XChat is a popular Internet Relay Chat (IRC) client. It has a choice of a tabbed document interface or tree interface, support for multiple servers and is highly configurable.
XChat is a full-featured IRC client and includes all basic functionalities that are found in most other IRC clients, including CTCP, DCC file transfers and chats.
It supports a plugin system for various languages (including C, C++, Perl, Python, Tcl, Ruby, Lua, CLISP, D, and DMDScript). By writing plugins, the features and functionality of XChat can be extended and customized.
* The userlist and treeview can now be placed on the same side, with a resize handle in between them. They can also be dragged and dropped into place.
* The resize handles between two panes are now smaller (3 pixels) and invisible.
* Scrollbars are now placed inside the frame they scroll (more Windows like).
* If you have a tree on one side and userlist on the other, they'll both now have a resize handle, previously the tree's size was fixed.
* The userlist can be hidden and shown with CTRL+F7.
* Added a feature that reloads conversations from last time you used XChat (/set text_replay 0 to disable it).
* /MENU now supports a $CHAN root aswell (see plugin20.html).
* Fixed a problem some people were having with minimize to tray (the feature added in 2.8.3e).
* Fixed /LastLog printing everything twice if you had Indented Nicks off.
* Added /set gui_tweaks for GUI fine tunning.
* A better quit dialog which warns you if you're connected to IRC or have active file transfers.
* The Channel List's minimum users spin-button can now be set downward even on networks that sent a list of channels of only a larger size. In this case the Download button will flash to indicate you need to download a new list.
* Fixed bug:  Doesn't recognize nicks with halfop mode on hovering.