How to update Galaxy S4 SGH-I337 to Android 4.3

Update Galaxy S4  to  Android 4.3 JB Custom ROM :-

The CyanogenMod unofficial custom firmware based on Android 4.3 Jelly Bean . This unofficial firmware is an early build of final CM10.2 firmware. This tutorial will guide you in the process of flashing the unofficial CyanogenMod 10.2 nightly build based on Android 4.3 Jelly Bean for Samsung Galaxy S4 SGH-I337  LTE.

How to update Galaxy S4 SGH-I337  to Android 4.3 CM10.2 custom firmware:

Required files: download the CM 10.2 unofficial custom firmware zip for SGS3 i9305 from here and save it on your computer. Do not extract the contents.

• Connect Samsung Galaxy S4 SGH-I337 to your computer using a USB cable and copy the zip file to your phone’s SD card.
• Disconnect the USB cord and power off your Galaxy S3 I9305 LTE.
• Boot it into recovery mode and perform a Nandroid backup of your current OS; important step to revert back to current state. Go to Backup > backup and restore on ClockworkMod.
• Wipe data operation: from CWM recovery menu, select wipe data / factory reset and confirm the process. You can skip this step if you are already on a CM 10.1 ROM.
• From recovery menu, select install zip from sdcard followed by choose zip from sdcard. Locate the CM 10.2 Android 4.3 Nightly firmware zip and confirm the flashing process.
• When done, follow the above step for GApps package installation.
• Return back to main recovery menu and reboot your S4 SGH-I337 into the new ROM. First boot takes a good 5 minutes so kindly be patient.