Facebook has announced an overhaul of its Messenger smartphone app in an effort to simplify the service for its 1.3 billion monthly global users. The social network began rolling out a redesigned version featuring three tabs instead of nine, saying it was "going back to its roots" seven years after the standalone app's launch. "We build one feature after another; they're piling up," Messenger chief Stan Chudnovsky said on Tuesday of the service, which has grown from a simple messaging app to one that lets users make video calls, send money and more. The updated tabs allow users to navigate between their conversations under "Chats," stories and contacts at "People," and "Discovery," which is devoted to games and exchanges with businesses. Facebook has positioned Messenger as a tool for businesses to efficiently handle customer questions or concerns. Talking to customers via the app is free - but businesses can also pay for Facebook ads that let customers start a conversation or visit their page with one click. Messenger is part of Facebook's effort to expand outside the social network - particularly when it comes to staying relevant to mobile lifestyles and younger people, who have been moving away from the service.