The following is a history of all versions of Yahoo! Messenger on all platforms by Yahoo!, Inc.
Contents
Windows
There are many versions between those listed here and prior to last version listed here. These are "major releases". See one of several sites listed in external links to find other, older versions of the product.
Oldest version for which customer care support is available: 8.0 (as of April 2, 2007)
Oldest version that can log in (has not reached end of life): 8.0 (as of September 30, 2009)
Unix/Linux
The last public version of Yahoo! Messenger for Unix was released in September 2003, while an unofficial beta (v1.0.6) from a Yahoo employee was released around the same time.
Yahoo! Messenger for Vista
A special version was designed to exploit the new design elements of Vista's Windows Presentation Foundation and entitled a whole new user interface and features. It lacked some basic functions such as webcam support and Chat, and has since been discontinued. It was arguably the better looking and functional in respect to windows and tabs management but was eventually discontinued by Yahoo.
Yahoo! Web Messenger and Yahoo! Mail integration
Beginning in 2006, Yahoo made known its intention to provide a web interface for Yahoo! Messenger, culminating in the Gmail-like web archival and indexing of chat conversations through Yahoo! Mail. However, while Yahoo! Mail integrated much of the rudimentary features of Messenger beginning in 2007, Yahoo did not succeed initially in integrating archival of chat conversations into Mail. Instead, a separate Adobe Flex-based web messenger was released in 2007 with archival of conversations which take place inside the web messenger itself.
In 2011, Messenger 11 Beta began to archive past messages on an online server which is accessible through the client.