Let's Encrypt 預計於 2018年1月推出 Wildcard Certificates，同時 Wildcard Certificates 會需要走 ACME v2 API 來認證。
下述摘錄自此篇：Wildcard Certificates Coming January 2018
Wildcard certificates will be offered free of charge via our upcoming ACME v2 API endpoint. We will initially only support base domain validation via DNS for wildcard certificates, but may explore additional validation options over time.
Wildcard 推出之後，之後會省事不少~
- 註：Let's Encrypt 已經發出1億個憑證了，參見：Milestone: 100 Million Certificates Issued