If you own the epic photography centric Nokia Lumia 1020, the latest Lumia Cyan Update is rolling out now which brings it up to speed with the latest Windows Phone 8.1 operating system. The updates should be pushing to your device via OTA (Over the Air) and if you haven’t got it yet, you can check under Settings > Phone update.
Looking at the roll out speed, it shouldn’t take too long for the rest (Lumia 520, Lumia 525, Lumia 620, Lumia 720, Lumia 820 & Lumia 920) to receive the update. Before the Lumia 1020, the Cyan Update has been rolled out to the Lumia 1520, Lumia 1320, Lumia 925 and Lumia 625.
Thanks @raytmc for the tip!