diff --git a/pom.xml b/pom.xml
index 9b2666a..f2bade1 100644
--- a/pom.xml
+++ b/pom.xml
@@ -2,7 +2,7 @@
 	<modelVersion>4.0.0</modelVersion>
 	<groupId>de.malkusch.km200</groupId>
 	<artifactId>km200</artifactId>
-	<version>2.1.4-SNAPSHOT</version>
+	<version>3.0.0-SNAPSHOT</version>
 	<name>KM200</name>
 	<description>KM200 API</description>
 	<parent>
@@ -17,8 +17,8 @@
 	</scm>
 	<properties>
 		<github.repository>malkusch/km200</github.repository>
-		<maven.compiler.source>17</maven.compiler.source>
-		<maven.compiler.target>17</maven.compiler.target>
+		<maven.compiler.source>21</maven.compiler.source>
+		<maven.compiler.target>21</maven.compiler.target>
 		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 	</properties>
 	<dependencies>
diff --git a/src/main/java/de/malkusch/km200/KM200.java b/src/main/java/de/malkusch/km200/KM200.java
index da9df32..f80fc0b 100644
--- a/src/main/java/de/malkusch/km200/KM200.java
+++ b/src/main/java/de/malkusch/km200/KM200.java
@@ -212,19 +212,15 @@ public String query(String path) throws KM200Exception, IOException, Interrupted
             throw new KM200Exception("No response when querying " + path);
         }
         var decrypted = comm.decodeMessage(device, encrypted);
-        if (decrypted == null) {
-            throw new KM200Exception("Could not decrypt query " + path);
-        }
-        if (path.equals("/gateway/firmware")) {
-            return decrypted;
-        } else {
-            if (!decrypted.startsWith("{")) {
-                throw new KM200Exception(
-                        String.format("Could not decrypt query %s. Body was:\n%s\n\n Decrypted was:\n%s", path,
-                                encrypted, decrypted));
-            }
-        }
-        return decrypted;
+
+        return switch (decrypted) {
+        case String d when path.equals("/gateway/firmware") -> decrypted;
+        case String d when d.startsWith("{") -> decrypted;
+
+        case null -> throw new KM200Exception("Could not decrypt query " + path);
+        case String d -> throw new KM200Exception(String.format(
+                "Could not decrypt query %s. Body was:\n%s\n\n Decrypted was:\n%s", path, encrypted, decrypted));
+        };
     }
 
     public double queryDouble(String path) throws KM200Exception, IOException, InterruptedException {
@@ -267,8 +263,13 @@ private static void assertHttpUri(String var) {
         assertNotBlank(var, "Wrong uri " + var);
         var uri = URI.create(var);
 
-        var scheme = uri.getScheme();
-        if (scheme == null || !(scheme.equalsIgnoreCase("http") || scheme.equalsIgnoreCase("https"))) {
+        switch (uri.getScheme()) {
+        case String s when s.equalsIgnoreCase("http"):
+            break;
+        case String s when s.equalsIgnoreCase("https"):
+            break;
+
+        case null, default:
             throw new IllegalArgumentException("Wrong uri " + var);
         }
     }
diff --git a/src/main/java/de/malkusch/km200/KM200Endpoint.java b/src/main/java/de/malkusch/km200/KM200Endpoint.java
index 9d13945..0a9dc81 100644
--- a/src/main/java/de/malkusch/km200/KM200Endpoint.java
+++ b/src/main/java/de/malkusch/km200/KM200Endpoint.java
@@ -12,7 +12,7 @@
 
 import de.malkusch.km200.KM200Exception.Forbidden;
 
-public abstract class KM200Endpoint {
+public abstract sealed class KM200Endpoint {
     private final String path;
     private final String type;
 
@@ -30,7 +30,7 @@ public String toString() {
         return String.format("%s [%s]", path, type);
     }
 
-    public static class Value extends KM200Endpoint {
+    public static final class Value extends KM200Endpoint {
         private final String body;
         private final boolean writeable;
         private final boolean recordable;
@@ -57,13 +57,13 @@ public String toString() {
         }
     }
 
-    public static class ForbiddenNode extends KM200Endpoint {
+    public static final class ForbiddenNode extends KM200Endpoint {
         ForbiddenNode(String path) {
             super(path, "Forbidden");
         }
     }
 
-    public static class UnknownNode extends KM200Endpoint {
+    public static final class UnknownNode extends KM200Endpoint {
         private final String value;
 
         UnknownNode(String path, String type, String value) {
@@ -139,14 +139,11 @@ private static Value value(String path, String type, JsonNode json) {
             var writeable = json.path("writeable").asBoolean(false);
             var recordable = json.path("recordable").asBoolean(false);
 
-            String value;
-            if (json.has("value")) {
-                value = json.get("value").asText();
-            } else if (json.has("values")) {
-                value = json.get("values").toString();
-            } else {
-                value = json.toString();
-            }
+            String value = switch (json) {
+            case JsonNode j when j.has("value") -> json.get("value").asText();
+            case JsonNode j when j.has("values") -> json.get("values").toString();
+            default -> json.toString();
+            };
 
             String allowedValues = null;
             if (json.has("allowedValues")) {
diff --git a/src/main/java/de/malkusch/km200/http/Http.java b/src/main/java/de/malkusch/km200/http/Http.java
index 6659b4f..11e3d8c 100644
--- a/src/main/java/de/malkusch/km200/http/Http.java
+++ b/src/main/java/de/malkusch/km200/http/Http.java
@@ -41,19 +41,15 @@ public final Response post(String path, byte[] body) throws KM200Exception, IOEx
     protected abstract Response exchange(Request request) throws IOException, InterruptedException, KM200Exception;
 
     static Response assertHttpOk(Request request, Response response) throws KM200Exception {
-        var status = response.status();
-        if (status >= 200 && status <= 299) {
-            return response;
-
-        } else {
-            throw switch (status) {
-            case 400 -> new KM200Exception.BadRequest(request + " was a bad request");
-            case 403 -> new KM200Exception.Forbidden(request + " is forbidden");
-            case 404 -> new KM200Exception.NotFound(request + " was not found");
-            case 423 -> new KM200Exception.Locked(request + " was locked");
-            case 500 -> new KM200Exception.ServerError(request + " resulted in a server error");
-            default -> new KM200Exception(request + " failed with response code " + status);
-            };
-        }
+        return switch ((Integer) response.status()) {
+        case Integer status when (status >= 200 && status <= 299) -> response;
+
+        case 400 -> throw new KM200Exception.BadRequest(request + " was a bad request");
+        case 403 -> throw new KM200Exception.Forbidden(request + " is forbidden");
+        case 404 -> throw new KM200Exception.NotFound(request + " was not found");
+        case 423 -> throw new KM200Exception.Locked(request + " was locked");
+        case 500 -> throw new KM200Exception.ServerError(request + " resulted in a server error");
+        default -> throw new KM200Exception(request + " failed with response code " + response.status());
+        };
     }
 }
diff --git a/src/main/java/de/malkusch/km200/http/RetryHttp.java b/src/main/java/de/malkusch/km200/http/RetryHttp.java
index 9c0a042..b95695f 100644
--- a/src/main/java/de/malkusch/km200/http/RetryHttp.java
+++ b/src/main/java/de/malkusch/km200/http/RetryHttp.java
@@ -34,17 +34,12 @@ public Response exchange(Request request) throws IOException, InterruptedExcepti
             return retry.get(() -> http.exchange(request));
 
         } catch (FailsafeException e) {
-            if (e.getCause() instanceof IOException cause) {
-                throw cause;
-
-            } else if (e.getCause() instanceof InterruptedException cause) {
-                throw cause;
-
-            } else if (e.getCause() instanceof KM200Exception cause) {
-                throw cause;
-
-            } else {
-                throw new KM200Exception("Unexpected retry error for " + request.path(), e);
+            switch (e.getCause()) {
+            case IOException cause -> throw cause;
+            case InterruptedException cause -> throw cause;
+            case KM200Exception cause -> throw cause;
+            case Throwable cause -> throw new KM200Exception("Unexpected retry error for " + request.path(), cause);
+            case null -> throw new KM200Exception("Unexpected retry error for " + request.path(), e);
             }
         }
     }
diff --git a/src/main/java/de/malkusch/km200/http/UrlHttp.java b/src/main/java/de/malkusch/km200/http/UrlHttp.java
index becd95c..fe445fe 100644
--- a/src/main/java/de/malkusch/km200/http/UrlHttp.java
+++ b/src/main/java/de/malkusch/km200/http/UrlHttp.java
@@ -1,6 +1,7 @@
 package de.malkusch.km200.http;
 
 import java.io.IOException;
+import java.io.InputStream;
 import java.net.HttpURLConnection;
 import java.net.MalformedURLException;
 import java.net.SocketTimeoutException;
@@ -45,9 +46,11 @@ protected Response exchange(Request request) throws IOException, InterruptedExce
                 throw new IOException(request + " received invalid HTTP response");
             }
 
-            try (var input = connection.getErrorStream() != null ? connection.getErrorStream()
-                    : connection.getInputStream()) {
-
+            var input = switch (connection.getErrorStream()) {
+            case InputStream error -> error;
+            case null -> connection.getInputStream();
+            };
+            try (input) {
                 var body = input.readAllBytes();
                 var response = new Response(status, body);
                 return assertHttpOk(request, response);
@@ -63,7 +66,12 @@ protected Response exchange(Request request) throws IOException, InterruptedExce
 
     private HttpURLConnection connect(Request request) throws IOException {
         try {
-            var connection = (HttpURLConnection) new URL(uri + request.path()).openConnection();
+            var url = new URL(uri + request.path());
+
+            if (!(url.openConnection() instanceof HttpURLConnection connection)) {
+                throw new IllegalStateException(url + " is not a http url");
+            }
+
             connection.setConnectTimeout(timeoutMillis);
             connection.setReadTimeout(timeoutMillis);
             connection.setRequestProperty("User-Agent", userAgent);
@@ -74,7 +82,6 @@ private HttpURLConnection connect(Request request) throws IOException {
             }
 
             connection.connect();
-
             return connection;
 
         } catch (MalformedURLException e) {