Apple today released 2009 Aluminum Keyboard Firmware Update 1.0, addressing battery life issues with Apple's recently-redesigned wireless keyboard when used with other Bluetooth devices.
This firmware update improves battery performance of the 2009 Aluminum Apple Wireless Keyboard when used in combination with other Bluetooth devices (example. Magic Mouse, Bluetooth headsets).
The update appears to address severe battery life issues blamed on Apple's multi-touch Magic Mouse when paired with a computer at the same time as the keyboard. Apple released a similar update for its older wireless keyboard last month.