The primary reason for the 2.4.0 release was the option of finally building Coin from source on MS Windows without having to go through the Cygwin process.

There had also been various optimization work on rendering traversal code, file i/o and other things.

For v2.4.1, SoExtSelection LASSO and RECTANGLE select could be aborted by the end-user by hitting the 'END' key. No API-changes was needed for this of course.

For v2.4.2, we hacked in support for compressed textures through an API/ABI-invisible field in SoTexture2, called "enableCompressedTexture". This field will remain "invisible" until Coin v3.0.0 is released, and can only be accessed from .iv-file input or through the SoFieldContainer API.

For v2.4.6, SbViewVolume::getAlignRotation() was implemented, and SoToVRML2Action got support for SoUnits in relation to SoVRMLTransform nodes.