Developers can test new versions of the Web Receiver SDK prior to release using the preview URL at
<script src="https://www.gstatic.com/cast/sdk/libs/caf_receiver/preview/cast_receiver_framework.js"></script>
When testing, make sure to test using a non-production version of your web receiver application.
Updates to the preview URL will be made prior to planned new releases of the Web Receiver SDK. Hotfix releases to address urgent issues will not be pushed for preview. The preview lead times for the production release may vary and can be affected by issues found during internal testing. The preview URL for an upcoming release is expected to be generally available at least one week prior to production release.
Developers are encouraged to subscribe to the cast-sdk-announcements@googlegroups.com Google Group to get the latest updates on the Cast SDK, including preview availability and release updates.
Bugs should be promptly reported through the Cast SDK Issue Tracker or with your Nest Technical Account Manager.