The official Android 4.4.2 AUCUCMLG KitKat is expected to be launched OTA soon for the AT&T Samsung Galaxy Note 3 devices. However, it would be released in phases and might take a good few weeks. You can also choose to install leaked AUCUCMLG Android 4.4.2 on Galaxy Note 3 AT&T variant N900A.

Enjoy the KitKat experience before even official release!

Pre-reqs to install leaked AUCUCMLG Android 4.4.2 on Galaxy Note 3:

• Create a backup of all important data in your Galaxy device.
• Download and install USB drivers for Samsung Galaxy Note 3 in your computer.
• Enable USB debugging option by pressing Menu > Settings > Applications. Navigate and tap on Developer Options to ensure that USB Debugging is enabled.
• Ensure that your AT&T Samsung Galaxy Note 3 carries more than 80% of charge. 

How to install Leaked AUCUCMLG Android 4.4.2 on Galaxy Note 3:

Files required: download the leaked AUCUCMLG Android 4.4.2 firmware from this link. Also download the Odin3 v3.09 for installation from here. Unzip leaked firmware file inside the extracted Odin folder.

• Install Odin on your PC and launch it.
• Switch your Samsung Galaxy Note 3 off and boot it in Download mode: press and hold Volume Down and Home buttons together. When connected successfully, you will get a message in Odin saying Added!!. (In case you don’t get it, try another USB port. If that doesn't help either, then re-install USB drivers).
• Open PA on Odin; from the new window, locate the leaked Android 4.4.2 file and hit the Start button to initiate the update process.
• When update installation is successfully completed, on Odin ID:COM will turn green and Odin will show you a PASS message.
• AT&T Samsung Galaxy Note 3 will then restart and you can then disconnect your device from computer.

Happy KitKating!