how to downgrade from 13.4 to 13.3.1
Hi, how do I downgrade? I have the signed file from apple for 13.3.1 I am using windows and Jaws for windows help is greatly appreciated.
Plug in your phone to your computer, and start up iTunes. In the summary section, which should be the one that appears by default when you open your phone in iTunes, find the check for updates button. Hold down shift and press space to click on it. This should give you a dialog to select an IPSW file, and after that you just let iTunes perform the downgrade.
You can also hold down shift and press space on the restore button instead. This will reinstall the older iOS while also wiping your data, starting the phone out fresh. If you have a backup stored in iCloud or a local backup that was made before you upgraded, this is also a good and theoretically safer option, but iOS won't restore a backup made on a newer version onto an older one which is why I'd suggest you do it via the update button instead.
Edit: For anyone looking on how to do this on a Mac, the procedure is exactly the same, except you do it from the Finder instead of iTunes if you're running Catalina.