Messenger Update Required

The protocols used by the .NET Messenger instant messaging (IM) service are being changed, forcing users to upgrade older Microsoft IM clients before Oct. 15 to continue using the service. As a result of the change, third-party multi-IM clients, such as Trillian, will be blocked. Microsoft did not explain all the reasons for the change, but did say that the modified protocols will offer better security. Unfortunately, this message was communicated in a way that led some users to believe that Microsoft’s IM clients had an exploitable security vulnerability. (See the sidebar “Security E-Mail Raises Alarm“.)

Who Is Affected?

Users who employ the following desktop IM clients to access the .NET Messenger service (formerly known as the MSN Messenger service) must update their software before Oct. 15 or lose their ability to log on to the service:

• Windows Messenger clients older than version 4.7.2000 (Windows XP shipped with version 4.0.0155, and Service Pack 1 shipped with version 4.7.0041,