diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index d7bea65..279fe85 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -33,18 +33,20 @@ jobs:
         run: |
           source $GITHUB_WORKSPACE/travis/common.sh
           cd $GITHUB_WORKSPACE
-          echo -en "::set-output name=matrix::"
-          echo -en "["
 
-          get_sketches_json_matrix arduino $GITHUB_WORKSPACE/examples/esp8266 esp8266 1.8.19 esp8266com:esp8266:generic:xtal=80,dbg=Serial1
-          echo -en ","
+          echo -en "matrix=" >> $GITHUB_OUTPUT
+          echo -en "[" >> $GITHUB_OUTPUT
 
-          get_sketches_json_matrix arduino $GITHUB_WORKSPACE/examples/esp8266 esp8266 1.8.19 esp8266com:esp8266:generic:xtal=80,eesz=1M,FlashMode=qio,FlashFreq=80
-          echo -en ","
+          get_sketches_json_matrix arduino $GITHUB_WORKSPACE/examples/esp8266_pico esp8266 1.8.19 esp8266com:esp8266:generic:xtal=80,vt=flash,exception=disabled,stacksmash=disabled,ssl=all,mmu=3232,non32xfer=fast,ResetMethod=nodemcu,CrystalFreq=26,FlashFreq=80,FlashMode=qio,eesz=4M2M,led=2,sdk=nonosdk_190703,ip=lm2f,dbg=Serial1,lvl=SSL,wipe=none,baud=115200 >> $GITHUB_OUTPUT
+          echo -en "," >> $GITHUB_OUTPUT
 
-          get_sketches_json_matrix arduino $GITHUB_WORKSPACE/examples/esp32 esp32 1.8.19 espressif:esp32:esp32:FlashFreq=80
+          get_sketches_json_matrix arduino $GITHUB_WORKSPACE/examples/esp8266_pico esp8266 1.8.19 esp8266com:esp8266:generic:xtal=80,vt=flash,exception=disabled,stacksmash=disabled,ssl=all,mmu=3232,non32xfer=fast,ResetMethod=nodemcu,CrystalFreq=26,FlashFreq=80,FlashMode=qio,eesz=4M2M,led=2,sdk=nonosdk_190703,ip=lm2f,dbg=Disabled,lvl=None____,wipe=none,baud=115200 >> $GITHUB_OUTPUT
+          echo -en "," >> $GITHUB_OUTPUT
 
-          echo -en "]"
+          get_sketches_json_matrix arduino $GITHUB_WORKSPACE/examples/esp32 esp32 1.8.19 espressif:esp32:esp32:FlashFreq=80 >> $GITHUB_OUTPUT
+
+          echo -en "]" >> $GITHUB_OUTPUT
+          echo >> $GITHUB_OUTPUT
     outputs:
       matrix: ${{ steps.set-matrix.outputs.matrix }}
 
@@ -63,7 +65,7 @@ jobs:
       - name: Get Date
         id: get-date
         run: |
-          echo "::set-output name=date::$(/bin/date -u "+%Y%m%d")"
+          echo "date=$(/bin/date -u "+%Y%m%d")" >> $GITHUB_OUTPUT
         shell: bash
 
       - uses: actions/cache@v2
@@ -125,7 +127,7 @@ jobs:
       - name: Get Date
         id: get-date
         run: |
-          echo "::set-output name=date::$(/bin/date -u "+%Y%m%d")"
+          echo "date=$(/bin/date -u "+%Y%m%d")" >> $GITHUB_OUTPUT
         shell: bash
 
       - uses: actions/cache@v2
@@ -161,11 +163,13 @@ jobs:
 
       - name: config IDE
         run: |
+          set +x
           export DISPLAY=:1.0
           export PATH="$HOME/arduino_ide:$PATH"
           arduino --board $BOARD --save-prefs
+          arduino --pref update.check=false --pref build.verbose=false --pref cache.enable=true --pref compiler.cache_core=true --pref compiler.warning_level=default --save-prefs
           arduino --get-pref sketchbook.path
-          arduino --pref update.check=false
+          arduino --get-pref
 
       - name: build example
         timeout-minutes: 20
diff --git a/README.md b/README.md
index 26d124c..83faaab 100644
--- a/README.md
+++ b/README.md
@@ -26,6 +26,7 @@ a WebSocket Server and Client for Arduino based on RFC6455.
  - ESP8266 [Arduino for ESP8266](https://github.com/esp8266/Arduino/)
  - ESP32 [Arduino for ESP32](https://github.com/espressif/arduino-esp32)
  - ESP31B
+ - Raspberry Pi Pico W [Arduino for Pico](https://github.com/earlephilhower/arduino-pico)
  - Particle with STM32 ARM Cortex M3
  - ATmega328 with Ethernet Shield (ATmega branch)
  - ATmega328 with enc28j60 (ATmega branch)
diff --git a/examples/esp8266/WebSocketClient/WebSocketClient.ino b/examples/esp8266_pico/WebSocketClient/WebSocketClient.ino
similarity index 100%
rename from examples/esp8266/WebSocketClient/WebSocketClient.ino
rename to examples/esp8266_pico/WebSocketClient/WebSocketClient.ino
diff --git a/examples/esp8266/WebSocketClientOTA/README.md b/examples/esp8266_pico/WebSocketClientOTA/README.md
similarity index 100%
rename from examples/esp8266/WebSocketClientOTA/README.md
rename to examples/esp8266_pico/WebSocketClientOTA/README.md
diff --git a/examples/esp8266/WebSocketClientOTA/WebSocketClientOTA.ino b/examples/esp8266_pico/WebSocketClientOTA/WebSocketClientOTA.ino
similarity index 83%
rename from examples/esp8266/WebSocketClientOTA/WebSocketClientOTA.ino
rename to examples/esp8266_pico/WebSocketClientOTA/WebSocketClientOTA.ino
index 2c87c25..3a988a5 100644
--- a/examples/esp8266/WebSocketClientOTA/WebSocketClientOTA.ino
+++ b/examples/esp8266_pico/WebSocketClientOTA/WebSocketClientOTA.ino
@@ -8,25 +8,29 @@
 #include <Arduino.h>
 #include <ArduinoJson.h>
 
-#ifdef ESP8266
+#if defined(ESP8266)
     #include <ESP8266WiFi.h>
+    #include <ESP8266WiFiMulti.h>
     #include <ESP8266mDNS.h>
-	#include <Updater.h>
-#endif
-#ifdef ESP32
-    #include "WiFi.h"
+    #include <Updater.h>
+    #include <Hash.h>
+
+    ESP8266WiFiMulti WiFiMulti;
+#elif defined(ESP32)
+    #include <WiFi.h>
+    #include <WiFiMulti.h>
     #include "ESPmDNS.h"
-	#include <Update.h>
+    #include <Update.h>
+
+    WiFiMulti WiFiMulti;
+#else
+    #error Unsupported device
 #endif
 
 #include <WiFiUdp.h>
-#include <ESP8266WiFiMulti.h>
-
 #include <WebSocketsClient.h>
 
-#include <Hash.h>
 
-ESP8266WiFiMulti WiFiMulti;
 WebSocketsClient webSocket;
 
 #define USE_SERIAL Serial
@@ -48,19 +52,12 @@ uint32_t maxSketchSpace = 0;
 int SketchSize = 0;
 bool ws_conn = false;
 
-String IpAddress2String(const IPAddress& ipAddress)
-{
-    return String(ipAddress[0]) + String(".") +
-           String(ipAddress[1]) + String(".") +
-           String(ipAddress[2]) + String(".") +
-           String(ipAddress[3]);
-}
 
 void greetings_(){
 	StaticJsonDocument<200> doc;
 	doc["type"] = "greetings";
-	doc["mac"] = WiFi.macAddress();
-	doc["ip"] = IpAddress2String(WiFi.localIP());
+	doc["mac"] = WiFi.macAddress().c_str();
+	doc["ip"] = WiFi.localIP().toString().c_str();
 	doc["version"] = version;
 	doc["name"] = name;
 	doc["chip"] = chip;
@@ -73,7 +70,7 @@ void greetings_(){
 void register_(){
 	StaticJsonDocument<200> doc;
 	doc["type"] = "register";
-    doc["mac"] = WiFi.macAddress();
+    doc["mac"] = WiFi.macAddress().c_str();
 
 	char data[200];
 	serializeJson(doc, data);
@@ -88,11 +85,10 @@ typedef struct {
    CALLBACK_FUNCTION  func;
 } RESPONSES_STRUCT;
 
-void OTA(JsonDocument &msg){
+void OTA_RESPONSES(JsonDocument &msg){
     USE_SERIAL.print(F("[WSc] OTA mode: "));
-    const char* go = "go";
-    const char* ok = "ok";
-    if(strncmp( msg["value"], go, strlen(go)) == 0 ) {
+    String val = msg["value"];
+    if(val == "go") {
         USE_SERIAL.print(F("go\n"));
         SketchSize = int(msg["size"]);
         maxSketchSpace = (ESP.getFreeSketchSpace() - 0x1000) & 0xFFFFF000;
@@ -103,27 +99,31 @@ void OTA(JsonDocument &msg){
             Update.printError(Serial);
             ESP.restart();
         }
-    } else if (strncmp( msg["value"], ok, strlen(ok)) == 0) {
+    } else if (val == "ok") {
         USE_SERIAL.print(F("OK\n"));
         register_();
     } else {
         USE_SERIAL.print(F("unknown value : "));
-        USE_SERIAL.print(msg["value"].as<char>());
+        USE_SERIAL.print(val);
         USE_SERIAL.print(F("\n"));
     }
 }
 
-void STATE(JsonDocument &msg){
+void STA_RESPONSES(JsonDocument &msg){
     // Do something with message
 }
 
-RESPONSES_STRUCT responses[] = {
-  {"ota",           OTA},
-  {"state",      STATE},
+// Count of responses handled by RESPONSES_STRUCT
+// increase increase if another response handler is added
+const int nrOfResponses = 2;
+
+RESPONSES_STRUCT responses[nrOfResponses] = {
+  {"ota",        OTA_RESPONSES},
+  {"state",      STA_RESPONSES},
 };
 
 void text(uint8_t * payload, size_t length){
-    // Convert mesage to something usable
+    // Convert message to something usable
     char msgch[length];
     for (unsigned int i = 0; i < length; i++)
     {
@@ -145,9 +145,10 @@ void text(uint8_t * payload, size_t length){
     // Handle each TYPE of message
     int b = 0;
 
-    for( b=0 ; strlen(responses[b].type) ; b++ )
+    String t = doc_in["type"];
+    for( b=0 ; b<nrOfResponses ; b++ )
     {
-        if( strncmp(doc_in["type"], responses[b].type, strlen(responses[b].type)) == 0 ) {
+        if(t == responses[b].type) {
             responses[b].func(doc_in);
         }
     }
diff --git a/examples/esp8266/WebSocketClientOTA/python_ota_server/main.py b/examples/esp8266_pico/WebSocketClientOTA/python_ota_server/main.py
similarity index 92%
rename from examples/esp8266/WebSocketClientOTA/python_ota_server/main.py
rename to examples/esp8266_pico/WebSocketClientOTA/python_ota_server/main.py
index 7e7fba1..92acc95 100644
--- a/examples/esp8266/WebSocketClientOTA/python_ota_server/main.py
+++ b/examples/esp8266_pico/WebSocketClientOTA/python_ota_server/main.py
@@ -55,7 +55,7 @@ async def binary_send(websocket, fw_file):
     with open(fw_file, "rb") as binaryfile:
 
         while True:
-            chunk = binaryfile.read(2048)
+            chunk = binaryfile.read(4096)
             if not chunk:
                 break
             try:
@@ -63,7 +63,7 @@ async def binary_send(websocket, fw_file):
             except Exception as exception:
                 Logger.exception(exception)
                 return False
-            time.sleep(0.2)
+            asyncio.sleep(0.2)
 
 
 def version_checker(name, vdev, vapp):
@@ -79,7 +79,7 @@ def version_checker(name, vdev, vapp):
 class WsOtaHandler (threading.Thread):
     """Thread handling ota update
 
-    Runing ota directly from message would kill WS
+    Running ota directly from message would kill WS
     as message bus would timeout.
     """
     def __init__(self, name, message, websocket):
@@ -90,7 +90,7 @@ def __init__(self, name, message, websocket):
 
     def run(self, ):
         try:
-            asyncio.run(self.start_)
+            asyncio.run(self.start_())
         except Exception as exception:
             Logger.exception(exception)
         finally:
@@ -163,7 +163,7 @@ async def _register(websocket, message):
     Logger.info("Client(%s) mac: %s", name, mac)
     # Some code
 
-    response = {'response_type': 'registry', 'state': 'ok'}
+    response = {'type': 'registry', 'state': 'ok'}
     await websocket.send(json.dumps(response))
 
 
@@ -173,13 +173,13 @@ async def _state(websocket, message):
     Logger.info("Client(%s) mac: %s", name, mac)
     # Some code
 
-    response = {'response_type': 'state', 'state': 'ok'}
+    response = {'type': 'state', 'state': 'ok'}
     await websocket.send(json.dumps(response))
 
 
-async def _unhandleld(websocket, msg):
+async def _unhandled(websocket, msg):
     Logger.info("Unhandled message from device: %s", str(msg))
-    response = {'response_type': 'response', 'state': 'nok'}
+    response = {'type': 'response', 'state': 'nok'}
     await websocket.send(json.dumps(response))
 
 
@@ -206,7 +206,7 @@ async def message_received(websocket, message) -> None:
 
         type_ = msg_json.get('type')
         name = msg_json.get('name')
-        func = switcher.get(type_, _unhandleld)
+        func = switcher.get(type_, _unhandled)
         Logger.debug("Client(%s)said: %s", name, type_)
 
         try:
@@ -225,7 +225,7 @@ async def ws_server(websocket, path) -> None:
 async def main():
     """Server starter
 
-    Normal user can bind only port nubers greater than 1024
+    Normal user can bind only port numbers greater than 1024
     """
     async with websockets.serve(ws_server, "10.0.1.5", 8081):
         await asyncio.Future()  # run forever
diff --git a/examples/esp8266/WebSocketClientOTA/python_ota_server/requirements.txt b/examples/esp8266_pico/WebSocketClientOTA/python_ota_server/requirements.txt
similarity index 100%
rename from examples/esp8266/WebSocketClientOTA/python_ota_server/requirements.txt
rename to examples/esp8266_pico/WebSocketClientOTA/python_ota_server/requirements.txt
diff --git a/examples/esp8266/WebSocketClientSSL/WebSocketClientSSL.ino b/examples/esp8266_pico/WebSocketClientSSL/WebSocketClientSSL.ino
similarity index 100%
rename from examples/esp8266/WebSocketClientSSL/WebSocketClientSSL.ino
rename to examples/esp8266_pico/WebSocketClientSSL/WebSocketClientSSL.ino
diff --git a/examples/esp8266/WebSocketClientSSLWithCA/WebSocketClientSSLWithCA.ino b/examples/esp8266_pico/WebSocketClientSSLWithCA/WebSocketClientSSLWithCA.ino
similarity index 100%
rename from examples/esp8266/WebSocketClientSSLWithCA/WebSocketClientSSLWithCA.ino
rename to examples/esp8266_pico/WebSocketClientSSLWithCA/WebSocketClientSSLWithCA.ino
diff --git a/examples/esp8266/WebSocketClientSocketIO/WebSocketClientSocketIO.ino b/examples/esp8266_pico/WebSocketClientSocketIO/WebSocketClientSocketIO.ino
similarity index 100%
rename from examples/esp8266/WebSocketClientSocketIO/WebSocketClientSocketIO.ino
rename to examples/esp8266_pico/WebSocketClientSocketIO/WebSocketClientSocketIO.ino
diff --git a/examples/esp8266/WebSocketClientSocketIOack/WebSocketClientSocketIOack.ino b/examples/esp8266_pico/WebSocketClientSocketIOack/WebSocketClientSocketIOack.ino
similarity index 100%
rename from examples/esp8266/WebSocketClientSocketIOack/WebSocketClientSocketIOack.ino
rename to examples/esp8266_pico/WebSocketClientSocketIOack/WebSocketClientSocketIOack.ino
diff --git a/examples/esp8266/WebSocketClientStomp/WebSocketClientStomp.ino b/examples/esp8266_pico/WebSocketClientStomp/WebSocketClientStomp.ino
similarity index 100%
rename from examples/esp8266/WebSocketClientStomp/WebSocketClientStomp.ino
rename to examples/esp8266_pico/WebSocketClientStomp/WebSocketClientStomp.ino
diff --git a/examples/esp8266/WebSocketClientStompOverSockJs/WebSocketClientStompOverSockJs.ino b/examples/esp8266_pico/WebSocketClientStompOverSockJs/WebSocketClientStompOverSockJs.ino
similarity index 100%
rename from examples/esp8266/WebSocketClientStompOverSockJs/WebSocketClientStompOverSockJs.ino
rename to examples/esp8266_pico/WebSocketClientStompOverSockJs/WebSocketClientStompOverSockJs.ino
diff --git a/examples/esp8266/WebSocketServer/WebSocketServer.ino b/examples/esp8266_pico/WebSocketServer/WebSocketServer.ino
similarity index 100%
rename from examples/esp8266/WebSocketServer/WebSocketServer.ino
rename to examples/esp8266_pico/WebSocketServer/WebSocketServer.ino
diff --git a/examples/esp8266/WebSocketServerAllFunctionsDemo/WebSocketServerAllFunctionsDemo.ino b/examples/esp8266_pico/WebSocketServerAllFunctionsDemo/WebSocketServerAllFunctionsDemo.ino
similarity index 100%
rename from examples/esp8266/WebSocketServerAllFunctionsDemo/WebSocketServerAllFunctionsDemo.ino
rename to examples/esp8266_pico/WebSocketServerAllFunctionsDemo/WebSocketServerAllFunctionsDemo.ino
diff --git a/examples/esp8266/WebSocketServerFragmentation/WebSocketServerFragmentation.ino b/examples/esp8266_pico/WebSocketServerFragmentation/WebSocketServerFragmentation.ino
similarity index 100%
rename from examples/esp8266/WebSocketServerFragmentation/WebSocketServerFragmentation.ino
rename to examples/esp8266_pico/WebSocketServerFragmentation/WebSocketServerFragmentation.ino
diff --git a/examples/esp8266/WebSocketServerHooked/WebSocketServerHooked.ino b/examples/esp8266_pico/WebSocketServerHooked/WebSocketServerHooked.ino
similarity index 100%
rename from examples/esp8266/WebSocketServerHooked/WebSocketServerHooked.ino
rename to examples/esp8266_pico/WebSocketServerHooked/WebSocketServerHooked.ino
diff --git a/examples/esp8266/WebSocketServerHooked/emu b/examples/esp8266_pico/WebSocketServerHooked/emu
similarity index 100%
rename from examples/esp8266/WebSocketServerHooked/emu
rename to examples/esp8266_pico/WebSocketServerHooked/emu
diff --git a/examples/esp8266/WebSocketServerHooked/ws-testclient.py b/examples/esp8266_pico/WebSocketServerHooked/ws-testclient.py
similarity index 100%
rename from examples/esp8266/WebSocketServerHooked/ws-testclient.py
rename to examples/esp8266_pico/WebSocketServerHooked/ws-testclient.py
diff --git a/examples/esp8266/WebSocketServerHttpHeaderValidation/WebSocketServerHttpHeaderValidation.ino b/examples/esp8266_pico/WebSocketServerHttpHeaderValidation/WebSocketServerHttpHeaderValidation.ino
similarity index 100%
rename from examples/esp8266/WebSocketServerHttpHeaderValidation/WebSocketServerHttpHeaderValidation.ino
rename to examples/esp8266_pico/WebSocketServerHttpHeaderValidation/WebSocketServerHttpHeaderValidation.ino
diff --git a/examples/esp8266/WebSocketServer_LEDcontrol/WebSocketServer_LEDcontrol.ino b/examples/esp8266_pico/WebSocketServer_LEDcontrol/WebSocketServer_LEDcontrol.ino
similarity index 100%
rename from examples/esp8266/WebSocketServer_LEDcontrol/WebSocketServer_LEDcontrol.ino
rename to examples/esp8266_pico/WebSocketServer_LEDcontrol/WebSocketServer_LEDcontrol.ino
diff --git a/library.json b/library.json
index 2f7aec6..d29c1a7 100644
--- a/library.json
+++ b/library.json
@@ -16,10 +16,10 @@
     "keywords": "wifi, http, web, server, client, websocket",
     "license": "LGPL-2.1",
     "name": "WebSockets",
-    "platforms": "atmelavr, espressif8266, espressif32",
+    "platforms": "atmelavr, espressif8266, espressif32, raspberrypi",
     "repository": {
         "type": "git",
         "url": "https://github.com/Links2004/arduinoWebSockets.git"
     },
-    "version": "2.3.6"
+    "version": "2.4.0"
 }
\ No newline at end of file
diff --git a/library.properties b/library.properties
index b9899d0..097048e 100644
--- a/library.properties
+++ b/library.properties
@@ -1,5 +1,5 @@
 name=WebSockets
-version=2.3.6
+version=2.4.0
 author=Markus Sattler
 maintainer=Markus Sattler
 sentence=WebSockets for Arduino (Server + Client)
diff --git a/src/WebSockets.cpp b/src/WebSockets.cpp
index 49f5480..260129f 100644
--- a/src/WebSockets.cpp
+++ b/src/WebSockets.cpp
@@ -482,7 +482,7 @@ void WebSockets::handleWebsocketPayloadCb(WSclient_t * client, bool ok, uint8_t
         switch(header->opCode) {
             case WSop_text:
                 DEBUG_WEBSOCKETS("[WS][%d][handleWebsocket] text: %s\n", client->num, payload);
-                // no break here!
+                // fallthrough
             case WSop_binary:
             case WSop_continuation:
                 messageReceived(client, header->opCode, payload, header->payloadLen, header->fin);
diff --git a/src/WebSockets.h b/src/WebSockets.h
index 60c13d9..db6c0e8 100644
--- a/src/WebSockets.h
+++ b/src/WebSockets.h
@@ -50,7 +50,7 @@
         DEBUG_ESP_PORT.flush();             \
     }
 #else
-//#define DEBUG_WEBSOCKETS(...) os_printf( __VA_ARGS__ )
+// #define DEBUG_WEBSOCKETS(...) os_printf( __VA_ARGS__ )
 #endif
 #endif
 
@@ -67,7 +67,7 @@
 #define WEBSOCKETS_USE_BIG_MEM
 #define GET_FREE_HEAP ESP.getFreeHeap()
 // moves all Header strings to Flash (~300 Byte)
-//#define WEBSOCKETS_SAVE_RAM
+// #define WEBSOCKETS_SAVE_RAM
 
 #if defined(ESP8266)
 #define WEBSOCKETS_YIELD() delay(0)
@@ -84,6 +84,15 @@
 #define GET_FREE_HEAP System.freeMemory()
 #define WEBSOCKETS_YIELD()
 #define WEBSOCKETS_YIELD_MORE()
+
+#elif defined(ARDUINO_ARCH_RP2040)
+
+#define WEBSOCKETS_MAX_DATA_SIZE (15 * 1024)
+#define WEBSOCKETS_USE_BIG_MEM
+#define GET_FREE_HEAP rp2040.getFreeHeap()
+#define WEBSOCKETS_YIELD() yield()
+#define WEBSOCKETS_YIELD_MORE() delay(1)
+
 #else
 
 // atmega328p has only 2KB ram!
@@ -94,7 +103,9 @@
 #define WEBSOCKETS_YIELD_MORE()
 #endif
 
+#ifndef WEBSOCKETS_TCP_TIMEOUT
 #define WEBSOCKETS_TCP_TIMEOUT (5000)
+#endif
 
 #define NETWORK_ESP8266_ASYNC (0)
 #define NETWORK_ESP8266 (1)
@@ -102,6 +113,7 @@
 #define NETWORK_ENC28J60 (3)
 #define NETWORK_ESP32 (4)
 #define NETWORK_ESP32_ETH (5)
+#define NETWORK_RP2040 (6)
 
 // max size of the WS Message Header
 #define WEBSOCKETS_MAX_HEADER_SIZE (14)
@@ -110,12 +122,16 @@
 // select Network type based
 #if defined(ESP8266) || defined(ESP31B)
 #define WEBSOCKETS_NETWORK_TYPE NETWORK_ESP8266
-//#define WEBSOCKETS_NETWORK_TYPE NETWORK_ESP8266_ASYNC
-//#define WEBSOCKETS_NETWORK_TYPE NETWORK_W5100
+// #define WEBSOCKETS_NETWORK_TYPE NETWORK_ESP8266_ASYNC
+// #define WEBSOCKETS_NETWORK_TYPE NETWORK_W5100
 
 #elif defined(ESP32)
 #define WEBSOCKETS_NETWORK_TYPE NETWORK_ESP32
-//#define WEBSOCKETS_NETWORK_TYPE NETWORK_ESP32_ETH
+// #define WEBSOCKETS_NETWORK_TYPE NETWORK_ESP32_ETH
+
+#elif defined(ARDUINO_ARCH_RP2040)
+#define WEBSOCKETS_NETWORK_TYPE NETWORK_RP2040
+
 #else
 #define WEBSOCKETS_NETWORK_TYPE NETWORK_W5100
 
@@ -199,6 +215,15 @@
 #define WEBSOCKETS_NETWORK_CLASS WiFiClient
 #define WEBSOCKETS_NETWORK_SERVER_CLASS WiFiServer
 
+#elif(WEBSOCKETS_NETWORK_TYPE == NETWORK_RP2040)
+
+#include <WiFi.h>
+#include <WiFiClientSecure.h>
+#define SSL_BARESSL
+#define WEBSOCKETS_NETWORK_CLASS WiFiClient
+#define WEBSOCKETS_NETWORK_SSL_CLASS WiFiClientSecure
+#define WEBSOCKETS_NETWORK_SERVER_CLASS WiFiServer
+
 #else
 #error "no network type selected!"
 #endif
diff --git a/src/WebSockets4WebServer.h b/src/WebSockets4WebServer.h
index ba2b020..595f38b 100644
--- a/src/WebSockets4WebServer.h
+++ b/src/WebSockets4WebServer.h
@@ -28,23 +28,29 @@
 #include <WebSocketsServer.h>
 #include <ESP8266WebServer.h>
 
-#if WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP8266 && WEBSERVER_HAS_HOOK
+#if((WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP8266) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_RP2040)) && WEBSERVER_HAS_HOOK
 
 class WebSockets4WebServer : public WebSocketsServerCore {
+#if defined(ESP8266)
+    using WebServerClass = ESP8266WebServer;
+#else
+    using WebServerClass = WebServer;
+#endif
+
   public:
     WebSockets4WebServer(const String & origin = "", const String & protocol = "arduino")
         : WebSocketsServerCore(origin, protocol) {
         begin();
     }
 
-    ESP8266WebServer::HookFunction hookForWebserver(const String & wsRootDir, WebSocketServerEvent event) {
+    WebServerClass::HookFunction hookForWebserver(const String & wsRootDir, WebSocketServerEvent event) {
         onEvent(event);
 
-        return [&, wsRootDir](const String & method, const String & url, WiFiClient * tcpClient, ESP8266WebServer::ContentTypeFunction contentType) {
+        return [&, wsRootDir](const String & method, const String & url, WiFiClient * tcpClient, WebServerClass::ContentTypeFunction contentType) {
             (void)contentType;
 
             if(!(method == "GET" && url.indexOf(wsRootDir) == 0)) {
-                return ESP8266WebServer::CLIENT_REQUEST_CAN_CONTINUE;
+                return WebServerClass::CLIENT_REQUEST_CAN_CONTINUE;
             }
 
             // allocate a WiFiClient copy (like in WebSocketsServer::handleNewClients())
@@ -63,7 +69,7 @@ class WebSockets4WebServer : public WebSocketsServerCore {
             }
 
             // tell webserver to not close but forget about this client
-            return ESP8266WebServer::CLIENT_IS_GIVEN;
+            return WebServerClass::CLIENT_IS_GIVEN;
         };
     }
 };
diff --git a/src/WebSocketsClient.cpp b/src/WebSocketsClient.cpp
index 2be6f32..f1155e0 100644
--- a/src/WebSocketsClient.cpp
+++ b/src/WebSocketsClient.cpp
@@ -76,6 +76,8 @@ void WebSocketsClient::begin(const char * host, uint16_t port, const char * url,
 
 #ifdef ESP8266
     randomSeed(RANDOM_REG32);
+#elif defined(ARDUINO_ARCH_RP2040)
+    randomSeed(rp2040.hwrand32());
 #else
     // todo find better seed
     randomSeed(millis());
@@ -224,7 +226,7 @@ void WebSocketsClient::loop(void) {
                 _client.ssl->setCACert(_CA_cert);
 #elif defined(ESP8266) && defined(SSL_AXTLS)
                 _client.ssl->setCACert((const uint8_t *)_CA_cert, strlen(_CA_cert) + 1);
-#elif defined(ESP8266) && defined(SSL_BARESSL)
+#elif(defined(ESP8266) || defined(ARDUINO_ARCH_RP2040)) && defined(SSL_BARESSL)
                 _client.ssl->setTrustAnchors(_CA_cert);
 #else
 #error setCACert not implemented
@@ -426,9 +428,9 @@ bool WebSocketsClient::isConnected(void) {
     return (_client.status == WSC_CONNECTED);
 }
 
-//#################################################################################
-//#################################################################################
-//#################################################################################
+// #################################################################################
+// #################################################################################
+// #################################################################################
 
 /**
  *
@@ -473,7 +475,7 @@ void WebSocketsClient::messageReceived(WSclient_t * client, WSopcode_t opcode, u
 void WebSocketsClient::clientDisconnect(WSclient_t * client) {
     bool event = false;
 
-#if(WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP8266) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP32)
+#if(WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP8266) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP32) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_RP2040)
     if(client->isSSL && client->ssl) {
         if(client->ssl->connected()) {
             client->ssl->flush();
@@ -733,7 +735,7 @@ void WebSocketsClient::handleHeader(WSclient_t * client, String * headerLine) {
                 client->cExtensions = headerValue;
             } else if(headerName.equalsIgnoreCase(WEBSOCKETS_STRING("Sec-WebSocket-Version"))) {
                 client->cVersion = headerValue.toInt();
-            } else if(headerName.equalsIgnoreCase(WEBSOCKETS_STRING("Set-Cookie"))) {
+            } else if(headerName.equalsIgnoreCase(WEBSOCKETS_STRING("Set-Cookie")) && headerValue.indexOf(" io=") > -1) {
                 if(headerValue.indexOf(';') > -1) {
                     client->cSessionId = headerValue.substring(headerValue.indexOf('=') + 1, headerValue.indexOf(";"));
                 } else {
@@ -864,7 +866,7 @@ void WebSocketsClient::connectedCb() {
     _client.tcp->setTimeout(WEBSOCKETS_TCP_TIMEOUT);
 #endif
 
-#if(WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP8266) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP32)
+#if(WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP8266) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP32) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_RP2040)
     _client.tcp->setNoDelay(true);
 #endif
 
diff --git a/src/WebSocketsServer.cpp b/src/WebSocketsServer.cpp
index c2f533b..79a52ce 100644
--- a/src/WebSocketsServer.cpp
+++ b/src/WebSocketsServer.cpp
@@ -85,6 +85,8 @@ void WebSocketsServerCore::begin(void) {
 #elif defined(ESP32)
 #define DR_REG_RNG_BASE 0x3ff75144
     randomSeed(READ_PERI_REG(DR_REG_RNG_BASE));
+#elif defined(ARDUINO_ARCH_RP2040)
+    randomSeed(rp2040.hwrand32());
 #else
     // TODO find better seed
     randomSeed(millis());
@@ -394,7 +396,7 @@ bool WebSocketsServerCore::clientIsConnected(uint8_t num) {
     return clientIsConnected(client);
 }
 
-#if(WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP8266) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP8266_ASYNC) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP32)
+#if(WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP8266) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP8266_ASYNC) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP32) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_RP2040)
 /**
  * get an IP for a client
  * @param num uint8_t client id
@@ -412,9 +414,9 @@ IPAddress WebSocketsServerCore::remoteIP(uint8_t num) {
 }
 #endif
 
-//#################################################################################
-//#################################################################################
-//#################################################################################
+// #################################################################################
+// #################################################################################
+// #################################################################################
 
 /**
  * handle new client connection
@@ -439,7 +441,7 @@ WSclient_t * WebSocketsServerCore::newClient(WEBSOCKETS_NETWORK_CLASS * TCPclien
             client->tcp->setTimeout(WEBSOCKETS_TCP_TIMEOUT);
 #endif
             client->status = WSC_HEADER;
-#if(WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP8266) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP8266_ASYNC) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP32)
+#if(WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP8266) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP8266_ASYNC) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP32) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_RP2040)
 #ifndef NODEBUG_WEBSOCKETS
             IPAddress ip = client->tcp->remoteIP();
 #endif
@@ -521,7 +523,7 @@ void WebSocketsServerCore::dropNativeClient(WSclient_t * client) {
     }
     if(client->tcp) {
         if(client->tcp->connected()) {
-#if(WEBSOCKETS_NETWORK_TYPE != NETWORK_ESP8266_ASYNC) && (WEBSOCKETS_NETWORK_TYPE != NETWORK_ESP32)
+#if(WEBSOCKETS_NETWORK_TYPE != NETWORK_ESP8266_ASYNC) && (WEBSOCKETS_NETWORK_TYPE != NETWORK_ESP32) && (WEBSOCKETS_NETWORK_TYPE != NETWORK_RP2040)
             client->tcp->flush();
 #endif
             client->tcp->stop();
@@ -540,7 +542,7 @@ void WebSocketsServerCore::dropNativeClient(WSclient_t * client) {
  * @param client WSclient_t *  ptr to the client struct
  */
 void WebSocketsServerCore::clientDisconnect(WSclient_t * client) {
-#if(WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP8266) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP32)
+#if(WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP8266) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP32) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_RP2040)
     if(client->isSSL && client->ssl) {
         if(client->ssl->connected()) {
             client->ssl->flush();
@@ -614,7 +616,7 @@ WSclient_t * WebSocketsServerCore::handleNewClient(WEBSOCKETS_NETWORK_CLASS * tc
 
     if(!client) {
         // no free space to handle client
-#if(WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP8266) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP32)
+#if(WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP8266) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP32) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_RP2040)
 #ifndef NODEBUG_WEBSOCKETS
         IPAddress ip = tcpClient->remoteIP();
 #endif
@@ -627,6 +629,7 @@ WSclient_t * WebSocketsServerCore::handleNewClient(WEBSOCKETS_NETWORK_CLASS * tc
         client           = &dummy;
         client->tcp      = tcpClient;
         dropNativeClient(client);
+        return nullptr;
     }
 
     WEBSOCKETS_YIELD();
@@ -638,7 +641,7 @@ WSclient_t * WebSocketsServerCore::handleNewClient(WEBSOCKETS_NETWORK_CLASS * tc
  * Handle incoming Connection Request
  */
 void WebSocketsServer::handleNewClients(void) {
-#if(WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP8266) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP32)
+#if(WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP8266) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP32) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_RP2040)
     while(_server->hasClient()) {
 #endif
 
@@ -651,7 +654,7 @@ void WebSocketsServer::handleNewClients(void) {
 
         handleNewClient(tcpClient);
 
-#if(WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP8266) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP32)
+#if(WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP8266) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP32) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_RP2040)
     }
 #endif
 }
@@ -922,7 +925,7 @@ void WebSocketsServer::begin(void) {
 
 void WebSocketsServer::close(void) {
     WebSocketsServerCore::close();
-#if(WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP8266)
+#if(WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP8266) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_RP2040)
     _server->close();
 #elif(WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP32) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP8266_ASYNC)
     _server->end();
diff --git a/src/WebSocketsServer.h b/src/WebSocketsServer.h
index 543cba9..197c37f 100644
--- a/src/WebSocketsServer.h
+++ b/src/WebSocketsServer.h
@@ -90,7 +90,7 @@ class WebSocketsServerCore : protected WebSockets {
     void enableHeartbeat(uint32_t pingInterval, uint32_t pongTimeout, uint8_t disconnectTimeoutCount);
     void disableHeartbeat();
 
-#if(WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP8266) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP8266_ASYNC) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP32)
+#if(WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP8266) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP8266_ASYNC) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_ESP32) || (WEBSOCKETS_NETWORK_TYPE == NETWORK_RP2040)
     IPAddress remoteIP(uint8_t num);
 #endif
 
diff --git a/src/WebSocketsVersion.h b/src/WebSocketsVersion.h
index e0ab39c..e349bbf 100644
--- a/src/WebSocketsVersion.h
+++ b/src/WebSocketsVersion.h
@@ -1,6 +1,6 @@
 /**
  * @file WebSocketsVersion.h
- * @date 08.03.2021
+ * @date 01.05.2023
  * @author Markus Sattler
  *
  * Copyright (c) 2015 Markus Sattler. All rights reserved.
@@ -25,12 +25,12 @@
 #ifndef WEBSOCKETSVERSION_H_
 #define WEBSOCKETSVERSION_H_
 
-#define WEBSOCKETS_VERSION "2.3.6"
+#define WEBSOCKETS_VERSION "2.4.0"
 
 #define WEBSOCKETS_VERSION_MAJOR 2
-#define WEBSOCKETS_VERSION_MINOR 3
-#define WEBSOCKETS_VERSION_PATCH 6
+#define WEBSOCKETS_VERSION_MINOR 4
+#define WEBSOCKETS_VERSION_PATCH 0
 
-#define WEBSOCKETS_VERSION_INT 2003006
+#define WEBSOCKETS_VERSION_INT 2004000
 
 #endif /* WEBSOCKETSVERSION_H_ */
diff --git a/src/libb64/cdecode.c b/src/libb64/cdecode.c
index e135da2..615068a 100644
--- a/src/libb64/cdecode.c
+++ b/src/libb64/cdecode.c
@@ -9,7 +9,7 @@ For details, see http://sourceforge.net/projects/libb64
 #include <core_esp8266_features.h>
 #endif
 
-#if defined(ESP32)
+#if defined(ESP32) || defined(ARDUINO_ARCH_RP2040)
 #define CORE_HAS_LIBB64
 #endif
 
diff --git a/src/libb64/cencode.c b/src/libb64/cencode.c
index afe1463..cdc0f67 100644
--- a/src/libb64/cencode.c
+++ b/src/libb64/cencode.c
@@ -9,7 +9,7 @@ For details, see http://sourceforge.net/projects/libb64
 #include <core_esp8266_features.h>
 #endif
 
-#if defined(ESP32)
+#if defined(ESP32) || defined(ARDUINO_ARCH_RP2040)
 #define CORE_HAS_LIBB64
 #endif
 
diff --git a/travis/common.sh b/travis/common.sh
index c1c2328..2754bdc 100644
--- a/travis/common.sh
+++ b/travis/common.sh
@@ -1,6 +1,6 @@
 #!/bin/bash
 
-set -ex
+set -x
 
 function build_sketches()
 {
@@ -33,7 +33,7 @@ function build_sketch()
 {
     local arduino=$1
     local sketch=$2
-    $arduino --verify $sketch;
+    $arduino --verify --verbose $sketch;
     local result=$?
     if [ $result -ne 0 ]; then
         echo "Build failed ($sketch) build verbose..."