That is a 4.3 kernel. Joshua said that as of *4.4* the updated bits will be included in the kernel. 4.4 is a week or two off, I believe.
It's both actually. This is a 4.4 kernel which has been released early because it's related to a security update. the -42.0.2 kernel does indeed "Just Work" with the 9550 cards, so you should be able to update just the kernel without problem.