Apple has released iOS 13.1.3 for the iPhone and iPadOS 13.1.3 for the iPad. The company has been working to fix bugs and improve performance of iOS 13 over the past month, and this is the fifth iOS 13 update that the company has released since iOS 13’s launch on September 19th.
Step 1 Connect your iDevice to PC with an original USB cable and launch 3uTools.
Step 2 Go to Flash & JB → Easy Flash, select firmware iOS 13.1.3. If you want to update with data, please check the box "Retain User's Data". There will be a pop reminder after you click "Flash", please read it with caution.
You are recommended to back up your iDevice regularly in case of data loss.
Step 3 Keep the stabilization of network and USB connection while flashing, wait patiently for around 5 to 10 minutes. Your iDevice will be updated to iOS 13.1.3 after reboot.