Action may be required to prevent your Let's Encrypt certificate renewals from
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 7 days. Below is a list of names and IP addresses
validated (max of one per account):
ffnw.de (2a01:4f8:192:832b:3: on 2019-02-11
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.
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.
Our staging environment already has TLS-SNI-01 disabled, so if you'd like to
test whether your system will work after February 13, you can run against
If you're a Certbot user, you can find more information here:
Our forum has many threads on this topic. Please search to see if your question
has been answered, then open a new thread if it has not:
For more information about the TLS-SNI-01 end-of-life, please see our API
Let's Encrypt Staff