Unpredictable Sandbox Environment for IAP Auto-renewable Subscriptions

https://denkeni.medium.com/unpredictable-sandbox-environment-for-iap-auto-renewable-subscriptions-44461d7b1378

Speaking @ iPlayground 2020, main slides here ;) some in Traditional Chinese https://speakerdeck.com/denkeni/iap-at-iplayground-2020

Transcript

1. © 2020 Denken All rights reserved. Redistribution or public display not permitted without written permission from Denken.
   https://denkeni.medium.com/unpredictable-sandbox-environment-for-iap-auto-renewable-subscriptions-44461d7b1378
   Unpredictable Sandbox
   Environment for IAP
   Auto-renewable Subscriptions
   Denken Chen, Confused iOS App Developer
   #WWDC20
   
   #WorldWideDevelopersConfused20
   

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2. Sandbox Tester
   
   Subscription Management
   
   Billing Retry Service
   
   App Store Server Notification
   

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3. Sandbox Tester
   

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4. Purchase
   
   develop on simulator
   Sandbox
   
   /verifyReceipt
   
   develop on device
   Production
   
   /verifyReceipt
   
   develop on device
   

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5. Sandbox Tester
   On iOS 14 simulator
   
   WWDC20 Introducing StoreKit Testing in Xcode
   No Account
   Purchase
   
   develop on simulator
   Sandbox
   
   /verifyReceipt
   
   develop on device
   Production
   
   /verifyReceipt
   
   develop on device
   

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6. Sandbox Tester
   Only on real iOS device
   
   Just use your Apple ID
   Single Account
   Purchase
   
   develop on simulator
   Sandbox
   
   /verifyReceipt
   
   develop on device
   Production
   
   /verifyReceipt
   
   develop on device
   

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7. Sandbox Tester
   Create more sandbox testers on App Store Connect
   
   Email address that has never been used as an Apple ID
   
   Apple officially recommends using subaddressing
   
   You may still get stuck for multiple unclear reasons
   Multiple Accounts: Creation
   

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8. Sandbox Tester
   iOS device — Settings — iTunes & App Store
   
   Log out current account
   
   DO NOT log in sandbox tester account here
   
   Purchase IAP with sandbox tester account
   Multiple Accounts: How to Use
   

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9. Sandbox Tester
   “Important: Don’t use your test user account to sign in to
   the production environment. If you do, the test user
   account becomes invalid and can no longer be used.” from
   In-App Purchase Programming Guide — Retrieving Product
   Information — Suggested Testing Steps
   Multiple Accounts: Warning
   

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10. Sandbox Tester
    Xcode 12
    App Review
    Purchase
    
    develop on simulator
    Sandbox
    
    /verifyReceipt
    
    develop on device
    Production
    
    /verifyReceipt
    
    develop on device
    Xcode
    
    TestFlight
    
    App Review App Store
    “Verify your receipt first with the production URL; proceed to verify with
    the sandbox URL if you receive a 21007 status code.”
    

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11. Subscription Management
    

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12. Subscription Management
    Xcode 12 →
    Subscription
    Options(?)
    Purchase
    
    develop on simulator
    Sandbox
    
    /verifyReceipt
    
    develop on device
    Production
    
    /verifyReceipt
    
    develop on device
    iOS 14 Settings →
    App Store →
    Sandbox Account
    iOS Settings or
    App Store →
    Profile →
    Subscriptions
    

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13. Subscription Management
    “Maximum” 5 automatic renewals*
    
    Usually starts with 5 renewals, and no renewal afterwards.
    
    How long the cooldown time is? Probably hours.
    Auto-renewable Subscriptions
    * WWDC 2018 Session 704 slides P.37
    

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14. Billing Retry Service
    

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15. Billing Retry Service
    Recovery Rate from 30.0% to 77.4%, just amazing(*)
    
    is_in_billing_retry_period randomly for true
    
    DID_FAIL_TO_RENEW and DID_RECOVER notification
    * WWDC 2019 Session 302 slides P.215
    

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16. App Store Server Notification
    

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17. App Store Server
    Your Server
    Status Polling
    App Store Notifications
    Server-to-Server Notifications
    
    Status Update Notifications
    NSNotificationCenter
    
    Apple Push Notification Service
    /verifyReceipt
    Receipt
    

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18. App Store Server Notification
    CANCEL
    Indicates that either Apple customer support canceled the subscription or
    the user upgraded their subscription. (*1)
    
    This event is not the same as when the user enters their iTunes account —
    Subscription section, and indicates that they choose not to allow an
    existing auto-renewing subscription to renew. (*2, and see
    DID_CHANGE_RENEWAL_STATUS)
    RTFM
    (*1) https://developer.apple.com/documentation/appstoreservernotifications/notification_type
    (*2) https://forums.developer.apple.com/thread/98894#thread-message-301062
    

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19. App Store Server Notification
    RTFM
    (*1) https://developer.apple.com/documentation/appstoreservernotifications/notification_type
    (*2) https://forums.developer.apple.com/thread/98894#thread-message-301062
    RENEWAL (it’s been renamed as DID_RECOVER)
    Indicates a successful automatic renewal of an expired subscription that
    failed to renew in the past. Check expires_date to determine the next
    renewal date and time. (*1, and see DID_RENEW)
    
    In general, iTunes will attempt to charge the user account a day before an
    auto-renewing subscription is scheduled to expire... in the few cases that
    iTunes is unable to renew the subscription (generally there was a
    connection problem with the credit card server)... technically considered
    “expired”. However, iTunes will still continue to attempt to renew the
    subscription. If iTunes is successful, then the “RENEWAL” event is sent. (*2)
    

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20. App Store Server Notification
    DID_CHANGE_RENEWAL_PREF
    Indicates that the customer made a change in their subscription plan that
    takes effect at the next renewal. (Downgrade)
    
    DID_CHANGE_RENEWAL_STATUS
    Indicates a change in the subscription renewal status. (Toggling auto-renew
    on/off.)
    
    INTERACTIVE_RENEWAL
    Indicates the customer renewed a subscription interactively, ... (Upgrade or
    renew)
    RTFM
    * https://developer.apple.com/documentation/appstoreservernotifications/notification_type
    * https://developer.apple.com/videos/play/wwdc2020/10661/?time=14m19s
    

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21. App Store Server Notification
    RTFM
    * https://developer.apple.com/wwdc20/10661?time=16m52s
    

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22. Summary
    Beware of sandbox tester creation
    
    Subscription Management is okay in 2020
    
    Billing Retry Service is okay in 2020
    
    App Store Server Notification — RTFM
    

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