Hello DeepuBC,
If you are having trouble updating your iPhone wirelessly, here are a few things you can try:
Resolve issues with an over-the-air iOS update - Apple Support
https://support.apple.com/en-us/HT201435
If you get a message that "an error occurred downloading iOS," try again later. If the issue persists, try updating your device in another network or use iTunes to update your device. Learn more about iOS updates.
If you're installing the update and the progress bar appears to move slowly, be patient. The time an update takes depends on the size of the update and the number of files on the device.
When you're updating over the air, keep your device connected to a power source so that it doesn't run out of power. If your device does run out of power, connect it to a power source and turn on the device to let the update or restore complete.
If the update never completes and the progress bar hasn't moved for an extended time, try restarting your device. If you still see the issue after you restart, see what to do if your device appears frozen or won't start.
Last Modified: Jun 5, 2015
Take care,