Exchange Server Versions, Release Date, & Build Numbers Info
It has been almost thirty years since the first of the countless Exchange Server versions was released to the public. Ever since then, it has stood as a cornerstone of business communication.
The on-premise Exchange Server has set the standard for handling day-to-day emails, calendars, and contacts for organizations worldwide. With iterative updates, it has transformed from a simple mail server to a sophisticated collaboration platform.
Let us take a look at its journey, see when the key updates happened, plus the Exchange build numbers associated with every update.
This information guide will explain Exchange’s evolution from its beginnings in 1996 to the upcoming Subscription Edition.
The Earliest Exchange Server Versions: Foundational Years (1996-1999)
Our first introduction to Exchange Server was with v4.0. This simple yet powerful mail server gave the world many never-seen-before features like the Jet-based MAPI store and native support for X.400 mail.
Moreover, it was also capable of handling Internet mail (SMTP/MIME) via a proprietary Internet Mail Connector (IMC with IMAIL library).
Here are the specifics for Exchange Server 4.0:
| Product | Release Date | Exchange Server Version Numbers |
| Exchange Server 4.0 RTM | Jun 11, 1996 | 4.0.837 |
| SP1 | May 1, 1996 | 4.0.838 |
| SP2 | Jul 19, 1996 | 4.0.993 |
| SP3 | Oct 29, 1996 | 4.0.994 |
| SP4 | Mar 28, 1997 | 4.0.995 |
| SP5 | May 5, 1998 | 4.0.996 |
Next among the Exchange Server versions was 5.0. Released just a year later in 1997. Exchange veterans consider it a relatively minor update; even then, it came with all-new (for that time, of course) POP3 mail access. The internal architecture remained identical to the previous v4.0.
Release details for Exchange Server 5.0:
| Product | Release Date | Exchange Build Numbers |
| Exchange Server 5.0 RTM | May 23, 1997 | 5.0.1457 |
| SP1 | Jun 18, 1997 | 5.0.1458 |
| SP2 | Feb 19, 1998 | 5.0.1460 |
The real leap in this early era was Exchange Server 5.5 (late 1997). This was a significant upgrade, bringing native IMAP4 support and greatly improving Internet mail processing by optimizing Internet mail (MIME) conversion.
It also came with native public folder enhancements and noticeable improvements to OWA.
Exchange 5.5 was also the last version compatible with Windows NT 4.0.
Version specifics for Exchange Server 5.5:
| Product | Release Date | Exchange Server Version Numbers |
| Exchange Server 5.5 RTM | Feb 3, 1998 | 5.5.1960 |
| SP1 | Aug 5, 1998 | 5.5.2232 |
| SP2 | Dec 23, 1998 | 5.5.2448 |
| SP3 | Sep 9, 1999 | 5.5.2650 |
| SP4 | Nov 1, 2000 | 5.5.2653 |
Entering the New Millennium: Active Directory and Web Access (2000-2005)
With the turn of the millennium came Exchange 2000 Server (v6.0). This was a landmark release because it was the first version built to natively use Windows 2000 Active Directory. Exchange 2000 also introduced a fully redesigned Outlook Web Access (OWA) with a richer HTML interface and native calendaring. Moreover, there were added features like better storage management.
However, this version had no support for Windows NT 4.0 (as it ran on Win2K Server/AD).
Details for Exchange 2000 Server:
| Product | Release Date | Exchange Server Version Numbers |
| Exchange 2000 Server RTM | Nov 29, 2000 | 6.0.4417 |
| SP1 | Jun 21, 2001 | 6.0.4712 |
| SP2 | Nov 29, 2001 | 6.0.5762 |
| SP3 | Jul 18, 2002 | 6.0.6249 |
Building on this new foundation, Exchange Server 2003 (v6.5) arrived, focusing on performance and manageability. A headline feature was “Outlook Anywhere” (RPC over HTTP) for remote Outlook access.
This included streaming of OWA attachments, memory improvements, and built-in spam filtering. Also added support for MobileFAX and faster mailbox store.
Release information for Exchange Server 2003:
| Product | Release Date | Exchange Build Numbers |
| Exchange Server 2003 RTM | Sep 28, 2003 | 6.5.6944 |
| SP1 | May 25, 2004 | 6.5.7226 |
| SP2 | Oct 19, 2005 | 6.5.7683 |
Exchange Server Versions with Roles and Robustness (2007-2012)
Exchange Server 2007 (v8.0) represented a major architectural overhaul, introducing five distinct server roles (Mailbox, CAS, Hub, Edge, UM) with enabled scale-out deployment.
A brand new Unified Messaging (voicemail integration) and integrated anti-spam/anti-virus also became part of the Exchange on-premises servers. Moreover, users got an all-new OWA interface with improved high availability options (CCR, SCR).
Version details for Exchange Server 2007:
| Product | Release Date | Exchange Build Numbers |
| Exchange Server 2007 RTM | Mar 8, 2007 | 8.0.685.25 |
| SP1 (November Update Rollup) | Nov 29, 2007 | 8.1.240.6 |
| SP2 | Aug 24, 2009 | 8.2.176.2 |
| SP3 | Jun 7, 2010 | 8.3.83.6 |
| UR23 (for SP3) | Mar 21, 2017 | 8.3.517.0 |
Exchange Server 2010 (v14.0)
Improved upon the 2007 version by adding Database Availability Groups (DAGs) for mailbox HA and site resilience.
Different server roles (like Mailbox, CAS) were merged together. Users could now archive mailboxes and use VoIP, with UM enhancements.
A design refresh made the OWA richer (by adding Conversations, PowerShell-based admin control). There were minor improvements to Exchange Management Shell as well.
Release specifics for Exchange Server 2010:
| Product | Release Date | Exchange Server Version Numbers |
| Exchange Server 2010 RTM | Nov 9, 2009 | 14.0.639.21 |
| SP1 | Aug 23, 2010 | 14.1.218.15 |
| SP2 | Dec 4, 2011 | 14.2.247.5 |
| SP3 | Feb 12, 2013 | 14.3.123.4 |
| Last SP3 Update (UR32) | Mar 2, 2021 | 14.3.513.0 |
Start of Modern Exchange Server Versions with MS Exchange 2013
Exchange Server 2013 (v15.0) further streamlined the architecture, reducing server roles and making the Client Access server stateless.
New thin Client Access role with no data rendering. Built-in DLP and deep content analysis for compliance, smart people-centric search, and a refreshed touch-friendly OWA. Edge Transport was reintroduced in SP1 for perimeter security.
Architecture changes defined new roles that replaced RPC for simplified deployments.
Details for Exchange Server 2013:
| Product Name | Release Date | Exchange Server Version Numbers |
| Exchange Server 2013 RTM | Oct 11, 2012 | 15.0.516.32 |
| CU1 | Apr 2, 2013 | 15.0.620.29 |
| CU2 | Jul 9, 2013 | 15.0.712.24 |
| CU3 | Nov 25, 2013 | 15.0.775.38 |
| SP1 (CU4) | Feb 25, 2014 | 15.0.847.32 |
| CU5 | May 27, 2014 | 15.0.913.22 |
| CU6 | Aug 26, 2014 | 15.0.995.29 |
| CU7 | Dec 9, 2014 | 15.0.1044.25 |
| CU8 | Mar 17, 2015 | 15.0.1076.9 |
| CU9 | Jun 16, 2015 | 15.0.1104.5 |
| CU10 | Sep 15, 2015 | 15.0.1130.7 |
| CU11 | Dec 15, 2015 | 15.0.1156.6 |
| CU12 | Mar 15, 2016 | 15.0.1178.4 |
| CU13 | Jun 21, 2016 | 15.0.1210.3 |
| CU14 | Sep 20, 2016 | 15.0.1236.3 |
| CU15 | Dec 13, 2016 | 15.0.1263.5 |
| CU16 | Mar 21, 2017 | 15.0.1293.2 |
| CU17 | Jun 27, 2017 | 15.0.1320.4 |
| CU18 | Sep 19, 2017 | 15.0.1347.2 |
| CU19 | Dec 19, 2017 | 15.0.1365.1 |
| CU20 | Mar 20, 2018 | 15.0.1367.3 |
| CU21 | Jun 19, 2018 | 15.0.1395.3 |
| CU22 | Oct 16, 2018 | 15.0.1417.2 |
| CU23 | Jun 18, 2019 | 15.0.1497.2 |
| CU23 Aug22SU (Last public SU) | Aug 9, 2022 | 15.0.1497.46 |
Exchange Server 2016 Version Brought Protocol Enhancements with Cloud Integration (v15.1)
Built upon the already excellent 2013 architecture, this new version was the first to establish MAPI/HTTP as the default Outlook protocol. At the same time, OWA was renamed to “Outlook on the web.” It was not a simple rename, but an all-new web interface with collaboration features (document sharing via OneDrive) and performance gains. Moreover, there were improvements to the hybrid configuration (cloud-updated wizard). Plus, the popular email archiving and compliance features were carried forward from 2013 with minor tweaks.
Version information for Exchange Server 2016:
| Product Name | Release Date | Exchange Build Numbers |
| Exchange Server 2016 RTM | Oct 1, 2015 | 15.1.225.42 |
| CU1 | Mar 15, 2016 | 15.1.396.30 |
| CU2 | Jun 21, 2016 | 15.1.466.34 |
| CU3 | Sep 20, 2016 | 15.1.544.27 |
| CU4 | Dec 13, 2016 | 15.1.669.32 |
| CU5 | Mar 21, 2017 | 15.1.845.34 |
| CU6 | Jun 27, 2017 | 15.1.1034.26 |
| CU7 | Sep 19, 2017 | 15.1.1261.35 |
| CU8 | Dec 19, 2017 | 15.1.1415.2 |
| CU9 | Mar 20, 2018 | 15.1.1466.3 |
| CU10 | Jun 19, 2018 | 15.1.1531.3 |
| CU11 | Oct 16, 2018 | 15.1.1591.3 |
| CU12 | Mar 12, 2019 | 15.1.1713.5 |
| CU13 | Jun 18, 2019 | 15.1.1779.2 |
| CU14 | Sep 17, 2019 | 15.1.1847.3 |
| CU15 | Dec 17, 2019 | 15.1.1913.5 |
| CU16 | Mar 17, 2020 | 15.1.1979.3 |
| CU17 | Jun 16, 2020 | 15.1.2044.4 |
| CU18 | Sep 15, 2020 | 15.1.2106.2 |
| CU19 | Dec 15, 2020 | 15.1.2176.2 |
| CU20 | Mar 16, 2021 | 15.1.2242.4 |
| CU21 | Jun 29, 2021 | 15.1.2308.8 |
| CU22 | Nov 23, 2021 | 15.1.2375.7 |
| CU23 | Apr 20, 2022 | 15.1.2507.6 |
| CU23 Nov24SU | Nov 12, 2024 | 15.1.2507.41 |
| CU23 Apr25HU | Apr 18, 2025 | 15.1.2507.44 |
Exchange Server 2019 (v15.2): Security and Performance Focus
Exchange Server 2019 (v15.2) focuses on security and performance, which is seen by the support for Windows Server Core and default TLS 1.2 encryption. Although Unified Messaging was removed, OWA was modernized (Bing-powered search, new look), and performance was improved.
Release specifics for Exchange Server 2019:
| Product Name | Release Date | Exchange Server Version Numbers |
| Exchange Server 2019 RTM | Oct 22, 2018 | 15.2.221.12 |
| CU1 | Mar 12, 2019 | 15.2.330.5 |
| CU2 | Jun 18, 2019 | 15.2.397.3 |
| CU3 | Sep 17, 2019 | 15.2.464.5 |
| CU4 | Dec 17, 2019 | 15.2.529.5 |
| CU5 | Mar 17, 2020 | 15.2.595.3 |
| CU6 | Jun 16, 2020 | 15.2.659.4 |
| CU7 | Sep 15, 2020 | 15.2.721.2 |
| CU8 | Dec 15, 2020 | 15.2.792.3 |
| CU9 | Mar 16, 2021 | 15.2.858.5 |
| CU10 | Jun 29, 2021 | 15.2.922.7 |
| CU11 | Nov 23, 2021 | 15.2.986.5 |
| CU12 (2022H1) | Apr 20, 2022 | 15.2.1118.7 |
| CU13 (2023H1) | Apr 18, 2023 | 15.2.1258.12 |
| CU14 (2024H1) | Feb 13, 2024 | 15.2.1544.4 |
| CU15 (2025H1) | Feb 10, 2025 | 15.2.1748.10 |
| CU15 Apr25HU | Apr 18, 2025 | 15.2.1748.24 |
The Next Chapter: Exchange Server Subscription Edition (SE, 2025 and Beyond)
Looking ahead, Microsoft has announced Exchange Server Subscription Edition (SE). This upcoming edition will use the same codebase as the final Exchange 2019 Cumulative Update (CU15) but will shift to a subscription licensing model.
Users will get TLS 1.3 and GUI certificate management in the Import PST to Exchange Server using EAC The Exchange Server SE will run on future Windows Server releases (e.g., Windows Server 2025).
Planned release information:
| Product | Release Date | Exchange Build Numbers |
| Exchange Server Subscription Edition (SE) | Early Q3 2025 (planned) | (pending) |
An Ever-Evolving Workhorse
Here in this write-up, we saw that from its start in 1996 to this day, there have been many different Microsoft Exchange Server versions. Each update brought in new features and built a service that is now used worldwide for on-premises email management. We saw how Microsoft’s priorities slowly shifted from a local-oriented to a service, which welcomed the cloud. Despite so many different changes, perhaps none would be as impactful as the one that’s happening this year, where the entire model on which Exchange Server operates is being changed from a one-time payment to a subscription-based model.