Churn Rate is the number of subscription cancellations.
Keep in mind the difference between churned subscription and Auto Renew Off (cancelled subscription) event. Auto Renew Off is sent as soon as a user opts-out from prolonging the subscription (a user still can use the app's paid features until the end of a paid period), while Subscription Cancelled is sent at the end of the current billing period.
Subscription Churn is always followed by a Cancelled Subscription.
Apple/Google will let you know about Churn Rates via server2server notifications. Handle, store and process them to build custom views with Grace Period's analytics.
There're 3 reasons for subscription cancellations:
Most users cancel a subscription with a Voluntarily Cancelled reason.
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