This plugin will add additional meta data information about your WooCommerce subscription.  The API data will add the following information to the  WooCommerce Order endpoints:

• subscription_id – The ID of the subscription.
• no_of_orders – The total number of orders from a subscription.

This plugin was developed to help companies identify how many orders are within a subscription so they may apply filtering on their end (such as shipping on every other order).

Sources:

• Subscription Order & Cart Function Reference – WooCommerce Docs
• Get the Subscription id from the Order ID – Stack Overflow

Credits to:

• Codup.io
• Duane Leem