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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Apple Testing Three Significant iOS 8 Updates Simultaneously Ahead of Major Product Launches
Web server analytics indicate Apple is currently actively testing iOS 8.1, 8.2 and 8.3. The development is an unusual one, as Apple typically only publicly tests one of each iOS version (full, major update, minor update) at a time, releasing major updates months apart after the initial September rollout. An example is iOS 7, which debuted in September 2013 and was not updated to iOS 7.1 until March 2014.
The most likely explanation for this change in pattern involves major product launches over the coming months. The company is preparing to roll out Apple Pay in October, with the new NFC-based payment system almost certainly falling into the major software update category. Other products on the horizon include the upcoming Apple Watch and a rumored 12.9-inch "iPad Pro", both of which appear set to launch early next year and which would also require significant iOS updates to support them.
Apple released iOS 8 earlier this month with a handful of new features including support for extensions, widget notifications, and third-party keyboards. iOS 8 has had a rocky start, with the company temporarily removing HealthKit-enabled apps at launch due to an unspecified issue. Apple also released and quickly removed iOS 8.0.1 after the update disabled cellular connectivity and Touch ID on iPhone 6 and 6 Plus devices.