There are so many new features in iOS 12, such as Screen Time, Group FaceTime and more. But if you can't update to iPhone to iSO 12, What should you do? This article list some reasons why you can't update iPhone to iOS 12.
1. iPhone Storage is not enough
The iPhone's remaining storage is not enough to download and install the iOS update package, which usually becomes the main reason why it cannot be updated to the new iOS 12.
Go to iPhone Settings -> General -> iPhone Storage, to view and check which apps takes up your iPhone space.
2. iPhone Device Compatibility issue
The new iOS12 version requires iPhone5S and above to update. If you are using iPhone 4S or earlier, the iPhone cannot be updated to iOS 12 because the device is not compatible with the software.
Upgrade your iPhone to iPhone 5s and later, then install the new iOS 12 version.
3. Check the network connection
Make sure your connect has connected with wifi, and open a website on safari to check if the connection is normal. If the website can't open, you can reconnect with wifi.
Launch Settings from your iPhone Home screen. Tap WLAN. Tap the WLAN Off/On switch.
Or you can consider to reboot the modern-router.
Switch off the modem-router and also unplug their power cables. Wait for 30 seconds and turn on.
4. The current iOS version is beta
If you are using the beta iOS version, you can update to new iOS 12 directly on iPhone.
Back up your iPhone before doing everything.
Remove iOS beta Software profile.
Go to Settings -> General ->Profiles -> iOS Beta Software Profile -> Remove Profile.
Then restart your iPhone, and put the iPhone into the Recovery Mode(press and hold the Sleep/Wake and Home buttons at the same time, keep holding until you see the iTunes logo )
Connect the iPhone with iTunes, and open iTunes, then iTunes will pop-up the window about "There is a problem with the iPhone that requires it to be updated or restored."
Click the Update button, your iPhone will update to iOS 12 official version after the process has completed.