I've written a blog post to explain the situation with the old Let's Encrypt root certificate expiration which will happen on 2021-09-30 and the behavior of OpenSSL 1.0.2 with that root certificate.
Please read, if interested: https://www.openssl.org/blog/blog/2021/09/13/LetsEncryptRootCertExpire/ Regards, -- Tomáš Mráz No matter how far down the wrong road you've gone, turn back. Turkish proverb [You'll know whether the road is wrong if you carefully listen to your conscience.]
