I installed the latest version of reCAPTCHA and everything works fine. However the comment page is no longer xhtml 1.0 strict compliant. Even after I checked the "make it compliant" checkbox in the wordpress setting.
Here's an example:
The validation error says:
there is no attribute "aria-required".
…size="22" tabindex="1" aria-required='true' /
What is aria-required attribute for?