Does Schema.org markup require a HTML 5 doctype?

[cmaddison]

I would like to implement Schema/microdata on a clients website, but the site is currently XHTML. Is html5 required for the micro data tags to be recognised? Will it work if I implement micro data on my XHTML site? Thanks for any advice you can offer.

[EGOL]

Does Schema.org markup require a HTML 5 doctype?

No.

These are signals/data for search engines, not coding that will be rendered by browsers.