Microsoft today also released Messenger for Mac 5.1, the latest version of the company’s instant messaging conversation. Version 5.1 offers the following new features for customers using Live Communications Server, including: file transfers sent to external contacts will now be encrypted for better security outside of the firewall; if a user is logged into Live Communications Server on more than one machine, version 5.1 ensures that messages are sent to the appropriate location; and for IT administrators, the update will provide more control over saving chats at an organizational level.