Reviewers highlighted the significant updates to iMessage, Siri, Photos, 3D Touch, and the lock screen as welcome changes.

The third-party extension support to iMessage meant it was "becoming a platform," although the user interface was criticized for being difficult to understand.

Reviewers were impressed with the image recognition technology in Photos, although noting it was still a "work in progress" with a higher error rate than the competition.

The lock screen was "far more customizable than before," and reviewers enjoyed that notification bubbles could be expanded to see more information without needing to unlock the phone.

[15] The update added QuickType virtual keyboards, which, by word-completion capabilities, could predict likely responses to questions and suggest relevant information based on location, calendar availability or contacts.

[16] The "Define" feature in previous iOS versions was replaced by "Look Up," and was expanded in utility from just providing definitions to retrieving information from locations, web browsing history, downloaded apps, suggested websites, and more.

[20][21][22] The "slide to unlock" mechanism on the lock screen was removed in favor of pressing the home button.

[31] A new Magnifier setting was added which allowed users to triple-click the home button to launch the Camera app with magnification enabled.

[40] The Settings allowed the user the option to have routes in the Maps app avoid toll roads[41] and/or highways.

[42] In iOS 10.3, Settings was updated to feature information relating to a user's Apple ID account in the main menu,[43][44] and featured a section that allows users to see which old, unmaintained apps won't work in future versions of iOS.

[60] iOS 10 allowed developers to buy advertisement spots in the App Store when users search for content.

An option in Settings let users revert to the previous threading system with the most recent message on top.

[87] The app began to help users find the nearest gas station, fast-food restaurant or coffee shop, by swiping up from the bottom of the screen.

[91] In iOS 10.3, the app also allows the user to see a weather forecast by using 3D Touch on the current temperature.

[105][106] Tapbacks have been added, allowing users to react to messages with love, like, dislike, laugh, emphasize, or question.

Users tap a "round yellow badge with a person and a plus sign" and can then send invitations through text, email, or by link.

[116] A new "Memories" feature can automatically recognize and compile related photos and create short, shareable music videos.

[74] Users can save voicemails through AirDrop, iMessage, iCloud Drive, and other apps through a share menu.

Developers can: iOS 10 allows third-party camera apps to capture RAW image format pictures.

In his review, The Verge's Dieter Bohn wrote that the new features introduced in iOS 10 are "an evolution of some of the design and interaction ideas that Apple has been working on for a couple of years".

Regarding third-party support in Siri, he called it "great", while noting the limited class of apps ("calls, messaging, payments, photos, ride-sharing apps, some CarPlay systems, and workouts"), and that sometimes a button press was required to complete the process.

Bohn particularly enjoyed the new lock screen, where he highlighted that notification bubbles can be 3D Touch-ed to access more information, all without needing to unlock the phone.

In regard to iMessage, he wrote that it has new features that are "particularly useful", including "Invisible ink" that obscures text in a conversation when others might be looking, but criticized the user interface, writing that it "needs some work".

He finished by writing that although iOS 10 does add features seen in Google's Android operating system before, the mobile industry is "shamelessly getting "inspired" by the competition".

"[148] User adoption increased to 76% of active devices in January 2017,[149] 79% in February 2017,[150] 86% in June 2017,[151] 87% in July 2017,[152] and 89% in September 2017 before the release of iOS 11.

[153] The initial public release of iOS 10 on September 13, 2016 saw many iPhones and iPads sent into recovery mode, by the over-the-air update, requiring devices to be connected to a Mac or PC with iTunes in order to retry the update or restore the device to factory settings.

[155] Apple acknowledged the problem, said it planned to issue a security update, but also stated that iCloud backups were not affected.

These led to concerns that Apple was instituting planned obsolescence policies in order to encourage sales of newer iPhone models, a controversy dubbed Batterygate.

[165] Later that month, Apple admitted that since iOS 10.2.1, it had been implementing performance management techniques on older iPhone models to preserve system stability, especially in situations where their batteries are "less capable of supplying peak current demands," such as cold weather, age, or low charge.

Apple stated that these measures were intended to help "deliver the best experience for customers, which includes overall performance and prolonging the life of their devices.