Let’s Encrypt, a free, automated, and open certificate signing authority, has issued a billion certificates since its launch in 2015. The CA issued its first certificate in September 2015, before eventually reaching 100 million in June 2017. Apple recently announced that starting 1st September 2020, Safari will reject new HTTPS certificates that expire more than 13 months (or 398 days) from their creation date, effectively bringing down the maximum certificate lifetime from 825 days. Apple has also announced technical specifications for a new cryptographic protocol called “Delegated Credentials for TLS”
Source: https://thehackernews.com/2020/02/lets-encrypt-ssl-certificate.html