diff --git a/Software/co2ampel/co2ampel.ino b/Software/co2ampel/co2ampel.ino
index 9dde224..9a0bd7d 100644
--- a/Software/co2ampel/co2ampel.ino
+++ b/Software/co2ampel/co2ampel.ino
@@ -207,7 +207,8 @@ void setup()
   digitalWrite(GPIO_BUZZER,0);
 
   delay(500);
-  Serial.println("Start CO2-Ampel");
+  Serial.print("Start CO2-Ampel Version: ");
+  Serial.println(VERSION);
 
   configStatus=configManager.readConfig("/config.json");
   ledSetBrightnes(configManager.getUintValue("led_brightness", LED_BRIGHTNES));
diff --git a/Software/co2ampel/config.h b/Software/co2ampel/config.h
index 2feb189..68792f4 100644
--- a/Software/co2ampel/config.h
+++ b/Software/co2ampel/config.h
@@ -10,7 +10,7 @@
 #define CONFIG_H
 
 /******************************* Version **************************************/
-#define VERSION 3
+#define VERSION 4
 
 /******************************* MQTT **************************************/
 
@@ -38,7 +38,7 @@ enum Color {GREEN, YELLOW, RED, BLUE, DARK, WHITE, GREEN2, YELLOW2, RED2};
 #define SCD30_CALIBRATION_MIN_RUNTIME 180 //seconds
 #define SCD30_MEASUREMENT_INTERVAL 2 // seconds (recalibrate, if you change this value)
 #define SCD30_MIN_PPM 350
-#define SCD30_CALIBRATION_PPM 410
+#define SCD30_CALIBRATION_PPM 450 
 
 /******************************* thresholds **************************************/
 #define TH_GREEN 800 //overriden by th_green from config.json