main features are: * Modifiers can now be in any order in the modifier stack * DerivedMesh now has a standard framework for custom element data to be passed through the stack with mesh data (being copied and interpolated as appropriate), so modifiers can access whatever data they need * The modifier stack code has been refactored and a number of bugs have been removed * The EdgeSplit modifier has been added: http://mediawiki.blender.org/index.php/BlenderDev/EdgeSplitModifier * The DerivedMesh modifier has been added: http://mediawiki.blender.org/index.php/BlenderDev/DisplaceModifier * The UVProject modifier has been added: http://mediawiki.blender.org/index.php/BlenderDev/UVProjectModifier For more info, see: http://mediawiki.blender.org/index.php/User:Artificer/ModifierStackUpgrade (currently undergoing reorganisation)