Did this change? wp-content/plugins/woocommerce/templates/checkout/thankyou.php

To track whole order, use the following code. Edit file wp-content/plugins/woocommerce/templates/checkout/thankyou.php and place the code below line:
<?php do_action( ‘woocommerce_thankyou’, $order->id ); ?>

Has the file name changed?

http://wordpress.org/plugins/woocommerce/