The strut design is very different and actually creates a complete X all they way back to the battery chamber. The struts between the motor mounts and ducts are fragile and break easily. So these upgraded frames stiffen the struts considerably. The struts themselves have a flat cross section which creates more bonding area with the duct.
Here is the review by krachall at RCGroups.
This plastic durable package can protect the package from deformation during
the shipping process.