to the device's web interface (typically 192.168.1.20 ). Navigate to the System tab.
Yes, but only via TFTP or the Web UI (if downgrade is allowed). Some later 1.2.x and 1.3.x versions prevent downgrading to very old builds for security reasons. Upgrade Firmware Version 1.255 Ubnt -FREE- Download
If an update is available, a "Click to Update" or "Upgrade" link will appear next to the device. to the device's web interface (typically 192