anchor.diff:        description = "Default group to store mail for virtual users.";
       };
   
  -    createMailUser = mkOption {
  -      type = types.bool;
  -      default = true;
  -      description = ''Whether to automatically create the user
  -        given in <option>services.dovecot.user</option> and the group
  -        given in <option>services.dovecot.group</option>.'';
  -    };
  +    createMailUser = mkEnableOption ''automatically creating the user
  +      given in <option>services.dovecot.user</option> and the group
  +      given in <option>services.dovecot.group</option>.'' // { default = true; };
   
       modules = mkOption {
         type = types.listOf types.package;
  
positive.code:       description = "Path to the server's private key.";
      };
  
      enablePAM = mkOption {
        type = types.bool;
        default = true;
        description = "Whether to create a own Dovecot PAM service and configure PAM user logins.";
      };
  
      enableDHE = mkEnableOption "enable ssl_dh and generation of primes for the key exchange." // { default = true; };
  
  
negative.code:       description = "Sieve scripts to be executed. Key is a sequence, e.g. 'before2', 'after' etc.";
      };
  
      showPAMFailure = mkEnableOption "showing the PAM failure message on authentication error (useful for OTPW).";
  
      mailboxes = mkOption {
        type = with types; coercedTo
  