Apple has released the fourth developer beta version of iOS 13 and iPadOS 13 (likely alongside new seeds of watchOS 6, tvOS 13) today. Apple’s new software version won’t be complete until the fall, however, so testers should still expect performance and stability issues when running the iOS 13 beta on primary devices.
So, let's take a look at how to install iOS 13 beta 4 on 3uTools.
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 13.0beta4. 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 Beta 4 after reboot.