Hello, Would it be possible to set an hostname in the ISPConfig VHost file? For the moment I replaced the "_" in the NGinx config file by the hostname I secured with Letsencrypt but on every update it is overriden.
Sure, just set it in the ispconfig.vhost file. And ISPConfig does not overwrite any custom templates on update that you have set correctly in conf custom or conf-custom/install/, depending on template type. Search forum for conf-custom, it has been explained many times.