diff --git a/ampel-firmware/config.public.h b/ampel-firmware/config.public.h
index 6b87993ce03f4489ae242a48b2c6f2c87afe6e63..00339350cf751165bbd1c1ac46f78ef859e46ed5 100644
--- a/ampel-firmware/config.public.h
+++ b/ampel-firmware/config.public.h
@@ -109,7 +109,6 @@
 #  define MQTT_PORT 8883
 #  define MQTT_USER ""
 #  define MQTT_PASSWORD ""
-#  define MQTT_SERVER_FINGERPRINT "EE BC 4B F8 57 E3 D3 E4 07 54 23 1E F0 C8 A1 56 E0 D3 1A 1C" // SHA1 for test.mosquitto.org
 
 /**
  * LoRaWAN
diff --git a/ampel-firmware/mqtt.cpp b/ampel-firmware/mqtt.cpp
index ebb4ad24182c9eeec721c44ca59e892c7056a54c..2e71ae2417fefb24f52761072d9ba20fb3c2d423 100644
--- a/ampel-firmware/mqtt.cpp
+++ b/ampel-firmware/mqtt.cpp
@@ -9,7 +9,6 @@ namespace config {
   const uint16_t mqtt_port = MQTT_PORT;
   const char *mqtt_user = MQTT_USER;
   const char *mqtt_password = MQTT_PASSWORD;
-  const char *fingerprint PROGMEM = MQTT_SERVER_FINGERPRINT;
   const bool allow_mqtt_commands = ALLOW_MQTT_COMMANDS;
   const unsigned long wait_after_fail = 900; // [s] Wait 15 minutes after an MQTT connection fail, before trying again.
 }
@@ -32,7 +31,7 @@ namespace mqtt {
     json_sensor_format = PSTR("{\"time\":\"%s\", \"co2\":%d, \"temp\":%.1f, \"rh\":%.1f}");
     publish_topic = topic;
 #if defined(ESP8266)
-    espClient.setFingerprint(config::fingerprint); // not supported by ESP32
+    espClient.setInsecure(); // Sorry, we don't want to flash the sensors every 3 months.
 #endif
     // mqttClient.setSocketTimeout(config::mqtt_timeout); //NOTE: somehow doesn't seem to have any effect on connect()
     mqttClient.setServer(config::mqtt_server, config::mqtt_port);