For more information about our enterprise plan, which includes unlimited referred revenue, and fully custom features & integrations, contact us.
Referred Revenue: When a Friend uses the discount code they received to place an order, the total order value counts as referred revenue.
If you hit a limit for your plan, the app will send you an email prompting you to upgrade - the app doesn't automatically upgrade you. You are also free to downgrade your plan at any time by going to Settings > Manage Subscription within the app. Shopify will pro-rate / credit you so you only pay the higher rate for the number of days you were on the higher plan.