Consider ARI "replaced" status in expiration-mailer

[aarongable]

@Osiris

I do see a new draft (4) has been published recently at draft-ietf-acme-ari-04 - Automated Certificate Management Environment (ACME) Renewal Information (ARI) Extension, so maybe it has already been addressed?

Draft -04 has only minor updates (such as improving the list of current implementations, adding acknowledgements, and a couple other rephrasings) over draft-03; none of the protocol itself has changed.

@Nummer378

Yes, there may be more or less rare edge cases where the "replaces" field isn't sufficient and there will be a certificate that is in fact replaced, but couldn't be marked as such. But where's the problem with that? In such a case, we might still have cases where the renewal mailer sends mails when it doesn't need to. But that's the status quo.

I concur with this statement. While I can certainly imagine a version of ARI that allows the "replaces" field to list as many certificates as one likes, it does not appear to be a common use-case, and it's not even clear what commands or configuration one would issue to a hypothetical client to get it to submit such a request.

@Nummer378

We certainly don't need to mail a user about a certificate that has been marked as replaced

We plan to do this. If you'd like to follow the progress, you can file a bug for this feature request and you'll be notified when we actually implement it.