Yeah

Here's the change list.
http://irrlicht.sourceforge.net/changes.txt
But also await for several API breaking changes
Here's a list of problems to cope with:
* Some types changed from s32 to void* for 64bit compatibility
* Camera nodes are now using camera animators instead of separate scene nodes
* If VBOs are enabled for a meshbuffer, you need to call setDirty after changing vertex or index data in that buffer
* Some methods have been renamed, usually the old ones still exist, but are deprecated (so avoid them, they'll be removed in Irrlicht 1.6)
* One of these major renamings: addRenderTargetTexture replaces createRenderTargetTexture, which means that you don't have to drop the texture anymore, but you must remove it from the texture cache

* MaterialTypeParam==0.f is now interpreted as 0, not 0.5, for transparent materials. This means that transparency is really smooth, but if 0.5 was desired you have to make that explicit
* core::string constructors with only one POD parameter are explicit now, so you might have to add core::stringc() around your integers or variables.
* draw2DImage handles RTTs internally now also under OpenGL, so workarounds will flip the images now
* The window pointer for external window rendering has been moved from endScene to beginScene
* Particle Sizes have to be set in the emitter, not in the ParticleSystemSceneNode.
* Collision response gravity and FPS jump speed have to be adjusted
* The FPS cam constructor movement speed is now in units/ms not units/s as in previous versions, so divide the value by 1000.f

* Terrain heightmap and texture are flipped. This will lead to a terrain that has the same origin as the original image of heightmap and texture.

* Some Light properties must be changed via methods from ILightSceneNode now, instead via the SLight struct. This affects radius, ShadowCast, and LightType.

Moreover, the initial attenuation has changed back to the old values of older Irrlicht versions.
Ok, I hope that I remembered all things. Will add others once they pop up
