Starting September 1, Safari will not honor new certificates that have validity periods longer than one year. I don't have a link to their documentation because the announcement was reportedly made at a face-to-face meeting at the CA/Browser Forum in February. https://www.thesslstore.com/blog/ssl-certificate-validity-wi...

Safari will will no longer be honoring certificates valid for more than 13 months starting September [0]

[0]: https://www.theregister.co.uk/2020/02/20/apple_shorter_cert_...