Twitter v 6.1 release full change log:
• Click on a Tweet and reply with a photo by selecting the gallery icon. • Easily mention other users when you Tweet a photo. • Improvements to the photo cropping and image rotation. • Various improvements to the photo viewer. • Users with login verification enabled no longer need temporary passwords to log in to their device. • When you’ve read all the latest Tweets, pull to refresh and see recommendations for new content on Twitter.
Twitter officially announced after Android update, it would be rolled out on iOS device too. Right now the latest version above mentioned.