The update also removes support for video services from Mobypicture, Vodpod, and Posterous, leaving Twitpic and yFrog as the last remaining video uploading services for the iOS app.
This update includes enhancements to search and other improvements.Twitter for iOS is a universal app that can be downloaded from the App Store for free. [Direct Link]
-As you search you'll see more topic and user suggestions for your query, based on what's happening in real time. You'll also see these suggestions when adding a hashtag or username as you compose a new Tweet.
-Top Tweets from big moments in the past pop out when you search for a given term. For example, searching for “election” might highlight Tweets from several months ago.
-When you open a web page you can now see the related Tweet for more context. Just pull the tray icon up or down to see or hide the Tweet.
-It's easier to see long conversations in the Tweet details view, which now shows all of the replies to any Tweet
-When you block a user in the app, their Tweets will instantly disappear from the Connect tab in the app
-Pull-to-refresh in Discover shows a new, smoother animation
-Support for traditional Chinese
-Logout support (iOS 6 only)
-Uploading videos vie Mobypicture, Vodpod and Posterous is no longer supported
-Additional bug fixes and improvements