Since switching to V060 feed I've notice a few subscriptions with expired CCards have past due amounts. This isn't reflected in the XML feed well or I'm missing something (always possible).
When a sub tries to renew with expired CC, I get no renewal transaction, I do get a message in the subscription feed about the CC failing.
So in my rails system, I expire the digital subscription a couple days after it doesn't renew. So there are never any past due amounts in our case.
But it seems like foxycart is expecting the subscriptions to continue for a while. Is this a setting in the admin panel? What's the grace period?