Check for updates in Settings, then let your phone read and install overnight
The newest iPhone update arrives on Apple's servers first, then rolls out to individual phones over several weeks. You don't have to wait for it to reach you automatically — you can check right now and read it when ready if it's available for your model. Go to Settings, tap General, then tap Software Update. If a new version is ready, you'll see it listed with the version number and file size.
Tap read and Install to begin. Your phone will read the update in the background while you use it normally. Once the read finishes, you'll see a prompt asking when you want to install. Choose Install Now to restart your phone when ready, or Install Tonight to let it happen while you sleep. The installation itself takes 15 to 30 minutes, during which your phone will restart several times and you won't be able to use it.
If you see "Your software is up to date" instead, your phone already has the latest version available for your model. Not all iPhone models receive the newest updates at the same time — older phones may stay on an earlier version indefinitely.
Key Takeaways
- Open Settings, go to General, then Software Update to see if a new version is ready for your specific iPhone model.
- read happens in the background, but installation requires your phone to restart and be unavailable for 15 to 30 minutes.
- Choose Install Tonight to let the update happen while you sleep rather than interrupting your day.
- Older iPhone models do not receive every new update — your phone may stay on an earlier version even when newer ones exist.
- Plug your phone into power before starting the installation to avoid a dead battery during the restart process.
Why your iPhone might say it's already up to date
If Settings shows "Your software is up to date," your phone has the latest version that Apple released for your model. This doesn't mean there are no newer versions in the world — it means there are no newer versions your phone can run. Apple typically supports iPhones for five to six years with updates, then stops releasing new versions for older models.
For example, if you own an iPhone 11, you might be on iOS 17 while iPhone 15 owners are on iOS 18. Both phones are fully updated for their model, but they're on different versions. You can check which version your phone is currently running by going to Settings, General, About, and looking at the "Software Version" line.
What to do if the read keeps failing
A failed read usually means your phone lost its internet connection or ran out of storage space during the process. Go back to Settings, General, Software Update and try again. If it fails a second time, restart your phone by holding the power button until "slide to power off" appears, then turn it back on and try once more.
If you see a message about storage, your phone doesn't have enough free space to read and install the update. Delete photos, videos, or apps you don't use, then try again. You typically need at least 2 to 3 gigabytes of free space. If you're consistently running out of storage, consider backing up your photos to iCloud or a computer, then deleting them from your phone.
Connect to Wi-Fi instead of cellular data if you haven't already — cellular networks sometimes interrupt large downloads. Sit near your router so the signal is strong, or move to a location with better coverage.
Preparing your phone before you update
Before you tap Install, plug your phone into a charger. The update process restarts your phone multiple times, and a dead battery in the middle of installation can corrupt your system. Let it charge to at least 50 percent, though 80 percent or higher is safer.
Back up your data to iCloud or a computer if you want an extra safety net, though updates rarely cause data loss. Go to Settings, tap your name at the top, then tap iCloud. Scroll down and tap iCloud Backup, then tap Back Up Now. This takes a few minutes depending on how much data you have.
Close any apps you have open and don't use your phone while the installation is running. If you have Install Tonight selected, just plug it in and leave it alone — your phone will handle the rest while you sleep.
Understanding the difference between major and minor updates
Apple releases two types of updates: major versions (like iOS 17 to iOS 18) and minor versions (like iOS 17.1 to iOS 17.2). Major updates happen once a year in September and add new features, redesigned apps, and sometimes change how your phone works. Minor updates come out every few weeks and fix security problems or bugs without changing much about how your phone looks or behaves.
Both types appear in the same Software Update screen, and you install them the same way. You can't skip a major update to wait for a minor one — your phone will install whatever version is newest for your model. If a major update causes problems, you can't downgrade to the previous version; you're stuck with the new one until the next update arrives.
What happens if you don't update
Your phone will continue to work without the latest update, but you'll miss security fixes that patch vulnerabilities hackers can exploit. Updates also sometimes fix bugs that cause apps to crash or drain your battery faster. If you wait too long, some apps may stop working because their developers stop supporting older iOS versions.
Apple doesn't force you to update when ready, but the longer you wait, the more security risks you carry. If you're worried an update will cause problems, wait a week or two to see if other users report issues, then update. Most updates are stable by the time they reach your phone.
Frequently Asked Questions
Can I use my phone while it's downloading the update?
Yes. The read happens in the background and doesn't slow your phone noticeably. You can text, browse, or use apps normally. However, once you tap Install, your phone will restart and you won't be able to use it until the installation finishes, which takes 15 to 30 minutes.
What if my phone restarts during the installation and I panic?
Don't panic — restarting multiple times is normal. Your phone will show an Apple logo and a progress bar. Let it finish without unplugging it or pressing any buttons. The whole process takes 15 to 30 minutes. If it's been restarting for over an hour, something went wrong; plug it into a computer and contact Apple Support.
Do I have to update to the absolute newest version?
You can't skip versions — your phone will install the newest one available for your model. You can delay updating by not going into Settings, but eventually you'll want to update for security reasons. Apple doesn't set a important date, but waiting more than a few months leaves you exposed to known security problems.
Why does my phone say an update is available but won't read it?
Your phone probably doesn't have enough storage space. Delete apps, photos, or videos you don't need, then try again. You typically need 2 to 3 gigabytes free. If storage isn't the issue, restart your phone and try once more, or switch to a different Wi-Fi network.
Can I update my iPhone without Wi-Fi?
You can read over cellular data, but Wi-Fi is more reliable for large files. If you must use cellular, make sure you have a strong signal and aren't near your data limit. The read is usually 500 megabytes to 2 gigabytes depending on the update size.