From 15 March 2027 no newly issued public TLS certificate, still usually called an SSL certificate, may be valid for more than 100 days. The limit is set by the CA/B Forum Baseline Requirements , the rules every certificate authority has to follow. Let's Encrypt moves first: from 10 February 2027 its certificates will last 64 days by default.

If your certificate renews itself, all you need to check is that someone hears when a renewal fails. A certificate installed by hand will have to be replaced at least three times a year from March, and in practice four.

The limit falls from 200 to 100 days

A certificate issued before 15 March 2026 could be valid for 398 days, just over a year, which is where the habit of a yearly swap comes from. The limit has been 200 days since 15 March 2026, so a certificate issued today won't last even seven months.…