Google has finally pushed Hangouts 4.0 to Android users. Hangouts 4.0 has been available to iOS users for some time now. And while Android users may have felt left out, they can finally experience the new material look. Some notable changes in this version include floating button to compose new chats with frequent contacts, new contacts, video calls, etc. Its very similar to Inbox by Gmail layout. Below are screenshots from a friend of ours. Parts of it are blurred out for privacy.
If this update has not reached your phone, you can manually force it to your Android phone by clicking here: Hangouts 4.0