I am curious what sort of testing strategy was being employed? Stripe offers pretty good testing / staging environment which is intended to be used for testing.

I am curious what sort of testing strategy was being employed? Stripe offers pretty good testing / staging environment which is intended to be used for testing. Surely, one would assume renewals / auto renewal functionality should be exercised _before_ code was pushed to prod. Maybe Stripe's staging environment is too much of an overkill. A integration test covering the 'renew_early_protected' method would have flagged this issue as well. Spinning up a Mongo instance and executing queries and asserting their correctness is imperative as I am too paranoid to trust dependency upgrades to maintain strict compatibility. OP, its great that you apologize to your users but your write up does not capture any actions that you would take to avoid recurrence of these issues in the future.