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. The intro tutorial is also quite nice looking now. The features appear to be identical, but we'll keep checking.
Update: There's a new option to lock or cancel your physical Google Wallet card in this update. The app contains new options to add money automatically on a schedule and get notifications of low balances.
The APK is signed by Google and upgrades your existing app. The cryptographic signature guarantees that the file is safe to install and was not tampered with in any way. Rather than wait for Google to push this download to your devices, which can take days, download and install it just like any other APK.
File name: com.google.android.apps.walletnfcrel-7.0-R188-v14-718814400-minAPI15.apk.
Version: 7.0-R188-v14 (718814400) (Android 4.0.3+).