I received an email from Let’s Encrypt a few hours ago. I received the same email on
The significant part of the contents of the email received a few hours ago is
Your certificate (or certificates) for the names listed below will expire in 10 days (on 18 Oct 20 02:29 +0000). Please make sure to renew your certificate before then, or visitors to your website will encounter errors.
We recommend renewing certificates automatically when they have a third of their
total lifetime left. For Let's Encrypt's current 90-day certificates, that means
renewing 30 days before expiration. See
https://letsencrypt.org/docs/integration-guide/ for details.
However, I believe that the email is inaccurate, as SSL Labs indicates that the certificate expires on Thu, 12 Nov 2020 15:09:53 UTC (expires in 1 month and 4 days)
So it seems that the email is sent in error.
Had the certificate been renewed in the last few hours then the certificate should be valid for 90 days.