The new version of Google Music (which is apparently from Ice Cream Sandwich, but works with Gingerbread just fine) hasn't added a ton of new features — it's just changed around how the interface works. First off, it's a lot prettier — in fact, it looks just like the iOS version. In addition, the play and skip buttons at the bottom of the library screen have been replaced with an easy-access search button, the album art is much more prominent in the Now Playing screen, and tapping on the album art brings up many more options than in Google Music 3 (see the screenshot above).
The only downside with the new version is that the "Available Offline" option is strangely missing, meaning you can't manually select tracks for offline storage. We're not sure why yet, but for now, if that's a feature you use often, you may want to hold off on upgrading.
To install the new Google Music, just uninstall the version on your phone, download the APK below to your device, and then tap it to begin the installation. You may need to head into Settings > Applications > Music and hit Clear Data if your phone doesn't sync your music after installing.
Google Music 4 is a free download for Android devices.