Twitter had begun rolling out a massive new design overhaul focused on consistency, which calling #letsfly, and is available now in a freshly updated Twitter for iPhone.
The #letsfly update aims to make your Twitter experience faster and simpler. Your main timeline is now called "Home" and your mentions are now "Connect" and they added a quick way to access hash tags and searches which is called "Discover". It certainly does look fresh and clean, and may be more accessible to new users.
On the down side, Direct Messages (DM's) have been buried under the "Me" tab, as has account switching. (Though you can swipe up to get DM's and left to switch accounts, slightly speeding up the process.)
Notably, this is the first major update since Loren Brichter -- the innovative developer behind the original Twitter for iPhone and Mac (called Tweetie before it was bought out) and iPad -- left Twitter a short time ago.
The #letsfly update for Twitter for iPhone is available now in the App Store.