Microsoft’s Exchange Server was born out of the company’s move from a Xenix based messaging system to a new client-server based application that delivered electronic mail, calendaring, contacts, and tasks. This was originally used internally as Exchange Server Beta 1, and by April of 1996, a large portion of the company’s internal users were using the product.
The original public version, Exchange Server 4.0, was released on June 11th, 1996 as an upgrade to Microsoft Mail 3.5. It was based on an entirely new system and model, utilizing X.500 directory services which eventually moved to Active Directory with Microsoft’s creation of the LDAP directory service.
Exchange Server went through several versions throughout the years, and eventually gained a dominant foothold as the de-facto messaging system for corporate e-mail and messaging. Exchange 5.0 was released on May 23rd, 1997, followed by 5.5 in November. Exchange 2000 arrived in November, 2000 and was followed by Exchange 2003 on September 28th, 2003. The current versions are Exchange 2007 released on November 30th, 2006 and the latest release, Exchange 2010, was made available on November 9th, 2009.