ACME-based challenge mode is the most popular mechanism. It will renew your certificate and install it in the right place.
There are two types of certificates.
Fixed domain (like synergy.myserver.com)
Wildcard (*.myserver.com).
Both of these require different steps, but we recommend using a fixed domain for simplicity.
Any ACME- compatible server can be used, but the 12d Synergy Certificate tool defaults to LetsEncrypt.