anchor.diff:      (mkRemovedOptionModule [ "services" "piwik" "phpfpmProcessManagerConfig" ] "Use services.phpfpm.pools.<name>.settings")
       (mkRemovedOptionModule [ "services" "matomo" "phpfpmProcessManagerConfig" ] "Use services.phpfpm.pools.<name>.settings")
       (mkRenamedOptionModule [ "services" "piwik" "nginx" ] [ "services" "matomo" "nginx" ])
  +    (mkRenamedOptionModule [ "services" "matomo" "periodicArchiveProcessingUrl" ] [ "services" "matomo" "hostname" ])
     ];
   
     options = {
  
positive.code:       # References:
        # https://fralef.me/piwik-hardening-with-nginx-and-php-fpm.html
        # https://github.com/perusio/piwik-nginx
        "${user}.${fqdn}" = mkMerge [ cfg.nginx {
          # don't allow to override the root easily, as it will almost certainly break Matomo.
          # disadvantage: not shown as default in docs.
          root = mkForce "${cfg.package}/share";
  
negative.code:         '';
        };
  
        hostname = mkOption {
          type = types.str;
          default = "${user}.${fqdn}";
          example = "matomo.yourdomain.org";
  