Can I ask for more context?
OP's application doesn't use SDK but instead works at a lower level. This new update broke his application and he is making the argument that it was a directed update. They specifically removed a part of their code that allowed for this functionality.
Edit: looks like it's limited to 5 Mbps at 720p. http://www.anandtech.com/show/7186/google-chromecast-review-...
Casting a tab is like using logmein to watch a movie on another computer. Casting either the RAW or the local file directly is like playing something off a NAS
If anyone knows how to get around this, please reply to this with the solution. Googling for anything Chromecast related gets mostly pop-tech articles.