This is an important release that mainly fixes a serious compatibility issue with the new ATI drivers, specifically 10.x+
Generally the 2.x series has recently (2.2+) gotten improved compatibility for newer Windows releases, 64 bit architectures as well as lots of stability and improvements for applets.
2.3
new: Removed support for indirect buffers as arguments to GL functions
new: Added missing tokens in GL30 & GL32
new: Added support for AMD_seamless_cubemap_per_texture & AMD_shader_stencil_export
fix: Improved compatibility mode detection - Required for all ATI 10.x Drivers.
fix: Complete overhaul of the linux focus system when using Display.setParent().
fix: WaveData - updated to use available() on audio stream
http://lwjgl.org/forum/index.php/topic,3212.0.html