July 2013 Breaking Changes
I've received several warnings from facebook recently. The warnings say something like:
Your app, [App Name] has not enabled the migration for the July 2013 Breaking Changes.
[App Name], is currently using the following deprecated features:
Social Plugins (Like Button, Like Box) without absolute URL's in their `href` parameter.
Like buttons and other social plugins produced by Drupal for Facebook already use absolute hrefs. I have yet to find a single social plugin using a relative href in any of the apps which facebook is warning me about.
So, I'm pretty confident that facebook's warning system, while trying to help, is flat out broken and causing developers to worry about nothing.
That said, if you've installed Drupal for Facebook and have manually set up a block or content with a social plugin tag in it, you should double-check that all your hrefs are absolute and not relative.
Also, if anyone can find an actual example of a relative href being rendered by Drupal for Facebook, please let me know. As far as I know this has not been a problem and no updates to your Drupal system are necessary.