I see some people still think iOS 10 is going to get some sort of dark mode like tvOS did. It's not happening in iOS 10, and here's why. Apps respond to changes in the user interface (like rotating an iPhone 6 Plus from portrait to landscape and making the necessary UI changes) by responding to changes in the UITraitCollection class. It tells apps how much room they have to work with, whether the language is left-to-right or right-to-left, whether there's 3D Touch support, etc. So UITraitCollection is a familiar, established way that developers use to respond to the many different device variables (traits) an iOS app needs to account for. UITraitCollection, as its name implies, is a member of UIKit, which is the set of building blocks used by most iOS apps—and tvOS apps, too. So, as developers, we can take a peek at the traits that apps for each OS is supposed to account for. For tvOS, there's a userInterfaceStyle trait. This tells a tvOS app whether the user has selected the dark or light UI for tvOS. But for iOS, userInterfaceStyle is simply not available, and it never has been. An app has no way to tell which user interface style is selected because there's no setting for it…and it has no way to read said nonexistent setting. Either way, if a dark mode's coming in iOS 10, we'd probably have found out by now. With UI changes, Apple really does like to give developers plenty of notice. As an example, in 2012 and 2013, Apple was practically begging iOS developers to start using layout constraints and Auto Layout, subtly hinting that maybe there might be an iPhone size other than 3.5" or 4" in the not-so-distant future. I mean, iOS 7 is the perfect opportunity to totally redesign your app! Then, in 2014, they introduced two larger iPhones, leaving behind the developers who didn't heed their warnings to use Auto Layout. (You remember the few apps you had that took forever to optimize for iPhone 6 and 6 Plus? That's generally why they took forever.) The same would happen here. If a dark mode were coming in iOS 10, iOS developers would have found out at WWDC this year at the latest. Period. Because designs have to be reconsidered for this—it's not just like flipping a switch. Developers would have to redefine colors for every single object in their app, and that's a lot more complicated than some of you likely think at first glance. But there is hope for an iOS dark mode in the future. With rumors pointing to an OLED iPhone, something that may necessitate the addition of a dark mode, and the addition of the userInterfaceStyle trait for tvOS, which increases developer familiarity with how this might work on iOS, it's definitely not impossible. It's just not happening in iOS 10.