How to Stop Already Started iOS Update
iOS devices are one of the most used gadgets across the globe and reasonably so. One key reason for iOS products popularity can be its security and regular updates. Installing iOS updates can be done effortlessly, but at times you wish to stop the update mid-way. The device may not seem to allow the users to do so, but it is possible. We are providing various methods to stop the downloading process of your iOS update mid-way.
Stopping iOS Updates While Downloading 
First of all, turn on the Airplane mode on your device. To do so, follow these points:
  1. Go to the Control Center.
  2. Then, tap the Airplane option to switch it ON. It will automatically turn your internet connection to OFF.
  3. In case the downloading process in process, then go to the Settings and then hit the General tab there. It will be located on your iOS device.
  4. After that, wait a bit for the storage section to appear on your screen.
  5. Now, scroll down the page and look for the running update option that you wish to stop.
  6. Hit the option “Delete Update.”
  7. Now, you will see that your selected iOS update stops successfully.
Note: The canceled update might trigger sometime in the future. If you wish to prevent the particular update that you don’t wish to get updated automatically for any reason, you can turn the feature to OFF; otherwise, it may update automatically anytime.
You can also check if the canceled update can trigger in the future or not. To do so, follow these easy to use steps:
  1. First of all, navigate to the Settings application.
  2. Then, hit the “Software Update” segment there.
  3. After that, check the update option on whether the canceled update can be activated or not. If you turned your apps settings to ON for automatically update option, then it might update when it gets connected to the internet network (Wi-Fi or cellular).
While Preparing to stop Ongoing iOS Update, follow these instructions:
  • Do not try to cancel the update during Installation. It might harm your device and may corrupt your applications.
  • Do not turn off your iOS device during Installation. 
  • Do not try to make any other changes if your device iOS is under Installation.
  • There is no way to stop a downloaded installation process. You may only stop the process during downloading by abiding above mentioned steps.
If you try to stop the installation process, it may cause data loss or leave your device useless. In this case, you might be required to perform a full system reset, factory reset or sometimes needs DFU to restore to access all the previous applications and features.
Note: In case, you use to install iOS updates via iTunes, then you will be required to turn off the iTunes downloading feature on your iOS device.
Daniel Ryan is a self-professed security expert; she has been making the people aware of the security threats. Her passion is to write about Cyber security, cryptography, malware, social engineering, internet, utility software and new media. She writes for Microsoft products at office.com/setup.

 Source : http://officecom-setup-go.uk.com/how-to-stop-already-started-ios-update/