Works great!

Even though the plugin hasn’t been updated for a while, it still works great on the newest Woocommerce version (tested in 4.5.2).

A small hack. I prefer to set the default order status for duplicated orders to ‘pending’. That’s easy to achieve by changing 1 line of code in class-clone-order.php
$order->update_status(‘on-hold’);
to
$order->update_status(‘pending’);