TLS/SSL certs from the free Let’s Encrypt service are currently valid for 90 days. But the validity is being reduced to 64 days from February, with the aim of reducing the vulnerability window if a certificate key should get compromised. And yes, even further reductions are planned in the future. <https://arstechnica.com/gadgets/2026/10/lets-encrypt-cuts-certificate-lifetimes-to-64-days-starting-february-2027/> On a standard CertBot install on a Debian system, the certificate renewals are checked twice a day, so this change probably won’t make a noticeable difference to anything. But if you’ve bodged together your own scripts to manage the renewal process, you may need to recheck your work.