Twitter’s official iOS client has just been updated with a number of new enhancements and improved search features.

First up, version 5.4 of the app will provide more topic and user suggestions for a search query, based on what’s happening in real time. Those suggestions will also be available when adding a hashtag or username when composing a tweet.

And now when searching, top tweets from big moments in the past will pop up, allowing users to see more relevant information about the search term.

To make sense of longer conversations on the tweet details view, all of the replies to any tweet are shown.

As we reported late last month, the update also changes where users can upload videos. Mobypicture, Vodpod, and Posterous are no longer supported in the app.

Finally, the pull-to-refresh gesture in the Discover tab shows a new and smoother animation.

Twitter is a universal app for the iPhone/iPod touch and iPad/iPad mini. It can be downloaded in the App Store now for free.

On Monday, Twitter also made app news by announcing that TweetDeck for iPhone will be pulled from the App Store in early May. Twitter purchased TweetDeck in 2011 and wants to focus on Web-based versions of the application favored by power users.