Yahoo will retire older versions of Yahoo Messenger on September 30. If you are using any version lower than 8.0, it will no longer work after this month, the company announced on its blog.
To continue accessing the service, you can download 9.0, the latest version of Messenger, use the Web-based Messenger product, or use the built-in Messenger feature in Yahoo Mail. Messenger is also available on mobile phones, including the iPhone.
Last month, Yahoo introduced a beta version of Messenger 10.