Let's Encrypt DST Root CA X3 certificate set to expire
If you've been using Let's Encrypt for a while, you may have noticed that their certificates are signed by a root certificate titled DST Root CA X3. That root certificate is set to expire in a few hours. Any certificates still signed by that root will no longer be valid. But luckily, that shouldn't form a problem for most Let's Encrypt users. For a while now, new SSL issuances by Let's Encrypt have issued certificates against DST Root CA X3 (the one that is about to expire) and ISRG Root X1.