The first patch Tuesday of 2013 brings a raft of updates for Windows RT including a firmware update for the Surface. The firmware update has improved audio playback when in standby which hopefully is a fix for the strange audio distortion with audio nonfictions when the device is in standby. It also includes additional capabilities for low battery states.
As well as the Firmware update there are updates for Office 2013 RT, security updates for RT and Flash Player is updated. You can find the updates in PC Settings/Windows Update.