Xiaomi actually started the war against smartphone bezels with the Mi Mix in 2016 before other OEMs decided to follow suit. They'll be releasing the sucessor of the Mi Mix on 11th September. This information was shown on a post on Chinese social networking site Weibo.
Nothing else about the phone has been officially confirmed yet, although some speculations so indicate the device may come with a dual rear-camera setup. It's very likely that the bezels will be even thinner this time, and the handset is also said to offer 3D facial recognition support.