From the Bluetooth SIG:
Building on 20 years of innovation, LE Audio will not only enhance the performance of Bluetooth audio, but will bring all its benefits to people with hearing loss and introduce Audio Sharing, an innovative new use case with the potential to once again change the way we connect with each other and experience the world around us.
As the names suggest, Classic Audio operates on the Bluetooth Classic radio while LE Audio operates on the Bluetooth Low Energy radio. LE Audio will not only support development of the same audio products and use cases as Classic Audio, it will introduce exciting new features that promise to improve their performance as well as enable the creation of new products and use cases.
LE Audio will include a new high-quality, low-power audio codec, the Low Complexity Communications Codec (LC3). Providing high quality even at low data rates, LC3 will bring tremendous flexibility to developers, allowing them to make better design tradeoffs between key product attributes such as audio quality and power consumption.
Apparently, listening tests have shown that LC3 will provide improvements in audio quality over the SBC codec included with Classic Audio, even at a 50% lower bit rate. So there will be lower power drain per hour of listening, yet with an overall audio quality rise.
In addition, LE Audio is 'Multi-Stream', enabling the transmission of multiple, independent, synchronized audio streams between an audio source device, such as a smartphone, and one or more audio sink devices.
You can read more on the full LE Audio page.
Bluetooth continues to evolve and improve. I find myself listening wirelessly about 95% of the time now, whereas I was 95% wired just a couple of years ago. Interesting!