Billing Grace Period is Apple’s new feature. With Billing Grace Period turned on, Apple tries to charge subscriber within 16 days maximum. Developer must grant premium access to subscriber during this time. Once subscriber enters grace period, his subscription goes to Grace state, and Apphud SDK
isActive() method still returns
true. With Billing Grace Period turned off, subscription goes to Expired state and
isActive() method returns
false. However, Apple still attempts to recover subscription within up to 60 days but less aggressively. In both cases when subscription is reactivated, it will change to Regular state. You can manage Billing Grace Period feature in your app’s “Features” tab in App Store Connect.