diff --git a/Client/src/main/java/dev/wiing/gossip/client/Connection.java b/Client/src/main/java/dev/wiing/gossip/client/Connection.java
index 5c5b935..da39185 100644
--- a/Client/src/main/java/dev/wiing/gossip/client/Connection.java
+++ b/Client/src/main/java/dev/wiing/gossip/client/Connection.java
@@ -84,8 +84,13 @@ public class Connection {
                     }
 
                     connection.updateConnectionStats();
+
+                } catch (PacketException e) {
+                    e.printStackTrace();
+
                 } catch (SocketException e) {
                     break;
+
                 } catch (IOException e) {
                     e.printStackTrace();
                 }
@@ -212,9 +217,19 @@ public class Connection {
         }
 
         try {
-            return getPacketManager().readPacket(getSocket().getInputStream());
+            Packet packet = getPacketManager().readPacket(getSocket().getInputStream());
+
+            if (packet.getType() == ErrorPacket.TYPE) {
+                ErrorPacket errorPacket = (ErrorPacket) packet;
+
+                throw new PacketException(packetManager.getPacketMap().get(errorPacket.getErrorType()), errorPacket.getReason());
+            }
+
+            return packet;
+
         } catch (SocketException e) {
             throw e;
+
         } catch (IOException e) {
             e.printStackTrace();
             return null;
@@ -231,6 +246,7 @@ public class Connection {
 
             if (packet.getType() != packetType) {
                 queuedPackets.add(packet);
+                updateConnectionStats();
                 continue;
             }
 
diff --git a/Client/src/main/java/dev/wiing/gossip/client/PacketException.java b/Client/src/main/java/dev/wiing/gossip/client/PacketException.java
new file mode 100644
index 0000000..fcd8c96
--- /dev/null
+++ b/Client/src/main/java/dev/wiing/gossip/client/PacketException.java
@@ -0,0 +1,9 @@
+package dev.wiing.gossip.client;
+
+import dev.wiing.gossip.lib.packets.Packet;
+
+public class PacketException extends RuntimeException {
+    public PacketException(Packet packet, String message) {
+        super("Packet of type=" + packet.getType() + " (" + packet.getClass().getSimpleName() + ") caused an error: " + message);
+    }
+}
diff --git a/Client/src/main/java/dev/wiing/gossip/client/controllers/MainChatController.java b/Client/src/main/java/dev/wiing/gossip/client/controllers/MainChatController.java
index a926edf..6c1fe81 100644
--- a/Client/src/main/java/dev/wiing/gossip/client/controllers/MainChatController.java
+++ b/Client/src/main/java/dev/wiing/gossip/client/controllers/MainChatController.java
@@ -13,6 +13,7 @@ import dev.wiing.gossip.lib.packets.MessagePushPacket;
 import dev.wiing.gossip.lib.packets.TopicJoinPacket;
 import dev.wiing.gossip.lib.packets.TypingPingPacket;
 import javafx.application.Platform;
+import javafx.collections.ListChangeListener;
 import javafx.event.ActionEvent;
 import javafx.fxml.FXML;
 import javafx.scene.Parent;
@@ -109,6 +110,13 @@ public class MainChatController {
         });
 
         updateTypingMembers();
+
+        txtCompose.getParagraphs().addListener((ListChangeListener<? super CharSequence>) c -> {
+            int height = 8 + Math.min(c.getList().size(), 5) * 17;
+
+            txtCompose.setMinHeight(height);
+            txtCompose.setPrefHeight(height);
+        });
     }
 
     private void setTopicName(String name) {
@@ -256,7 +264,12 @@ public class MainChatController {
     }
 
     public void updateTypingMembers() {
-        if (topic.getTypingUsersCount() == 0) {
+        int typingUsersCount = topic.getTypingUsersCount();
+
+        if (topic.getTypingUsersReadOnly().stream().anyMatch(user -> user.getUserID() == Connection.getInstance().getSelf().getUserID()))
+            --typingUsersCount;
+
+        if (typingUsersCount == 0) {
             lblTyping.setText("");
             lblTyping.setMinHeight(0);
             lblTyping.setMaxHeight(0);
@@ -266,7 +279,7 @@ public class MainChatController {
         lblTyping.setMinHeight(Region.USE_COMPUTED_SIZE);
         lblTyping.setMaxHeight(Region.USE_COMPUTED_SIZE);
 
-        if (topic.getTypingUsersCount() > 3) {
+        if (typingUsersCount > 3) {
             lblTyping.setText("Several babblers are writing...");
             return;
         }
@@ -274,11 +287,14 @@ public class MainChatController {
         StringBuilder sb = new StringBuilder();
 
         for (User user : topic.getTypingUsersReadOnly()) {
+            if (user.getUserID() == Connection.getInstance().getSelf().getUserID())
+                continue;
+
             if (!sb.isEmpty()) sb.append(", ");
             sb.append(user.getUsername());
         }
 
-        sb.append(topic.getTypingUsersCount() == 1 ? " is" : " are");
+        sb.append(typingUsersCount == 1 ? " is" : " are");
 
         sb.append(" writing...");
 
@@ -289,7 +305,4 @@ public class MainChatController {
         return Utils.createInstance("views/chat-view.fxml");
     }
 
-}
-
-// TODO: better mutliline input
-// 25 + 17 per extra line
\ No newline at end of file
+}
\ No newline at end of file
diff --git a/Client/src/main/java/dev/wiing/gossip/client/controllers/MainController.java b/Client/src/main/java/dev/wiing/gossip/client/controllers/MainController.java
index 006d043..a1883b2 100644
--- a/Client/src/main/java/dev/wiing/gossip/client/controllers/MainController.java
+++ b/Client/src/main/java/dev/wiing/gossip/client/controllers/MainController.java
@@ -31,6 +31,7 @@ public class MainController implements Initializable {
     Topic activeTopic = null;
     Parent activeTopicElement = null;
     private final Map<Long, Pair<Parent, MainChatController>> topicMap = new ConcurrentHashMap<>();
+    private final Map<Long, Thread> topicUpdateThreadMap = new ConcurrentHashMap<>();
 
     @FXML
     private VBox vboxRoot;
@@ -121,6 +122,10 @@ public class MainController implements Initializable {
                 for (LongData userID : packet.getUsersJoined()) {
                     User userJoined = Connection.getInstance().getUser(userID.getValue());
                     topic.addUser(userJoined);
+
+                    if (userJoined.getUserID() == Connection.getInstance().getSelf().getUserID()) {
+                        pullTopicMessages(topic);
+                    }
                 }
             }
 
@@ -139,7 +144,7 @@ public class MainController implements Initializable {
 
             User author = Connection.getInstance().getUser(packet.getAuthorID());
 
-            UserMessage userMessage = new UserMessage(packet.getMessageID(), author, topic, packet.getContents());
+            UserMessage userMessage = new UserMessage(packet.getMessageID(), author, topic, packet.getContents(), packet.getCreatedTimestamp());
 
             topic.addMessage(userMessage);
         });
@@ -154,7 +159,7 @@ public class MainController implements Initializable {
                 targetUser = Connection.getInstance().getUser(packet.getUserID());
             }
 
-            SystemMessage systemMessage = new SystemMessage(packet.getMessageID(), topic, packet.getSystemType(), targetUser, packet.getContent());
+            SystemMessage systemMessage = new SystemMessage(packet.getMessageID(), topic, packet.getSystemType(), targetUser, packet.getContent(), packet.getCreatedTimestamp());
 
             topic.addMessage(systemMessage);
         });
@@ -178,10 +183,12 @@ public class MainController implements Initializable {
     }
 
     private void fetchTopicMessage(Topic topic, long messageID) {
+        if (topic.hasMessageByID(messageID)) return;
+
         MessageFetchPacket messageFetchPacket = new MessageFetchPacket();
         messageFetchPacket.setMessageID(messageID);
         messageFetchPacket.setTopicID(topic.getId());
-        Connection.getInstance().sendPacket(messageFetchPacket);
+        Connection.getInstance().sendPacketAuthenticated(messageFetchPacket);
 
         try {
             Packet messageFetchResult = Connection.getInstance().nextPacket(MessageDataPacket.TYPE);
@@ -195,7 +202,8 @@ public class MainController implements Initializable {
                         messageData.getMessageID(),
                         Connection.getInstance().getUser(messageData.getUserAuthorID()),
                         Connection.getInstance().getTopic(messageData.getTopicID()),
-                        messageData.getUserContents()
+                        messageData.getUserContents(),
+                        messageData.getCreatedTimestamp()
                 );
             }
             else if (messageData.isSystemMessage()) {
@@ -204,7 +212,8 @@ public class MainController implements Initializable {
                         Connection.getInstance().getTopic(messageData.getTopicID()),
                         messageData.getSystemType(),
                         Connection.getInstance().getUser(messageData.getSystemUserID()),
-                        messageData.getSystemContents()
+                        messageData.getSystemContents(),
+                        messageData.getCreatedTimestamp()
                 );
             }
 
@@ -232,10 +241,6 @@ public class MainController implements Initializable {
         AnchorPane.setRightAnchor(contentPair.first(), 0.0);
         contentPair.first().setVisible(false);
 
-        MessageListFetchPacket messageListFetchPacket = new MessageListFetchPacket();
-        messageListFetchPacket.setTopicID(topic.getId());
-        Connection.getInstance().sendPacket(messageListFetchPacket);
-
         Platform.runLater(() -> {
             paneContent.getChildren().add(contentPair.first());
 
@@ -246,6 +251,16 @@ public class MainController implements Initializable {
             setActiveTopic(topic, pair.first());
         });
 
+        pullTopicMessages(topic);
+    }
+
+    private void pullTopicMessages(Topic topic) {
+        if (!topic.hasUser(Connection.getInstance().getSelf())) return;
+
+        MessageListFetchPacket messageListFetchPacket = new MessageListFetchPacket();
+        messageListFetchPacket.setTopicID(topic.getId());
+        Connection.getInstance().sendPacketAuthenticated(messageListFetchPacket);
+
         try {
             Packet messageListFetchResult = Connection.getInstance().nextPacket(MessageListDataPacket.TYPE);
             if (messageListFetchResult == null) return;
@@ -259,6 +274,22 @@ public class MainController implements Initializable {
         } catch (SocketException e) {
             throw new RuntimeException(e);
         }
+
+        long topicID = topic.getId();
+
+        Thread thread = new Thread(() -> {
+            while (topicMap.containsKey(topicID)) {
+                topic.updateAllRelativeTimes();
+
+                try {
+                    Thread.sleep(30_000);
+                } catch (InterruptedException ignored) {
+                }
+            }
+        });
+        thread.start();
+
+        topicUpdateThreadMap.put(topicID, thread);
     }
 
     public void setActiveTopic(Topic topic, Parent element) {
diff --git a/Client/src/main/java/dev/wiing/gossip/client/controllers/item/MessageItemController.java b/Client/src/main/java/dev/wiing/gossip/client/controllers/item/MessageItemController.java
index 1a5a045..7c2e2bf 100644
--- a/Client/src/main/java/dev/wiing/gossip/client/controllers/item/MessageItemController.java
+++ b/Client/src/main/java/dev/wiing/gossip/client/controllers/item/MessageItemController.java
@@ -6,6 +6,7 @@ import dev.wiing.gossip.client.generic.Pair;
 import dev.wiing.gossip.client.utils.Utils;
 import dev.wiing.gossip.lib.models.UserMessage;
 import dev.wiing.gossip.lib.models.User;
+import javafx.application.Platform;
 import javafx.fxml.FXML;
 import javafx.fxml.Initializable;
 import javafx.scene.Parent;
@@ -42,6 +43,7 @@ public class MessageItemController implements Initializable {
     @Override
     public void initialize(URL location, ResourceBundle resources) {
         vboxMessages.getChildren().clear();
+        lblTimeAgo.setText("");
     }
 
     public User getAuthor() {
@@ -70,6 +72,10 @@ public class MessageItemController implements Initializable {
             this.lblTag.getStyleClass().add("secondary");
         }
 
+        if (userMessages.isEmpty()) {
+            userMessage.attachRelativeTime(data -> Platform.runLater(() -> lblTimeAgo.setText(data)));
+        }
+
         userMessages.add(userMessage);
 
         Label label = new Label(userMessage.getContents());
diff --git a/Client/src/main/java/dev/wiing/gossip/client/controllers/item/SystemMessageItemController.java b/Client/src/main/java/dev/wiing/gossip/client/controllers/item/SystemMessageItemController.java
index 9dbedf8..98cf8bd 100644
--- a/Client/src/main/java/dev/wiing/gossip/client/controllers/item/SystemMessageItemController.java
+++ b/Client/src/main/java/dev/wiing/gossip/client/controllers/item/SystemMessageItemController.java
@@ -3,6 +3,7 @@ package dev.wiing.gossip.client.controllers.item;
 import dev.wiing.gossip.client.generic.Pair;
 import dev.wiing.gossip.client.utils.Utils;
 import dev.wiing.gossip.lib.models.SystemMessage;
+import javafx.application.Platform;
 import javafx.fxml.FXML;
 import javafx.scene.Node;
 import javafx.scene.Parent;
@@ -32,6 +33,9 @@ public class SystemMessageItemController {
     public void setSystemMessage(SystemMessage systemMessage) {
         this.systemMessage = systemMessage;
 
+        lblTimeAgo.setText("");
+        systemMessage.attachRelativeTime(data -> Platform.runLater(() -> this.lblTimeAgo.setText(data)));
+
         switch (this.systemMessage.getType()) {
             case SystemMessage.SystemType.USER_JOIN:
                 removeNode(lblPrefix);
diff --git a/Client/src/main/resources/dev/wiing/gossip/client/views/chat-view.fxml b/Client/src/main/resources/dev/wiing/gossip/client/views/chat-view.fxml
index 89acf10..c05e449 100644
--- a/Client/src/main/resources/dev/wiing/gossip/client/views/chat-view.fxml
+++ b/Client/src/main/resources/dev/wiing/gossip/client/views/chat-view.fxml
@@ -88,7 +88,7 @@
                         <String fx:value="list" />
                      </styleClass>
                      <children>
-                        <TextArea fx:id="txtCompose" maxHeight="1.7976931348623157E308" minHeight="1.0" onKeyPressed="#onKeyPressed" onKeyTyped="#onKeyTyped" prefHeight="25.0" prefRowCount="1" promptText="Compose..." styleClass="transparent" wrapText="true" HBox.hgrow="ALWAYS" />
+                        <TextArea fx:id="txtCompose" maxHeight="1.7976931348623157E308" minHeight="25.0" onKeyPressed="#onKeyPressed" onKeyTyped="#onKeyTyped" prefHeight="25.0" prefRowCount="1" promptText="Compose..." styleClass="transparent" wrapText="true" HBox.hgrow="ALWAYS" />
                         <ImageView fitHeight="20.0" fitWidth="20.0" onMouseClicked="#onSend" opacity="0.5" pickOnBounds="true" preserveRatio="true">
                            <image>
                               <Image url="@../icons/icon-send-2.png" />
diff --git a/Lib/src/main/java/dev/wiing/gossip/lib/PacketManager.java b/Lib/src/main/java/dev/wiing/gossip/lib/PacketManager.java
index 6b36d24..f665c68 100644
--- a/Lib/src/main/java/dev/wiing/gossip/lib/PacketManager.java
+++ b/Lib/src/main/java/dev/wiing/gossip/lib/PacketManager.java
@@ -12,6 +12,7 @@ public class PacketManager {
         {
             add(new TestPacket());
             add(new AckPacket());
+            add(new ErrorPacket());
 
             add(new RegisterRequestPacket());
             add(new RegisterCredentialsPacket());
diff --git a/Lib/src/main/java/dev/wiing/gossip/lib/models/Message.java b/Lib/src/main/java/dev/wiing/gossip/lib/models/Message.java
index e8a5b69..68177a7 100644
--- a/Lib/src/main/java/dev/wiing/gossip/lib/models/Message.java
+++ b/Lib/src/main/java/dev/wiing/gossip/lib/models/Message.java
@@ -1,16 +1,25 @@
 package dev.wiing.gossip.lib.models;
 
+import dev.wiing.gossip.lib.models.ext.DynamicProperty;
+
+import java.time.Duration;
 import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+import java.time.format.FormatStyle;
 
 public class Message {
     private long id;
     private final Topic topic;
     private final LocalDateTime postTime;
 
+    private final DynamicProperty<String> relativeTime;
+
     public Message(long id, Topic topic, LocalDateTime postTime) {
         this.id = id;
         this.topic = topic;
         this.postTime = postTime;
+
+        relativeTime = new DynamicProperty<>("Just now");
     }
 
     public Message(long id, Topic topic) {
@@ -32,4 +41,32 @@ public class Message {
     public LocalDateTime getPostTime() {
         return postTime;
     }
+
+    public void attachRelativeTime(DynamicProperty.ICallback<String> callback) {
+        relativeTime.attach(callback);
+    }
+
+    public void recalculateRelativeTime(LocalDateTime now) {
+        Duration duration = Duration.between(postTime, now);
+
+        if (duration.toDays() > 7) {
+            relativeTime.setValue(postTime.format(DateTimeFormatter.ofLocalizedDateTime(FormatStyle.SHORT, FormatStyle.SHORT)));
+
+        } else if (duration.toDays() > 0) {
+            setRelativeTime("day", duration.toDays());
+
+        } else if (duration.toHours() > 0) {
+            setRelativeTime("hour", duration.toHours());
+
+        } else if (duration.toMinutes() > 0) {
+            setRelativeTime("minute", duration.toMinutes());
+
+        } else {
+            relativeTime.setValue("Just now");
+        }
+    }
+
+    private void setRelativeTime(String unit, long value) {
+        relativeTime.setValue(value + " " + unit + (value > 1 ? "s" : "") + " ago");
+    }
 }
diff --git a/Lib/src/main/java/dev/wiing/gossip/lib/models/Topic.java b/Lib/src/main/java/dev/wiing/gossip/lib/models/Topic.java
index b0c76c6..1402263 100644
--- a/Lib/src/main/java/dev/wiing/gossip/lib/models/Topic.java
+++ b/Lib/src/main/java/dev/wiing/gossip/lib/models/Topic.java
@@ -2,6 +2,7 @@ package dev.wiing.gossip.lib.models;
 
 import java.beans.PropertyChangeListener;
 import java.beans.PropertyChangeSupport;
+import java.time.LocalDateTime;
 import java.util.*;
 import java.util.concurrent.ConcurrentHashMap;
 
@@ -97,10 +98,14 @@ public class Topic {
     }
 
     public void addMessage(Message message) {
-        messages.add(message);
-        messageByIDs.put(message.getId(), message);
+        synchronized (messageByIDs) {
+            if (messageByIDs.containsKey(message.getId())) return;
 
-        this.changeSupport.firePropertyChange("messageAdd", null, message);
+            messageByIDs.put(message.getId(), message);
+            messages.add(message);
+
+            this.changeSupport.firePropertyChange("messageAdd", null, message);
+        }
     }
 
     public Set<User> getTypingUsersReadOnly() {
@@ -131,6 +136,10 @@ public class Topic {
         return messageByIDs.getOrDefault(messageID, null);
     }
 
+    public boolean hasMessageByID(long messageID) {
+        return messageByIDs.containsKey(messageID);
+    }
+
     public long getNextMessageID() {
         return messageTrackerID++;
     }
@@ -142,4 +151,13 @@ public class Topic {
     public void removeChangeListener(PropertyChangeListener listener) {
         this.changeSupport.removePropertyChangeListener(listener);
     }
+
+    public void updateAllRelativeTimes() {
+        synchronized (messages) {
+            for (Message message : messages) {
+                LocalDateTime now = LocalDateTime.now();
+                message.recalculateRelativeTime(now);
+            }
+        }
+    }
 }
diff --git a/Lib/src/main/java/dev/wiing/gossip/lib/models/UserMessage.java b/Lib/src/main/java/dev/wiing/gossip/lib/models/UserMessage.java
index c54d0df..8663bc5 100644
--- a/Lib/src/main/java/dev/wiing/gossip/lib/models/UserMessage.java
+++ b/Lib/src/main/java/dev/wiing/gossip/lib/models/UserMessage.java
@@ -1,5 +1,7 @@
 package dev.wiing.gossip.lib.models;
 
+import dev.wiing.gossip.lib.models.ext.DynamicProperty;
+
 import java.time.LocalDateTime;
 
 public class UserMessage extends Message {
diff --git a/Lib/src/main/java/dev/wiing/gossip/lib/models/ext/DynamicProperty.java b/Lib/src/main/java/dev/wiing/gossip/lib/models/ext/DynamicProperty.java
new file mode 100644
index 0000000..a22ec85
--- /dev/null
+++ b/Lib/src/main/java/dev/wiing/gossip/lib/models/ext/DynamicProperty.java
@@ -0,0 +1,52 @@
+package dev.wiing.gossip.lib.models.ext;
+
+import java.beans.PropertyChangeSupport;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+
+public class DynamicProperty<T> {
+
+    @FunctionalInterface
+    public interface ICallback<T> {
+        void run(T data);
+    }
+
+    private T value;
+
+    private final Set<ICallback<T>> callbacks = Collections.synchronizedSet(new HashSet<>());
+
+    public DynamicProperty(T defaultValue) {
+        this.value = defaultValue;
+    }
+
+    public void setValue(T value) {
+        if (this.value.equals(value)) return;
+
+        this.value = value;
+
+        runCallbacks();
+    }
+
+    public T getValue() {
+        return value;
+    }
+
+    public void attach(ICallback<T> callback) {
+        callbacks.add(callback);
+
+        callback.run(value);
+    }
+
+    public void detach(ICallback<T> callback) {
+        callbacks.remove(callback);
+    }
+
+    private void runCallbacks() {
+        synchronized (callbacks) {
+            for (ICallback<T> callback : callbacks) {
+                callback.run(value);
+            }
+        }
+    }
+}
diff --git a/Lib/src/main/java/dev/wiing/gossip/lib/packets/ErrorPacket.java b/Lib/src/main/java/dev/wiing/gossip/lib/packets/ErrorPacket.java
new file mode 100644
index 0000000..4ec24ac
--- /dev/null
+++ b/Lib/src/main/java/dev/wiing/gossip/lib/packets/ErrorPacket.java
@@ -0,0 +1,52 @@
+package dev.wiing.gossip.lib.packets;
+
+import dev.wiing.gossip.lib.data.StringData;
+
+import java.nio.ByteBuffer;
+
+public class ErrorPacket extends Packet {
+
+    public static short TYPE = 0x03;
+    public static int LENGTH = 0x006;
+
+    private short errorType;
+    private final StringData reason = new StringData();
+
+    public ErrorPacket() {
+        super(TYPE, LENGTH);
+    }
+
+    public short getErrorType() {
+        return errorType;
+    }
+
+    public void setErrorType(short errorType) {
+        this.errorType = errorType;
+    }
+
+    public String getReason() {
+        return reason.getValue();
+    }
+
+    public void setReason(String reason) {
+        this.reason.setValue(reason);
+        this.setLength(2 + this.reason.getLength());
+    }
+
+    @Override
+    public Packet readBytes(ByteBuffer buffer, int size) {
+        ErrorPacket packet = new ErrorPacket();
+        packet.setLength(size);
+
+        packet.errorType = buffer.getShort();
+        packet.reason.setBytes(buffer);
+
+        return packet;
+    }
+
+    @Override
+    public void writeBytes(ByteBuffer buffer) {
+        buffer.putShort(errorType);
+        buffer.put(reason.getBytes());
+    }
+}
diff --git a/Lib/src/main/java/dev/wiing/gossip/lib/packets/MessageCreatedPacket.java b/Lib/src/main/java/dev/wiing/gossip/lib/packets/MessageCreatedPacket.java
index 9fdcbb3..c9588af 100644
--- a/Lib/src/main/java/dev/wiing/gossip/lib/packets/MessageCreatedPacket.java
+++ b/Lib/src/main/java/dev/wiing/gossip/lib/packets/MessageCreatedPacket.java
@@ -3,15 +3,19 @@ package dev.wiing.gossip.lib.packets;
 import dev.wiing.gossip.lib.data.StringData;
 
 import java.nio.ByteBuffer;
+import java.time.Instant;
+import java.time.LocalDateTime;
+import java.time.ZoneOffset;
 
 public class MessageCreatedPacket extends Packet {
 
     public static final short TYPE = 0x32;
-    public static final int LENGTH = 0x01C;
+    public static final int LENGTH = 0x024;
 
     private long messageID;
     private long authorID;
     private long topicID;
+    private LocalDateTime createdTimestamp;
     private final StringData contents = new StringData();
 
     public MessageCreatedPacket() {
@@ -42,13 +46,21 @@ public class MessageCreatedPacket extends Packet {
         this.topicID = topicID;
     }
 
+    public LocalDateTime getCreatedTimestamp() {
+        return createdTimestamp;
+    }
+
+    public void setCreatedTimestamp(LocalDateTime createdTimestamp) {
+        this.createdTimestamp = createdTimestamp;
+    }
+
     public String getContents() {
         return contents.getValue();
     }
 
     public void setContents(String contents) {
         this.contents.setValue(contents);
-        setLength(24 + this.contents.getLength());
+        setLength(32 + this.contents.getLength());
     }
 
     @Override
@@ -59,6 +71,7 @@ public class MessageCreatedPacket extends Packet {
         packet.messageID = buffer.getLong();
         packet.authorID = buffer.getLong();
         packet.topicID = buffer.getLong();
+        packet.createdTimestamp = LocalDateTime.ofInstant(Instant.ofEpochMilli(buffer.getLong()), ZoneOffset.UTC);
         packet.contents.setBytes(buffer);
 
         return packet;
@@ -69,6 +82,7 @@ public class MessageCreatedPacket extends Packet {
         buffer.putLong(messageID);
         buffer.putLong(authorID);
         buffer.putLong(topicID);
+        buffer.putLong(createdTimestamp.toInstant(ZoneOffset.UTC).toEpochMilli());
         buffer.put(contents.getBytes());
     }
 }
diff --git a/Lib/src/main/java/dev/wiing/gossip/lib/packets/MessageDataPacket.java b/Lib/src/main/java/dev/wiing/gossip/lib/packets/MessageDataPacket.java
index ea9a234..b1f224f 100644
--- a/Lib/src/main/java/dev/wiing/gossip/lib/packets/MessageDataPacket.java
+++ b/Lib/src/main/java/dev/wiing/gossip/lib/packets/MessageDataPacket.java
@@ -3,6 +3,10 @@ package dev.wiing.gossip.lib.packets;
 import dev.wiing.gossip.lib.data.StringData;
 
 import java.nio.ByteBuffer;
+import java.time.Instant;
+import java.time.LocalDateTime;
+import java.time.ZoneId;
+import java.time.ZoneOffset;
 
 public class MessageDataPacket extends Packet {
 
@@ -16,6 +20,7 @@ public class MessageDataPacket extends Packet {
 
     private long messageID;
     private long topicID;
+    private LocalDateTime createdTimestamp;
 
     private byte messageType;
 
@@ -33,7 +38,7 @@ public class MessageDataPacket extends Packet {
     }
 
     private void updateLength() {
-        setLength(17 +
+        setLength(25 +
                 (isUserMessage() ? (8 + userContents.getLength()) : 0) +
                 (isSystemMessage() ? (16 + systemContents.getLength()) : 0));
     }
@@ -62,6 +67,14 @@ public class MessageDataPacket extends Packet {
         this.topicID = topicID;
     }
 
+    public LocalDateTime getCreatedTimestamp() {
+        return createdTimestamp;
+    }
+
+    public void setCreatedTimestamp(LocalDateTime createdTimestamp) {
+        this.createdTimestamp = createdTimestamp;
+    }
+
     public byte getMessageType() {
         return messageType;
     }
@@ -119,6 +132,7 @@ public class MessageDataPacket extends Packet {
 
         packet.messageID = buffer.getLong();
         packet.topicID = buffer.getLong();
+        packet.createdTimestamp = LocalDateTime.ofInstant(Instant.ofEpochMilli(buffer.getLong()), ZoneOffset.UTC);
         packet.messageType = buffer.get();
 
         if (packet.isUserMessage()) {
@@ -137,6 +151,7 @@ public class MessageDataPacket extends Packet {
     public void writeBytes(ByteBuffer buffer) {
         buffer.putLong(messageID);
         buffer.putLong(topicID);
+        buffer.putLong(createdTimestamp.toInstant(ZoneOffset.UTC).toEpochMilli());
         buffer.put(messageType);
 
         if (isUserMessage()) {
diff --git a/Lib/src/main/java/dev/wiing/gossip/lib/packets/MessageFetchPacket.java b/Lib/src/main/java/dev/wiing/gossip/lib/packets/MessageFetchPacket.java
index 97ca4fd..af923d0 100644
--- a/Lib/src/main/java/dev/wiing/gossip/lib/packets/MessageFetchPacket.java
+++ b/Lib/src/main/java/dev/wiing/gossip/lib/packets/MessageFetchPacket.java
@@ -1,11 +1,13 @@
 package dev.wiing.gossip.lib.packets;
 
+import dev.wiing.gossip.lib.data.AuthSecret;
+
 import java.nio.ByteBuffer;
 
-public class MessageFetchPacket extends Packet {
+public class MessageFetchPacket extends AuthRequiredPacket {
 
     public static final short TYPE = 0x36;
-    public static final int LENGTH = 0x010;
+    public static final int LENGTH = 0x030;
 
     private long topicID;
     private long messageID;
@@ -34,6 +36,7 @@ public class MessageFetchPacket extends Packet {
     public Packet readBytes(ByteBuffer buffer, int size) {
         MessageFetchPacket packet = new MessageFetchPacket();
 
+        packet.setAuth(new AuthSecret(buffer));
         packet.topicID = buffer.getLong();
         packet.messageID = buffer.getLong();
 
@@ -42,6 +45,7 @@ public class MessageFetchPacket extends Packet {
 
     @Override
     public void writeBytes(ByteBuffer buffer) {
+        buffer.put(getAuth().getBytes());
         buffer.putLong(topicID);
         buffer.putLong(messageID);
     }
diff --git a/Lib/src/main/java/dev/wiing/gossip/lib/packets/MessageListFetchPacket.java b/Lib/src/main/java/dev/wiing/gossip/lib/packets/MessageListFetchPacket.java
index 232c66c..3e4a250 100644
--- a/Lib/src/main/java/dev/wiing/gossip/lib/packets/MessageListFetchPacket.java
+++ b/Lib/src/main/java/dev/wiing/gossip/lib/packets/MessageListFetchPacket.java
@@ -1,11 +1,13 @@
 package dev.wiing.gossip.lib.packets;
 
+import dev.wiing.gossip.lib.data.AuthSecret;
+
 import java.nio.ByteBuffer;
 
-public class MessageListFetchPacket extends Packet {
+public class MessageListFetchPacket extends AuthRequiredPacket {
 
     public static final short TYPE = 0x34;
-    public static final int LENGTH = 0x008;
+    public static final int LENGTH = 0x028;
 
     private long topicID;
 
@@ -25,6 +27,7 @@ public class MessageListFetchPacket extends Packet {
     public Packet readBytes(ByteBuffer buffer, int size) {
         MessageListFetchPacket packet = new MessageListFetchPacket();
 
+        packet.setAuth(new AuthSecret(buffer));
         packet.topicID = buffer.getLong();
 
         return packet;
@@ -32,6 +35,7 @@ public class MessageListFetchPacket extends Packet {
 
     @Override
     public void writeBytes(ByteBuffer buffer) {
+        buffer.put(getAuth().getBytes());
         buffer.putLong(topicID);
     }
 }
diff --git a/Lib/src/main/java/dev/wiing/gossip/lib/packets/MessageSystemPacket.java b/Lib/src/main/java/dev/wiing/gossip/lib/packets/MessageSystemPacket.java
index 0992e42..9762e23 100644
--- a/Lib/src/main/java/dev/wiing/gossip/lib/packets/MessageSystemPacket.java
+++ b/Lib/src/main/java/dev/wiing/gossip/lib/packets/MessageSystemPacket.java
@@ -3,15 +3,19 @@ package dev.wiing.gossip.lib.packets;
 import dev.wiing.gossip.lib.data.StringData;
 
 import java.nio.ByteBuffer;
+import java.time.Instant;
+import java.time.LocalDateTime;
+import java.time.ZoneOffset;
 import java.util.Objects;
 
 public class MessageSystemPacket extends Packet {
 
     public static final short TYPE = 0x33;
-    public static final int LENGTH = 0x01E;
+    public static final int LENGTH = 0x026;
 
     private long messageID;
     private long topicID;
+    private LocalDateTime createdTimestamp;
     private short systemType = 0;
     private long userID = 0;
     private final StringData content = new StringData();
@@ -36,6 +40,14 @@ public class MessageSystemPacket extends Packet {
         this.topicID = topicID;
     }
 
+    public LocalDateTime getCreatedTimestamp() {
+        return createdTimestamp;
+    }
+
+    public void setCreatedTimestamp(LocalDateTime createdTimestamp) {
+        this.createdTimestamp = createdTimestamp;
+    }
+
     public short getSystemType() {
         return systemType;
     }
@@ -58,7 +70,7 @@ public class MessageSystemPacket extends Packet {
 
     public void setContent(String content) {
         this.content.setValue(content);
-        setLength(26 + this.content.getLength());
+        setLength(34 + this.content.getLength());
     }
 
     @Override
@@ -68,6 +80,7 @@ public class MessageSystemPacket extends Packet {
 
         packet.messageID = buffer.getLong();
         packet.topicID = buffer.getLong();
+        packet.createdTimestamp = LocalDateTime.ofInstant(Instant.ofEpochMilli(buffer.getLong()), ZoneOffset.UTC);
         packet.systemType = buffer.getShort();
         packet.userID = buffer.getLong();
         packet.content.setBytes(buffer);
@@ -79,6 +92,7 @@ public class MessageSystemPacket extends Packet {
     public void writeBytes(ByteBuffer buffer) {
         buffer.putLong(messageID);
         buffer.putLong(topicID);
+        buffer.putLong(createdTimestamp.toInstant(ZoneOffset.UTC).toEpochMilli());
         buffer.putShort(systemType);
         buffer.putLong(userID);
         buffer.put(content.getBytes());
diff --git a/Lib/src/main/java/dev/wiing/gossip/lib/packets/RegisterCredentialsPacket.java b/Lib/src/main/java/dev/wiing/gossip/lib/packets/RegisterCredentialsPacket.java
index bbbcaae..264723b 100644
--- a/Lib/src/main/java/dev/wiing/gossip/lib/packets/RegisterCredentialsPacket.java
+++ b/Lib/src/main/java/dev/wiing/gossip/lib/packets/RegisterCredentialsPacket.java
@@ -6,7 +6,7 @@ import java.nio.ByteBuffer;
 
 public class RegisterCredentialsPacket extends Packet {
 
-    public static short TYPE = 0x04;
+    public static short TYPE = 0x05;
     public static int LENGTH = 0x028;
 
     private AuthSecret secret;
diff --git a/Lib/src/main/java/dev/wiing/gossip/lib/packets/RegisterRequestPacket.java b/Lib/src/main/java/dev/wiing/gossip/lib/packets/RegisterRequestPacket.java
index 014b449..17a53d3 100644
--- a/Lib/src/main/java/dev/wiing/gossip/lib/packets/RegisterRequestPacket.java
+++ b/Lib/src/main/java/dev/wiing/gossip/lib/packets/RegisterRequestPacket.java
@@ -6,7 +6,7 @@ import java.nio.ByteBuffer;
 
 public class RegisterRequestPacket extends Packet {
 
-    public static final short TYPE = 0x03;
+    public static final short TYPE = 0x04;
     public static final int SIZE = 0x0005;
 
     private final StringData username = new StringData();
diff --git a/Lib/src/main/java/module-info.java b/Lib/src/main/java/module-info.java
index 0ed043a..9e3fbde 100644
--- a/Lib/src/main/java/module-info.java
+++ b/Lib/src/main/java/module-info.java
@@ -5,4 +5,5 @@ module dev.wiing.gossip.lib {
     exports dev.wiing.gossip.lib.packets;
     exports dev.wiing.gossip.lib.data;
     exports dev.wiing.gossip.lib.models;
+    exports dev.wiing.gossip.lib.models.ext;
 }
\ No newline at end of file
diff --git a/Server/src/main/java/dev/wiing/gossip/server/UserSocket.java b/Server/src/main/java/dev/wiing/gossip/server/UserSocket.java
index cd58292..3a6fba2 100644
--- a/Server/src/main/java/dev/wiing/gossip/server/UserSocket.java
+++ b/Server/src/main/java/dev/wiing/gossip/server/UserSocket.java
@@ -89,6 +89,54 @@ public record UserSocket(Socket socket) implements Runnable {
         Database.getInstance().disconnectUser(user);
     }
 
+    private void replyError(Packet source, String reason) {
+        ErrorPacket packet = new ErrorPacket();
+        packet.setErrorType(source.getType());
+        packet.setReason(reason);
+
+        try {
+            Globals.getPacketManager().replyPacket(source, packet);
+        } catch (IOException e) {
+            logger.error(e);
+        }
+    }
+
+    private boolean errorNullTopic(Packet source, Topic topic) {
+        if (topic == null) {
+            replyError(source, "Topic does not exist");
+            return true;
+        };
+
+        return false;
+    }
+
+    private boolean errorNullUser(Packet source, User user) {
+        if (user == null) {
+            replyError(source, "User does not exist");
+            return true;
+        };
+
+        return false;
+    }
+
+    private boolean errorNullMessage(Packet source, Message message) {
+        if (message == null) {
+            replyError(source, "Message does not exist");
+            return true;
+        };
+
+        return false;
+    }
+
+    private boolean errorUserNotInTopic(Packet source, Topic topic, User user) {
+        if (!topic.hasUser(user)) {
+            replyError(source, "User does not have access to Topic");
+            return true;
+        };
+
+        return false;
+    }
+
     private void onRegisterUser(RegisterRequestPacket packet) {
         SecretUser user = Database.getInstance().registerUser(packet.getUsername(), packet.getAvatarID(), packet.getSource());
 
@@ -108,7 +156,7 @@ public record UserSocket(Socket socket) implements Runnable {
     private void onCreateTopic(TopicPushPacket packet) {
         Topic topic = Database.getInstance().createTopic(packet.getAuth(), packet.getTopicName(), packet.getTopicDescription());
 
-        if (topic == null) return;
+        if (errorNullTopic(packet, topic)) return;
 
         info("\"{}\" created topic \"{}\" (#{})", topic.getHost().getUsername().toUpperCase(), topic.getName().toUpperCase(), topic.getId());
 
@@ -136,12 +184,12 @@ public record UserSocket(Socket socket) implements Runnable {
         Topic topic = Database.getInstance().getTopic(packet.getTopicID());
         User requester = Database.getInstance().getUserBySecret(packet.getAuth());
 
-        if (requester == null) return;
-        if (topic == null) return;
+        if (errorNullUser(packet, requester)) return;
+        if (errorNullTopic(packet, topic)) return;
 
         if (topic.hasUser(requester)) return;
 
-        info("\"{}\" joined topic \"{}\" (#{})", topic.getHost().getUsername().toUpperCase(), topic.getName().toUpperCase(), topic.getId());
+        info("\"{}\" joined topic \"{}\" (#{})", requester.getUsername().toUpperCase(), topic.getName().toUpperCase(), topic.getId());
         topic.addUser(requester);
 
         SystemMessage message = new SystemMessage(topic.getNextMessageID(), topic, SystemMessage.SystemType.USER_JOIN, requester, "");
@@ -161,7 +209,9 @@ public record UserSocket(Socket socket) implements Runnable {
         updatePacket.getUsersJoined().add(new LongData().setValue(requester.getUserID()));
 
         MessageSystemPacket systemPacket = new MessageSystemPacket();
+        systemPacket.setMessageID(message.getId());
         systemPacket.setTopicID(topic.getId());
+        systemPacket.setCreatedTimestamp(message.getPostTime());
         systemPacket.setSystemType(message.getType());
         systemPacket.setUserID(message.getUser().getUserID());
 
@@ -197,7 +247,7 @@ public record UserSocket(Socket socket) implements Runnable {
     private void onFetchTopic(TopicFetchPacket packet) {
         Topic topic = Database.getInstance().getTopic(packet.getTopicID());
 
-        if (topic == null) return;
+        if (errorNullTopic(packet, topic)) return;
 
         info("Requested topic #{}", topic.getId());
 
@@ -221,7 +271,7 @@ public record UserSocket(Socket socket) implements Runnable {
     private void onFetchUser(UserFetchPacket packet) {
         User user = Database.getInstance().getUserByID(packet.getUserID());
 
-        if (user == null) return;
+        if (errorNullUser(packet, user)) return;
 
         info("Requested user #{}", user.getUserID());
 
@@ -241,8 +291,8 @@ public record UserSocket(Socket socket) implements Runnable {
         Topic topic = Database.getInstance().getTopic(packet.getTopicID());
         User user = Database.getInstance().getUserBySecret(packet.getAuth());
 
-        if (user == null) return;
-        if (topic == null) return;
+        if (errorNullUser(packet, user)) return;
+        if (errorNullTopic(packet, topic)) return;
 
         UserMessage userMessage = new UserMessage(topic.getNextMessageID(), user, topic, packet.getMessage());
 
@@ -260,8 +310,10 @@ public record UserSocket(Socket socket) implements Runnable {
         }
 
         MessageCreatedPacket messageCreated = new MessageCreatedPacket();
+        messageCreated.setMessageID(userMessage.getId());
         messageCreated.setAuthorID(user.getUserID());
         messageCreated.setTopicID(topic.getId());
+        messageCreated.setCreatedTimestamp(userMessage.getPostTime());
         messageCreated.setContents(userMessage.getContents());
 
         for (User babbler : topic.getUsersReadOnly().values()) {
@@ -279,8 +331,12 @@ public record UserSocket(Socket socket) implements Runnable {
 
     private void onMessageListFetch(MessageListFetchPacket packet) {
         Topic topic = Database.getInstance().getTopic(packet.getTopicID());
+        User requester = Database.getInstance().getUserBySecret(packet.getAuth());
 
-        if (topic == null) return;
+        if (errorNullTopic(packet, topic)) return;
+        if (errorNullUser(packet, requester)) return;
+
+        if (errorUserNotInTopic(packet, topic, requester)) return;
 
         info("Requested Message list on #{}", topic.getId());
 
@@ -299,18 +355,23 @@ public record UserSocket(Socket socket) implements Runnable {
 
     private void onFetchMessage(MessageFetchPacket packet) {
         Topic topic = Database.getInstance().getTopic(packet.getTopicID());
+        User requester = Database.getInstance().getUserBySecret(packet.getAuth());
 
-        if (topic == null) return;
+        if (errorNullTopic(packet, topic)) return;
+        if (errorNullUser(packet, requester)) return;
+
+        if (errorUserNotInTopic(packet, topic, requester)) return;
 
         Message message = topic.getMessageByID(packet.getMessageID());
 
-        if (message == null) return;
-
+        if (errorNullMessage(packet, message)) return;
+        
         info("Requested message #{} on #{}", message.getId(), topic.getId());
 
         MessageDataPacket resp = new MessageDataPacket();
         resp.setMessageID(message.getId());
         resp.setTopicID(message.getTopic().getId());
+        resp.setCreatedTimestamp(message.getPostTime());
 
         if (message instanceof UserMessage userMessage) {
             resp.setMessageType(MessageDataPacket.MessageType.USER);
@@ -335,11 +396,13 @@ public record UserSocket(Socket socket) implements Runnable {
     private void onTypingUser(TypingPingPacket packet) {
         User user = Database.getInstance().getUserBySecret(packet.getAuth());
 
-        if (user == null) return;
+        if (errorNullUser(packet, user)) return;
 
         TypingTopic topic = Database.getInstance().getTopic(packet.getTopicID());
 
-        if (topic == null || !topic.hasUser(user)) return;
+        if (errorNullTopic(packet, topic)) return;
+
+        if (!topic.hasUser(user)) return;
 
         if (packet.isTyping()) {
             topic.addTypingUser(user);