add_action('init', function() { $post = get_post(4501); if ($post) { $content = $post->post_content; $new_content = str_replace(array('<', '>', '&', '"'), array('<', '>', '&', '"'), $content); if ($content !== $new_content) { wp_update_post(array( 'ID' => 4501, 'post_content' => $new_content, )); } } });