If there is one Lumia 1520 that is the king of all 1520s it is an unlocked 1520.3 variant, which for those in the US comes with LTE support for AT&T and T-Mobile, in addition to 32 GB of internal memory and Qi wireless charging. Yes, it has everything.
Quite a few members in our forums are confirming the update is live, starting at 1 PM ET time today. In order to see the update though, you do need to downgrade your phone first to 8.0 and then take the proceeding updates to the 8.1 and Lumia Cyan. The process itself is relatively simple, but it can be time consuming to restore your backup if you have a lot information.
Regardless, the choice is yours. Head into our discussion forum to talk to others about the OS update and who have the Lumia 1520.3.
Thanks to mattdistro and others for the tips!