Possible bug in HTML Tidy

After adding iframes to a couple of my XHTML documents yesterday, running Tidy  on them results in

     Warning: Element <iframe> not supported in XHTML 1.0 Strict.

The XHTML references and other documentation I've checked don't seem to agree with this: E.g., according to http://www.w3.org/TR/xhtml1/ iframe's name attribute has been deprecated - which indicates <iframe> itself has not.
In case it matters: I'm runningTidy for Windows released on 1st February 2003.

Yours,

Marit Skrede