Here is my ‘swap’ related config :

            {
              module: 'swap',   // as supplied by KirAsh4
              config: {
                showsecs: 30,   // seconds each module is shown (default =30)
                fadems: 4000,   // fade time in ms (default = 4000)
                modA: 'MMM-YrNow',  // both modules need to be listed NEXT
                modB: 'MMM-YrThen' // they should be of similar size and in the same location
              }
            },

            {
            module: 'MMM-YrNow',
            position: 'top_right',
            config: {
                    locationId: '1-24780',
                   showWeatherForecast: true
                    }
            },

            {
            module: 'MMM-YrThen',
            position: 'top_right',
            config: {
                    location: '1-24780',
                    numDetails: 1,
                    }
            },

Thanks, Wolfgang