There's a new software update rolling out to the Shield Android TV today. Shield upgrade 3.3 brings several improvements to pass-through audio in apps, and also adds an updated version of the Vulkan graphics API. This update is still based on Marshmallow, though.
Here's the full changelog.
- DTS:X Audio: Experience immersive, lifelike audio with DTS:X pass-through in Plex, Kodi v17, and MX Player
- Adds Dolby Atmos audio pass-through support in Plex
- Delivers the latest monthly Android security updates
- Adds support for Vulkan 220.127.116.11 Conformance Test Suite
If you're using any of the above apps (especially Plex) with audio pass-through, it might sound nicer after the update. The Vulkan update is just improving on what was already deployed. If there were bugs in Vulkan games before, you might see fewer of them now. The update is supposed to be available today, but I'm not seeing it yet on my device.