昨天收到來自 Let's Encrypt 的 mail

Hello,

**Action is required to prevent your Let's Encrypt certificate renewals from breaking.**

Your Let’s Encrypt client used ACME TLS-SNI-01 domain validation to issue a certificate in the past 60 days.

TLS-SNI-01 validation is reaching end-of-life and will stop working on **February 13th, 2019.**

You need to update your ACME client to use an alternative validation method (HTTP-01, DNS-01 or TLS-ALPN-01) before this date or your certificate renewals will break and existing certificates will start to expire.

我是使用certbot來更新

原來的指令是

/usr/bin/certbot renew

預設就是使用 TLS-SNI-01

所以要把指令改成

/usr/bin/certbot --preferred-challenges http-01 renew