letsencryptよりメールで下記のようなメッセージが来ていた
2019年2月13日移行廃止予定とのこと
メール内の公式情報をみると
https://community.letsencrypt.org/t/how-to-stop-using-tls-sni-01-with-certbot/83210
Certbotのバージョンが0.28以上
だとか。
早速更新しましょ

1.バージョン確認

#certbot --version
certbot 0.27.1

2.certbot更新

#yum update certbot
…
Dependency Updated:
python2-certbot.noarch 0:0.29.1-1.el7
Complete!

3.dry-runで更新テスト
エラー：acmeバージョン0.29.0以上が見つからん

#certbot renew --dry-run --preferred-challenges http
pkg_resources.DistributionNotFound: acme>=0.29.0

4.acmeを更新

#yum --enablerepo=epel update python2-acme

5.再度dry-runで更新テストでクリア

以下メール内容

Hello,

Action may be required to prevent your Let’s Encrypt certificate renewals
from breaking.

If you already received a similar e-mail, this one contains updated
information.

Your Let’s Encrypt client used ACME TLS-SNI-01 domain validation to issue
a certificate in the past 60 days. Below is a list of names and IP
addresses validated (max of one per account):

xxxx.com (IPアドレス) on 日付

TLS-SNI-01 validation is reaching end-of-life. It will stop working
temporarily on February 13th, 2019, and permanently on March 13th, 2019.
Any certificates issued before then will continue to work for 90 days
after their issuance date.