My certbot configuration is setup to renew certificates well before expiration, which I believe is standard/recommended practice. Cert replacement does not revoke the older cert. Therefore, I get expiration alert(s) for cert(s) that have/has been replaced. I fully realize this is all working as designed.
I currently have four (4) certificates which have been replaced but not expired. However, the message in the expiration alerts provides no means to determine to which certificate an alert refers. This somewhat reduces the usefulness of the alerts.
Every certificate has a start date. It seems to me it should not be terribly difficult to at least add the start date to the information already included in the alert emails.
One additional feature would make this even more useful: Issue an alert when a cert is replaced. for a particular domain, giving start and end dates fior both the old and the new cert.