Google has confirmed that the iOS version of its Inbox by Gmail app will soon be compatible with Apple's notch-totting iPhone X.
Also, this didn’t make the column, but: Inbox for iPhone X is coming. Google says soon. It did a bunch of crazy one-off interface stuff that the X totally broke, and it took way longer to update then Google expected. (Also Gmail is clearly more important.)— David Pierce (@pierce) April 25, 2018
As you can see, Google says a lot of Inbox features were broken due to the unorthodox display of the iPhone X and that's the reason it took so long for the company to bring a compatible version.
The more popular Gmail app has been already made iPhone X compatible by the company. Recently, Amazon also updated its Alexa app to include iPhone X related optimizations.