Google Duo video calls are in 720p HD video.It is optimized for low-bandwidth mobile networks through WebRTC and uses QUIC over UDP. In an email sent to Android phone manufacturers on October 5, 2016, Google announced that, starting December 1, 2016, Google Duo will replace Hangouts within the suite of Google apps Android phone makers must pre-install on devices, with Hangouts instead becoming an optional app for phone makers to pre-install.! Google Duo was announced at Google's developer conference on May 28, 2016,and began its international rollout on Android and iOS devices starting August 16, 2016.It quickly climbed to the spot as the number one free app on Google Play within two days of its initial release,but it fell to the 127th place after approximately one month. Duo replaces Hangouts as part of the suite of Google apps manufacturers must pre-install on Android devices. However, it fell to 127th place after approximately one month. Within two days of its release, the app climbed to the number one spot on Google Play's list of free apps. An update in April 2017 lets users worldwide make audio-only calls. A 'Knock Knock' feature, exclusively available on Android, lets users see a live preview of the caller before answering.

The app automatically switches between Wi-Fi and cellular networks. Duo is based on phone numbers, allowing users to call someone from their contact list. End-to-end encryption is enabled by default. It is optimized for low-bandwidth networks. Google Duo lets users make video calls in high definition. It was announced at Google's developer conference on May 18, 2016, and began its worldwide release on August 16, 2016. Google Duo is a video chat mobile app developed by Google, available on the Android and iOS operating systems.

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