diff --git a/build.gradle b/build.gradle
index 83ca068..72a1d4a 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1,108 +1,85 @@
 plugins {
     id 'application'
-    id 'com.github.johnrengelman.shadow' version '7.1.1'
-
-    // Used by release.gradle
+    id 'com.github.johnrengelman.shadow' version '8.1.1'
     id 'maven-publish'
-    id 'signing'
-    id 'io.codearte.nexus-staging' version '0.30.0'
 }
 
-apply plugin: 'application'
-apply plugin: 'com.github.johnrengelman.shadow'
-
-group 'nl.martijndwars'
-version '5.1.2'
+group 'com.nexxto'
+version '6.0.1'
 
 repositories {
-    mavenLocal()
     mavenCentral()
+    maven {
+        name = "GitHubPackages"
+        url = "https://maven.pkg.github.com/nexxto/webpush-java" 
+        credentials {
+            username = System.getenv("GPR_USER")
+            password = System.getenv("GPR_TOKEN")
+        }
+    }
 }
 
-dependencies {
-    // For CLI
-    implementation group: 'com.beust', name: 'jcommander', version: '1.81'
-
-    // For making HTTP requests
-    implementation group: 'org.apache.httpcomponents', name: 'httpasyncclient', version: '4.1.5'
-
-    // For making async HTTP requests
-    implementation group: 'org.asynchttpclient', name: 'async-http-client', version: '2.12.4'
-
-    // For cryptographic operations
-    shadow group: 'org.bouncycastle', name: 'bcprov-jdk15on', version: '1.70'
-
-    // For creating and signing JWT
-    implementation group: 'org.bitbucket.b_c', name: 'jose4j', version: '0.9.6'
-
-    // For parsing JSON
-    testImplementation group: 'com.google.code.gson', name: 'gson', version: '2.8.9'
-
-    // For making HTTP requests
-    testImplementation group: 'org.apache.httpcomponents', name: 'fluent-hc', version: '4.5.13'
-
-    // For testing, obviously
-    testImplementation group: 'org.junit.jupiter', name: 'junit-jupiter-api', version: '5.8.1'
-
-    // For running JUnit tests
-    testRuntimeOnly group: 'org.junit.jupiter', name: 'junit-jupiter-engine', version: '5.8.1'
-
-    // For turning InputStream to String
-    testImplementation group: 'commons-io', name: 'commons-io', version: '2.11.0'
-
-    // For reading the demo vapid keypair from a pem file
-    testImplementation group: 'org.bouncycastle', name: 'bcpkix-jdk15on', version: '1.70'
-
-    // For verifying Base64Encoder results in unit tests
-    testImplementation group: 'com.google.guava', name: 'guava', version: '33.4.8-jre'
+publishing {
+    publications {
+        mavenJava(MavenPublication) {
+            from components.java
+        }
+    }
+    repositories {
+        maven {
+            name = "GitHubPackages"
+            url = "https://maven.pkg.github.com/nexxto/webpush-java"
+            credentials {
+                username = project.findProperty("gprUser") ?: System.getenv("GPR_USER")
+                password = project.findProperty("gprToken") ?: System.getenv("GPR_TOKEN")
+            }
+        }
+    }
 }
 
-wrapper {
-    gradleVersion = '5.1'
-}
 
-compileJava {
-    sourceCompatibility = 1.8
-    targetCompatibility = 1.8
-}
 
-compileTestJava {
-    sourceCompatibility = 1.8
+dependencies {
+    implementation 'com.beust:jcommander:1.81'
+    implementation 'org.apache.httpcomponents:httpasyncclient:4.1.5'
+    implementation 'org.asynchttpclient:async-http-client:2.12.4'
+    implementation 'org.bitbucket.b_c:jose4j:0.9.6'
+
+    // Include BouncyCastle in the fat JAR
+    shadow 'org.bouncycastle:bcprov-jdk18on:1.81'
+
+    testImplementation 'com.google.code.gson:gson:2.8.9'
+    testImplementation 'org.apache.httpcomponents:fluent-hc:4.5.13'
+    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.8.1'
+    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.8.1'
+    testImplementation 'commons-io:commons-io:2.11.0'
+    testImplementation 'org.bouncycastle:bcprov-jdk18on:1.81'
+    testImplementation 'com.google.guava:guava:33.4.8-jre'
 }
 
-mainClassName = 'nl.martijndwars.webpush.cli.Cli'
-
-run {
-    classpath configurations.shadow.files
+wrapper {
+    gradleVersion = '8.5'
+    distributionType = Wrapper.DistributionType.ALL
 }
 
-test {
-    useJUnitPlatform()
-
-    testLogging {
-        events 'PASSED', 'FAILED', 'SKIPPED'
-        showStandardStreams true
-        exceptionFormat 'full'
+java {
+    toolchain {
+        languageVersion = JavaLanguageVersion.of(21) // Use your installed JDK 21
     }
-
-    exclude '**/SeleniumTests.class'
 }
 
-task javadocJar(type: Jar) {
-    classifier = 'javadoc'
-    from javadoc
+tasks.withType(JavaCompile).configureEach {
+    options.release = 17 // Compile as if targeting Java 17
 }
 
-task sourcesJar(type: Jar) {
-    classifier = 'sources'
-    from sourceSets.main.allSource
+application {
+    mainClass = 'nl.martijndwars.webpush.cli.Cli'
 }
 
-artifacts {
-    archives javadocJar
-    archives sourcesJar
-}
-
-if (hasProperty('release')) {
-    apply from: 'release.gradle'
+testing {
+    suites {
+        test {
+            useJUnitJupiter()
+        }
+    }
 }
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index ffed3a2..d0d403e 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.5-all.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
diff --git a/gradlew b/gradlew
index 1b6c787..c53aefa 100755
--- a/gradlew
+++ b/gradlew
@@ -1,7 +1,7 @@
 #!/bin/sh
 
 #
-# Copyright © 2015-2021 the original authors.
+# Copyright © 2015-2021 the original authors.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -32,10 +32,10 @@
 #       Busybox and similar reduced shells will NOT work, because this script
 #       requires all of these POSIX shell features:
 #         * functions;
-#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
-#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
-#         * compound commands having a testable exit status, especially «case»;
-#         * various built-in commands including «command», «set», and «ulimit».
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
 #
 #   Important for patching:
 #
diff --git a/src/test/java/nl/martijndwars/webpush/selenium/BrowserTest.java b/src/test/java/nl/martijndwars/webpush/selenium/BrowserTest.java
deleted file mode 100644
index 37ed6d2..0000000
--- a/src/test/java/nl/martijndwars/webpush/selenium/BrowserTest.java
+++ /dev/null
@@ -1,78 +0,0 @@
-package nl.martijndwars.webpush.selenium;
-
-import com.google.gson.Gson;
-import com.google.gson.JsonArray;
-import com.google.gson.JsonObject;
-import com.google.gson.JsonPrimitive;
-import nl.martijndwars.webpush.Notification;
-import nl.martijndwars.webpush.PushService;
-import nl.martijndwars.webpush.Subscription;
-import org.apache.http.HttpResponse;
-import org.junit.jupiter.api.function.Executable;
-
-import java.security.GeneralSecurityException;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-
-public class BrowserTest implements Executable {
-    public static final String GCM_API_KEY = "AIzaSyBAU0VfXoskxUSg81K5VgLgwblHbZWe6tA";
-    public static final String PUBLIC_KEY = "BNFDO1MUnNpx0SuQyQcAAWYETa2+W8z/uc5sxByf/UZLHwAhFLwEDxS5iB654KHiryq0AxDhFXS7DVqXDKjjN+8=";
-    public static final String PRIVATE_KEY = "AM0aAyoIryzARADnIsSCwg1p1aWFAL3Idc8dNXpf74MH";
-    public static final String VAPID_SUBJECT = "http://localhost:8090";
-
-    private TestingService testingService;
-    private Configuration configuration;
-    private int testSuiteId;
-
-    public BrowserTest(TestingService testingService, Configuration configuration, int testSuiteId) {
-        this.configuration = configuration;
-        this.testingService = testingService;
-        this.testSuiteId = testSuiteId;
-    }
-
-    /**
-     * Execute the test for the given browser configuration.
-     *
-     * @throws Throwable
-     */
-    @Override
-    public void execute() throws Throwable {
-        PushService pushService = getPushService();
-
-        JsonObject test = testingService.getSubscription(testSuiteId, configuration);
-
-        int testId = test.get("testId").getAsInt();
-
-        Subscription subscription = new Gson().fromJson(test.get("subscription").getAsJsonObject(), Subscription.class);
-
-        String message = "Hëllö, world!";
-        Notification notification = new Notification(subscription, message);
-
-        HttpResponse response = pushService.send(notification);
-        assertEquals(201, response.getStatusLine().getStatusCode());
-
-        JsonArray messages = testingService.getNotificationStatus(testSuiteId, testId);
-        assertEquals(1, messages.size());
-        assertEquals(new JsonPrimitive(message), messages.get(0));
-    }
-
-    protected PushService getPushService() throws GeneralSecurityException {
-        PushService pushService;
-
-        if (!configuration.isVapid()) {
-            pushService = new PushService(GCM_API_KEY);
-        } else {
-            pushService = new PushService(PUBLIC_KEY, PRIVATE_KEY, VAPID_SUBJECT);
-        }
-        return pushService;
-    }
-
-    /**
-     * The name used by JUnit to display the test.
-     *
-     * @return
-     */
-    public String getDisplayName() {
-        return "Browser " + configuration.browser + ", version " + configuration.version + ", vapid " + configuration.isVapid();
-    }
-}
diff --git a/src/test/java/nl/martijndwars/webpush/selenium/Configuration.java b/src/test/java/nl/martijndwars/webpush/selenium/Configuration.java
deleted file mode 100644
index 5b4e4e1..0000000
--- a/src/test/java/nl/martijndwars/webpush/selenium/Configuration.java
+++ /dev/null
@@ -1,24 +0,0 @@
-package nl.martijndwars.webpush.selenium;
-
-public class Configuration {
-    protected final String browser;
-    protected final String version;
-    protected final String publicKey;
-    protected final String gcmSenderId;
-
-    Configuration(String browser, String version, String publicKey, String gcmSenderId) {
-        this.browser = browser;
-        this.version = version;
-        this.publicKey = publicKey;
-        this.gcmSenderId = gcmSenderId;
-    }
-
-    public boolean isVapid() {
-        return publicKey != null && !publicKey.isEmpty();
-    }
-
-    @Override
-    public String toString() {
-        return browser + ", " + version + ", " + publicKey;
-    }
-}
diff --git a/src/test/java/nl/martijndwars/webpush/selenium/SeleniumTests.java b/src/test/java/nl/martijndwars/webpush/selenium/SeleniumTests.java
deleted file mode 100644
index 1054486..0000000
--- a/src/test/java/nl/martijndwars/webpush/selenium/SeleniumTests.java
+++ /dev/null
@@ -1,81 +0,0 @@
-package nl.martijndwars.webpush.selenium;
-
-import org.bouncycastle.jce.provider.BouncyCastleProvider;
-import org.junit.jupiter.api.AfterAll;
-import org.junit.jupiter.api.DynamicTest;
-import org.junit.jupiter.api.TestFactory;
-
-import java.io.IOException;
-import java.security.Security;
-import java.util.Base64;
-import java.util.stream.Stream;
-
-import static org.junit.jupiter.api.DynamicTest.dynamicTest;
-
-/**
- * SeleniumTest performs integration testing.
- */
-public class SeleniumTests {
-    protected static final String GCM_SENDER_ID = "759071690750";
-    protected static final String PUBLIC_KEY = "BNFDO1MUnNpx0SuQyQcAAWYETa2+W8z/uc5sxByf/UZLHwAhFLwEDxS5iB654KHiryq0AxDhFXS7DVqXDKjjN+8=";
-
-    protected static TestingService testingService = new TestingService("http://localhost:8090/api/");
-    protected static int testSuiteId;
-
-    public SeleniumTests() {
-        Security.addProvider(new BouncyCastleProvider());
-    }
-
-    /**
-     * End the test suite.
-     *
-     * @throws IOException
-     */
-    @AfterAll
-    public static void tearDown() throws IOException {
-        testingService.endTestSuite(testSuiteId);
-    }
-
-    /**
-     * Generate a stream of tests based on the configurations.
-     *
-     * @return
-     */
-    @TestFactory
-    public Stream<DynamicTest> dynamicTests() throws IOException {
-        testSuiteId = testingService.startTestSuite();
-
-        return getConfigurations().map(configuration -> {
-            BrowserTest browserTest = new BrowserTest(testingService, configuration, testSuiteId);
-
-            return dynamicTest(browserTest.getDisplayName(), browserTest);
-        });
-    }
-
-    /**
-     * Get browser configurations to test.
-     *
-     * @return
-     */
-    protected Stream<Configuration> getConfigurations() {
-        String PUBLIC_KEY_NO_PADDING = Base64.getUrlEncoder().withoutPadding().encodeToString(
-                Base64.getUrlDecoder().decode(PUBLIC_KEY)
-        );
-
-        return Stream.of(
-                new Configuration("chrome", "stable", null, GCM_SENDER_ID),
-                new Configuration("chrome", "beta", null, GCM_SENDER_ID),
-                //new Configuration("chrome", "unstable", null, GCM_SENDER_ID), See #90
-
-                new Configuration("firefox", "stable", null, GCM_SENDER_ID),
-                new Configuration("firefox", "beta", null, GCM_SENDER_ID),
-
-                new Configuration("chrome", "stable", PUBLIC_KEY_NO_PADDING, null),
-                new Configuration("chrome", "beta", PUBLIC_KEY_NO_PADDING, null),
-                //new Configuration("chrome", "unstable", PUBLIC_KEY_NO_PADDING, null), See #90
-
-                new Configuration("firefox", "stable", PUBLIC_KEY_NO_PADDING, null),
-                new Configuration("firefox", "beta", PUBLIC_KEY_NO_PADDING, null)
-        );
-    }
-}
diff --git a/src/test/java/nl/martijndwars/webpush/selenium/TestingService.java b/src/test/java/nl/martijndwars/webpush/selenium/TestingService.java
deleted file mode 100644
index a89f9a9..0000000
--- a/src/test/java/nl/martijndwars/webpush/selenium/TestingService.java
+++ /dev/null
@@ -1,160 +0,0 @@
-package nl.martijndwars.webpush.selenium;
-
-import com.google.gson.JsonArray;
-import com.google.gson.JsonElement;
-import com.google.gson.JsonObject;
-import com.google.gson.JsonParser;
-import org.apache.commons.io.IOUtils;
-import org.apache.http.HttpEntity;
-import org.apache.http.client.fluent.Request;
-import org.apache.http.entity.ContentType;
-import org.apache.http.entity.StringEntity;
-import org.apache.http.util.EntityUtils;
-
-import java.io.IOException;
-
-import static java.nio.charset.StandardCharsets.UTF_8;
-
-/**
- * Java wrapper for interacting with the Web Push Testing Service.
- */
-public class TestingService {
-    private String baseUrl;
-
-    public TestingService(String baseUrl) {
-        this.baseUrl = baseUrl;
-    }
-
-    /**
-     * Start a new test suite.
-     *
-     * @return
-     */
-    public int startTestSuite() throws IOException {
-        String startTestSuite = request(baseUrl + "start-test-suite/");
-
-        JsonElement root = JsonParser.parseString(startTestSuite);
-
-        return root
-                .getAsJsonObject()
-                .get("data")
-                .getAsJsonObject()
-                .get("testSuiteId")
-                .getAsInt();
-    }
-
-    /**
-     * Get a test ID and subscription for the given test case.
-     *
-     * @param testSuiteId
-     * @param configuration
-     * @return
-     * @throws IOException
-     */
-    public JsonObject getSubscription(int testSuiteId, Configuration configuration) throws IOException {
-        JsonObject jsonObject = new JsonObject();
-        jsonObject.addProperty("testSuiteId", testSuiteId);
-        jsonObject.addProperty("browserName", configuration.browser);
-        jsonObject.addProperty("browserVersion", configuration.version);
-
-        if (configuration.gcmSenderId != null) {
-            jsonObject.addProperty("gcmSenderId", configuration.gcmSenderId);
-        }
-
-        if (configuration.publicKey != null) {
-            jsonObject.addProperty("vapidPublicKey", configuration.publicKey);
-        }
-
-        HttpEntity entity = new StringEntity(jsonObject.toString(), ContentType.APPLICATION_JSON);
-
-        String getSubscription = request(baseUrl + "get-subscription/", entity);
-
-        return getData(getSubscription);
-    }
-
-    /**
-     * Get the notification status for the given test case.
-     *
-     * @param testSuiteId
-     * @param testId
-     * @return
-     * @throws IOException
-     */
-    public JsonArray getNotificationStatus(int testSuiteId, int testId) throws IOException {
-        JsonObject jsonObject = new JsonObject();
-        jsonObject.addProperty("testSuiteId", testSuiteId);
-        jsonObject.addProperty("testId", testId);
-
-        HttpEntity entity = new StringEntity(jsonObject.toString(), ContentType.APPLICATION_JSON);
-
-        String notificationStatus = request(baseUrl + "get-notification-status/", entity);
-
-        return getData(notificationStatus).get("messages").getAsJsonArray();
-    }
-
-    /**
-     * End the given test suite.
-     *
-     * @return
-     */
-    public boolean endTestSuite(int testSuiteId) throws IOException {
-        JsonObject jsonObject = new JsonObject();
-        jsonObject.addProperty("testSuiteId", testSuiteId);
-
-        HttpEntity entity = new StringEntity(jsonObject.toString(), ContentType.APPLICATION_JSON);
-
-        String endTestSuite = request(baseUrl + "end-test-suite/", entity);
-
-        return getData(endTestSuite).get("success").getAsBoolean();
-    }
-
-    /**
-     * Perform HTTP request and return response.
-     *
-     * @param uri
-     * @return
-     */
-    protected String request(String uri) throws IOException {
-        return request(uri, null);
-    }
-
-    /**
-     * Perform HTTP request and return response.
-     *
-     * @param uri
-     * @return
-     */
-    protected String request(String uri, HttpEntity entity) throws IOException {
-        return Request.Post(uri).body(entity).execute().handleResponse(httpResponse -> {
-            String json = EntityUtils.toString(httpResponse.getEntity());
-
-            if (httpResponse.getStatusLine().getStatusCode() != 200) {
-                JsonElement root = JsonParser.parseString(json);
-                JsonObject error = root.getAsJsonObject().get("error").getAsJsonObject();
-
-                String errorId = error.get("id").getAsString();
-                String errorMessage = error.get("message").getAsString();
-
-                String body = IOUtils.toString(entity.getContent(), UTF_8);
-
-                throw new IllegalStateException("Error while requesting " + uri + " with body " + body + " (" + errorId + ": " + errorMessage);
-            }
-
-            return json;
-        });
-    }
-
-    /**
-     * Get the a JSON object of the data in the JSON response.
-     *
-     * @param response
-     */
-    protected JsonObject getData(String response) {
-        JsonElement root = JsonParser.parseString(response);
-
-        return root
-                .getAsJsonObject()
-                .get("data")
-                .getAsJsonObject();
-    }
-}