The aspect ratio of smartphone has been changed ever since the rising popularity of ultra narrow bezel (or bezel-less) smartphone in the market. Today the market is saturated with smartphone in various aspect ratio display from 16:9, 18:9 even to notch, dew drop and more of a kind. SONY mobile has make their brave move with the new 21:9 aspect ratio display, which means the smartphone will be much more longer than a common on.
In the new Ice universe Twitter feed, he/she had released the alleged Xperia XZ4 glass protector with a comparison with the size of iPhone XS Max.
By stretching both end, the display is now able to fit 21:9 aspect ratio videos such as common movie display sizes. However, smartphone will be longer in shape which could be an annoying factor for one handed operation.