diff --git a/include/d3d10_1.idl b/include/d3d10_1.idl
index c380c5a08be..5724b63b169 100644
--- a/include/d3d10_1.idl
+++ b/include/d3d10_1.idl
@@ -118,3 +118,5 @@ interface ID3D10Device1 : ID3D10Device
 
     D3D10_FEATURE_LEVEL1 GetFeatureLevel();
 }
+
+const UINT D3D10_1_SDK_VERSION = 0x20;