You can install the needed transformation by importing the assets in censhare-Server/install/assets/optional/email-transformation with the Import server action. The transformation represents only a "Hello world!" example and you must edit it accordingly before use. You can enable and configure the module in the censhare Admin Client under Modules|E-Mail|Send E-Mail using XSLT. Here you must select an appropriate mail transformation in the drop-down menu.
Only use one server name inModules|E-Mail|Send E-Mail using XSLT. Otherwise, as many e-mails are sent as there are active servers.