Most notably, Notes received the ability to draw sketches with different tools, image insertion, prominent visual appearance for website links and map locations, and advanced list formatting; an all-new Apple News app aggregates articles from different sources; and Apple Maps received mass transit support, although in a limited number of locations at launch.

For searching, the proactive intelligence can display instant results in a widget-like format, including weather, sports, news, and more.

In iOS 9.3, Apple added a Night Shift mode that changes the color of the device's display to a warmer, less "blue light" containing shade, to reduce any negative eye health effects on users' circadian rhythms.

Additionally, iOS 9 brought new user experience functions, including Quick Actions, and Peek and Pop, based on the touch-sensitive display technology in the iPhone 6s.

Critics praised proactivity and Siri for making the Notification Center a central location for all information, and the potential for future updates to improve the functionality.

With the release of iOS 10, Apple introduced the Today view, which was accessed on the lock screen by swiping to the right.

[4][5][6] This marked the first time that the general public had been able to test new versions of iOS before official release, with Eddy Cue, Apple's Senior Vice President of Internet Software and Services, telling Fast Company that the public beta program was started "because of Maps", referring to the company's Apple Maps launch that had significant issues in its early days.

Apple has also added Low Power Mode, which modifies the amount of energy dedicated to background services and animations.

[17][18] When the shift button is inactive, lowercase letters are displayed on the keyboard, instead of the all-caps representation on previous iOS versions.

The mode shifts the colors of the device's display to be warmer, similar to F.lux, a popular program for Microsoft Windows and Apple macOS computers.

[34] Intelligence is one of the main features in iOS 9, consisting of the newly integrated Siri and Search (previously known as Spotlight), as well as "proactivity" throughout the operating system.

When typing, Search has also been improved to display instant answers in an at-a-glance, widget-like format, similar to that provided in the Siri interface.

It also added support for reproductive health, UV exposure, water intake and sedentary state data types.

"[64] The Maps app now also has enhanced location details, including a Nearby feature that recommends shops, restaurants and places to drink in close proximity to the user.

Dan Seifert of The Verge praised the improvements in Proactivity and Siri, highlighting how the notification drop-down contains most, if not all, the information the user needs.

He did, however, criticize the low number of decent-looking articles in Apple News, writing that "you'll notice a discrepancy in how some articles are handled – most are just formatted text on a white background with the outlet's logo up top" and also noted the limited number of locations in Apple Maps that, at launch, supported mass transit directions.

[89] Matt Swider of TechRadar wrote that Siri and Proactivity lists were "robust," and enjoyed that notifications were sorted chronologically rather than by app.

[94][95] In February 2016, news outlets reported that users who updated to iOS 9 on a particular device that had components repaired by a third-party (notably the Touch ID fingerprint recognition sensor) rendered their phone unusable.

[98] Apple stated:[99] We protect fingerprint data using a secure enclave, which is uniquely paired to the Touch ID sensor.

Without this unique pairing, a malicious Touch ID sensor could be substituted, thereby gaining access to the secure enclave.

When iOS detects that the pairing fails, Touch ID, including Apple Pay, is disabled so the device remains secure.

[105] However, Apple explained in August that the timing was a coincidence, and the iBooks app crash was a result of a server issue, not the software update.

Pegasus could intercept and read text messages, emails, track calls, trace phone location, activate the microphone, and gather information from apps, including (but not limited to) iMessage, Gmail, Viber, Facebook, WhatsApp, Telegram, and Skype.

Arab human rights defender Ahmed Mansoor received a suspicious text message with a link and sent it to Citizen Lab.

An investigation ensued with collaboration from Lookout that revealed that if Mansoor clicked the link, it would have jailbroken his phone and implanted it with the spyware.

Citizen Lab linked the attack to an Israeli surveillance company known as NSO Group that sells Pegasus to governments for "lawful interception.

"[110] News of the spyware received significant media attention,[111][112][113][114][115] particularly for being called the "most sophisticated" smartphone attack ever,[116][117] and for being the first time in iPhone history that a remote jailbreak exploit has been detected.

[118] In July 2017, information on a critical Wi-Fi security vulnerability affecting 1 billion iOS and Android devices was published.

A settlement was reached in 2022, such that users who downloaded iOS 9 onto an iPhone 4s, while living in New York or New Jersey, could receive $15 each, from a fund of $20,000,000 paid by Apple.

[125][126][127] Around early 2018, some users who still had devices running iOS 9 with the A9 chip reported being prompted by an "Activation Error" screen that occurred at any random time.