Connect your Apple to your PC and launch iTunes for Downgrade i OS 7 To i OS 6.1.3
Select your device from the pane on the left or click the ‘iPhone’ button on the top right.
On the main screen of iTunes, you should see two buttons; one says Check for Update and the other one says Restore iPhone. If you’re on Windows, hold down the left Shift key on your keyboard and click on Restore iPhone.
IPSW file Click then click on Restore.
iTunes will verify the IPSW firmware.Please Wait :) you are almost done.The restore process might take a while, so sit back, relax and wait for the restore process to complete. Once done, you will have 6.1.3/6.1.4 running on your device.
If you found error 3194,then how to fix it
go to Host file to your Pc, like this
If you’re on Windows, navigate to Windows > System32 > driver / etc.
Scroll all the way down and locate the line saying “188.8.131.52 gs.apple.com”. Simply put a # sign before this whole thread.
Copy the hosts file back to the etc folder.
Congratulation You are Done :)