Flash Carbon AOSP for Samsung Galaxy S4 i9505 Android 4.3 JB

Carbon custom ROM has been released with its latest build based on Android 4.3 Jelly Bean. The custom firmware combines the features from CyanogenMod 10.2 and Android 4.3 Jelly Bean AOSP. Follow this tutorial to flash Carbon AOSP Android 4.3 custom firmware on your Samsung Galaxy S4!
Note: this guide is only written for the international variant of Samsung Galaxy S4 model number I9505. Kindly do not try it on other variants/devices.

Prerequisites to update Carbon AOSP for Samsung Galaxy S4 i9505 LTE:

Download and install USB drivers for Samsung Galaxy S4 on your computer.
Enable USB debugging mode from developer menu on your SGS4.
Your smartphone should be unlocked and rooted.
You should have a custom recovery tool like TWRP or CWM installed on your Galaxy S4 LTE.
Backup any important data before going forward.
Make sure that your device carries more than 70% of charge.

How to flash Carbon AOSP for Samsung Galaxy S4 I9505 LTE Android 4.3:

Required files: download the latest build of Carbon AOSP custom ROM based on Android 4.3 JB from this link and not extract the content.

Connect your International Samsung Galaxy S4 with PC using a USB cable and copy the custom ROM and GApps files on the phone’s memory card.
Disconnect your Galaxy S4 LTE from computer when the copy is done and switch it off.
Reboot in recovery mode and perform Nandroid backup of your current OS of SGS4: Backup and Restore > Backup.
Data wiping tasks: select wipe data / factory reset, wipe cache partition, and lastly wipe dalvik cache.
Return to main recovery menu and select Install zip from sdcard followed by choose zip from sdcard. Locate the downloaded Carbon AOSP custom firmware file for your smartphone and confirm installation.
Once the custom ROM is successfully installed on your Samsung Galaxy S4, repeat the above step but select GApps file instead.
When done, reboot your smartphone into the newly installed firmware.

Ta da! You have successfully managed to update your Samsung Galaxy S4 LTE with Carbon AOSP custom ROM based on Android 4.3 JB.