The official Twitter app for iPhone, iPad, and Mac has just been updated and one of the biggest new additions is direct message (DM) sync across devices. Basically meaning if you mark a message as read on your iPad, it will sync the read status to your iPhone, Mac, and the full and mobile web versions. Other updates include a new reply composer in the tweet details view and search enhancements. According to Twitter's blog:
For Android, iPhone, iPad and mobile.twitter.com, we’re making more improvements to search results. Now when you search for people on Twitter, you may see an expanded user result that shows a full bio. This account preview makes it easier and faster to find and learn more about the accounts you’re looking for. And if you swipe the preview to the left, you’ll find similar accounts –– for example, if you search for the MLB, you’ll see suggestions for ESPN, Ken Rosenthal, and other MLB-related accounts. Additionally, a new in-app indicator in search results will show you when there are new Tweets for your query, making it easier for you to stay up to date on the latest Twitter conversation.
The only other notable changes are a new reply composer and changes to search including new tweet notifications when your queries match newly posted tweets. You can also access the unwanted tweets section from the more menu now.