In iOS 9, some of the best features are the ones that aren't readily visible. iOS 9 has several under-the-hood updates that boost battery life, improve security, and cut down on the amount of storage space iOS updates and apps use on iPhones and iPads.

Even disregarding all of the consumer facing features, these quiet improvements make the upgrade to iOS 9 from iOS 8 or iOS 7 well worth it on all supported devices: the iPhone 4s and up, the iPad 2 and up, and all iPad mini models.

Battery Life

With operating system optimizations, Apple is able to eke out an additional hour of battery life on iPhones under normal usage conditions. One of these improvements, for example, pertains to the iPhone's ambient light and proximity sensor. When the iPhone is placed facedown, it now detects that the screen isn't visible, so an incoming notification does not light up the screen.

batterysettings
There's also a new Low Power Mode on the iPhone that can add another three hours of battery life by cutting down on battery-draining features. Low Power Mode turns off automatic Mail fetch, disables background app refresh, disables motion effects, and disables animated wallpapers.

Low Power mode also throttles the performance of the iPhone so it drains less power. Benchmark testing suggests Low Power mode reduces an iPhone's performance by about 40 percent to cut down on power usage.

Security

iOS 9 prompts users to create 6-digit passcodes instead of 4-digit passcodes for additional security. It's still possible to create a 4-digit passcode, but Apple recommends a 6-digit code because it adds one million possible combinations instead of 10,000, making a passcode harder to crack. Two-factor authentication support is also enhanced in iOS 9.

ios9security

Installation Size

With iOS 9, Apple's cut way down on the installation size, so far less free space is required to download the new update. While iOS required 4.58 GB of space to install, iOS 9 requires only 1.3 GB of space to install, making it more accessible to users who have 16 GB iOS devices.

appdeletionstuff
For devices that still don't have enough space to install the iOS 9 update, Apple has a new auto app delete/reinstall feature. When attempting to install iOS 9 on a device with insufficient space, there's a popup that offers to temporarily delete some apps in order to make room for the update. Apps that are deleted are then reinstalled and replaced after the operating system update is completed.

App Thinning

Apps from third-party developers also require less installation space thanks to a feature called App Thinning. With App Thinning, apps can be optimized for specific devices, allowing them to take up less space on iOS devices.

An app for the iPhone doesn't need all of the iPad assets, so those won't be downloaded. That means faster installs, faster launch times, and more storage space left for other apps and content.

App Thinning also includes on-demand resources like image and sound files, which can be downloaded only when needed. The imagery for later levels in a game, for example, might not be downloaded until it's necessary.

Metal

Apps in iOS 9 take advantage of Metal, making more efficient use of the CPU and GPU for faster scrolling, smoother animations, and better performance. Email, messages, web pages, and PDFs all render faster.

Top Rated Comments

Parasprite Avatar
80 months ago
This is pretty minor, but for devices with a keyboard, they've also added a helpful popup when you hold cmd that shows what keyboard shortcuts you can use.


Not a huge feature, but it's definitely a nice touch.
Score: 12 Votes (Like | Disagree)
nagromme Avatar
80 months ago
...
Why Apple engineers don't design software on less capable devices first and move on from there?
Because then the software will be less capable, and devices newer than the 4S would go to waste.
Score: 10 Votes (Like | Disagree)
elmateo487 Avatar
80 months ago
so much effort required from so many developers (Apple, 3rd party) so that Apple can save $5/device by not moving to 64GB base...
Are you saying app thinning is a bad thing? I shouldn't have to download resources I don't need...
Score: 9 Votes (Like | Disagree)
postpc Avatar
80 months ago
I've been hard on Apple for the last couple of months, but IOS 9 feels brilliant. No Safari crashes so far, and its snappyness has been taken up or notch, everything feels fast and fluent on my dated Ipad 4. Looks like this could be the long awaited Snow Leopard release.
Well done Apple, credit where credit is due.
Score: 8 Votes (Like | Disagree)
TMRJIJ Avatar
80 months ago
iPhone 4S: battery sucks big time (6% lost in almost 5 minutes) and performance without Low power mode enabled is awful!
Why Apple engineers don't design software on less capable devices first and move on from there?
It's the first day and it's indexing. You can complain about it tomorrow but right now we hold your review with a grain of salt.
Score: 8 Votes (Like | Disagree)
cariacou Avatar
80 months ago
so much effort required from so many developers (Apple, 3rd party) so that Apple can save $5/device by not moving to 64GB base...
Score: 7 Votes (Like | Disagree)

Related Stories

studio buds family

Beats Studio Buds Debuting Today With Active Noise Cancellation, Stemless Design, and More for $150

Monday June 14, 2021 8:00 am PDT by
We've seen a lot of teasers about the Beats Studio Buds over the past month since they first showed up in Apple's beta software updates, and today they're finally official. The Beats Studio Buds are available to order today in red, white, and black ahead of a June 24 ship date, and they're priced at $149.99. The Studio Buds are the first Beats-branded earbuds to truly compete with AirPods...
YouTube Picture in Picture Feature

YouTube Premium Subscribers Can Now Use iOS Picture-in-Picture: Here's How

Wednesday August 25, 2021 3:55 am PDT by
Google has rolled out picture-in-picture support as an "experimental" feature for YouTube premium subscribers, allowing them to watch video in a small window when the app is closed. If you're a premium YouTube subscriber looking to try out picture-in-picture, follow these steps: Launch a web browser and sign into your YouTube account at YouTube.com. Navigate to www.youtube.com/new. Scroll...
gradiente iphone white

Brazilian Electronics Company Revives Long-Running iPhone Trademark Dispute

Tuesday May 19, 2020 1:06 pm PDT by
Apple has been involved in a long-running iPhone trademark dispute in Brazil, which was revived today by IGB Electronica, a Brazilian consumer electronics company that originally registered the "iPhone" name in 2000. IGB Electronica fought a multi-year battle with Apple in an attempt to get exclusive rights to the "iPhone" trademark, but ultimately lost, and now the case has been brought to...
youtube apple tv

YouTube Discontinuing 3rd-Generation Apple TV App, AirPlay Still Available

Wednesday February 3, 2021 3:09 pm PST by
YouTube is planning to stop supporting its YouTube app on the third-generation Apple TV models, where YouTube has long been available as a channel option. A 9to5Mac reader received a message about the upcoming app discontinuation, which is set to take place in March.Starting early March, the YouTube app will no longer be available on Apple TV (3rd generation). You can still watch YouTube on...
ryanscoolios13thumbnail

Apple Releases iOS 13.1.3 With Bug Fixes for Phone, Mail, Health, and More

Tuesday October 15, 2019 10:09 am PDT by
Apple today released iOS 13.1.3 and iPadOS 13.1.3, minor updates to the iOS 13.1.2 software that was released two weeks ago. This is the fourth update to the iOS 13 operating system that came out in September. The iOS and iPadOS 13.1.3 updates are available on all eligible devices over-the-air in the Settings app. To access the updates, go to Settings > General > Software Update....
bluetti eb70 main

MacRumors Giveaway: Win a Bluetti EB70 Portable Power Station and 200W Solar Panel

Friday September 3, 2021 11:13 am PDT by
For this week's giveaway, we've teamed up with MAXOAK to offer MacRumors readers a chance to win a Bluetti portable power station and an accompanying solar panel. Bluetti makes a range of portable power station options that are useful for camping, emergencies, power outages, off-grid living, and similar situations. The Bluetti EB70 is a solid middle of the road option that offers 716Wh and...
M1X MBP Feature

Leaker: Upcoming MacBook Pro to See Price Hike Over Current Model, Equal Performance Across 14 and 16-Inch Sizes

Tuesday August 24, 2021 5:28 am PDT by
The upcoming 14-inch MacBook Pro is set to be more expensive than the current 13-inch MacBook Pro and both the 14 and 16-inch models will offer the same performance, according to the leaker known as "Dylandkt." The leaker shared the information on Twitter, explaining that both of the upcoming MacBook Pro models, expected to come in 14 and 16-inch sizes, will feature the same performance due...
iphone 13 teal with text

Apple Expecting iPhone and iPad Supply Constraints in September Quarter

Tuesday July 27, 2021 2:34 pm PDT by
During today's earnings call covering the third fiscal quarter of 2021 (second calendar quarter), Apple CFO Luca Maesteri said that Apple is expecting supply constraints to affect the iPhone and the iPad in the coming quarter. "The supply constraints that we've seen in the June quarter will be higher in the September quarter," said Maestri. The constraints will impact iPhone and iPad sales...
os x mountain lion macs 16x9 2

Apple Makes OS X Lion and Mountain Lion Free to Download

Wednesday June 30, 2021 12:19 pm PDT by
Apple recently dropped the $19.99 fee for OS X Lion and Mountain Lion, making the older Mac updates free to download, reports Macworld. Apple has kept OS X 10.7 Lion and OS X 10.8 Mountain Lion available for customers who have machines limited to the older software, but until recently, Apple was charging $19.99 to get download codes for the updates. As of last week, these updates no...
maxresdefault

Craig Federighi and Greg Joswiak Discuss iPadOS 15, macOS Monterey, Privacy, Shortcuts on Mac, and More

Saturday June 12, 2021 6:12 am PDT by
As is tradition, Apple executives Craig Federighi and Greg Joswiak joined Daring Fireball's John Gruber in an episode of The Talk Show to discuss several announcements that Apple made over this weeks WWDC, including iPadOS 15, macOS Monterey, and a large focus around privacy. Federighi kicks off the conversation discussing the common architecture, now thanks to Apple silicon, across all of...