An industry-wide requirement set by Apple and Google, stating that any two-year SSL certificate issued after August 30, 2020, will be distrusted in their browsers.
That’s right: 398 days is the maximum length for a publicly issued server cert. If it’s longer, browsers and other HTTPS code will reject the cert as invalid.
Beginning UTC 12.00 am August 19, 2020, Sectigo will only be issuing one-year (up to 398 days) SSL certificates. And Digicert is highly doing the same at the end of August. Kindly note that this only applies to public TLS certificates. Other types of certificates (e.g. Code Signing Certificates, S/MIME certificates, etc.) will be unaffected and will have the same maximum validity that they have today.
However, any two-year SSL certificate issued before 12:00 am UTC on August 19, 2020, will be valid for two-years (up to 825 days).
Therefore we recommend you renew the certificate and top your certificate validity before the deadline, save time, and trouble for you to go through the validation process next year (especially for OV&EV certificate).