Attach a function to Stripe webhook payload

The action hook um_stripe_webhook_payload_event_init is triggered every time the Stripe sends a request to your site and update any subscription data with a customer.

add_action( 'um_stripe_webhook_payload_event_init', 'um_09202023_stripe_webhook_payload_event_init', 10, 1 );
function um_09202023_stripe_webhook_payload_event_init( $event ){
   
   error_log( "Event ID: " . $event->id );

}

You can check the Stripe Webhook event types in this doc article.