In addition to the updated guide, the DRM standard has gotten even better with the addition of xHE-AAC compatibility from Fraunhofer. E(x)tended HE-AAC "improves significantly the audio quality of music and speech particularly at very low bit rates of 8 kbit/s and more, and is compatible with HE-AAC streams." Don't just take their word for it, listen to the audio on this short slide presentation.
From what I hear, this is an amazing improvement and may help robustness through stations being able to reduce audio data payload. I'd love to see someone do a side-by-side comparison with AAC+ at similar bitrates. The 12k example would appear to rival what we now hear via AAC+ at about 20k!
