Auto-renewable in-app subscriptions do renew automatically, you don’t need to do anything for that. You just need to check if a subscriber has an active subscription when using your app. You can also activate the grace period in App Store Connect for your subscription, so your users will have access for additional 16 days if Apple could not renew the subscription. You can read more here https://developer.apple.com/documentation/storekit/in-app_purchase/subscriptions_and_offers/reducing_involuntary_subscriber_churn
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