Night mode is an automatic setting which takes advantage of the new wide-angle camera that's in the iPhone 11 and 11 Pro models. It's equipped with a larger sensor that is able to let in more light, allowing for brighter photos when the light is low.
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Here's the New iOS 13 Volume Indicator
The new volume interface takes up much less room on the display, expanding from a small bar at the side of the display when you first press the volume up or down buttons into an even thinner bar as you keep adjusting the volume.
In portrait mode, this new volume HUD is located at the left side of the iOS device, both on the Home screen and within apps.
When you're adjusting the volume with the iPhone held in landscape mode with a landscape mode app, the volume interface appears at the top of the display.
An updated volume interface is a feature that iOS users have been wanting for years, and iOS 13 definitely delivers a more streamlined volume experience that should be a relief for those tired of seeing a giant volume indicator in the middle of the display.