Normally, subscriptions may be canceled immediately, or they may be marked to be canceled at the end of the billing period.
If a subscription is past due, however, it may now only be canceled immediately.
When a subscription becomes past due, it is managed by the dunning rules configured for the site. We found a conflict between this process and canceling a subscription at the end of the billing period.
We previously removed the ability to mark a past due subscription to be canceled at the end of the billing period from the Admin UI, but it was still possible via the API.
As of June 28, 2016, if you attempt to update a past due subscription via the API and set the
cancel_at_end_of_period flag to
true, you will receive a 422 Unprocessable Entity error.