Apple releases major iOS updates once a year, usually in September
Apple announces a new major iOS version each year at its Worldwide Developers Conference in June, then releases it to the public in September or early October. The exact date shifts year to year — iOS 17 came out September 18, 2023, while iOS 16 arrived September 16, 2022. Apple does not announce the release date until a few weeks before it happens, so you cannot plan around a specific calendar day months in advance.
Between major releases, Apple sends out smaller updates roughly every two to four weeks. These are numbered like iOS 17.1, 17.2, or 17.1.1, and they fix security problems, patch bugs, and add minor features. You do not have to wait for September to get security fixes — they arrive throughout the year on whatever schedule Apple decides.
Your iPhone will notify you when an update is ready. You can check manually by going to Settings, then General, then Software Update. The update usually takes 15 to 30 minutes to read and install, and your phone will restart during the process.
Key Takeaways
- Major iOS updates arrive once yearly in September or October, with the exact date announced only weeks beforehand.
- Security and bug-fix updates come out every few weeks throughout the year, independent of the major release schedule.
- Your iPhone will prompt you to update, but you can also check manually in Settings > General > Software Update.
- Updates take 15 to 30 minutes and require your phone to restart, so plan for a time when you do not need it when ready.
- Delaying an update for a few days is safe, but security updates should not be postponed for weeks.
Why the release date is not set in stone
Apple ties the iOS release to the launch of new iPhone hardware, which also happens in September. The company wants both to arrive at the same time so new phones ship with the latest software. But if hardware production runs late or a critical bug is found in the final weeks, Apple will push the release back a few days or a week.
This unpredictability is why Apple does not publish a release calendar the way some software companies do. The company prefers to announce the date once it is certain, rather than promise a date and miss it. If you need to know when to expect the update, checking Apple's official newsroom or the Apple Support website in late August will give you the most reliable information.
The difference between major updates and security patches
A major update like iOS 17 or iOS 18 includes new features, redesigned apps, and changes to how your phone works. These arrive once a year and are large downloads — often 3 to 5 gigabytes. They can take longer to install and occasionally cause problems with older apps or settings, though this is rare.
Security updates and bug fixes are much smaller. They might be 50 to 500 megabytes and focus on closing vulnerabilities or fixing crashes. These come out whenever Apple discovers a problem that needs fixing, not on a set schedule. If a serious security hole is found, Apple may release an update within days. If the issues are minor, you might wait three or four weeks for the next batch.
Both types of updates appear in the same Settings menu, and your phone treats them the same way — it will remind you to install them. The difference matters mainly for planning: a major update is worth doing when you have time to spare, while a security update should not be delayed for weeks.
How to check what version you are running now
Open Settings, tap General, then tap About. The first item listed is "Software Version" — that number tells you which iOS you have. If it says 17.2.1, you are on iOS 17 with the 2.1 security update applied. If it says 18.0, you are on the latest major version with no additional patches yet.
You can also see the build number on this same screen, which is a longer code that Apple uses internally to track exactly which version you have. You do not need to memorize it, but it can be useful if you contact Apple Support about a problem.
What happens if you delay an update
Your iPhone will keep reminding you to update, usually with a notification badge on the Settings app. You can dismiss these reminders and keep using your phone normally. Delaying a major update by a few days or even a week is safe — the old version will continue to work.
Delaying a security update for weeks is riskier. If a vulnerability is discovered and Apple releases a patch, phones still running the old version become targets for hackers. Security updates are small and quick to install, so there is little reason to put them off. A good practice is to install security updates within a week or two of release, and major updates whenever you have time.
If you are concerned about a new major update causing problems with an app you rely on, you can wait a few days to see if other users report issues. But once a few days have passed without widespread complaints, the update is usually safe to install.
Automatic updates and scheduled installation
You can turn on automatic updates so your iPhone installs them without asking. Go to Settings, General, Software Update, then tap "Automatic Updates." You can choose to read updates automatically, install them automatically, or both. If you select automatic installation, your phone will install the update overnight when plugged in and connected to Wi-Fi.
This is convenient if you do not want to think about updates, but it means your phone might restart in the middle of the night or early morning. If that bothers you, you can turn on automatic downloads but keep manual installation — your phone will read the update in the background, then ask you when to install it.
Turning off automatic updates entirely means you will see notifications but have full control over when to install. This is useful if you want to wait a few days after release to make sure no problems emerge, or if you prefer to install updates at a specific time of day.
Preparing your phone before a major update
Before installing a major iOS update, back up your phone. You can back up to iCloud by going to Settings, [your name], iCloud, then iCloud Backup, and tapping "Back Up Now." You can also connect to a computer and back up through the Finder (on Mac) or iTunes (on Windows). A backup takes 10 to 30 minutes depending on how much data you have.
Make sure your phone has at least 50 percent battery before starting the update, or plug it in and leave it plugged in throughout. The update process can take 30 minutes to an hour, and if your battery dies partway through, you could have problems. Also connect to Wi-Fi — updates are large and using cellular data could be slow or count against your data limit.
You do not need to delete apps or clear space unless your phone is nearly full. iOS updates compress during installation, so they take up less space than the read size suggests. If you have less than 2 gigabytes free, you may need to delete some apps temporarily, but this is uncommon.
Frequently Asked Questions
Can I see what features are in a new iOS update before I install it?
Yes. Apple publishes a full list of new features and changes on its website and in the Release Notes section of the Software Update screen. You can read these before installing to see if the update includes anything that matters to you. Apple also posts videos and articles about major features on its newsroom.
What if an update breaks an app I use every day?
Contact the app developer through the App Store and let them know which app and which iOS version is causing the problem. Developers usually release updates to fix compatibility issues within days of a new iOS release. In the meantime, you can often work around the problem by force-closing the app and reopening it, or by restarting your phone.
Do I have to update my iPhone, or can I stay on an older iOS forever?
You can delay updates, but Apple stops supporting old versions after about two years. Once support ends, your phone stops receiving security patches, which means new vulnerabilities will not be fixed. For security reasons, staying on an old iOS for years is not recommended. Most people should update within a few months of a major release.
Will a new iOS update slow down my phone?
New iOS versions are usually optimized for the phones they run on, so they do not typically make your phone slower. Older phones may feel slightly slower with a major new version, but this is usually because the new version has more features running in the background. Restarting your phone after the update often helps performance return to normal.
How do I know if a security update is important?
Apple does not always announce which vulnerabilities a security update fixes, but you can check the Security Updates page on Apple's website to see details. If the update mentions a vulnerability that affects your device and could be exploited by hackers, it is important to install it soon. When in doubt, installing a security update within a week or two is the safe choice.