The latest iOS update brings security patches, performance changes, and new features to your iPhone
Apple releases iOS updates several times a year. The most recent updates focus on closing security gaps, speeding up your phone, and adding features that change how you use everyday apps. Some updates are small and quick to install; others add visible changes to how your home screen looks or how you control your phone.
The specific changes depend on which version you're running and which version you're updating to. If you're on an older iPhone, some new features won't appear on your device even after you update — Apple sometimes limits new capabilities to newer hardware. Before you update, it helps to know what will actually change on your phone and whether the update will slow it down or speed it up.
Key Takeaways
- iOS updates arrive as automatic notifications on your phone, but you control when they install — don't feel pressured to update when ready on day one.
- Security patches in iOS updates close holes that hackers use, so delaying updates for weeks or months leaves your phone vulnerable to known attacks.
- New features often work only on iPhone 14 and newer, or iPhone 15 and newer, so check Apple's official specs before expecting a feature to appear on your device.
- Older iPhones sometimes run slower after a major iOS update, but smaller security updates usually don't affect speed noticeably.
- You can see exactly what changed by going to Settings > General > About and looking at the version number, then checking Apple's official release notes online.
Security patches are the main reason to update
Every iOS update includes fixes for security problems that Apple's engineers or outside researchers found. These fixes close doors that hackers use to steal passwords, access your photos, or take control of your phone without your permission. The longer you wait to install an update, the longer your phone stays vulnerable to attacks that use these known holes.
Apple publishes a security document for each update that lists which problems were fixed. You won't see the technical details — Apple doesn't explain exactly how the holes worked, because that would help hackers target older phones. But the document does say whether the fixes address problems that hackers were already using in real attacks, which tells you how urgent the update is.
If you see a notification that says "Important Security Update" or "Critical Security Update," that's Apple's way of saying hackers are already exploiting the hole. In that case, update within a few days. If the notification just says "iOS Update Available," you have more flexibility, but waiting longer than two weeks is risky.
New features often depend on your iPhone model
When Apple announces a new iOS version, the marketing materials show features that sound exciting. But many of those features only work on the newest iPhones. A feature that requires an A17 Pro chip, for example, won't appear on an iPhone 13, even after you update to the latest iOS.
Before you update, you can check Apple's official tech specs page for the iOS version to see which iPhones support which features. Search "iOS [version number] tech specs" and look for a table that lists features and the iPhone models that support them. If your phone isn't listed next to a feature, you won't see it after you update.
This doesn't mean the update is useless for older phones. You still get security patches and usually some smaller improvements. But if you're hoping for a specific new feature, confirm your phone is compatible before you update.
Performance changes vary by iPhone age and storage space
Major iOS updates — the kind that jump from iOS 17 to iOS 18 — sometimes make older iPhones run noticeably slower. This happens because new features require more processing power, and older chips have to work harder to keep up. If your iPhone is four years old or older, expect a small slowdown after a major update.
Smaller updates — the kind that go from iOS 18.1 to iOS 18.2 — usually don't affect speed. These are mostly security patches and bug fixes that don't add heavy new features.
Your phone's available storage also matters. If you have less than 5 gigabytes of free space, iOS updates can run slowly or fail partway through. Before you update, check Settings > General > iPhone Storage and delete apps or photos you don't need until you have at least 5 gigabytes free.
How to check what changed in your current iOS version
Your phone already tells you what version of iOS it's running. Go to Settings, tap General, then tap About. You'll see a line that says "Software Version" with a number like "17.4.1" or "18.0.2." Write down that number.
Then open a web browser and search "iOS [your version number] release notes." Apple's official page will list every change, security fix, and bug fix in that version. The security fixes are usually listed first, followed by new features, followed by problems that were fixed.
If you want to know what's coming in the next update before you install it, you can search the same way for the next version number. This lets you decide whether the new features matter to you or whether you want to wait a few days for any early problems to be reported.
When to update when ready versus when you can wait
Update when ready if Apple's notification says "Critical Security Update" or if you see news reports about a security hole that affects iPhones. These situations mean hackers are already using the hole, and waiting puts your data at risk.
Update within a week if it's a regular security update with no "critical" label. These fix real problems, but they're not being actively exploited yet.
You can wait a few days or even a week if it's a minor update that mainly adds new features. This gives time for early adopters to find bugs that Apple didn't catch. If a serious problem appears, Apple releases another update quickly.
Don't wait longer than two weeks for any update. Even non-critical security fixes eventually become targets for hackers once they've been public for a while.
What happens if you don't update
Your phone will keep working. Apps will continue to open, calls will come through, and you can use your phone normally. But each month that passes, more hackers learn about the security holes in your iOS version, and the risk of attack grows.
Eventually — usually after several months — Apple stops signing older iOS versions. This means you can't install them on a new phone, and if you restore your phone from a backup, you'll be forced to update to a newer version. At that point, you lose the choice of when to update.
Some apps may also stop working if you stay on an old iOS version for too long. Developers eventually require a minimum iOS version for their apps, and if you don't update, you'll get an error when you try to open them.
Frequently Asked Questions
Will the update delete my photos or messages?
No. iOS updates preserve everything on your phone — your photos, messages, contacts, and app data all stay exactly as they are. The update only changes the operating system itself, not your personal information. Make sure you have enough free storage space before you update, but you don't need to back anything up first.
Can I turn off automatic updates so I can choose when to update?
Yes. Go to Settings > General > Software Update > Automatic Updates and turn off "Install iOS Updates." Your phone will still notify you when updates are available, but it won't install them without your permission. You can then tap "Install Now" whenever you're ready.
What if my phone is too old to get the latest iOS?
Apple stops supporting iPhones after about six years. If your phone is older than that, it won't receive new iOS versions, even if you want to update. You'll stay on whatever iOS version your phone shipped with or the last version Apple released for it. You can still use your phone, but security patches will eventually stop coming.
Does updating to the latest iOS make my phone faster?
Sometimes. Minor updates often include performance improvements that make your phone slightly faster. Major updates can slow down older iPhones because they add features that require more processing power. If your iPhone is three years old or newer, a major update usually won't noticeably slow it down.
Can I go back to an older iOS version if I don't like the new one?
Not easily. Apple stops signing older iOS versions after a few weeks, which means you can't install them anymore. If you update and then change your mind, you're stuck with the new version. This is why it's worth waiting a few days after a major update to see if other users report serious problems.