title: woocommerce_order_status_changed hook: getting old and new status?
body: <p>How can I get the old status and new status of an order using the WooCommerce hook: <code>woocommerce_order_status_changed</code>?</p>
  
  <p>This is my code, but only the <code>$order_id</code> is filled.. </p>
  
  <pre><code>add_action('woocommerce_order_status_changed','woo_order_status_change_custom');
  function woo_order_status_change_custom($order_id,$old_status,$new_status) {
  //order ID is filled
  //old_status and new_status never
  //tested by logging the parameters
  }
  </code></pre>
  
  <p>Now I can easily get the new status using this code:</p>
  
  <pre><code> $order = new WC_Order( $order_id );
  $orderstatus = $order-&gt;status;
  </code></pre>
  
  <p>But how can I get the previous order status, since <code>$old_status</code> is empty?</p>