On February 10, 2027, all Let’s Encrypt subscribers will move to certificates with 64 day lifetimes by default unless they select an even shorter lifetime (45 or 6 days, as previously announced). This means that any certificate we issue or renew on and after that date will have a 64 day validity period, and we expect the last 90-day certificate to expire on May 11, 2027. We will not revoke valid certificates as a part of this process.
They’re moving to 45 days, so may as well make any changes based on the shorter lifespan.
https://letsencrypt.org/2025/12/02/from-90-to-45