I'm getting a host of errors and warnings using W3C HTML5 validation with version 2.4.6:
Attribute xmlns:fb not allowed here.
xmlns:fb="http://ogp.me/ns/fb#" prefix="og: http://ogp.me/ns#">
Element g:plusone not allowed as child of element div in this context. (Suppressing further errors from this subtree.)
Are there any plans to make the plugin HTML5 compatible?