2007-H1 Microsoft WGF (DirectX 10 or DirectX 9.0L) New version of DirectX, aka 9.0+ or 9.L succeeding DirectX 9.0c. Now reuniting DirectX with DirectDraw. The name is changed from DirectX to WGF (Windows Graphic Foundation) and then back again. Longhorn's user interface will for example be based on WGF version 2.0 (coming in 2006). Includes Shader Model 4.0 support, and likely to be part of XNA. Will be included in Longhorn and will also support programming Xbox2. Includes "Classic", "Aero", and "Aero Glass" modes (see Beyond3D link below).
DX10 is a much cleaned up version designed to run faster. Removes backwards compatibility with DX 9 and older. For running older games an extra layer of software will be used. May cause older games to run slower.