What will happen with my subscriptions when the product goes out of stock?

The auto-charging subscriptions will be renewed even if the product is out of stock. However, when you will open such order in your Shopify Admin -> Orders, you will see a notice that the products in this order are out of stock.
The recurring invoice subscriptions won't be able to get renewed if you have the app set up to use the newest product prices in recurring orders. However, if you set the app to always bypass inventory or if you set the app to keep prices from the initial order, yet the price of the products in the subscription differs from the actual product price, then the app will create the draft order with a custom line item, which means that these items will bypass your inventory and your customers will be able to complete the order.

We recommend that you regularly check the inventory forecast so you will know how many of specific items you need if all subscriptions get renewed successfully in the next week or month. You can see the inventory forecast in Seal Subscriptions app dashboard.