Inside iOS 9: Under-the-Hood Improvements for Battery Life, Security, and More

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.

Related Forum: iOS 9

Popular Stories

iphone se 4 modified flag edges

iPhone SE 4 With Face ID Said to Be Priced Below $500

Monday May 20, 2024 3:43 am PDT by
Apple is targeting a sub-$500 starting price for its upcoming fourth-generation iPhone SE model despite a raft of rumored upgrades coming to the more affordable device. According to leaker Revegnus on X, the U.S. launch price of the fourth-generation iPhone SE will either remain at the same $429 starting price as the current model, or will see an increase of around 10%. Either way, Apple's...
iOS 17

Apple Releases iOS 17.5.1 With Fix for Reappearing Photos Bug

Monday May 20, 2024 10:11 am PDT by
Apple today released iOS 17.5.1 and iPadOS 17.5.1, minor updates to the iOS 17 and iPadOS 17 operating system updates that came out last September. The 17.5.1 updates come a week after the launch of iOS 17.5 and iPadOS 17.5. iOS 17.5.1 and iPadOS 17.5.1 can be downloaded on eligible iPhones and iPads over-the-air by going to Settings > General > Software Update. According to Apple's...
iPhone 16 Camera Lozenge 2 Perspective

iPhone 16 Lineup Rumored to Come in These Two New Colors

Sunday May 19, 2024 11:08 am PDT by
Apple analyst Ming-Chi Kuo today outlined his expectations for the iPhone 16 lineup's color options, revealing that two new colors should replace two of the existing shades. Kuo outlined his expectations in a post on X (formerly Twitter) earlier today. He believes that the iPhone 16 Pro and iPhone 16 Pro Max will be available in black, white or silver, gray or "Natural Titanium," and rose....
microsoft surface pro qualcomm

Microsoft Says New Surface Pro is Faster Than 15" M3 MacBook Air

Monday May 20, 2024 3:19 pm PDT by
Microsoft is going all in on AI, today introducing a series of Copilot+ PCs that have AI-focused hardware. The new Surface Pro is one of the first Copilot+ PCs, equipped with Qualcomm's Arm-based Snapdragon X Elite processor. Microsoft is already pitting the Surface Pro against Apple's M3 MacBook Air, and in marketing materials, claims that the Surface Pro has superior processing power and...
iOS 17

iOS 17.5 Bug May Also Resurface Deleted Photos on Wiped, Sold Devices [Updated]

Friday May 17, 2024 12:24 pm PDT by
A bug in iOS 17.5 is apparently causing photos that have been deleted to reappear, and the issue seems to impact even iPhones and iPads that have been erased and sold off to other people. A Reddit user wiped an iPad following Apple's guidelines in September of 2023 before selling it off to a friend. That friend updated the iPad to iPadOS 17.5 this week, and began seeing the Reddit user's old ...
iphone se 4 modified flag edges

When to Expect the Next iPhone SE to Launch

Friday May 17, 2024 2:03 pm PDT by
It has been over two years since Apple released the third-generation iPhone SE, and rumors continue to surface about a new model. The latest word comes from The Information, which today reported that Apple plans to release a new iPhone SE with a design similar to the standard iPhone 14 in the spring of 2025. If this rumor is accurate, the iPhone SE would finally gain Face ID and a notch...

Top Rated Comments

Parasprite Avatar
113 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
113 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
113 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
113 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
113 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
113 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)