I think this concerns a lot of us who are using the youtube API.
I submitted my old player with an upgrade to V3 instead of removing it so my buyers will not be empty handed.
Next week I will update my WP version.
I think Envato should make an announcement about this
Here the message from youtube
In March 2014, we announced that the v2 API would be retired on April 20, 2015, and would be shut down soon thereafter. To help you with your migration, we published the migration guide in September. Now, we'd like to provide you with more details on the v2 retirement timeline.
As of April 20, 2015, v2 API endpoints will be shut off with the following exception: We will keep the v2 versions of the comments, captions, and flagging features accessible for a grace period past the shutdown date. These features are still listed as “To be supported” in the migration guide. The grace period is designed to give you time to implement the new v3 versions of these features as they become available. In addition, the v2 API endpoint for uploading videos will also remain open during this time.
Please migrate your app to the YouTube Data API v3 at your earliest convenience to avoid any outage.
For more information please visit: YouTube Data API v2 Turndown FAQ.