Google has opened up a beta for the Google Cast Receiver app, allowing developers to ensure their apps will always work when a new version is getting pushed. Sure, we aren’t developers, but we still want the latest builds out there, so anyone can join if you’re interested and own the required hardware.
If you download and want to ensure you’re on the beta, look for version 1.26.93139, that’s the current beta build. With it, you can test anything you want, but again, it’s mostly for developers.
If you do intend on downloading and then run into issues, feel free to shoot feedback over to firstname.lastname@example.org. I’m sure the good folks at Google would love to hear about any issues you encounter.
Have at it.