In addition to being the alleged pre-order date for the Nexus 6, this is still an update Wednesday. Google Wallet is getting a big update too. It's jumping all the way from v2 to v7 with a full material design interface. It looks really nice, very #materiyolo.
So far, it seems to be just the UI that has been changed. It has all the animations and icons you'd expect from a proper material app.