certificates during upgrades
One answer
It depends on what you will change during the upgrade and where the certificate is placed. Since you said the the users could login without the prompt, I assume that the certificate is CA-signed, rather than self-signed - in this case, you need to locate the certificate file and put it in the right place of the setup. Here are some links for your reference.
https://jazz.net/forum/questions/170184/how-to-configure-ca-signed-certificate-in-was-for-ram
https://jazz.net/wiki/bin/view/Deployment/ConfigureCLMEnterpriseReverseProxy
(The steps can be quite different depending you use IBM HTTP Server or not)
https://jazz.net/forum/questions/170184/how-to-configure-ca-signed-certificate-in-was-for-ram
https://jazz.net/wiki/bin/view/Deployment/ConfigureCLMEnterpriseReverseProxy
(The steps can be quite different depending you use IBM HTTP Server or not)