What was once a test is now official. Twitter is rolling out a new version of its Android app which adheres to Material Design, the paper-like visual language developed by Google. The app is now split into four tabs -- Home, Moments, Notifications and Messages -- which you can move between by tapping the icons at the top of the screen, or using a horizontal swipe. Dragging across from the left-hand edge will reveal a side menu with shortcuts to your profile, lists and Twitter highlights. The drop-down arrow at the top of the menu will let you switch accounts, meanwhile.