I've implemented PayPal gateway in my application, and I'm looking for a way to send a notification to my customer when an upcoming renewal is coming.
Unfortunately in the documentation I didn't find a depth explaination about INVOICING.INVOICE.SCHEDULED but I'm guessing should be the same as invoice.upcoming of Stripe which is triggered when a recurring payment is going to be renewed.
My question is: INVOICING.INVOICE.SCHEDULED is sended by PayPal automatically when a recurring payment is going to be renewed?
Invoicing and Subscriptions are two separate PayPal products. I would not expect an Invoicing webhook in relation to a Subscription recurring payment.
The subscription webhooks are listed here: https://developer.paypal.com/docs/integration/direct/webhooks/event-names/#subscriptions
If you are looking for one that happens "in advance" of a scheduled payment, I am not aware of one.