You can do the following to improve the security of your certificates:
Increase the size of the keys to increases the strength of their signatures.
Specify that only secure hash signature algorithms (sha256WithRSAEncryption, sha384WithRSAEncryption, or sha512WithRSAEncryption) be used. Certificates with the sha1WithRSAEncryption signature algorithm will be removed from the default CA list, and from the Web server and MTA.
Important
If the Web server or MTA certificate is removed, it is replaced by the system self-signed certificate.
You can also modify the minimum Transport Layer Security (TLS) version that should be used.
Prerequisites
Operator or Admin access