My question is much like the OP's which was not really answered. There is an option to have an email sent when a product/subscription is purchased. What we would like to know is if an option could be added to also email that same list, or a separate list of emails upon a subscription getting expired. This is what is missing.
However the hacky work around is to use a custom php action and have php sendmail to a defined list. This is what we decided to do. An example for the need was so our Membership Services Department staff and director would be alerted when a member allowed is membership subscription to expire. Some things are still not handled automatically with access etc. (since we have some other systems beyond IPB). The challenge was knowing when one of many members expired so our staff could make the necessary manual changes.