With the release of Graph API
v2.3, the Like Box plugin is deprecated. Please use the new Page Plugin instead. The Page Plugin allows you to embed a simple feed of content from a Page into your websites.
If you did not manually upgrade to the Page Plugin, your Like Box plugin implementation will automatically fall back to the Page Plugin.
The Like Box is a special version of the Like Button designed only for Facebook Pages. It allows admins to promote their Pages and embed a simple feed of content from a Page into other sites.