Flash Player Public Beta
The goal of this public beta is to help us make sure that existing content continues to work as expected, and that the player is 100% backwards compatible. The goal is not to test new features.
Note that the beta is intended for developers and content creators, and not for end users (that is why the page is not linked from the download page).
So, install the new player, check your content, and if you find any problems, make sure that you let us know by logging a bug.
You can install the beta from here.
You can report issues with the new player here.