Samsung has started rolling out a new Android 4.4.2 KitKat update with firmware build number M919UVUFNB4 for the T-Mobile version of Galaxy S4 (SGH-M919).
Samsung Galaxy S4 (T-Mobile) SGH-M919 users who have already updated  their devices with Android 4.4.2 KitKat, may root their devices using  the tutorial below.
This tutorial uses CF-Auto-Root file released by Senior Recognized XDA-Developers, Chainfire. Head over to the CF-Auto-Root main thread to learn more about the root method.
Disclaimer: Rooting  voids the warranty of your device. We and the  developer of this  rooting procedures shall not be held responsible if  any undesirable  outcomes may happen to your device. use of this root  guide is solely at  your own risk!
Pre-requisites
1. Install USB Drivers for Samsung Galaxy S4 on the computer.
2. Enable USB Debugging Mode on the phone by navigating to Settings >> Developer Options.
3. Make a backup of all your important data before following the guide.
4. Ensure the battery of the phone is charged more than 80 percent.
5.  The CF-Auto-Root file works only on the T-Mobile version of Galaxy S4   (SGH-M919). Applying this to any incorrect variant might brick the   device. Verify the model number of the Galaxy S4 by navigating to  Settings >> About Phone.
Files Required
1. CF-Auto-Root (Mirror Link) (CF-Auto-Root-jfltetmo-jfltetmo-sghm919.zip)
2. Odin 3.09
Steps to Root Galaxy S4 (T-Mobile) SGH-M919 Running on Android 4.4.2 KitKat Firmware
Step 1: Extract the CF-Auto-Root and Odin 3.09 files using WinRAR/7-Zip/WinZip or any other extracting tool.
Step 2: Switch off the Galaxy S4. Then boot into Download Mode by pressing and holding Volume Down, Home and Power buttons together until a construction Android robot icon with a warning triangle appears on screen. Now press the Volume Up button to enter Download Mode.
Step 3: Launch Odin on the computer as an Administrator.
Step 4: Connect the Galaxy S4 to the computer using USB cable  while it is in the Download Mode. Wait until Odin  detects the device.  When the device is connected successfully, the ID:  COM box will turn to  light blue with the COM port number.  Additionally, the successful  connected will be indicated by a message  saying Added.
Step 5: In Odin, click the AP button and select the CF-Auto-Root-jfltetmo-jfltetmo-sghm919.tar.md5 file.
Step 6: Make sure that the Re-Partition checkbox is NOT selected in Odin.
Step 7: Double-check and click Start button in Odin. The installation process will now begin.
Step 8: Once the installation process completes, your phone will restart and soon you will see a PASS message with green background in the left-most box at the very top of  the Odin. You can now unplug the USB cable to disconnect it from the  computer.
Samsung Galaxy S4 (T-Mobile) SGH-M919 running on Android 4.4.2  KitKat is  now rooted successfully. Open the app drawer of the phone  and check for  an app called SuperSU. Verify the root status of the  device by  downloading Root Checker app from Google Play Store.
Note: Many Samsung devices store a flash counter that keeps track of how many times you have flashed custom firmwares to your device. Triangle Away can be used to reset the flash counter to zero.
How to Fix "Unfortunately, SuperSU has stopped"?
Step 1: Download and install the latest APK of SuperSU on your device.
Step 2: Open SuperSU app (update the binary if prompted) and allow it to disable KNOX.
Step 3: Reboot your device.



