For those who have upgraded their devices to iOS 7 but are looking to downgrade back to iOS 6.1.3 on their iPhone 4S, iPod touch 5, iPhone 4 or iOS 6.1.4 on their iPhone 5, here’s a step-by-step tutorial on how to do so (via RedmondPie). Like always, remember to back up your data using iTunes before starting the process.
Now connect your device to the computer using the USB cable and launch iTunes.
On the screen where you have “Check for Update” and “Restore” options, click on “Restore” while holding down the option key on a Mac or shift key on Windows.
Now browse and select the download iOS 6.1.3 / 6.1.4 .IPSW file and click OK.
Once the restore process is finished, you’ll have iOS 6.1.3 / 6.1.4 running on your device.
That’s it, enjoy!