Nokia released an update for AT&T's Nokia Lumia 1520 phablet. This brings the device's software to version 1028.3534.1347.2001, although an US owner reported the version as 1028.3562.1407.1001. The update seems to only contain general performance and usability improvements. However, users claim that the phablet runs smoother, and hope that the update solves the strange occurrence of random reboots in the evening hours.
The update should be available over the air, so check the Settings-> Phone Update option if you haven't been prompted yet.