I'm changing whisper and voice handlers. I think that the COMPRESSED flag is important, it may signal you to reset your decoder for each incoming packet. Not sure.

src/main/java/com/github/manevolent/ts3j/protocol/packet/handler/client/LocalClientHandlerFull.java

@@ -55,12 +55,12 @@ public abstract class LocalClientHandlerFull extends LocalClientHandler {
 
                 break;
             case VOICE:
-                Consumer<PacketBody0Voice> handler = getClient().getVoiceHandler();
-                if (handler != null) handler.accept((PacketBody0Voice) packet.getBody());
+                Consumer<Packet> handler = getClient().getVoiceHandler();
+                if (handler != null) handler.accept(packet);
                 break;
             case VOICE_WHISPER:
-                Consumer<PacketBody1VoiceWhisper> whisperConsumer = getClient().getWhisperHandler();
-                if (whisperConsumer != null) whisperConsumer.accept((PacketBody1VoiceWhisper) packet.getBody());
+                Consumer<Packet> whisperConsumer = getClient().getWhisperHandler();
+                if (whisperConsumer != null) whisperConsumer.accept(packet);
                 break;
         }
     }

src/main/java/com/github/manevolent/ts3j/protocol/socket/client/AbstractTeamspeakClientSocket.java

@@ -70,8 +70,8 @@ public abstract class AbstractTeamspeakClientSocket
 
     private CommandProcessor commandProcessor;
 
-    private Consumer<PacketBody0Voice> voiceHandler;
-    private Consumer<PacketBody1VoiceWhisper> whisperHandler;
+    private Consumer<Packet> voiceHandler;
+    private Consumer<Packet> whisperHandler;
 
     private Consumer<Throwable> exceptionHandler = Throwable::printStackTrace;
 
@@ -897,19 +897,19 @@ public abstract class AbstractTeamspeakClientSocket
         this.exceptionHandler = exceptionHandler;
     }
 
-    public Consumer<PacketBody0Voice> getVoiceHandler() {
+    public Consumer<Packet> getVoiceHandler() {
         return voiceHandler;
     }
 
-    public void setVoiceHandler(Consumer<PacketBody0Voice> voiceHandler) {
+    public void setVoiceHandler(Consumer<Packet> voiceHandler) {
         this.voiceHandler = voiceHandler;
     }
 
-    public Consumer<PacketBody1VoiceWhisper> getWhisperHandler() {
+    public Consumer<Packet> getWhisperHandler() {
         return whisperHandler;
     }
 
-    public void setWhisperHandler(Consumer<PacketBody1VoiceWhisper> whisperHandler) {
+    public void setWhisperHandler(Consumer<Packet> whisperHandler) {
         this.whisperHandler = whisperHandler;
     }
 

src/main/java/com/github/manevolent/ts3j/protocol/socket/client/LocalTeamspeakClientSocket.java

@@ -605,7 +605,7 @@ public class LocalTeamspeakClientSocket
         private void handleComplete(SingleCommand command) throws IOException, TimeoutException {
             try {
                 synchronized (commandSendLock) {
-                    awaitingCommands.remove(returnCode);
+                    awaitingCommands.remove(getReturnCode());
                     acceptingReturnCode = calculateAcceptingReturnCode();
                 }
 
@@ -690,12 +690,11 @@ public class LocalTeamspeakClientSocket
         switch (getState()) {
             case RETRIEVING_DATA:
             case CONNECTED:
-                Command banCommand = new SingleCommand("clientupdate", ProtocolRole.CLIENT);
-
-                banCommand.add(new CommandSingleParameter("client_nickname", nickname));
+                Command command = new SingleCommand("clientupdate", ProtocolRole.CLIENT);
+                command.add(new CommandSingleParameter("client_nickname", nickname));
 
                 try {
-                    executeCommand(banCommand).complete();
+                    executeCommand(command).complete();
                 } catch (Exception e) {
                     throw new RuntimeException(e);
                 }

src/test/java/com/github/manevolent/ts3j/ServerConnectionTest.java

@@ -24,7 +24,7 @@ public class ServerConnectionTest  {
 
         Ts3Debugging.setEnabled(true);
 
-        LocalIdentity identity = LocalIdentity.generateNew(9);
+        LocalIdentity identity = LocalIdentity.generateNew(10);
 
         client.setIdentity(identity);
         client.setNickname("ts3j issue 2");