updated 02:42 pm EDT, Mon September 24, 2012
Audio output now supports AirPlay-ready speakers
(Updated with details of the security measures included with the firmware) Apple has released a major firmware update for second- and third-generation Apple TVs. The v5.1 upgrade implements several new features, most notably the ability to save several iTunes accounts on the same unit and switch between them. App icons can now be reordered by holding down the select button, and new advanced network options can be set via configuration profiles. People with AirPlay-compatible speakers, AirPort Express routers, and/or other Apple TVs can use AirPlay to stream audio to them.
The firmware also allows viewing shared iCloud Photo Streams, and improves subtitle support, for instance enabling SDH for the deaf. New screensaver types include Cascade, Shrinking Tiles, and Sliding Panels.
Apple TV owners can download v5.1 through the General section under Settings.