When I sent it in previously it was a repair, as one of the drivers was blown. He put in new drivers, but everything was the same, and he happened to apply new magic goop to the inside of the enclosure. This recent upgrade is what I believe people call the "i" upgrade and includes a new cable and the enclosures are modified further beyond goop to the best of my knowledge - on the phone he said it involves refinishing the enclosures to change the porosity of the metal or something along those lines Mumba jumbo etcetera. And apparently he has a new earpad design or modification.