In this update there is a new Tweet Composer that helps make tweeting a bit easier. It gives you quick access to your camera roll and a clear preview of how your tweet will actually look when you send it. There are also richer notifications that include details like avatar and how many people are interacting with you. This is only for Android 4.0+ sporting devices of course. The timeline is also wider and taller in all parts of the app including profiles, search and Discover.
You can hit the Play Store and check for updates, or just hit the link below to go grab it.
Twitter Play Store link