Let's Encrypt is shortening its default TLS certificate validity period. Starting February 10, 2027, new and renewed certificates will have a 64-day lifespan. This change applies to all certificates issued or renewed from that date forward. Existing certificates unaffected by this transition will remain valid until their original expiration. Let's Encrypt anticipates the last 90-day certificate to expire on May 11, 2027. No valid certificates will be revoked during this upcoming transition. To assist administrators, a staging environment with 64-day certificates will be available from October 14, 2026. This move aims to enhance web security by limiting the usability of compromised certificates. Furthermore, Let's Encrypt plans to reduce the default validity to 45 days in 2028. Domain authorization reuse periods will also be reduced, from 30 days to 10 days, and then to seven hours in 2028.