Google Duo finally confirm that multi-device support is in the works so by this New update user can use more then one device to use Duo.
Unlike Hangouts and other Google messaging apps, Duo accounts are tied to phone numbers rather than email addresses. This prevents Duo users from registering more than one device to one Duo account.
User can able to signup or log in with their Duo with Google account while Duo will add soon Notification and block calls fro particular sender, Also, Duo has redesigned its full contacts page to make it more convenient.
Also show a search bar that peeks halfway from the bottom of the screen to remind you of the contacts page.