• The first one is supposed to show temperature, but seems it is not reached as I only see co2 values.

    maybe because you commented out line 14 ?

    //return characteristic.startNotifications();
  • Thx, but I've tried that as well. If I uncomment it, I get a message on next line Unreachable 'return' after 'return', and this time only the temperature is being shown, not the co2 value. So I assume a function can only return one "thing", not several.