Hi Alex,
I know that there are ways to fix this, I've done some of the work on previous releases.
Here are the errors I get in the validation tool. Could you please recommend of ways to fix this (beside changing the DOCTYPE as it cause more errors...):
element X undefined
Line 1185, column 205: element "fb:like-box" undefined
Line 1905, column 207: element "fb:recommendations-bar" undefined
Line 150, column 10: there is no attribute "property"
Line 328, column 12: there is no attribute "background"
Line 888, column 16: there is no attribute "data-mce-bogus"
Line 1185, column 41: there is no attribute "show_faces"
Line 1185, column 55: there is no attribute "header"
and so on
thanks