When adding a custom field to a product
- The field is not added to existing plan products.
When adding a custom field to a plan
- The custom field becomes available for existing subscriptions of that plan
- But the default value will not be populated on existing subscriptions, but will be populated in completely new ones created after the plan's defaults were added or changed.
When adding a custom field to a plan product
- The custom field becomes available to existing instances of that plan product in subscription products
- The default value will not be populated on existing subscription products