iAnyGo is a professional free iOS firmware download tool to help you get the latest iOS beta version in the first place and one click to update iOS version to the most recent one without any stuck issue you may encounter while updating via iTunes or OTA. Moreover, it also supports to downgrade your iOS version to a lower one without the help of iTunes whilst keep your data safe.
Download this software and install it on your computer. Then follow the guide below to upgrade or downgrade iPhone software without using iTunes.
Run iAnyGo on your computer after installation. Then you'll see two options: "One-click to upgrade iOS" and "One-click to downgrade iOS".
Then this software will list your iPhone info as well as the available firmware packages. You can choose an suitable one and click "Download" to save it on your computer.
When the firmware package id downloaded successfully, you can simply click "Upgrade Now" or "Downgrade Now" to start upgrading or downgrading iPhone software.