Bopup Messenger is a business messenger that helps offices and organizations in any sphere to organize and improve their IM and real-time communications over LANs, WANs and large networks including connections over Internet. It requires an IM server and provides encryption of personal instant messages and group file transfers. That makes private conversations and user collaboration more safe and secure. The messenger offers a great functionality on sending and receiving instant messages with formatting font and color, insertion of URLs, links and emotions (smileys) into the text of messages. Since the communication is organized via a central IM server an offline messaging and document exchange are provided. Bopup Messenger sends messages and files even a recipient is not available and receives stored offline data from the communications server. New versions are automatically downloaded and installed from the instant messaging server so there are no needs to handle installations and deploy updates manually on user workstations. This IM client has a built-in branding support that shows a company logo uploaded on the server in the messenger interface. Since Bopup Messenger is intended for use in organizations and business environments it offers various authentication methods to secure connections and to login to the IM network. For small LANs the Simple or Login/Password authorization can be chosen but for large networks based on a Windows Domain architecture the Windows Authentication mode is more preferred. The messenger also supports Terminal Server and Citrix so multiple instances can be run on the same server/computer. Many options allow to tune and set up the program for the best way. Bopup Messenger can be also distributed and installed with a set of pre-defined or non-modified settings. MSI installation package for deployment via GPO (Active Directory) is also available for download.