If you are developing a client, this change to authorization creation may be of interest to you.
Soon (within the next few weeks) we’ll turn on a Boulder flag that will enable transparent reuse of existing, valid authorizations. This shouldn’t require any changes to clients, and we’ve tested it using Certbot without issue.
If you ask Boulder to create a new authorization, and Boulder already has a valid authorization for the same FQDN, and there is more than a day left before that authorization expires, Boulder will simply return the existing authorization object.
To work around some client quirks, Boulder will no longer reject POSTs to authorization objects that are already valid. That way, clients that create a new authorization and then POST to it without checking its status will still succeed.
As always we’ll turn this on in staging first, and I’ll post again here once it’s enabled there. I’ll also post again once it’s enabled in prod.