It's much more of an artistic update than a technical one. At worst, the resolution of a couple of textures, and the polygon count of a couple of meshes, have been heightened. But I don't see any additional graphic tricks, like bloom or ambient occlusion, going on. Hell, I doubt League even uses deferred shading, so there's a limit to what they can do.
I learnt most of those terms at a course last year, I don't expect you to understand what I'm talking about, just showing off.