PHP Version 5.0.1 ignores charactar encoding header

I use this: header("Content-Type: text/html; charset=utf-8") to allow a
server to detect charactar encoding.

When I validate the html of webpages on PHP Version 4.3.4, charactar
encoding is detected with no problem.

When I validate same page served on PHP Version 5.0.1, I am told that
the charactar encoding could not be detected. Is there some change in
PHP Version 5.0.1 I should know about ?


red