Below is the version history of the XtraTreeList control since version v2006 vol 2. Only the main feautures and major functionality changes are listed below.
VERSION 2008 vol 2
·    Node Customization - Nodes can now display check boxes so that end-users can toggle the check state of individual nodes.
 ·	Drag and Drop Improvements - In previous versions, to insert a node prior to the required node you had to hold the SHIFT key pressed. Now, there is no need to use the SHIFT key.

VERSION 2007 vol 3
·    8 new filter conditions: BeginsWith, EndsWith, Contains, NotContains, Like, NotLike, IsBlank and IsNotBlank.
·	Animation - Support for animated GIF files when using the ImageEdit and PictureEdit controls for in-place editing.

VERSION 2007 vol 2
·	Support for data editing in the TreeList control when binding to a business object –The IVirtualTreeListData interface has been extended to include a new method that can be overridden to support data editing. Alternatively, the new DevExpress.XtraTreeList.TreeList.VirtualTreeSetCellValue event can be handled instead.

VERSION 2007 vol 1
ü	Miscellaneous
·	Print visible nodes - now only visible nodes, whose Visible property is set to true are printed.
·	The ability to customize the appearance of column headers has been added. To access the appearance settings used to paint the column's header, use the TreeListColumn.AppearanceHeader property.
·	The DragObjectStart, DragObjectOver and DragObjectDrop events have been added.
•	The XtraTreeList control supports the IDXDataErrorInfo interface. If a data source implements this interface, the tree list bound to this data source will display error icons within cells. Multiple error icon types are supported.

VERSION 2006 vol 3
ü	Data Specifics 
·	Fixed Columns - the XtraTreeList allows its columns to be anchored to its left or right edge. When the column is anchored, its content isn't horizontally scrolled.
·	The ColumnByFieldName method allows locating columns by the name of the field which they are bound to.
ü	Data Representation Specifics 
·	The TreeList.FilterNodes method forces the XtraTreeList control to re-filter its data.
·	The StartIncrementalSearch and StopIncrementalSearch methods allow the Incremental Search to be started and stopped manually, in code.
ü	Miscellaneous
·	End-users can move focus away from the XtraTreeList control by pressing the CTRL+TAB keyboard keys.

VERSION 2006 vol 2
ü	Data Specifics 
·	Binding to a Business Object - With this feature, you are able to bind the TreeList control to any object that represents a tree structure. You can do this by implementing the DevExpress.XtraTreeList.IVirtualTreeListData interface for the business object or via the TreeList's VirtualTreeGetChildNodes and VirtualTreeGetCellValue events. 
ü	Data Representation Specifics 
·	Filtering Nodes - This feature allows you to flexibly control the visibility of nodes. You can filter nodes based upon the contents of a column. It's also possible to handle the FilterNode event to dynamically specify which nodes need to be currently displayed or hidden. Or you can change a node's visibility directly via the node's Visible property. 
·	Incremental Searching - This allows end-users to quickly locate the required information within the XtraTreeList by typing a search string within a non-editable column. This functionality is controlled by the tree list's TreeListOptionsBehavior,AllowIncrementalSearch option and the column's TreeListColumn.AllowIncrementalSearch property. 
The TreeListOptionsBehavior.ExpandNodesOnIncrementalSearch option has been added which controls whether collapsed nodes are expanded to display the node if it matches the search criteria.
ü	Miscellaneous
·	Better Support for the  XtraPrinting Library. We have re-designed the XtraTreeList Suite to better support the XtraPrinting Library. Now the content of the XtraTreeList control can be correctly exported to all formats supported by the XtraPrinting Library, including PDF.
·	Export Data to XML, HTML, PDF, RTF, TXT, XLS, MHT and Import from XML.