Latest version breaks HTML5

Yes Html5 validation check is showing this as error from some time for contact form 7 plugin. To resolve this issue you can just add: html_name=”any-name-for-form” in your form shortcode.
For example: [contact-form-7 id=”894″ title=”Footer custom quote” html_name=”custom-quote-form” html_id=”contact-form-894″ ]

This will assign name and id to your form and the error will be resolved.Let me know if this resolves your problem.

Thanks.