Exchange Server Build Numbers and Release Product Dates
Every version of Microsoft Exchange Server comes with a different build number, and it is a number that is altered when Service Packs are installed. More information on this subject can be found at mycomputeraid.com

The list below though indicates the build numbers and release dates for the various released versions -

Version    Build number    Release date
Microsoft Exchange Server 4.0    4.0.837    April 1996
Microsoft Exchange Server 4.0 (a)       4.0.993    August 1996
Microsoft Exchange Server 4.0 SP1    4.0.838    May 1996
Microsoft Exchange Server 4.0 SP2    4.0.993     August 1996
Microsoft Exchange Server 4.0 SP3    4.0.994    November 1996
Microsoft Exchange Server 4.0 SP4    4.0.995    April 1997
Microsoft Exchange Server 4.0 SP5    4.0.996    May 1998

Microsoft Exchange Server 5.0    5.0.1457    March 1997
Microsoft Exchange Server 5.0 SP1    5.0.1458    June 1997
Microsoft Exchange Server 5.0 SP2    5.0.1460     February 1998
Microsoft Exchange Server    5.5 5.5.1960    November 1997
Microsoft Exchange Server 5.5 SP1    5.5.2232    July 1998
Microsoft Exchange Server 5.5 SP2    5.5.2448    December 1998
Microsoft Exchange Server 5.5 SP3    5.5.2650    September 1999
Microsoft Exchange Server 5.5 SP4    5.5.2653    November 2000

Microsoft Exchange 2000 Server     6.0.4417    October 2000
Microsoft Exchange 2000 Server (a)    6.0.4417    January 2001
Microsoft Exchange 2000 Server SP1    6.0.4712    July 2001
Microsoft Exchange 2000 Server SP2    6.0.5762     December 2001
Microsoft Exchange 2000 Server SP3    6.0.6249    August 2002
Microsoft Exchange 2000 Server post-SP3    6.0.6487    September 2003
Microsoft Exchange 2000 Server post-SP3    6.0.6556    April 2004
Microsoft Exchange 2000 Server post-SP3    6.0.6603    August 2004
Microsoft Exchange Server 2003    6.5.6944    October 2003
Microsoft Exchange Server 2003 SP1    6.5.7226    May 2004
Microsoft Exchange Server 2003 SP2    6.5.7638    October 2005

Microsoft Exchange Server 2007    8.0.685.24 or 8.0.685.25    December 2006
Microsoft Exchange Server 2007 SP1    8.1.0240.006    November 2007

The build number can be found in the Exchange Management Console properties.

Article written by MyComputerAid.com

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Exchange server versions