |
| 5.5 | 5.5.x | 20 March 1998 | 31 December 2003 | 10 January 2006 | - |
| 2000 | 6.0.x | 29 November 2000 | 31 December 2005 | 11 January 2011 | - |
| 2003 | 6.5.x | 28 September 2003 | 14 April 2009 | 8 April 2014 | - |
| 2007 | 8..x | 8.0.x | 8 March 2007 | 10 April 2012 | 11 April 2017 |
| 2010 | 14..x | 14.0.x | 9 November 2009 | 13 January 2015 | 13 October 2020 |
| 2013 | 15.0.x | 15.00.x | 9 January 2013 | 10 April 2018 | 11 April 2023 |
| 2016 | 15.1.x | 15.01.x | 1 October 2015 | 13 October 2020 | 14 October 2025 |
| 2019 | 15.2.x | 15.02.x | 22 October 2018 | 9 January 2024 | 14 October 2025 |
| SE | 15.2.x | 15.02.x | 1 July 2025 |
Exchange Server 4.0
The first release of Exchange outside of Microsoft was Exchange Server 4.0 in April 1996, with five service packs being released over the next two years.Exchange Server 5.0
Initial release: May 23, 1997.Introduced the new Exchange Administrator console, as well as opening up "integrated" access to SMTP-based networks for the first time. Unlike Microsoft Mail, Exchange Server 5.0 could, with the help of an add-in called the Internet Mail Connector, communicate directly with servers using SMTP. Version 5.0 also introduced a new webmail interface called Exchange Web Access, which was rebranded as Outlook Web Access in a later service pack. Along with Exchange Server version 5.0, Microsoft released version 8.01 of Microsoft Outlook, version 5.0 of the 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 IMAP4 and LDAP 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, and Internet News Service, as well as software to interoperate with cc:Mail, Lotus Notes and Novell GroupWise.
;Enterprise Edition: Had an increased limit of 16 TB. Adds an connector, and interoperability software with SNADS and PROFS. Introduced two node clustering capability.
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 instant messaging, but that capability was later spun off to Microsoft Office Live Communications Server.Exchange Server 2003
Codenamed "Titanium", this version can be run on Windows 2000 Server and 32-bit Windows Server 2003, 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, 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, which allows administrators to bring the server online more quickly. This is done by allowing the server to send and receive mail while the message stores are being recovered from backup. Some features previously available in the Microsoft Mobile Information Server 2001/2002 products have been added to the core Exchange Server product, like Outlook Mobile Access and server-side Exchange ActiveSync, while the Mobile Information Server product itself has been dropped. Also new is the ability to drop inbound e-mail before being fully processed, thus preventing delays in the message routing system. There are also improved message and mailbox management tools, which allow administrators to execute common chores more quickly. Others, such as Instant Messaging and Exchange Conferencing Server have been extracted completely in order to form separate products. Microsoft now appears to be positioning a combination of Microsoft Office, 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:- Connection filtering: Messages are blocked from DNS RBL lists or from manually specified IP addresses/ranges
- Recipient filtering: Messages blocked when sent to manually specified recipients on the server or to any recipients not on the server
- Sender ID filtering: Sender ID, a form of Sender Policy Framework
- Intelligent Message Filter: Initially a free Microsoft add-on, later, part of service pack 2, that uses heuristic message analysis to block messages or direct them to the "Junk E-Mail" folder in Microsoft Outlook clients.
Editions
Standard Edition:- Supports up to two storage groups 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.
Exchange 2003 mainstream support ended on April 14, 2009. Extended support ended on April 8, 2014.
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,, and some API interfaces, amongst other features.Exchange Server 2007 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 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. 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.