NOTE: To use it, you must enable dns_ttl=1 for per-record TTL settings, or else the LE Wildcard checkbox won’t show up.
ACMEv2 is an updated version of our ACME protocol which has gone through the IETF standards process, taking into account feedback from industry experts and other organizations that might want to use the ACME protocol for certificate issuance and management some day.
Wildcard certificates allow you to secure all subdomains of a domain with a single certificate. Wildcard certificates can make certificate management easier in some cases, and we want to address those cases in order to help get the Web to 100% HTTPS. We still recommend non-wildcard certificates for most use cases.
Wildcard certificates are only available via ACMEv2. In order to use ACMEv2 for wildcard or non-wildcard certificates you’ll need a client that has been updated to support ACMEv2 It is our intent to transition all clients and subscribers to ACMEv2, though we have not set an end-of-life date for our ACMEv1 API yet.
Additionally, wildcard domains must be validated using the DNS-01 challenge type. This means that you’ll need to modify DNS TXT records in order to demonstrate control over a domain for the purpose of obtaining a wildcard certificate.
For more technical information about ACMEv2 and wildcard certificates, see this post.
We’re excited about the prospect of a 100% HTTPS Web and we’re working hard to get there. As a non-profit organization, we need strong support from our community so please consider getting involved, making a donation, or sponsoring Let’s Encrypt.