Update checker

api/src/main/java/com/discordsrv/api/discord/entity/message/ReceivedDiscordMessage.java

@@ -31,6 +31,7 @@ import com.discordsrv.api.discord.entity.channel.DiscordTextChannel;
 import com.discordsrv.api.discord.entity.guild.DiscordGuild;
 import com.discordsrv.api.discord.entity.guild.DiscordGuildMember;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 import org.jetbrains.annotations.Unmodifiable;
 
 import java.util.List;
@@ -43,10 +44,11 @@ import java.util.concurrent.CompletableFuture;
 public interface ReceivedDiscordMessage extends Snowflake {
 
     /**
-     * Gets the content of this message.
-     * @return the message content
+     * Gets the content of this message. This will return {@code null} if the bot doesn't have the MESSAGE_CONTENT intent,
+     * and this message was not from the bot, did not mention the bot and was not a direct message.
+     * @return the message content or {@code null}
      */
-    @NotNull
+    @Nullable
     String getContent();
 
     /**

common/src/main/java/com/discordsrv/common/AbstractDiscordSRV.java

@@ -33,6 +33,7 @@ import com.discordsrv.common.channel.GlobalChannelLookupModule;
 import com.discordsrv.common.command.game.GameCommandModule;
 import com.discordsrv.common.component.ComponentFactory;
 import com.discordsrv.common.config.connection.ConnectionConfig;
+import com.discordsrv.common.config.connection.UpdateConfig;
 import com.discordsrv.common.config.main.LinkedAccountConfig;
 import com.discordsrv.common.config.main.MainConfig;
 import com.discordsrv.common.config.manager.ConnectionConfigManager;
@@ -71,6 +72,8 @@ import com.discordsrv.common.placeholder.result.ComponentResultStringifier;
 import com.discordsrv.common.profile.ProfileManager;
 import com.discordsrv.common.storage.Storage;
 import com.discordsrv.common.storage.StorageType;
+import com.discordsrv.common.update.UpdateChecker;
+import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import net.dv8tion.jda.api.JDA;
 import net.dv8tion.jda.api.JDAInfo;
@@ -133,12 +136,15 @@ public abstract class AbstractDiscordSRV<B extends IBootstrap, C extends MainCon
     private LinkProvider linkProvider;
 
     // Version
+    private UpdateChecker updateChecker;
     private String version;
     private String gitRevision;
     private String gitBranch;
 
     private OkHttpClient httpClient;
-    private final ObjectMapper objectMapper = new ObjectMapper();
+    private final ObjectMapper objectMapper = new ObjectMapper()
+            .configure(DeserializationFeature.FAIL_ON_IGNORED_PROPERTIES, false)
+            .configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
 
     // Internal
     private final ReentrantLock lifecycleLock = new ReentrantLock();
@@ -165,6 +171,7 @@ public abstract class AbstractDiscordSRV<B extends IBootstrap, C extends MainCon
         this.discordConnectionDetails = new DiscordConnectionDetailsImpl(this);
         this.discordConnectionManager = new JDAConnectionManager(this);
         this.channelConfig = new ChannelConfigHelper(this);
+        this.updateChecker = new UpdateChecker(this);
         readManifest();
 
         Dispatcher dispatcher = new Dispatcher();
@@ -587,6 +594,27 @@ public abstract class AbstractDiscordSRV<B extends IBootstrap, C extends MainCon
             channelConfig().reload();
         }
 
+        // Update check
+        UpdateConfig updateConfig = connectionConfig().update;
+        if (updateConfig.security.enabled) {
+            if (updateChecker.isSecurityFailed()) {
+                // Security has already failed
+                return;
+            }
+
+            if (initial && !updateChecker.check(true)) {
+                // Security failed cancel startup & shutdown
+                invokeDisable();
+                return;
+            }
+        } else if (initial) {
+            // Not using security, run update check off thread
+            scheduler().run(() -> updateChecker.check(true));
+        }
+        if (initial) {
+            scheduler().runAtFixedRate(() -> updateChecker.check(false), 6L, TimeUnit.HOURS);
+        }
+
         if (flags.contains(ReloadFlag.LINKED_ACCOUNT_PROVIDER)) {
             LinkedAccountConfig linkedAccountConfig = config().linkedAccounts;
             if (linkedAccountConfig != null && linkedAccountConfig.enabled) {

common/src/main/java/com/discordsrv/common/config/connection/BotConfig.java

@@ -0,0 +1,31 @@
+/*
+ * This file is part of DiscordSRV, licensed under the GPLv3 License
+ * Copyright (c) 2016-2022 Austin "Scarsz" Shapiro, Henri "Vankka" Schubin and DiscordSRV contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.discordsrv.common.config.connection;
+
+import org.spongepowered.configurate.objectmapping.ConfigSerializable;
+import org.spongepowered.configurate.objectmapping.meta.Comment;
+
+@ConfigSerializable
+public class BotConfig {
+
+    @Comment("The Discord bot token from https://discord.com/developers/applications\n"
+            + "Requires a connection to: discord.com, gateway.discord.gg, cdn.discordapp.com")
+    public String token = "Token here";
+
+}

common/src/main/java/com/discordsrv/common/config/connection/ConnectionConfig.java

@@ -20,7 +20,6 @@ package com.discordsrv.common.config.connection;
 
 import com.discordsrv.common.config.Config;
 import org.spongepowered.configurate.objectmapping.ConfigSerializable;
-import org.spongepowered.configurate.objectmapping.meta.Comment;
 
 @ConfigSerializable
 public class ConnectionConfig implements Config {
@@ -32,15 +31,9 @@ public class ConnectionConfig implements Config {
         return FILE_NAME;
     }
 
-    public Bot bot = new Bot();
+    public BotConfig bot = new BotConfig();
 
     public StorageConfig storage = new StorageConfig();
 
-    @ConfigSerializable
-    public static class Bot {
-
-        @Comment("Don't know what this is? Neither do I")
-        public String token = "Token here";
-
-    }
+    public UpdateConfig update = new UpdateConfig();
 }

common/src/main/java/com/discordsrv/common/config/connection/UpdateConfig.java

@@ -0,0 +1,82 @@
+/*
+ * This file is part of DiscordSRV, licensed under the GPLv3 License
+ * Copyright (c) 2016-2022 Austin "Scarsz" Shapiro, Henri "Vankka" Schubin and DiscordSRV contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.discordsrv.common.config.connection;
+
+import org.spongepowered.configurate.objectmapping.ConfigSerializable;
+import org.spongepowered.configurate.objectmapping.meta.Comment;
+import org.spongepowered.configurate.objectmapping.meta.Setting;
+
+@ConfigSerializable
+public class UpdateConfig {
+
+    @Setting(value = "notification-enabled")
+    @Comment("On/off for notifications when a new version of DiscordSRV is available")
+    public boolean notificationEnabled = true;
+
+    @Setting(value = "notification-ingame")
+    @Comment("If players with the discordsrv.updatenotification permission should receive\n"
+            + "a update notification upon joining if there is a update available")
+    public boolean notificationInGame = true;
+
+    @Setting(value = "enable-first-party-api-for-notifications")
+    @Comment("Weather the DiscordSRV download API should be used for update checks\n"
+            + "Requires a connection to: download.discordsrv.com")
+    public boolean firstPartyNotification = true;
+
+    @Setting(value = "github")
+    public GitHub github = new GitHub();
+
+    @Setting(value = "security")
+    public Security security = new Security();
+
+    @ConfigSerializable
+    public static class GitHub {
+
+        @Setting(value = "enabled")
+        @Comment("Weather the GitHub API should be used for update checks\n"
+                + "This will be the secondary API if both first party and GitHub sources are enabled\n"
+                + "Requires a connection to: api.github.com")
+        public boolean enabled = true;
+
+        @Setting(value = "api-token")
+        @Comment("The GitHub API token used for authenticating to the GitHub api,\n"
+                + "if this isn't specified the API will be used 'anonymously'\n"
+                + "The token only requires read permission to DiscordSRV/DiscordSRV releases, workflows and commits")
+        public String apiToken = "";
+
+    }
+
+    @ConfigSerializable
+    public static class Security {
+
+        @Setting(value = "enabled")
+        @Comment("Uses the DiscordSRV download API to check if the version of DiscordSRV\n"
+                + "being used is vulnerable to known vulnerabilities, disabling the plugin if it is.\n"
+                + "Requires a connection to: download.discordsrv.com\n"
+                + "\n"
+                + "WARNING! DO NOT TURN THIS OFF UNLESS YOU KNOW WHAT YOU'RE DOING AND STAY UP-TO-DATE")
+        public boolean enabled = true;
+
+        @Setting(value = "force")
+        @Comment("If the security check needs to be completed for DiscordSRV to enable,\n"
+                + "if the security check fails, DiscordSRV will be disabled if this option is set to true")
+        public boolean force = false;
+
+    }
+}

common/src/main/java/com/discordsrv/common/config/manager/ConnectionConfigManager.java

@@ -22,6 +22,7 @@ import com.discordsrv.common.DiscordSRV;
 import com.discordsrv.common.config.connection.ConnectionConfig;
 import com.discordsrv.common.config.manager.loader.YamlConfigLoaderProvider;
 import com.discordsrv.common.config.manager.manager.TranslatedConfigManager;
+import org.spongepowered.configurate.ConfigurationOptions;
 import org.spongepowered.configurate.yaml.YamlConfigurationLoader;
 
 public abstract class ConnectionConfigManager<C extends ConnectionConfig>
@@ -32,6 +33,18 @@ public abstract class ConnectionConfigManager<C extends ConnectionConfig>
         super(discordSRV);
     }
 
+    @Override
+    public ConfigurationOptions defaultOptions() {
+        return super.defaultOptions()
+                .header("DiscordSRV's configuration file for connections to different external services.\n"
+                                + "This file is intended to contain connection details to services in order to keep them out of the config.yml\n"
+                                + "and to serve as a easy way to identify and control what external connections are being used.\n"
+                                + "\n"
+                                + "All domains listed as \"Requires a connection to\" require port 443 (https/wss) unless otherwise specified\n"
+                                + "\n"
+                                + " ABSOLUTELY DO NOT SEND THIS FILE TO ANYONE - IT ONLY CONTAINS SECRETS\n");
+    }
+
     @Override
     protected String fileName() {
         return ConnectionConfig.FILE_NAME;

common/src/main/java/com/discordsrv/common/config/manager/manager/TranslatedConfigManager.java

@@ -25,6 +25,7 @@ import org.jetbrains.annotations.Nullable;
 import org.spongepowered.configurate.CommentedConfigurationNode;
 import org.spongepowered.configurate.ConfigurateException;
 import org.spongepowered.configurate.ConfigurationNode;
+import org.spongepowered.configurate.ConfigurationOptions;
 import org.spongepowered.configurate.loader.AbstractConfigurationLoader;
 import org.spongepowered.configurate.serialize.SerializationException;
 import org.spongepowered.configurate.yaml.YamlConfigurationLoader;
@@ -37,6 +38,8 @@ import java.util.List;
 public abstract class TranslatedConfigManager<T extends Config, LT extends AbstractConfigurationLoader<CommentedConfigurationNode>>
         extends ConfigurateConfigManager<T, LT> {
 
+    private String header;
+
     public TranslatedConfigManager(DiscordSRV discordSRV) {
         super(discordSRV);
     }
@@ -48,6 +51,15 @@ public abstract class TranslatedConfigManager<T extends Config, LT extends Abstr
         super.save();
     }
 
+    @Override
+    public ConfigurationOptions defaultOptions() {
+        ConfigurationOptions options = super.defaultOptions();
+        if (header != null) {
+            options = options.header(header);
+        }
+        return options;
+    }
+
     @Override
     protected @Nullable ConfigurationNode getTranslation() throws ConfigurateException {
         ConfigurationNode translation = getTranslationRoot();
@@ -77,6 +89,8 @@ public abstract class TranslatedConfigManager<T extends Config, LT extends Abstr
             ConfigurationNode comments = translationRoot.node(fileIdentifier + "_comments");
 
             CommentedConfigurationNode node = loader().createNode();
+            this.header = comments.node("$header").getString();
+
             save(config, (Class<T>) config.getClass(), node);
             translateNode(node, translation, comments);
         } catch (ConfigurateException e) {

common/src/main/java/com/discordsrv/common/discord/connection/jda/JDAConnectionManager.java

@@ -27,6 +27,7 @@ import com.discordsrv.api.event.events.lifecycle.DiscordSRVShuttingDownEvent;
 import com.discordsrv.api.event.events.placeholder.PlaceholderLookupEvent;
 import com.discordsrv.api.placeholder.PlaceholderLookupResult;
 import com.discordsrv.common.DiscordSRV;
+import com.discordsrv.common.config.connection.BotConfig;
 import com.discordsrv.common.config.connection.ConnectionConfig;
 import com.discordsrv.common.discord.api.DiscordAPIImpl;
 import com.discordsrv.common.discord.api.entity.message.ReceivedDiscordMessageImpl;
@@ -101,6 +102,9 @@ public class JDAConnectionManager implements DiscordConnectionManager {
         // Disable all mentions by default for safety
         MessageRequest.setDefaultMentions(Collections.emptyList());
 
+        // Disable this warning (that doesn't even have a stacktrace)
+        Message.suppressContentIntentWarning();
+
         discordSRV.eventBus().subscribe(this);
     }
 
@@ -247,7 +251,7 @@ public class JDAConnectionManager implements DiscordConnectionManager {
                 TimeUnit.SECONDS
         );
 
-        ConnectionConfig.Bot botConfig = discordSRV.connectionConfig().bot;
+        BotConfig botConfig = discordSRV.connectionConfig().bot;
         DiscordConnectionDetails connectionDetails = discordSRV.discordConnectionDetails();
         Set<GatewayIntent> intents = connectionDetails.getGatewayIntents();
         boolean membersIntent = intents.contains(GatewayIntent.GUILD_MEMBERS);

common/src/main/java/com/discordsrv/common/logging/impl/DiscordSRVLogger.java

@@ -100,6 +100,12 @@ public class DiscordSRVLogger implements Logger {
 
     @Override
     public void log(@Nullable String loggerName, @NotNull LogLevel logLevel, @Nullable String message, @Nullable Throwable throwable) {
+        if (throwable != null && throwable.getMessage() != null
+                && (throwable.getStackTrace() == null || throwable.getStackTrace().length == 0)) {
+            // Empty stack trace
+            message = (message != null ? message + ": " : "") + throwable.getMessage();
+            throwable = null;
+        }
         if (throwable instanceof InsufficientPermissionException) {
             Permission permission = ((InsufficientPermissionException) throwable).getPermission();
             String msg = "The bot is missing the \"" + permission.getName() + "\" permission";

common/src/main/java/com/discordsrv/common/scheduler/Scheduler.java

@@ -83,7 +83,7 @@ public interface Scheduler {
     ScheduledFuture<?> runLater(Runnable task, long timeMillis);
 
     /**
-     * Schedules the given task without any initial delay.
+     * Schedules the given task at the given rate.
      *
      * @param task the task
      * @param rate the rate in the given unit
@@ -91,7 +91,7 @@ public interface Scheduler {
      */
     @ApiStatus.NonExtendable
     default ScheduledFuture<?> runAtFixedRate(@NotNull Runnable task, long rate, @NotNull TimeUnit unit) {
-        return runAtFixedRate(task, 0, rate, unit);
+        return runAtFixedRate(task, rate, rate, unit);
     }
 
     /**

common/src/main/java/com/discordsrv/common/update/UpdateChecker.java

@@ -0,0 +1,313 @@
+/*
+ * This file is part of DiscordSRV, licensed under the GPLv3 License
+ * Copyright (c) 2016-2022 Austin "Scarsz" Shapiro, Henri "Vankka" Schubin and DiscordSRV contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.discordsrv.common.update;
+
+import com.discordsrv.api.event.bus.Subscribe;
+import com.discordsrv.common.DiscordSRV;
+import com.discordsrv.common.config.connection.ConnectionConfig;
+import com.discordsrv.common.config.connection.UpdateConfig;
+import com.discordsrv.common.exception.MessageException;
+import com.discordsrv.common.logging.NamedLogger;
+import com.discordsrv.common.player.IPlayer;
+import com.discordsrv.common.player.event.PlayerConnectedEvent;
+import com.discordsrv.common.update.github.GitHubCompareResponse;
+import com.discordsrv.common.update.github.GithubRelease;
+import com.fasterxml.jackson.core.type.TypeReference;
+import net.kyori.adventure.text.Component;
+import net.kyori.adventure.text.event.ClickEvent;
+import net.kyori.adventure.text.format.NamedTextColor;
+import okhttp3.Request;
+import okhttp3.Response;
+import okhttp3.ResponseBody;
+import org.apache.commons.lang3.StringUtils;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+public class UpdateChecker {
+
+    private static final String USER_DOWNLOAD_URL = "https://discordsrv.com/download";
+    private static final String GITHUB_REPOSITORY = "DiscordSRV/DiscordSRV";
+    private static final String GITHUB_DEV_BRANCH = "master";
+
+    private static final String DOWNLOAD_SERVICE_HOST = "https://download.discordsrv.com";
+    private static final String DOWNLOAD_SERVICE_SNAPSHOT_CHANNEL = "snapshot";
+    private static final String DOWNLOAD_SERVICE_RELEASE_CHANNEL = "release";
+
+    private static final String GITHUB_API_HOST = "https://api.github.com";
+
+    private final DiscordSRV discordSRV;
+    private final NamedLogger logger;
+
+    private boolean securityFailed = false;
+    private VersionCheck latestCheck;
+    private VersionCheck loggedCheck;
+
+    public UpdateChecker(DiscordSRV discordSRV) {
+        this.discordSRV = discordSRV;
+        this.logger = new NamedLogger(discordSRV, "UPDATES");
+        discordSRV.eventBus().subscribe(this);
+    }
+
+    public boolean isSecurityFailed() {
+        return securityFailed;
+    }
+
+    /**
+     * @return if enabling is permitted
+     */
+    public boolean check(boolean logUpToDate) {
+        UpdateConfig config = discordSRV.connectionConfig().update;
+        boolean isSnapshot = discordSRV.version().endsWith("-SNAPSHOT");
+        boolean isSecurity = config.security.enabled;
+        boolean isFirstPartyNotification = config.firstPartyNotification;
+        boolean isNotification = config.notificationEnabled;
+
+        if (!isSecurity && !isNotification) {
+            // Nothing to do
+            return true;
+        }
+
+        if (isFirstPartyNotification || isSecurity) {
+            VersionCheck check = null;
+            try {
+                check = checkFirstParty(isSnapshot);
+                if (check == null && isSecurity) {
+                    securityFailed = true;
+                    return false;
+                }
+            } catch (Throwable t) {
+                List<String> failedThings = new ArrayList<>(2);
+                if (isSecurity) {
+                    failedThings.add("perform version security check");
+                }
+                if (isFirstPartyNotification) {
+                    failedThings.add("check for updates");
+                }
+                logger.warning("Failed to " + String.join(" and ", failedThings)
+                                       + " from the first party API", t);
+
+                if (config.security.force) {
+                    logger.error("Security check is required (as configured in " + ConnectionConfig.FILE_NAME + ")"
+                                         + ", startup will be cancelled.");
+                    securityFailed = true;
+                    return false;
+                }
+            }
+
+            if (isNotification && isFirstPartyNotification
+                    && check != null && check.status != VersionCheck.Status.UNKNOWN) {
+                latestCheck = check;
+                log(check, logUpToDate);
+                return true;
+            }
+        }
+
+        if (isNotification && config.github.enabled) {
+            VersionCheck check = null;
+            try {
+                check = checkGitHub(isSnapshot);
+            } catch (Throwable t) {
+                logger.warning("Failed to check for updates from GitHub", t);
+            }
+
+            if (check != null && check.status != VersionCheck.Status.UNKNOWN) {
+                latestCheck = check;
+                log(check, logUpToDate);
+                return true;
+            } else {
+                discordSRV.logger().error("Update check" + (isFirstPartyNotification ? "s" : "")
+                                                  + " failed: unknown version");
+            }
+        }
+
+        return true;
+    }
+
+    private ResponseBody checkResponse(Request request, Response response, ResponseBody responseBody) throws IOException {
+        if (responseBody == null || !response.isSuccessful()) {
+            String responseString = responseBody == null
+                             ? "response body is null"
+                             : StringUtils.substring(responseBody.string(), 0, 500);
+            throw new MessageException("Request to " + request.url().host() + " failed: " + response.code() + ": " + responseString);
+        }
+        return responseBody;
+    }
+
+    /**
+     * @return {@code null} for preventing shutdown
+     */
+    private VersionCheck checkFirstParty(boolean isSnapshot) throws IOException {
+        Request request = new Request.Builder()
+                .url(DOWNLOAD_SERVICE_HOST + "/v2/" + GITHUB_REPOSITORY
+                             + "/" + (isSnapshot ? DOWNLOAD_SERVICE_SNAPSHOT_CHANNEL : DOWNLOAD_SERVICE_RELEASE_CHANNEL)
+                             + "/version-check/" + (isSnapshot ? discordSRV.gitRevision() : discordSRV.version()))
+                .get().build();
+
+        String responseString;
+        try (Response response = discordSRV.httpClient().newCall(request).execute()) {
+            ResponseBody responseBody = checkResponse(request, response, response.body());
+            responseString = responseBody.string();
+        }
+
+        VersionCheck versionCheck = discordSRV.json().readValue(responseString, VersionCheck.class);
+        if (versionCheck == null) {
+            throw new MessageException("Failed to parse " + request.url() + " response body: " + StringUtils.substring(responseString, 0, 500));
+        }
+
+        boolean insecure = versionCheck.insecure;
+        List<String> securityIssues = versionCheck.securityIssues;
+        if (insecure) {
+            logger.error("This version of DiscordSRV is insecure, security issues are listed below, startup will be cancelled.");
+            for (String securityIssue : versionCheck.securityIssues) {
+                logger.error(securityIssue);
+            }
+
+            // Block startup
+            return null;
+        } else if (securityIssues != null && !securityIssues.isEmpty()) {
+            logger.warning("There are security warnings for this version of DiscordSRV, listed below");
+            for (String securityIssue : versionCheck.securityIssues) {
+                logger.warning(securityIssue);
+            }
+        }
+
+        return versionCheck;
+    }
+
+    private VersionCheck checkGitHub(boolean isSnapshot) throws IOException {
+        if (isSnapshot) {
+            Request request = new Request.Builder()
+                    .url(GITHUB_API_HOST + "/repos/" + GITHUB_REPOSITORY + "/compare/"
+                                 + GITHUB_DEV_BRANCH + "..." + discordSRV.gitRevision() + "?per_page=0")
+                    .get().build();
+
+            try (Response response = discordSRV.httpClient().newCall(request).execute()) {
+                ResponseBody responseBody = checkResponse(request, response, response.body());
+                GitHubCompareResponse compare = discordSRV.json().readValue(responseBody.byteStream(), GitHubCompareResponse.class);
+
+                VersionCheck versionCheck = new VersionCheck();
+                versionCheck.amount = compare.behind_by;
+                versionCheck.amountType = (compare.behind_by == 1 ? "commit" : "commits");
+                versionCheck.amountSource = VersionCheck.AmountSource.GITHUB;
+                if ("behind".equals(compare.status)) {
+                    versionCheck.status = VersionCheck.Status.OUTDATED;
+                } else if ("identical".equals(compare.status)) {
+                    versionCheck.status = VersionCheck.Status.UP_TO_DATE;
+                } else {
+                    versionCheck.status = VersionCheck.Status.UNKNOWN;
+                }
+
+                return versionCheck;
+            }
+        }
+
+        String version = discordSRV.version();
+
+        int versionsBehind = 0;
+        boolean found = false;
+
+        int perPage = 100;
+        int page = 0;
+        for (int i = 0; i < 3 /* max 3 loops */; i++) {
+            Request request = new Request.Builder()
+                    .url(GITHUB_API_HOST + "/repos/" + GITHUB_REPOSITORY + "/releases?per_page=" + perPage + "&page=" + page)
+                    .get().build();
+
+            try (Response response = discordSRV.httpClient().newCall(request).execute()) {
+                ResponseBody responseBody = checkResponse(request, response, response.body());
+                List<GithubRelease> releases = discordSRV.json().readValue(responseBody.byteStream(), new TypeReference<List<GithubRelease>>() {});
+
+                for (GithubRelease release : releases) {
+                    if (version.equals(release.tag_name)) {
+                        found = true;
+                        break;
+                    }
+                    versionsBehind++;
+                }
+                if (found || releases.size() < perPage) {
+                    break;
+                }
+            }
+        }
+
+        VersionCheck versionCheck = new VersionCheck();
+        versionCheck.amountSource = VersionCheck.AmountSource.GITHUB;
+        versionCheck.amountType = (versionsBehind == 1 ? "release" : "releases");
+        if (!found) {
+            versionCheck.status = VersionCheck.Status.UNKNOWN;
+            versionCheck.amount = -1;
+        } else {
+            versionCheck.status = versionsBehind == 0
+                                  ? VersionCheck.Status.UP_TO_DATE
+                                  : VersionCheck.Status.OUTDATED;
+            versionCheck.amount = versionsBehind;
+        }
+        return versionCheck;
+    }
+
+    private void log(VersionCheck versionCheck, boolean logUpToDate) {
+        switch (versionCheck.status) {
+            case UP_TO_DATE: {
+                if (logUpToDate) {
+                    logger.info("DiscordSRV is up-to-date.");
+                    loggedCheck = versionCheck;
+                }
+                break;
+            }
+            case OUTDATED: {
+                // only log if there is new information
+                if (loggedCheck == null || loggedCheck.amount != versionCheck.amount) {
+                    logger.warning(
+                            "DiscordSRV is outdated by " + versionCheck.amount + " " + versionCheck.amountType
+                                    + ". Get the latest version from https://discordsrv.com/dowload");
+                    loggedCheck = versionCheck;
+                }
+                break;
+            }
+            default:
+                throw new IllegalStateException("Unexpected version check status: " + versionCheck.status.name());
+        }
+    }
+
+    @Subscribe
+    public void onPlayerConnected(PlayerConnectedEvent event) {
+        UpdateConfig config = discordSRV.connectionConfig().update;
+        if (!config.notificationEnabled || !config.notificationInGame) {
+            return;
+        }
+
+        if (latestCheck == null || latestCheck.status != VersionCheck.Status.OUTDATED) {
+            return;
+        }
+
+        IPlayer player = event.player();
+        if (!player.hasPermission("discordsrv.updatenotification")) {
+            return;
+        }
+
+        player.sendMessage(
+                Component.text("There is a new version of DiscordSRV available, ", NamedTextColor.AQUA)
+                        .append(Component.text()
+                                        .content("click here to download it")
+                                        .clickEvent(ClickEvent.openUrl(USER_DOWNLOAD_URL)))
+        );
+    }
+}

common/src/main/java/com/discordsrv/common/update/VersionCheck.java

@@ -0,0 +1,43 @@
+/*
+ * This file is part of DiscordSRV, licensed under the GPLv3 License
+ * Copyright (c) 2016-2022 Austin "Scarsz" Shapiro, Henri "Vankka" Schubin and DiscordSRV contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.discordsrv.common.update;
+
+import java.util.List;
+
+public class VersionCheck {
+
+    public Status status;
+
+    public int amount;
+    public AmountSource amountSource;
+    public String amountType;
+
+    public boolean insecure;
+    public List<String> securityIssues;
+
+    public enum Status {
+        UP_TO_DATE,
+        OUTDATED,
+        UNKNOWN
+    }
+
+    public enum AmountSource {
+        GITHUB
+    }
+}

common/src/main/java/com/discordsrv/common/update/github/GitHubCompareResponse.java

@@ -0,0 +1,26 @@
+/*
+ * This file is part of DiscordSRV, licensed under the GPLv3 License
+ * Copyright (c) 2016-2022 Austin "Scarsz" Shapiro, Henri "Vankka" Schubin and DiscordSRV contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.discordsrv.common.update.github;
+
+public class GitHubCompareResponse {
+
+    public String status;
+    public int behind_by;
+
+}

common/src/main/java/com/discordsrv/common/update/github/GithubRelease.java

@@ -0,0 +1,24 @@
+/*
+ * This file is part of DiscordSRV, licensed under the GPLv3 License
+ * Copyright (c) 2016-2022 Austin "Scarsz" Shapiro, Henri "Vankka" Schubin and DiscordSRV contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.discordsrv.common.update.github;
+
+public class GithubRelease {
+
+    public String tag_name;
+}

i18n/src/main/java/com/discordsrv/config/DiscordSRVTranslation.java

@@ -81,6 +81,11 @@ public final class DiscordSRVTranslation {
             Config config = (Config) configManager.createConfiguration();
             String fileIdentifier = config.getFileName();
             ConfigurationNode commentSection = node.node(fileIdentifier + "_comments");
+            
+            String header = configManager.defaultOptions().header();
+            if (header != null) {
+                commentSection.node("$header").set(header);
+            }
 
             ObjectMapper.Factory mapperFactory = configManager.configObjectMapperBuilder()
                     .addProcessor(Untranslated.class, untranslatedProcessorFactory)