From VyPRESS Research:
Vypress Messenger is real-time messaging system specifically designed for business Intranets. Using a peer-to-peer architecture, it delivers text messages from workstation to workstation in real-time, without the typical delay associated with conventional e-mail.
What's new in this version:
Version 4.0.3 fixed the bug with sending a message when "Send the message without encryption" option has chosen in the "Message encryption" dialog.