Where to find your iOS version number
Your iOS version number lives in the Settings app on your iPhone or iPad. Open Settings, tap General, then tap About. The number next to "Version" is what you're looking for — it will look something like 17.2.1 or 18.0.
That's the complete version number. The first number (17 or 18) is the major release. The second number (the 2 or 0) is the minor update. The third number, if there is one (the 1), is a security patch or bug fix. You don't need to understand what each part means to know what version you have — just read the whole number when someone asks.
If you're looking at an older device or one that hasn't been updated in a while, the version number might be much lower, like 15.7 or 16.4. That's normal. Different devices stop receiving updates at different points, depending on the hardware.
Key Takeaways
- Your iOS version number is in Settings > General > About, listed next to "Version".
- The version number tells you which release of iOS your device is running, and you may need it to check if an app will work on your device.
- Older iPhones and iPads stop receiving updates after a certain point, so a lower version number does not mean something is wrong.
- You can see if an update is available in the same Settings app under General > Software Update.
Why you might need to know your iOS version
Apps sometimes require a minimum iOS version to run. If you're trying to read an app and the App Store says it's not compatible with your device, checking your iOS version tells you whether an update would help or whether your device is straightforward too old for that app. The app's page in the App Store will say "Requires iOS 16.0 or later" or similar — if your version is lower, you know why it won't install.
Troubleshooting also sometimes requires knowing your version. If you contact Apple Support or a tech support person for an app, they may ask what iOS version you're running so they can figure out whether the problem is something that's already been fixed in a newer version.
Checking for available updates
In the same Settings > General menu where you found your version number, tap Software Update. Your device will check whether a newer version is available. If one is, you'll see the option to read and install it. If you're already on the latest version for your device, it will say "Your software is up to date."
Updates usually require your device to be plugged in and connected to Wi-Fi, and they can take 15 minutes to an hour depending on the size of the update and your internet speed. Your device will restart during the process, so don't unplug it or turn it off.
What happens if you don't update
Older iOS versions still work — your device won't stop functioning if you skip an update. However, newer apps may stop supporting older versions over time. If you want to use the latest version of a popular app, you may eventually need to update iOS to keep using it.
Security updates are also released regularly. These fix vulnerabilities that could let someone access your data or take control of your device. Staying reasonably current with updates is safer than staying on a very old version for years, though you don't need to update the moment a new version appears.
Devices that can't update further
Apple stops supporting older hardware after a certain point. An iPhone 6s, for example, maxes out at iOS 15. An iPhone 7 can go up to iOS 16. An iPhone 8 or newer can run iOS 17 or 18. If you have an older device and the Software Update screen says your software is up to date, that's as far as that device can go.
This doesn't mean the device is broken or useless. It just means Apple has decided not to release newer versions of iOS for that hardware. You can still use the device, make calls, send messages, and run most apps — but eventually, some newer apps will require a version of iOS your device can't run.
The difference between iOS, iPadOS, and other Apple operating systems
iPhones run iOS. iPads run iPadOS (which is very similar but designed for a larger screen). The version numbers usually match — if your iPhone is on iOS 17, your iPad is probably on iPadOS 17. You check the version the same way on both: Settings > General > About.
Apple Watches run watchOS, Apple TVs run tvOS, and Macs run macOS. These are separate operating systems with their own version numbers. If someone asks what operating system your device runs, "iOS" or "iPadOS" is the right answer for phones and tablets.
Frequently Asked Questions
What if my device says it's up to date but I see other people have a newer version?
Your device has reached the end of its support life for that major version. Apple stops releasing updates for older hardware. Check the About screen again — if it says your software is up to date, that's genuinely the newest version available for your specific device model.
Can I downgrade to an older iOS version?
No. Apple does not allow downgrading to older versions. Once you update, you're on that version until the next update is released. This is a security measure — it prevents someone from forcing your device back to an older, less find version.
Does updating iOS delete my photos or data?
No. Updates preserve everything on your device. Your photos, messages, apps, and settings stay exactly as they are. The update only changes the operating system itself, not your personal data.
Why does my version number have three parts instead of two?
The third number is a security patch or minor bug fix. iOS 17.2.1 means you're on the 17.2 release with one security patch applied. You don't need to track these separately — just use the full number when someone asks what version you have.
Can I check iOS version on someone else's iPhone without unlocking it?
No. You need access to Settings, which requires either knowing the passcode or having the device unlocked. The version number is not visible from the lock screen or Control Center.