diff --git a/include/device.h b/include/device.h
index f3b4aca..d8bb27a 100644
--- a/include/device.h
+++ b/include/device.h
@@ -3,6 +3,7 @@
 
 #include <Arduino.h>
 #include <pgmspace.h>
+#include <ArduinoUniqueID.h>
 
 
 void setupDevice();
@@ -12,5 +13,6 @@ void deviceSetSleepInterval(long interval);
 long deviceGetSleepInterval();
 unsigned int deviceGetBootCount();
 
+extern char DeviceId[21 +1];
 
 #endif
\ No newline at end of file
diff --git a/platformio.ini b/platformio.ini
index 910850a..1a60e8c 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -29,6 +29,7 @@ lib_deps =
   https://github.com/kikuchan/pngle.git
 	JPEGDecoder@~1.8.0
 	Wire
+	ArduinoUniqueID@~1.0.9
 
   # Semantic Versioning Rules
   # http://docs.platformio.org/page/userguide/lib/cmd_install.html#description
diff --git a/src/app.cpp b/src/app.cpp
index cac20c7..3d502cd 100644
--- a/src/app.cpp
+++ b/src/app.cpp
@@ -78,6 +78,7 @@ void setupApp()
 		doc["wifi"]["dns"] = WiFi.dnsIP().toString();
 		doc["wifi"]["gateway"] = WiFi.gatewayIP().toString();
 
+		doc["device"]["id"] = DeviceId;
 		doc["device"]["heap"] = ESP.getFreeHeap();
 		doc["device"]["bootCycle"] = deviceGetBootCount();
 		doc["device"]["screen"]["width"] = 640;
@@ -393,26 +394,6 @@ void setupApiFace()
 void setupApiUpdate()
 {
 	server.on("/api/update", HTTP_GET, [](AsyncWebServerRequest *request) {
-		/*
-		int params = request->params();
-		for (int i = 0; i < params; i++)
-		{
-			AsyncWebParameter *p = request->getParam(i);
-			if (p->isFile())
-			{
-				Serial.printf("<li>FILE[%s]: %s, size: %u</li>", p->name().c_str(), p->value().c_str(), p->size());
-			}
-			else if (p->isPost())
-			{
-				Serial.printf("<li>POST[%s]: %s</li>", p->name().c_str(), p->value().c_str());
-			}
-			else
-			{
-				Serial.printf("<li>GET[%s]: %s</li>", p->name().c_str(), p->value().c_str());
-			}
-		}
-		*/
-
 		if (request->hasParam("datetime"))
 		{
 			Serial.println("update datetime...");
@@ -434,7 +415,7 @@ void setupApiUpdate()
 			updateCalendarData();
 		}
 
-		if (request->hasParam("file"))
+		if (request->getParam("url") && request->hasParam("file"))
 		{
 			Serial.println("file...");
 
diff --git a/src/device.cpp b/src/device.cpp
index 7d48d92..ca66cb2 100644
--- a/src/device.cpp
+++ b/src/device.cpp
@@ -6,6 +6,7 @@ RTC_DATA_ATTR unsigned int bootCount = 0;
 RTC_DATA_ATTR long config_DeepSleepInterval = 10; // sec
 
 unsigned long bootTime = 0;
+char DeviceId[21 + 1];
 
 // private methods
 void sleepDevice();
@@ -19,6 +20,9 @@ void setupDevice()
 	// increment boot number and print it every reboot
 	bootCount++;
 	bootTime = millis();
+
+	// create anonymous device id
+	sprintf(DeviceId, "%02X:%02X:%02X:%02X:%02X:%02X:%02X:%02X", UniqueID8[0], UniqueID8[1], UniqueID8[2], UniqueID8[3], UniqueID8[4], UniqueID8[5], UniqueID8[6], UniqueID8[7]);
 }
 
 void loopDevice()
@@ -58,7 +62,6 @@ unsigned int deviceGetBootCount()
 	return bootCount;
 }
 
-
 bool isBootTimeOver()
 {
 	return millis() - bootTime >= 60000;
diff --git a/src/download.cpp b/src/download.cpp
index a8fdcf9..b1d8bdc 100644
--- a/src/download.cpp
+++ b/src/download.cpp
@@ -1,6 +1,7 @@
 #include <HTTPClient.h>
 #include <SPIFFS.h>
 #include "download.h"
+#include "device.h"
 
 HTTPClient http;
 
@@ -24,8 +25,13 @@ bool downloadFile(String url, const char *path)
 		return false;
 	}
 
-	http.useHTTP10(true); // http1.1 chunked übertragung funktioniert irgendwie nicht
+	http.useHTTP10(true); // http1.1 chunked is not working correctly
 	http.setTimeout(7000);
+	http.setUserAgent("paperdash esp");
+
+	// use the last 8 bytes of the unique serial id
+	http.addHeader("X-PaperDash-Id", DeviceId);
+
 	http.begin(url);
 	int httpCode = http.GET();
 	if (httpCode != HTTP_CODE_OK)