Further improvements.

The main component here is the total revamp of the plugin channel identifier system - instead of Legacy/Modern channel IDs, you can have a modern channel or a modern channel paired with a legacy channel, which is much less confusing to work with.

api/src/main/java/com/velocitypowered/api/event/connection/PluginMessageEvent.java

@@ -11,9 +11,9 @@ import com.google.common.io.ByteArrayDataInput;
 import com.velocitypowered.api.event.ResultedEvent;
 import com.velocitypowered.api.proxy.connection.Player;
 import com.velocitypowered.api.proxy.connection.ServerConnection;
-import com.velocitypowered.api.proxy.messages.ChannelIdentifier;
 import com.velocitypowered.api.proxy.messages.ChannelMessageSink;
 import com.velocitypowered.api.proxy.messages.ChannelMessageSource;
+import com.velocitypowered.api.proxy.messages.PluginChannelId;
 import java.io.ByteArrayInputStream;
 
 /**
@@ -26,7 +26,7 @@ public interface PluginMessageEvent extends ResultedEvent<PluginMessageEvent.For
 
   ChannelMessageSink sink();
 
-  ChannelIdentifier channel();
+  PluginChannelId channel();
 
   byte[] rawMessage();
 

api/src/main/java/com/velocitypowered/api/event/connection/PluginMessageEventImpl.java

@@ -12,9 +12,9 @@ import com.google.common.io.ByteArrayDataInput;
 import com.google.common.io.ByteStreams;
 import com.velocitypowered.api.proxy.connection.Player;
 import com.velocitypowered.api.proxy.connection.ServerConnection;
-import com.velocitypowered.api.proxy.messages.ChannelIdentifier;
 import com.velocitypowered.api.proxy.messages.ChannelMessageSink;
 import com.velocitypowered.api.proxy.messages.ChannelMessageSource;
+import com.velocitypowered.api.proxy.messages.PluginChannelId;
 import java.io.ByteArrayInputStream;
 import java.util.Arrays;
 
@@ -26,7 +26,7 @@ public final class PluginMessageEventImpl implements PluginMessageEvent {
 
   private final ChannelMessageSource source;
   private final ChannelMessageSink target;
-  private final ChannelIdentifier identifier;
+  private final PluginChannelId identifier;
   private final byte[] data;
   private ForwardResult result;
 
@@ -39,7 +39,7 @@ public final class PluginMessageEventImpl implements PluginMessageEvent {
    * @param data the payload of the plugin message
    */
   public PluginMessageEventImpl(ChannelMessageSource source, ChannelMessageSink target,
-      ChannelIdentifier identifier, byte[] data) {
+      PluginChannelId identifier, byte[] data) {
     this.source = Preconditions.checkNotNull(source, "source");
     this.target = Preconditions.checkNotNull(target, "target");
     this.identifier = Preconditions.checkNotNull(identifier, "identifier");
@@ -68,7 +68,7 @@ public final class PluginMessageEventImpl implements PluginMessageEvent {
   }
 
   @Override
-  public ChannelIdentifier channel() {
+  public PluginChannelId channel() {
     return identifier;
   }
 

api/src/main/java/com/velocitypowered/api/event/player/PlayerChannelRegisterEvent.java

@@ -8,7 +8,7 @@
 package com.velocitypowered.api.event.player;
 
 import com.velocitypowered.api.proxy.connection.Player;
-import com.velocitypowered.api.proxy.messages.ChannelIdentifier;
+import com.velocitypowered.api.proxy.messages.PluginChannelId;
 import java.util.List;
 
 /**
@@ -19,5 +19,5 @@ public interface PlayerChannelRegisterEvent {
 
   Player player();
 
-  List<ChannelIdentifier> channels();
+  List<PluginChannelId> channels();
 }

api/src/main/java/com/velocitypowered/api/event/player/PlayerChannelRegisterEventImpl.java

@@ -9,7 +9,7 @@ package com.velocitypowered.api.event.player;
 
 import com.google.common.base.Preconditions;
 import com.velocitypowered.api.proxy.connection.Player;
-import com.velocitypowered.api.proxy.messages.ChannelIdentifier;
+import com.velocitypowered.api.proxy.messages.PluginChannelId;
 import java.util.List;
 
 /**
@@ -19,9 +19,9 @@ import java.util.List;
 public final class PlayerChannelRegisterEventImpl implements PlayerChannelRegisterEvent {
 
   private final Player player;
-  private final List<ChannelIdentifier> channels;
+  private final List<PluginChannelId> channels;
 
-  public PlayerChannelRegisterEventImpl(Player player, List<ChannelIdentifier> channels) {
+  public PlayerChannelRegisterEventImpl(Player player, List<PluginChannelId> channels) {
     this.player = Preconditions.checkNotNull(player, "player");
     this.channels = Preconditions.checkNotNull(channels, "channels");
   }
@@ -32,7 +32,7 @@ public final class PlayerChannelRegisterEventImpl implements PlayerChannelRegist
   }
 
   @Override
-  public List<ChannelIdentifier> channels() {
+  public List<PluginChannelId> channels() {
     return channels;
   }
 

api/src/main/java/com/velocitypowered/api/plugin/PluginManager.java

@@ -39,7 +39,7 @@ public interface PluginManager {
    *
    * @return the plugins
    */
-  Collection<PluginContainer> getPlugins();
+  Collection<PluginContainer> plugins();
 
   /**
    * Checks if a plugin is loaded based on its ID.

api/src/main/java/com/velocitypowered/api/proxy/messages/ChannelIdentifier.java

@@ -1,21 +0,0 @@
-/*
- * Copyright (C) 2018 Velocity Contributors
- *
- * The Velocity API is licensed under the terms of the MIT License. For more details,
- * reference the LICENSE file in the api top-level directory.
- */
-
-package com.velocitypowered.api.proxy.messages;
-
-/**
- * Represents a channel identifier for use with plugin messaging.
- */
-public interface ChannelIdentifier {
-
-  /**
-   * Returns the textual representation of this identifier.
-   *
-   * @return the textual representation of the identifier
-   */
-  String id();
-}

api/src/main/java/com/velocitypowered/api/proxy/messages/ChannelMessageSink.java

@@ -19,5 +19,5 @@ public interface ChannelMessageSink {
    * @param data the data to send
    * @return whether or not the message could be sent
    */
-  boolean sendPluginMessage(ChannelIdentifier identifier, byte[] data);
+  boolean sendPluginMessage(PluginChannelId identifier, byte[] data);
 }

api/src/main/java/com/velocitypowered/api/proxy/messages/ChannelRegistrar.java

@@ -10,7 +10,7 @@ package com.velocitypowered.api.proxy.messages;
 import com.velocitypowered.api.event.connection.PluginMessageEventImpl;
 
 /**
- * Represents an interface to register and unregister {@link ChannelIdentifier}s for the proxy to
+ * Represents an interface to register and unregister {@link PluginChannelId}s for the proxy to
  * listen on.
  */
 public interface ChannelRegistrar {
@@ -21,12 +21,12 @@ public interface ChannelRegistrar {
    *
    * @param identifiers the channel identifiers to register
    */
-  void register(ChannelIdentifier... identifiers);
+  void register(PluginChannelId... identifiers);
 
   /**
    * Removes the intent to listen for the specified channel.
    *
    * @param identifiers the identifiers to unregister
    */
-  void unregister(ChannelIdentifier... identifiers);
+  void unregister(PluginChannelId... identifiers);
 }

api/src/main/java/com/velocitypowered/api/proxy/messages/LegacyChannelIdentifier.java

@@ -1,64 +0,0 @@
-/*
- * Copyright (C) 2018 Velocity Contributors
- *
- * The Velocity API is licensed under the terms of the MIT License. For more details,
- * reference the LICENSE file in the api top-level directory.
- */
-
-package com.velocitypowered.api.proxy.messages;
-
-import com.google.common.base.Preconditions;
-import com.google.common.base.Strings;
-import java.util.Objects;
-import org.checkerframework.checker.nullness.qual.Nullable;
-
-/**
- * Reperesents a legacy channel identifier (for Minecraft 1.12 and below). For modern 1.13 plugin
- * messages, please see {@link MinecraftChannelIdentifier}. This class is immutable and safe for
- * multi-threaded use.
- */
-public final class LegacyChannelIdentifier implements ChannelIdentifier {
-
-  private final String name;
-
-  /**
-   * Creates a new legacy channel identifier.
-   *
-   * @param name the name for the channel
-   */
-  public LegacyChannelIdentifier(String name) {
-    Preconditions.checkArgument(!Strings.isNullOrEmpty(name), "provided name is empty");
-    this.name = name;
-  }
-
-  public String getName() {
-    return name;
-  }
-
-  @Override
-  public String toString() {
-    return name + " (legacy)";
-  }
-
-  @Override
-  public boolean equals(@Nullable Object o) {
-    if (this == o) {
-      return true;
-    }
-    if (o == null || getClass() != o.getClass()) {
-      return false;
-    }
-    LegacyChannelIdentifier that = (LegacyChannelIdentifier) o;
-    return Objects.equals(name, that.name);
-  }
-
-  @Override
-  public int hashCode() {
-    return Objects.hash(name);
-  }
-
-  @Override
-  public String id() {
-    return this.getName();
-  }
-}

api/src/main/java/com/velocitypowered/api/proxy/messages/MinecraftChannelIdentifier.java

@@ -1,114 +0,0 @@
-/*
- * Copyright (C) 2018 Velocity Contributors
- *
- * The Velocity API is licensed under the terms of the MIT License. For more details,
- * reference the LICENSE file in the api top-level directory.
- */
-
-package com.velocitypowered.api.proxy.messages;
-
-import com.google.common.base.Preconditions;
-import com.google.common.base.Strings;
-import java.util.Objects;
-import java.util.regex.Pattern;
-import org.checkerframework.checker.nullness.qual.Nullable;
-
-/**
- * Represents a Minecraft 1.13+ channel identifier. This class is immutable and safe for
- * multi-threaded use.
- */
-public final class MinecraftChannelIdentifier implements ChannelIdentifier {
-
-  private static final Pattern VALID_IDENTIFIER_REGEX = Pattern.compile("[a-z0-9/\\-_]*");
-
-  private final String namespace;
-  private final String name;
-
-  private MinecraftChannelIdentifier(String namespace, String name) {
-    this.namespace = namespace;
-    this.name = name;
-  }
-
-  /**
-   * Creates an identifier in the default namespace ({@code minecraft}). Plugins are strongly
-   * encouraged to provide their own namespace.
-   *
-   * @param name the name in the default namespace to use
-   * @return a new channel identifier
-   */
-  public static MinecraftChannelIdentifier forDefaultNamespace(String name) {
-    return new MinecraftChannelIdentifier("minecraft", name);
-  }
-
-  /**
-   * Creates an identifier in the specified namespace.
-   *
-   * @param namespace the namespace to use
-   * @param name the channel name inside the specified namespace
-   * @return a new channel identifier
-   */
-  public static MinecraftChannelIdentifier create(String namespace, String name) {
-    Preconditions.checkArgument(!Strings.isNullOrEmpty(namespace), "namespace is null or empty");
-    Preconditions.checkArgument(name != null, "namespace is null or empty");
-    Preconditions.checkArgument(VALID_IDENTIFIER_REGEX.matcher(namespace).matches(),
-        "namespace is not valid");
-    Preconditions
-        .checkArgument(VALID_IDENTIFIER_REGEX.matcher(name).matches(), "name is not valid");
-    return new MinecraftChannelIdentifier(namespace, name);
-  }
-
-  /**
-   * Creates an channel identifier from the specified Minecraft identifier.
-   *
-   * @param identifier the Minecraft identifier
-   * @return a new channel identifier
-   */
-  public static MinecraftChannelIdentifier from(String identifier) {
-    int colonPos = identifier.indexOf(':');
-    if (colonPos == -1) {
-      throw new IllegalArgumentException("Identifier does not contain a colon.");
-    }
-    if (colonPos + 1 == identifier.length()) {
-      throw new IllegalArgumentException("Identifier is empty.");
-    }
-    String namespace = identifier.substring(0, colonPos);
-    String name = identifier.substring(colonPos + 1);
-    return create(namespace, name);
-  }
-
-  public String getNamespace() {
-    return namespace;
-  }
-
-  public String getName() {
-    return name;
-  }
-
-  @Override
-  public String toString() {
-    return namespace + ":" + name + " (modern)";
-  }
-
-  @Override
-  public boolean equals(@Nullable Object o) {
-    if (this == o) {
-      return true;
-    }
-    if (o == null || getClass() != o.getClass()) {
-      return false;
-    }
-    MinecraftChannelIdentifier that = (MinecraftChannelIdentifier) o;
-    return Objects.equals(namespace, that.namespace)
-        && Objects.equals(name, that.name);
-  }
-
-  @Override
-  public int hashCode() {
-    return Objects.hash(namespace, name);
-  }
-
-  @Override
-  public String id() {
-    return namespace + ":" + name;
-  }
-}

api/src/main/java/com/velocitypowered/api/proxy/messages/MinecraftPluginChannelId.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2018 Velocity Contributors
+ *
+ * The Velocity API is licensed under the terms of the MIT License. For more details,
+ * reference the LICENSE file in the api top-level directory.
+ */
+
+package com.velocitypowered.api.proxy.messages;
+
+import com.google.common.base.Preconditions;
+import com.google.common.base.Strings;
+import java.util.Objects;
+import java.util.regex.Pattern;
+import net.kyori.adventure.key.Key;
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+/**
+ * Represents a Minecraft 1.13+ channel identifier.
+ */
+public final class MinecraftPluginChannelId implements PluginChannelId {
+
+  private final Key key;
+
+  MinecraftPluginChannelId(Key key) {
+    this.key = Preconditions.checkNotNull(key, "key");
+  }
+
+  public Key key() {
+    return key;
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+
+    MinecraftPluginChannelId that = (MinecraftPluginChannelId) o;
+
+    return key.equals(that.key);
+  }
+
+  @Override
+  public int hashCode() {
+    return key.hashCode();
+  }
+
+  @Override
+  public String toString() {
+    return key.asString();
+  }
+}

api/src/main/java/com/velocitypowered/api/proxy/messages/PairedPluginChannelId.java

@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2018 Velocity Contributors
+ *
+ * The Velocity API is licensed under the terms of the MIT License. For more details,
+ * reference the LICENSE file in the api top-level directory.
+ */
+
+package com.velocitypowered.api.proxy.messages;
+
+import com.google.common.base.Preconditions;
+import com.google.common.base.Strings;
+import net.kyori.adventure.key.Key;
+
+/**
+ * Reperesents a legacy channel identifier (for Minecraft 1.12 and below). For modern 1.13 plugin
+ * messages, please see {@link MinecraftPluginChannelId}. This class is immutable and safe for
+ * multi-threaded use.
+ */
+public final class PairedPluginChannelId implements PluginChannelId {
+
+  private final String legacyChannel;
+  private final Key modernChannelKey;
+
+  /**
+   * Creates a new legacy channel identifier.
+   *
+   * @param legacyChannel the name for the legacy channel name
+   * @param modernChannelKey the modern channel key to use
+   */
+  PairedPluginChannelId(String legacyChannel, Key modernChannelKey) {
+    Preconditions.checkArgument(!Strings.isNullOrEmpty(legacyChannel), "provided name is empty");
+    this.legacyChannel = legacyChannel;
+    this.modernChannelKey = Preconditions.checkNotNull(modernChannelKey, "modernChannelKey");
+  }
+
+  public String legacyChannel() {
+    return legacyChannel;
+  }
+
+  public Key modernChannelKey() {
+    return modernChannelKey;
+  }
+
+  @Override
+  public String toString() {
+    return legacyChannel + "/" + modernChannelKey.asString();
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (o == null || getClass() != o.getClass()) {
+      return false;
+    }
+
+    PairedPluginChannelId that = (PairedPluginChannelId) o;
+
+    if (!legacyChannel.equals(that.legacyChannel)) {
+      return false;
+    }
+    return modernChannelKey.equals(that.modernChannelKey);
+  }
+
+  @Override
+  public int hashCode() {
+    int result = legacyChannel.hashCode();
+    result = 31 * result + modernChannelKey.hashCode();
+    return result;
+  }
+}

api/src/main/java/com/velocitypowered/api/proxy/messages/PluginChannelId.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2018 Velocity Contributors
+ *
+ * The Velocity API is licensed under the terms of the MIT License. For more details,
+ * reference the LICENSE file in the api top-level directory.
+ */
+
+package com.velocitypowered.api.proxy.messages;
+
+import net.kyori.adventure.key.Key;
+
+/**
+ * Represents a channel identifier for use with plugin messaging.
+ */
+public interface PluginChannelId {
+
+  /**
+   * Wraps the specified Minecraft key so it can be used as a {@link PluginChannelId}.
+   * If the client is connected using Minecraft 1.12.2 or earlier, use the key as the
+   * channel name.
+   *
+   * @param key the key instance to wrap
+   * @return a wrapped plugin channel ID
+   */
+  static MinecraftPluginChannelId wrap(Key key) {
+    return new MinecraftPluginChannelId(key);
+  }
+
+  /**
+   * Wraps the specified Minecraft key so it can be used as a {@link PluginChannelId},
+   * with the specified {@code legacyChannel} for clients onnected using Minecraft 1.12.2
+   * or earlier.
+   *
+   * @param legacyChannel the legacy channel name
+   * @param modernChannelKey the key instance to wrap
+   * @return a wrapped plugin channel ID
+   */
+  static PairedPluginChannelId withLegacy(String legacyChannel, Key modernChannelKey) {
+    return new PairedPluginChannelId(legacyChannel, modernChannelKey);
+  }
+}

api/src/test/java/com/velocitypowered/api/proxy/messages/MinecraftChannelIdentifierTest.java

@@ -1,63 +0,0 @@
-/*
- * Copyright (C) 2018 Velocity Contributors
- *
- * The Velocity API is licensed under the terms of the MIT License. For more details,
- * reference the LICENSE file in the api top-level directory.
- */
-
-package com.velocitypowered.api.proxy.messages;
-
-import static com.velocitypowered.api.proxy.messages.MinecraftChannelIdentifier.create;
-import static com.velocitypowered.api.proxy.messages.MinecraftChannelIdentifier.from;
-import static org.junit.jupiter.api.Assertions.assertAll;
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertThrows;
-
-import org.junit.jupiter.api.Test;
-
-class MinecraftChannelIdentifierTest {
-
-  @Test
-  void createAllowsValidNamespaces() {
-    create("minecraft", "brand");
-  }
-
-  @Test
-  void createAllowsEmptyName() {
-    create("minecraft", "");
-  }
-
-  @Test
-  void createDisallowsNull() {
-    assertAll(
-        () -> assertThrows(IllegalArgumentException.class, () -> create(null, "")),
-        () -> assertThrows(IllegalArgumentException.class, () -> create("", "")),
-        () -> assertThrows(IllegalArgumentException.class, () -> create("minecraft", null))
-    );
-  }
-
-  @Test
-  void fromIdentifierIsCorrect() {
-    MinecraftChannelIdentifier expected = MinecraftChannelIdentifier.create("velocity", "test");
-    assertEquals(expected, MinecraftChannelIdentifier.from("velocity:test"));
-  }
-
-  @Test
-  void createAllowsSlashes() {
-    create("velocity", "test/test2");
-  }
-
-  @Test
-  void fromIdentifierThrowsOnBadValues() {
-    assertAll(
-        () -> assertThrows(IllegalArgumentException.class, () -> from("")),
-        () -> assertThrows(IllegalArgumentException.class, () -> from(":")),
-        () -> assertThrows(IllegalArgumentException.class, () -> from(":a")),
-        () -> assertThrows(IllegalArgumentException.class, () -> from("a:")),
-        () -> assertThrows(IllegalArgumentException.class, () -> from("hello:$$$$$$")),
-        () -> assertThrows(IllegalArgumentException.class, () -> from("hello::"))
-    );
-  }
-
-
-}

proxy/src/main/java/com/velocitypowered/proxy/VelocityServer.java

@@ -277,7 +277,7 @@ public class VelocityServer implements ProxyServer, ForwardingAudience {
     }
 
     // Register the plugin main classes so that we can fire the proxy initialize event
-    for (PluginContainer plugin : pluginManager.getPlugins()) {
+    for (PluginContainer plugin : pluginManager.plugins()) {
       Optional<?> instance = plugin.instance();
       if (instance.isPresent()) {
         try {
@@ -289,7 +289,7 @@ public class VelocityServer implements ProxyServer, ForwardingAudience {
       }
     }
 
-    logger.info("Loaded {} plugins", pluginManager.getPlugins().size());
+    logger.info("Loaded {} plugins", pluginManager.plugins().size());
   }
 
   public Bootstrap createBootstrap(@Nullable EventLoopGroup group, SocketAddress target) {

proxy/src/main/java/com/velocitypowered/proxy/command/builtin/VelocityCommand.java

@@ -270,7 +270,7 @@ public class VelocityCommand implements SimpleCommand {
         return;
       }
 
-      List<PluginContainer> plugins = ImmutableList.copyOf(server.pluginManager().getPlugins());
+      List<PluginContainer> plugins = ImmutableList.copyOf(server.pluginManager().plugins());
       int pluginCount = plugins.size();
 
       if (pluginCount == 0) {

proxy/src/main/java/com/velocitypowered/proxy/connection/backend/BackendPlaySessionHandler.java

@@ -28,7 +28,7 @@ import com.velocitypowered.api.event.command.PlayerAvailableCommandsEventImpl;
 import com.velocitypowered.api.event.connection.PluginMessageEvent;
 import com.velocitypowered.api.event.connection.PluginMessageEventImpl;
 import com.velocitypowered.api.network.ProtocolVersion;
-import com.velocitypowered.api.proxy.messages.ChannelIdentifier;
+import com.velocitypowered.api.proxy.messages.PluginChannelId;
 import com.velocitypowered.proxy.VelocityServer;
 import com.velocitypowered.proxy.connection.MinecraftConnection;
 import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
@@ -160,7 +160,7 @@ public class BackendPlaySessionHandler implements MinecraftSessionHandler {
       return true;
     }
 
-    ChannelIdentifier id = server.channelRegistrar().getFromId(packet.getChannel());
+    PluginChannelId id = server.channelRegistrar().getFromId(packet.getChannel());
     if (id == null) {
       return false;
     }

proxy/src/main/java/com/velocitypowered/proxy/connection/backend/BungeeCordMessageResponder.java

@@ -19,8 +19,8 @@ package com.velocitypowered.proxy.connection.backend;
 
 import com.velocitypowered.api.network.ProtocolVersion;
 import com.velocitypowered.api.proxy.connection.Player;
-import com.velocitypowered.api.proxy.messages.LegacyChannelIdentifier;
-import com.velocitypowered.api.proxy.messages.MinecraftChannelIdentifier;
+import com.velocitypowered.api.proxy.messages.PairedPluginChannelId;
+import com.velocitypowered.api.proxy.messages.PluginChannelId;
 import com.velocitypowered.api.proxy.server.RegisteredServer;
 import com.velocitypowered.api.util.UuidUtils;
 import com.velocitypowered.proxy.VelocityServer;
@@ -40,6 +40,7 @@ import java.net.SocketAddress;
 import java.util.Optional;
 import java.util.StringJoiner;
 import net.kyori.adventure.identity.Identity;
+import net.kyori.adventure.key.Key;
 import net.kyori.adventure.text.Component;
 import net.kyori.adventure.text.serializer.ComponentSerializer;
 import net.kyori.adventure.text.serializer.gson.GsonComponentSerializer;
@@ -50,10 +51,8 @@ import net.kyori.adventure.text.serializer.legacy.LegacyComponentSerializer;
     + "nothing.")
 public class BungeeCordMessageResponder {
 
-  private static final MinecraftChannelIdentifier MODERN_CHANNEL = MinecraftChannelIdentifier
-      .create("bungeecord", "main");
-  private static final LegacyChannelIdentifier LEGACY_CHANNEL =
-      new LegacyChannelIdentifier("BungeeCord");
+  private static final PairedPluginChannelId CHANNEL = PluginChannelId
+      .withLegacy("BungeeCord", Key.key("bungeecord", "main"));
 
   private final VelocityServer proxy;
   private final ConnectedPlayer player;
@@ -64,8 +63,8 @@ public class BungeeCordMessageResponder {
   }
 
   public static boolean isBungeeCordMessage(AbstractPluginMessagePacket<?> message) {
-    return MODERN_CHANNEL.id().equals(message.getChannel()) || LEGACY_CHANNEL.id()
-        .equals(message.getChannel());
+    return CHANNEL.modernChannelKey().asString().equals(message.getChannel())
+        || CHANNEL.legacyChannel().equals(message.getChannel());
   }
 
   private void processConnect(ByteBufDataInput in) {
@@ -293,7 +292,7 @@ public class BungeeCordMessageResponder {
     if (target.equals("ALL")) {
       try {
         for (RegisteredServer rs : proxy.registeredServers()) {
-          ((VelocityRegisteredServer) rs).sendPluginMessage(LEGACY_CHANNEL,
+          ((VelocityRegisteredServer) rs).sendPluginMessage(CHANNEL,
               toForward.retainedSlice());
         }
       } finally {
@@ -302,7 +301,7 @@ public class BungeeCordMessageResponder {
     } else {
       Optional<RegisteredServer> server = proxy.server(target);
       if (server.isPresent()) {
-        ((VelocityRegisteredServer) server.get()).sendPluginMessage(LEGACY_CHANNEL, toForward);
+        ((VelocityRegisteredServer) server.get()).sendPluginMessage(CHANNEL, toForward);
       } else {
         toForward.release();
       }
@@ -310,8 +309,8 @@ public class BungeeCordMessageResponder {
   }
 
   static String getBungeeCordChannel(ProtocolVersion version) {
-    return version.gte(ProtocolVersion.MINECRAFT_1_13) ? MODERN_CHANNEL.id()
-        : LEGACY_CHANNEL.id();
+    return version.gte(ProtocolVersion.MINECRAFT_1_13) ? CHANNEL.modernChannelKey().asString()
+        : CHANNEL.legacyChannel();
   }
 
   // Note: this method will always release the buffer!

proxy/src/main/java/com/velocitypowered/proxy/connection/backend/VelocityServerConnection.java

@@ -20,12 +20,13 @@ package com.velocitypowered.proxy.connection.backend;
 import static com.velocitypowered.proxy.VelocityServer.GENERAL_GSON;
 import static com.velocitypowered.proxy.connection.forge.legacy.LegacyForgeConstants.HANDSHAKE_HOSTNAME_TOKEN;
 import static com.velocitypowered.proxy.network.HandlerNames.HANDLER;
+import static com.velocitypowered.proxy.network.PluginMessageUtil.channelIdForVersion;
 
 import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableList;
 import com.velocitypowered.api.network.ProtocolVersion;
 import com.velocitypowered.api.proxy.connection.ServerConnection;
-import com.velocitypowered.api.proxy.messages.ChannelIdentifier;
+import com.velocitypowered.api.proxy.messages.PluginChannelId;
 import com.velocitypowered.api.proxy.player.ConnectionRequestBuilder;
 import com.velocitypowered.api.proxy.server.ServerInfo;
 import com.velocitypowered.api.util.GameProfile.Property;
@@ -236,7 +237,7 @@ public class VelocityServerConnection implements MinecraftConnectionAssociation,
   }
 
   @Override
-  public boolean sendPluginMessage(ChannelIdentifier identifier, byte[] data) {
+  public boolean sendPluginMessage(PluginChannelId identifier, byte[] data) {
     return sendPluginMessage(identifier, Unpooled.wrappedBuffer(data));
   }
 
@@ -246,13 +247,14 @@ public class VelocityServerConnection implements MinecraftConnectionAssociation,
    * @param data the data
    * @return whether or not the message was sent
    */
-  public boolean sendPluginMessage(ChannelIdentifier identifier, ByteBuf data) {
+  public boolean sendPluginMessage(PluginChannelId identifier, ByteBuf data) {
     Preconditions.checkNotNull(identifier, "identifier");
     Preconditions.checkNotNull(data, "data");
 
     MinecraftConnection mc = ensureConnected();
 
-    ServerboundPluginMessagePacket message = new ServerboundPluginMessagePacket(identifier.id(), data);
+    ServerboundPluginMessagePacket message = new ServerboundPluginMessagePacket(
+        channelIdForVersion(identifier, mc.getProtocolVersion()), data);
     mc.write(message);
     return true;
   }

proxy/src/main/java/com/velocitypowered/proxy/connection/client/ClientPlaySessionHandler.java

@@ -32,9 +32,7 @@ import com.velocitypowered.api.event.player.PlayerChatEventImpl;
 import com.velocitypowered.api.event.player.PlayerResourcePackStatusEventImpl;
 import com.velocitypowered.api.event.player.TabCompleteEventImpl;
 import com.velocitypowered.api.network.ProtocolVersion;
-import com.velocitypowered.api.proxy.messages.ChannelIdentifier;
-import com.velocitypowered.api.proxy.messages.LegacyChannelIdentifier;
-import com.velocitypowered.api.proxy.messages.MinecraftChannelIdentifier;
+import com.velocitypowered.api.proxy.messages.PluginChannelId;
 import com.velocitypowered.proxy.VelocityServer;
 import com.velocitypowered.proxy.connection.ConnectionTypes;
 import com.velocitypowered.proxy.connection.MinecraftConnection;
@@ -72,6 +70,7 @@ import java.util.Queue;
 import java.util.UUID;
 import java.util.concurrent.CompletableFuture;
 import net.kyori.adventure.identity.Identity;
+import net.kyori.adventure.key.Key;
 import net.kyori.adventure.text.Component;
 import net.kyori.adventure.text.format.NamedTextColor;
 import org.apache.logging.log4j.LogManager;
@@ -218,16 +217,21 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
       } else if (PluginMessageUtil.isRegister(packet)) {
         List<String> channels = PluginMessageUtil.getChannels(packet);
         player.getKnownChannels().addAll(channels);
-        List<ChannelIdentifier> channelIdentifiers = new ArrayList<>();
+
+        List<PluginChannelId> pluginChannelIds = new ArrayList<>();
+        if (player.protocolVersion().gte(MINECRAFT_1_13)) {
           for (String channel : channels) {
-          try {
-            channelIdentifiers.add(MinecraftChannelIdentifier.from(channel));
-          } catch (IllegalArgumentException e) {
-            channelIdentifiers.add(new LegacyChannelIdentifier(channel));
+            pluginChannelIds.add(PluginChannelId.wrap(Key.key(channel)));
+          }
+        } else {
+          for (String channel : channels) {
+            pluginChannelIds.add(PluginChannelId.withLegacy(channel,
+                Key.key(PluginMessageUtil.transformLegacyToModernChannel(channel))));
           }
         }
+
         server.eventManager().fireAndForget(new PlayerChannelRegisterEventImpl(player,
-                ImmutableList.copyOf(channelIdentifiers)));
+                ImmutableList.copyOf(pluginChannelIds)));
         backendConn.write(packet.retain());
       } else if (PluginMessageUtil.isUnregister(packet)) {
         player.getKnownChannels().removeAll(PluginMessageUtil.getChannels(packet));
@@ -259,7 +263,7 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
             // appropriately.
             loginPluginMessages.add(packet.retain());
           } else {
-            ChannelIdentifier id = server.channelRegistrar().getFromId(packet.getChannel());
+            PluginChannelId id = server.channelRegistrar().getFromId(packet.getChannel());
             if (id == null) {
               backendConn.write(packet.retain());
             } else {

proxy/src/main/java/com/velocitypowered/proxy/connection/client/ConnectedPlayer.java

@@ -19,6 +19,7 @@ package com.velocitypowered.proxy.connection.client;
 
 import static com.velocitypowered.api.proxy.player.ConnectionRequestBuilder.Status.ALREADY_CONNECTED;
 import static com.velocitypowered.proxy.connection.util.ConnectionRequestResults.plainResult;
+import static com.velocitypowered.proxy.network.PluginMessageUtil.channelIdForVersion;
 import static java.util.concurrent.CompletableFuture.completedFuture;
 
 import com.google.common.base.Preconditions;
@@ -42,7 +43,7 @@ import com.velocitypowered.api.permission.PermissionProvider;
 import com.velocitypowered.api.permission.Tristate;
 import com.velocitypowered.api.proxy.connection.Player;
 import com.velocitypowered.api.proxy.connection.ServerConnection;
-import com.velocitypowered.api.proxy.messages.ChannelIdentifier;
+import com.velocitypowered.api.proxy.messages.PluginChannelId;
 import com.velocitypowered.api.proxy.player.ClientSettings;
 import com.velocitypowered.api.proxy.player.ConnectionRequestBuilder;
 import com.velocitypowered.api.proxy.server.RegisteredServer;
@@ -709,10 +710,11 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player {
   }
 
   @Override
-  public boolean sendPluginMessage(ChannelIdentifier identifier, byte[] data) {
+  public boolean sendPluginMessage(PluginChannelId identifier, byte[] data) {
     Preconditions.checkNotNull(identifier, "identifier");
     Preconditions.checkNotNull(data, "data");
-    ClientboundPluginMessagePacket message = new ClientboundPluginMessagePacket(identifier.id(),
+    ClientboundPluginMessagePacket message = new ClientboundPluginMessagePacket(
+        channelIdForVersion(identifier, connection.getProtocolVersion()),
         Unpooled.wrappedBuffer(data));
     connection.write(message);
     return true;

proxy/src/main/java/com/velocitypowered/proxy/network/PluginMessageUtil.java

@@ -22,6 +22,9 @@ import static com.google.common.base.Preconditions.checkNotNull;
 
 import com.google.common.collect.ImmutableList;
 import com.velocitypowered.api.network.ProtocolVersion;
+import com.velocitypowered.api.proxy.messages.MinecraftPluginChannelId;
+import com.velocitypowered.api.proxy.messages.PairedPluginChannelId;
+import com.velocitypowered.api.proxy.messages.PluginChannelId;
 import com.velocitypowered.api.util.ProxyVersion;
 import com.velocitypowered.proxy.network.packet.AbstractPluginMessagePacket;
 import io.netty.buffer.ByteBuf;
@@ -174,6 +177,19 @@ public final class PluginMessageUtil {
     }
   }
 
+  public static String channelIdForVersion(PluginChannelId id, ProtocolVersion version) {
+    if (id instanceof MinecraftPluginChannelId) {
+      return ((MinecraftPluginChannelId) id).key().asString();
+    } else if (id instanceof PairedPluginChannelId) {
+      if (version.gte(ProtocolVersion.MINECRAFT_1_13)) {
+        return ((PairedPluginChannelId) id).modernChannelKey().asString();
+      } else {
+        return ((PairedPluginChannelId) id).legacyChannel();
+      }
+    }
+    throw new IllegalArgumentException("Unknown channel ID " + id.getClass().getName());
+  }
+
   private static final Pattern INVALID_IDENTIFIER_REGEX = Pattern.compile("[^a-z0-9\\-_]*");
 
   /**

proxy/src/main/java/com/velocitypowered/proxy/network/packet/AbstractPluginMessagePacket.java

@@ -32,9 +32,6 @@ public abstract class AbstractPluginMessagePacket<S extends AbstractPluginMessag
   protected static <P extends AbstractPluginMessagePacket<P>> PacketReader<P> decoder(final Factory<P> factory) {
     return (buf, version) -> {
       String channel = ProtocolUtils.readString(buf);
-      if (version.gte(ProtocolVersion.MINECRAFT_1_13)) {
-        channel = transformLegacyToModernChannel(channel);
-      }
       final ByteBuf data;
       if (version.gte(ProtocolVersion.MINECRAFT_1_8)) {
         data = buf.readRetainedSlice(buf.readableBytes());

proxy/src/main/java/com/velocitypowered/proxy/network/pipeline/GS4QueryHandler.java

@@ -201,7 +201,7 @@ public class GS4QueryHandler extends SimpleChannelInboundHandler<DatagramPacket>
 
   private List<QueryResponse.PluginInformation> getRealPluginInformation() {
     List<QueryResponse.PluginInformation> result = new ArrayList<>();
-    for (PluginContainer plugin : server.pluginManager().getPlugins()) {
+    for (PluginContainer plugin : server.pluginManager().plugins()) {
       PluginDescription description = plugin.description();
       result.add(QueryResponse.PluginInformation.of(description.name()
           .orElse(description.id()), description.version().orElse(null)));

proxy/src/main/java/com/velocitypowered/proxy/plugin/VelocityPluginManager.java

@@ -178,7 +178,7 @@ public class VelocityPluginManager implements PluginManager {
   }
 
   @Override
-  public Collection<PluginContainer> getPlugins() {
+  public Collection<PluginContainer> plugins() {
     return Collections.unmodifiableCollection(plugins.values());
   }
 

proxy/src/main/java/com/velocitypowered/proxy/server/VelocityRegisteredServer.java

@@ -28,7 +28,7 @@ import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableList;
 import com.velocitypowered.api.network.ProtocolVersion;
 import com.velocitypowered.api.proxy.connection.Player;
-import com.velocitypowered.api.proxy.messages.ChannelIdentifier;
+import com.velocitypowered.api.proxy.messages.PluginChannelId;
 import com.velocitypowered.api.proxy.server.RegisteredServer;
 import com.velocitypowered.api.proxy.server.ServerInfo;
 import com.velocitypowered.api.proxy.server.ServerPing;
@@ -137,7 +137,7 @@ public class VelocityRegisteredServer implements RegisteredServer, ForwardingAud
   }
 
   @Override
-  public boolean sendPluginMessage(ChannelIdentifier identifier, byte[] data) {
+  public boolean sendPluginMessage(PluginChannelId identifier, byte[] data) {
     return sendPluginMessage(identifier, Unpooled.wrappedBuffer(data));
   }
 
@@ -149,7 +149,7 @@ public class VelocityRegisteredServer implements RegisteredServer, ForwardingAud
    * @param data the data
    * @return whether or not the message was sent
    */
-  public boolean sendPluginMessage(ChannelIdentifier identifier, ByteBuf data) {
+  public boolean sendPluginMessage(PluginChannelId identifier, ByteBuf data) {
     for (ConnectedPlayer player : players.values()) {
       VelocityServerConnection connection = player.getConnectedServer();
       if (connection != null && connection.target() == this) {

proxy/src/main/java/com/velocitypowered/proxy/util/InformationUtils.java

@@ -52,8 +52,7 @@ public enum InformationUtils {
    * @return {@link JsonArray} containing zero or more {@link JsonObject}
    */
   public static JsonArray collectPluginInfo(ProxyServer proxy) {
-    List<PluginContainer> allPlugins = ImmutableList.copyOf(
-            proxy.pluginManager().getPlugins());
+    List<PluginContainer> allPlugins = ImmutableList.copyOf(proxy.pluginManager().plugins());
     JsonArray plugins = new JsonArray();
 
     for (PluginContainer plugin : allPlugins) {
@@ -190,7 +189,7 @@ public enum InformationUtils {
     if (address instanceof InetSocketAddress) {
       InetSocketAddress iaddr = (InetSocketAddress) address;
       if (iaddr.isUnresolved()) {
-        // Greetings form Netty 4aa10db9
+        // Greetings from Netty 4aa10db9
         info.addProperty("host", iaddr.getHostString());
       } else {
         info.addProperty("host", anonymizeInetAddress(iaddr.getAddress()));

proxy/src/main/java/com/velocitypowered/proxy/util/VelocityChannelRegistrar.java

@@ -18,55 +18,58 @@
 package com.velocitypowered.proxy.util;
 
 import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableSet;
 import com.velocitypowered.api.network.ProtocolVersion;
-import com.velocitypowered.api.proxy.messages.ChannelIdentifier;
 import com.velocitypowered.api.proxy.messages.ChannelRegistrar;
-import com.velocitypowered.api.proxy.messages.LegacyChannelIdentifier;
-import com.velocitypowered.api.proxy.messages.MinecraftChannelIdentifier;
-import com.velocitypowered.proxy.network.PluginMessageUtil;
+import com.velocitypowered.api.proxy.messages.MinecraftPluginChannelId;
+import com.velocitypowered.api.proxy.messages.PairedPluginChannelId;
+import com.velocitypowered.api.proxy.messages.PluginChannelId;
 import java.util.Collection;
-import java.util.HashSet;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
 public class VelocityChannelRegistrar implements ChannelRegistrar {
 
-  private final Map<String, ChannelIdentifier> identifierMap = new ConcurrentHashMap<>();
+  private final Map<String, PluginChannelId> byLegacyId = new ConcurrentHashMap<>();
+  private final Map<String, PluginChannelId> byKey = new ConcurrentHashMap<>();
 
   @Override
-  public void register(ChannelIdentifier... identifiers) {
-    for (ChannelIdentifier identifier : identifiers) {
-      Preconditions.checkArgument(identifier instanceof LegacyChannelIdentifier
-          || identifier instanceof MinecraftChannelIdentifier, "identifier is unknown");
+  public void register(PluginChannelId... identifiers) {
+    for (PluginChannelId identifier : identifiers) {
+      Preconditions.checkArgument(identifier instanceof PairedPluginChannelId
+          || identifier instanceof MinecraftPluginChannelId, "identifier is unknown");
     }
 
-    for (ChannelIdentifier identifier : identifiers) {
-      if (identifier instanceof MinecraftChannelIdentifier) {
-        identifierMap.put(identifier.id(), identifier);
+    for (PluginChannelId identifier : identifiers) {
+      if (identifier instanceof MinecraftPluginChannelId) {
+        MinecraftPluginChannelId modern = (MinecraftPluginChannelId) identifier;
+        byLegacyId.put(modern.key().asString(), identifier);
+        byKey.put(modern.key().asString(), identifier);
       } else {
-        String rewritten = PluginMessageUtil.transformLegacyToModernChannel(identifier.id());
-        identifierMap.put(identifier.id(), identifier);
-        identifierMap.put(rewritten, identifier);
+        PairedPluginChannelId paired = (PairedPluginChannelId) identifier;
+        byLegacyId.put(paired.legacyChannel(), identifier);
+        byKey.put(paired.modernChannelKey().asString(), identifier);
       }
     }
   }
 
   @Override
-  public void unregister(ChannelIdentifier... identifiers) {
-    for (ChannelIdentifier identifier : identifiers) {
-      Preconditions.checkArgument(identifier instanceof LegacyChannelIdentifier
-              || identifier instanceof MinecraftChannelIdentifier,
+  public void unregister(PluginChannelId... identifiers) {
+    for (PluginChannelId identifier : identifiers) {
+      Preconditions.checkArgument(identifier instanceof PairedPluginChannelId
+              || identifier instanceof MinecraftPluginChannelId,
           "identifier is unknown");
     }
 
-    for (ChannelIdentifier identifier : identifiers) {
-      if (identifier instanceof MinecraftChannelIdentifier) {
-        identifierMap.remove(identifier.id());
+    for (PluginChannelId identifier : identifiers) {
+      if (identifier instanceof MinecraftPluginChannelId) {
+        MinecraftPluginChannelId modern = (MinecraftPluginChannelId) identifier;
+        byKey.remove(modern.key().asString(), identifier);
       } else {
-        String rewritten = PluginMessageUtil.transformLegacyToModernChannel(identifier.id());
-        identifierMap.remove(identifier.id());
-        identifierMap.remove(rewritten);
+        PairedPluginChannelId paired = (PairedPluginChannelId) identifier;
+        byLegacyId.remove(paired.legacyChannel(), identifier);
+        byKey.remove(paired.modernChannelKey().asString(), identifier);
       }
     }
   }
@@ -77,11 +80,7 @@ public class VelocityChannelRegistrar implements ChannelRegistrar {
    * @return all legacy channel IDs
    */
   public Collection<String> getLegacyChannelIds() {
-    Collection<String> ids = new HashSet<>();
-    for (ChannelIdentifier value : identifierMap.values()) {
-      ids.add(value.id());
-    }
-    return ids;
+    return ImmutableSet.copyOf(this.byLegacyId.keySet());
   }
 
   /**
@@ -90,19 +89,14 @@ public class VelocityChannelRegistrar implements ChannelRegistrar {
    * @return the channel IDs for Minecraft 1.13 and above
    */
   public Collection<String> getModernChannelIds() {
-    Collection<String> ids = new HashSet<>();
-    for (ChannelIdentifier value : identifierMap.values()) {
-      if (value instanceof MinecraftChannelIdentifier) {
-        ids.add(value.id());
-      } else {
-        ids.add(PluginMessageUtil.transformLegacyToModernChannel(value.id()));
-      }
-    }
-    return ids;
+    return ImmutableSet.copyOf(this.byKey.keySet());
   }
 
-  public @Nullable ChannelIdentifier getFromId(String id) {
-    return identifierMap.get(id);
+  public @Nullable PluginChannelId getFromId(String id) {
+    if (id.indexOf(':') >= 0) {
+      return byKey.get(id);
+    }
+    return byLegacyId.get(id);
   }
 
   /**

proxy/src/main/java/com/velocitypowered/proxy/util/bossbar/AdventureBossBarManager.java

@@ -138,13 +138,12 @@ public class AdventureBossBarManager implements BossBar.Listener {
   }
 
   @Override
-  public void bossBarPercentChanged(@NonNull BossBar bar, float oldPercent, float newPercent) {
+  public void bossBarProgressChanged(@NonNull BossBar bar, float oldProgress, float newProgress) {
     BossBarHolder holder = this.getHandler(bar);
     if (holder == null) {
       return;
     }
-    ClientboundBossBarPacket packet = holder
-        .createPercentUpdate(newPercent);
+    ClientboundBossBarPacket packet = holder.createPercentUpdate(newProgress);
     for (ConnectedPlayer player : holder.subscribers) {
       player.getConnection().write(packet);
     }
@@ -170,8 +169,7 @@ public class AdventureBossBarManager implements BossBar.Listener {
     if (holder == null) {
       return;
     }
-    ClientboundBossBarPacket packet = holder
-        .createOverlayUpdate(newOverlay);
+    ClientboundBossBarPacket packet = holder.createOverlayUpdate(newOverlay);
     for (ConnectedPlayer player : holder.subscribers) {
       player.getConnection().write(packet);
     }

proxy/src/test/java/com/velocitypowered/proxy/plugin/MockPluginManager.java

@@ -39,7 +39,7 @@ public class MockPluginManager implements PluginManager {
   }
 
   @Override
-  public Collection<PluginContainer> getPlugins() {
+  public Collection<PluginContainer> plugins() {
     return ImmutableList.of();
   }
 

proxy/src/test/java/com/velocitypowered/proxy/testutil/FakePluginManager.java

@@ -58,7 +58,7 @@ public class FakePluginManager implements PluginManager {
   }
 
   @Override
-  public @NonNull Collection<PluginContainer> getPlugins() {
+  public @NonNull Collection<PluginContainer> plugins() {
     return ImmutableList.of(PC_A, PC_B);
   }
 

proxy/src/test/java/com/velocitypowered/proxy/util/VelocityChannelRegistrarTest.java

@@ -20,23 +20,18 @@ package com.velocitypowered.proxy.util;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import com.google.common.collect.ImmutableSet;
-import com.velocitypowered.api.proxy.messages.LegacyChannelIdentifier;
-import com.velocitypowered.api.proxy.messages.MinecraftChannelIdentifier;
+import com.velocitypowered.api.proxy.messages.MinecraftPluginChannelId;
+import com.velocitypowered.api.proxy.messages.PairedPluginChannelId;
+import com.velocitypowered.api.proxy.messages.PluginChannelId;
+import net.kyori.adventure.key.Key;
 import org.junit.jupiter.api.Test;
 
 class VelocityChannelRegistrarTest {
 
-  private static final MinecraftChannelIdentifier MODERN = MinecraftChannelIdentifier
-      .create("velocity", "test");
-  private static final LegacyChannelIdentifier SIMPLE_LEGACY =
-      new LegacyChannelIdentifier("VelocityTest");
-
-  private static final MinecraftChannelIdentifier MODERN_SPECIAL_REMAP = MinecraftChannelIdentifier
-      .create("bungeecord", "main");
-  private static final LegacyChannelIdentifier SPECIAL_REMAP_LEGACY =
-      new LegacyChannelIdentifier("BungeeCord");
-
-  private static final String SIMPLE_LEGACY_REMAPPED = "legacy:velocitytest";
+  private static final MinecraftPluginChannelId MODERN = PluginChannelId.wrap(
+      Key.key("velocity", "moderntest"));
+  private static final PairedPluginChannelId SIMPLE_LEGACY =
+      PluginChannelId.withLegacy("VelocityTest", Key.key("velocity", "test"));
 
   @Test
   void register() {
@@ -45,30 +40,21 @@ class VelocityChannelRegistrarTest {
 
     // Two channels cover the modern channel (velocity:test) and the legacy-mapped channel
     // (legacy:velocitytest). Make sure they're what we expect.
-    assertEquals(ImmutableSet.of(MODERN.id(), SIMPLE_LEGACY_REMAPPED), registrar
-        .getModernChannelIds());
-    assertEquals(ImmutableSet.of(SIMPLE_LEGACY.id(), MODERN.id()), registrar
+    assertEquals(
+        ImmutableSet.of(MODERN.key().asString(), SIMPLE_LEGACY.modernChannelKey().asString()),
+        registrar.getModernChannelIds());
+    assertEquals(
+        ImmutableSet.of(SIMPLE_LEGACY.legacyChannel(), MODERN.key().asString()), registrar
         .getLegacyChannelIds());
   }
 
-  @Test
-  void registerSpecialRewrite() {
-    VelocityChannelRegistrar registrar = new VelocityChannelRegistrar();
-    registrar.register(SPECIAL_REMAP_LEGACY, MODERN_SPECIAL_REMAP);
-
-    // This one, just one channel for the modern case.
-    assertEquals(ImmutableSet.of(MODERN_SPECIAL_REMAP.id()), registrar.getModernChannelIds());
-    assertEquals(ImmutableSet.of(MODERN_SPECIAL_REMAP.id(), SPECIAL_REMAP_LEGACY.id()),
-        registrar.getLegacyChannelIds());
-  }
-
   @Test
   void unregister() {
     VelocityChannelRegistrar registrar = new VelocityChannelRegistrar();
-    registrar.register(MODERN, SIMPLE_LEGACY);
+    registrar.register(MODERN);
     registrar.unregister(SIMPLE_LEGACY);
 
-    assertEquals(ImmutableSet.of(MODERN.id()), registrar.getModernChannelIds());
-    assertEquals(ImmutableSet.of(MODERN.id()), registrar.getLegacyChannelIds());
+    assertEquals(ImmutableSet.of(MODERN.key().asString()), registrar.getModernChannelIds());
+    assertEquals(ImmutableSet.of(MODERN.key().asString()), registrar.getLegacyChannelIds());
   }
 }