Chat application with administrative features, simple analog of ICQ (old messenger, like a Skype or Viber):
-Multithreaded client and server application;
-Special "waiting" connection in additional thread for avoid periodical requests (looks like Comet technology, but without 3-rd party components);
-Create account / login / logout;
-Send text message to all chatters;
-Send file to all chatters;
-Remote shell command execution to specific chatter;
-Update module (for create new versions and one-click update of application);
-Ban / unban users, delete users from chat;
-Resend unsent messages due connection problems when connection restored;
-Offline messages history.


Technologies: C#, Windows Forms, Windows Service, MS SQL, Linq, TCP/IP, Sockets.