The following changes can be enabled/disabled using the "March 2013 Breaking Changes" migration until March 6th when they will go into effect permanently for everyone.
It will no longer be possible to access the [message], [thread], or [mailbox_folder] FQL tables without a user session.
We will no longer show apps under
/me/accounts/ in the Graph API or in the [
page_admin] FQL table. You can access the list of apps a user is a developer on by hitting
/me/applications/developer/ or using the [
app_role] FQL table.
We will no longer return a redirect to the Graph API docs when hitting the URL
http(s)://graph.facebook.com with no path.