What the latest iOS update does to your iPhone
Apple releases a major iOS update once a year, usually in September, and smaller updates throughout the year to patch security holes and fix bugs. The latest version number appears in Settings > General > About, and you can see what changed by going to Settings > General > Software Update and tapping the release notes before you install it.
Each update includes three types of changes: security patches that close vulnerabilities hackers exploit, performance improvements that make your phone faster or use less battery, and new features Apple wants you to use. Security patches are the reason to update quickly. New features are optional — you can ignore them. Performance changes happen whether you want them or not.
You cannot choose to install only the security patches and skip the new features. iOS updates are all-or-nothing. If you want the security fix, you get the whole package, including any new settings you have to learn or features you did not ask for.
Key Takeaways
- iOS updates include security patches, performance changes, and new features bundled together — you cannot install one without the others.
- Security patches close vulnerabilities that hackers actively exploit, so delaying an update leaves your phone at risk for weeks or months.
- You can see what changed before you update by opening Settings > General > Software Update and reading the release notes.
- New features can usually be ignored or turned off in Settings, but performance and security changes explore to everyone.
- Older iPhones sometimes slow down after updates because Apple prioritizes security over speed on devices running older hardware.
Why security patches matter more than new features
When Apple discovers a vulnerability — a way hackers can break into your phone, steal your photos, or intercept your messages — they patch it in an update and announce it publicly. The moment they announce it, hackers know what the vulnerability is and start targeting phones that have not updated yet. The longer you wait, the more time you give them to attack.
A security patch might fix something you never see. You will not get a notification saying "we closed a hole that let hackers read your email." You just get safer. Delaying an update by a few weeks is the difference between being protected and being exposed to a known attack.
This is why security experts recommend updating within a few days of release, not waiting weeks. If your phone is too old to receive the latest update, that is a sign the hardware is reaching the end of its useful life — not because it is broken, but because it cannot be protected anymore.
Performance changes and why your phone might feel slower
Sometimes an iOS update makes your iPhone noticeably slower, especially if your phone is three or more years old. This usually happens because Apple added security protections that require more processing power, or because the new version of iOS is larger and takes up more storage space on a phone that was already full.
Apple does not intentionally slow down old phones to force you to buy new ones, despite what many people believe. What actually happens is that security improvements and new features are written for the newest hardware first, and then adapted to work on older devices. On older hardware, that adaptation sometimes means slower performance.
If your phone feels slower after an update, you can try clearing storage space (delete old photos, videos, or apps you do not use), restarting your phone, or turning off background app refresh for apps you do not need running constantly. These steps sometimes restore speed, but they do not always work — sometimes the update straightforward requires more power than your phone has.
New features you can turn off or ignore
Each iOS update includes new features Apple wants you to notice: new emoji, changes to the lock screen, new privacy settings, or new apps. You do not have to use any of them. Most new features can be turned off in Settings, and the ones that cannot be turned off can straightforward be ignored.
If a new feature is on by default and you do not want it, search for its name in Settings and toggle it off. For example, if a new lock screen feature is enabled and you prefer the old look, you can usually disable it. If you cannot find a toggle, the feature is probably just a visual change that does not affect how your phone works.
The exception is features related to security or privacy — Apple sometimes turns these on by default because they protect you, not because they are convenient. If you see a new privacy setting enabled, read what it does before you turn it off. You might want to keep it.
How to check what changed before you update
Before you install an update, you can read what Apple changed. Open Settings, tap General, then tap Software Update. If an update is available, you will see a button that says "Release Notes" or similar. Tap it to see what changed.
The release notes tell you which security vulnerabilities were patched, which bugs were fixed, and which new features were added. They are usually written in technical language, but you can scan for words like "security," "vulnerability," or "fix" to understand what matters.
If the release notes mention a security patch for something you use — like Mail, Messages, or Safari — that is a reason to update soon. If the notes only mention new emoji or minor visual changes, the update is less urgent, but you should still install it within a week or two.
When to update and when to wait
Install security updates within a few days of release if possible. If your phone is working well and you have time, do it the day the update comes out. If you are in the middle of something important, waiting a few days is acceptable, but do not wait weeks.
The best time to update is when you have a few minutes and your phone is plugged in. Updates can take 15 to 30 minutes, and if your battery dies during the process, your phone might not work until you plug it back in and try again. Plug in your phone, open Settings > General > Software Update, and tap Install Now.
If you see a message saying your phone is too old to receive the update, that means Apple has stopped supporting that model. You can keep using the phone, but it will not receive new security patches. At that point, you should plan to replace it within the next few months, because unpatched phones become increasingly vulnerable to attacks.
What happens if you never update
If you ignore updates for months, your phone becomes a target. Hackers know which vulnerabilities exist in older versions of iOS, and they can exploit them to steal your data, install malware, or lock you out of your own phone. The longer you go without updating, the more vulnerabilities pile up.
You might not notice anything wrong at first. Your phone will work normally. But in the background, someone could be reading your messages, accessing your photos, or using your phone to send spam. By the time you realize something is wrong, the damage is already done.
If you have not updated in more than a few months, update today. If you have not updated in more than a year, back up your phone first (go to Settings > [Your Name] > iCloud > iCloud Backup and tap Back Up Now), then update. A very old phone sometimes needs a backup before a major update, just in case something goes wrong.
Frequently Asked Questions
Will the new iOS update delete my photos or data?
No. iOS updates do not delete your data. They only change how your phone works. Your photos, messages, contacts, and apps stay exactly where they are. If you are worried, you can back up your phone before updating by going to Settings > [Your Name] > iCloud > iCloud Backup and tapping Back Up Now.
Can I go back to the old version of iOS if I do not like the new one?
No. Apple does not let you downgrade to an older version of iOS once you update. If you update and then change your mind, you are stuck with the new version. This is why reading the release notes before you update is important — you cannot undo it.
Why does my iPhone say it needs to update every time I restart it?
This usually means the update was downloaded but not installed. Go to Settings > General > Software Update and tap Install Now. Make sure your phone is plugged in and you have at least 30 minutes. If it keeps asking after you install, restart your phone and try again.
Is it safe to update over WiFi or should I use cellular data?
WiFi is better because updates are large and can use a lot of data. If you have unlimited cellular data, either works, but WiFi is faster and more reliable. Make sure you stay connected to the same network the whole time — if you leave the WiFi range, the update might fail and you will have to start over.
What if my phone runs out of storage space during the update?
The update will fail and your phone will ask you to try again. Delete some apps, photos, or videos to free up space, then go back to Settings > General > Software Update and tap Install Now. You need at least a few gigabytes free for the update to work.