nocache_headers()

function nocache_headers() {
	$headers = wp_get_nocache_headers();

	unset( $headers['Last-Modified'] );

	// In PHP 5.3+, make sure we are not sending a Last-Modified header.
	if ( function_exists( 'header_remove' ) ) {
		@header_remove( 'Last-Modified' );
	} else {
		// In PHP 5.2, send an empty Last-Modified header, but only as a
		// last resort to override a header already sent. #WP23021
		foreach ( headers_list() as $header ) {
			if ( 0 === stripos( $header, 'Last-Modified' ) ) {
				$headers['Last-Modified'] = '';
				break;
			}
		}
	}

	foreach ( $headers as $name => $field_value )
		@header("{$name}: {$field_value}");
}