[Q] Problem update unlocked AT&T note 4 topic

Hi,
I've just got an AT&T note 4 and it is sim - unlocked already, but i can not got the OTA update from the server, every time i clicked on the update it is always the latest but i know AT&T rolled out an update in December for Note 4, and i am still stucking in the factory build number. Can anyone help me :(