Hi, According to our records, the software client you're using to get Let's Encrypt TLS/SSL certificates issued or renewed at least one HTTPS certificate in the past two weeks using the ACMEv1 protocol. Here are the details of one recent ACMEv1 request from each of your account(s): Client IP address: 2a01:238:4387:cc00:1027:fc0d:cfe6:c387 User agent: CertbotACMEClient/0.17.0 (certbot; Debian GNU/Linux 8 (jessie)) Authenticator/webroot Installer/None (renew; flags: n) Py/2.7.9 Hostname(s): "protokolle.zapf.in" Request time: 2020-02-28 11:22:08 UTC Beginning June 1, 2020, we will stop allowing new domains to validate using the ACMEv1 protocol. You should upgrade to an ACMEv2 compatible client before then, or certificate issuance will fail. For most people, simply upgrading to the latest version of your existing client will suffice. You can view the client list at: https://letsencrypt.org/docs/client-options/ If you're unsure how your certificate is managed, get in touch with the person who installed the certificate for you. If you don't know who to contact, please view the help section in our community forum at https://community.letsencrypt.org/c/help and use the search bar to check if there's an existing solution for your question. If there isn't, please create a new topic and fill out the help template. ACMEv1 API deprecation details can be found in our community forum: https://community.letsencrypt.org/t/end-of-life-plan-for-acmev1 As a reminder: In the future, Let's Encrypt will be performing multiple domain validation requests for each domain name when you issue a certificate. While you're working on migrating to ACMEv2, please check that your system configuration will not block validation requests made by new Let's Encrypt IP addresses, or block multiple matching requests. Per our FAQ (https://letsencrypt.org/docs/faq/), we don't publish a list of IP addresses we use to validate, and this list may change at any time. To receive more frequent updates, subscribe to our API Announcements: https://community.letsencrypt.org/t/about-the-api-announcements-category Thank you for joining us on our mission to create a more secure and privacy- respecting Web! All the best, Let's Encrypt If you are receiving this email in error, unsubscribe at: http://mandrillapp.com/track/unsub.php?u=30850198&id=f89f1ae491b64cf3... Please note that this would also unsubscribe you from other Let's Encrypt service notices, like expiration reminders.