這個8.1b版是最新的版本沒錯,不過MS的DirectX team是先把檔案放上去,
說明跟正式的download網頁都還沒寫好就被挖出來了.....

以下是我在MS官方的DirectX mail list找到的,由Microsoft人員回覆的東西:


DirectX 8.1b Runtime
Microsoft DirectX® 8.1b is the latest version of DirectX technology, which delivers fast performance for DirectX-enabled games and other rich media software. This version of DirectX can replace all previous released versions of DirectX. It includes several critical fixes for Direct3D® and DirectShow® components.



DirectShow

Modifies kernel component stream.sys to correct failure of laptops to resume from hibernation as described in Knowledge Base article Q307207. This fix only affects Windows 2000 systems using a docking station having an attached USB camera.
Fixes a blocking issue in quartz.dll on Windows 2000 when running DirectShow in a service.
Corrects a boundary case in the MPEG-2 Demultiplexer where packets may be dropped. This condition can occur if the video stream packet size is an integral multiple of transport packet size. The fix is incorporated for all DirectX-supported platforms.


Direct3D

Fixes Direct3D-base screen savers, when the computer may be unable to enter standby or hibernation by using the timer in Power Management properties.
Fixes some recent game titles that use DrawIndexedPrimitive() API with clipped TL vertices.
Fixes flashing polygons/lines issues in some applications that used DirectX 8.0 DrawPrim(), DrawClippedPrim, DrawIndexedPrim() APIs.


Installation notes:

On Windows XP, you will need to download the latest Service Pack, or install the corresponding hot fixes. Please see the following Knowledge Base Articles Q321178, Q307207, and Q318507, for more information



If you are running Windows 98, Windows 98 SE, Windows Me, or Windows 2000, download the appropriate version for your system at right.



If you are running Windows 95, you should use the DirectX 8.0a runtime

DirectX 8.1b, which provides the latest update to the DirectX technology, will overwrite any earlier versions.



Because it is a system component, the DirectX 8.1 runtime cannot be uninstalled after installation without reinstalling your operating system.