diff --git a/pom.xml b/pom.xml
index d036d0d..0c98aab 100644
--- a/pom.xml
+++ b/pom.xml
@@ -28,7 +28,7 @@
 		<dependency>
 			<groupId>com.github.informatik-ag-ngl</groupId>
 			<artifactId>envoy-common</artifactId>
-			<version>develop-SNAPSHOT</version>
+			<version>f~compatibility_verification-SNAPSHOT</version>
 		</dependency>
 		<dependency>
 			<groupId>org.openjfx</groupId>
diff --git a/src/main/java/envoy/client/data/Chat.java b/src/main/java/envoy/client/data/Chat.java
index 7efbd7b..022904c 100644
--- a/src/main/java/envoy/client/data/Chat.java
+++ b/src/main/java/envoy/client/data/Chat.java
@@ -9,7 +9,7 @@ import java.util.Objects;
 import envoy.client.net.WriteProxy;
 import envoy.data.*;
 import envoy.data.Message.MessageStatus;
-import envoy.event.MessageStatusChangeEvent;
+import envoy.event.MessageStatusChange;
 
 /**
  * Represents a chat between two {@link User}s <br>
@@ -71,7 +71,7 @@ public final class Chat implements Serializable {
 	 *
 	 * @param writeProxy the write proxy instance used to notify the server about
 	 *                   the message status changes
-	 * @throws IOException if a {@link MessageStatusChangeEvent} could not be
+	 * @throws IOException if a {@link MessageStatusChange} could not be
 	 *                     delivered to the server
 	 * @since Envoy Client v0.3-alpha
 	 */
@@ -81,7 +81,7 @@ public final class Chat implements Serializable {
 			if (m.getSenderID() == recipient.getID()) if (m.getStatus() == MessageStatus.READ) break;
 			else {
 				m.setStatus(MessageStatus.READ);
-				writeProxy.writeMessageStatusChangeEvent(new MessageStatusChangeEvent(m));
+				writeProxy.writeMessageStatusChange(new MessageStatusChange(m));
 			}
 		}
 	}
diff --git a/src/main/java/envoy/client/data/ClientConfig.java b/src/main/java/envoy/client/data/ClientConfig.java
index 0b11e40..cde6b9a 100644
--- a/src/main/java/envoy/client/data/ClientConfig.java
+++ b/src/main/java/envoy/client/data/ClientConfig.java
@@ -4,6 +4,7 @@ import java.io.File;
 import java.util.function.Function;
 import java.util.logging.Level;
 
+import envoy.client.ui.Startup;
 import envoy.data.Config;
 import envoy.data.ConfigItem;
 import envoy.data.LoginCredentials;
@@ -109,5 +110,5 @@ public class ClientConfig extends Config {
 	 *         the registration option
 	 * @since Envoy Client v0.3-alpha
 	 */
-	public LoginCredentials getLoginCredentials() { return new LoginCredentials(getUser(), getPassword(), false); }
+	public LoginCredentials getLoginCredentials() { return new LoginCredentials(getUser(), getPassword(), false, Startup.VERSION); }
 }
diff --git a/src/main/java/envoy/client/data/LocalDB.java b/src/main/java/envoy/client/data/LocalDB.java
index 38aeea4..b8dc3c9 100644
--- a/src/main/java/envoy/client/data/LocalDB.java
+++ b/src/main/java/envoy/client/data/LocalDB.java
@@ -3,9 +3,9 @@ package envoy.client.data;
 import java.util.*;
 
 import envoy.data.*;
-import envoy.event.GroupResizeEvent;
-import envoy.event.MessageStatusChangeEvent;
-import envoy.event.NameChangeEvent;
+import envoy.event.GroupResize;
+import envoy.event.MessageStatusChange;
+import envoy.event.NameChange;
 
 /**
  * Stores information about the current {@link User} and their {@link Chat}s.
@@ -25,7 +25,7 @@ public abstract class LocalDB {
 	protected List<Chat>						chats			= new ArrayList<>();
 	protected IDGenerator						idGenerator;
 	protected Cache<Message>					messageCache	= new Cache<>();
-	protected Cache<MessageStatusChangeEvent>	statusCache		= new Cache<>();
+	protected Cache<MessageStatusChange>	statusCache		= new Cache<>();
 
 	/**
 	 * Initializes a storage space for a user-specific list of chats.
@@ -136,13 +136,13 @@ public abstract class LocalDB {
 	 * @return the offline status cache
 	 * @since Envoy Client v0.3-alpha
 	 */
-	public Cache<MessageStatusChangeEvent> getStatusCache() { return statusCache; }
+	public Cache<MessageStatusChange> getStatusCache() { return statusCache; }
 
 	/**
 	 * @param statusCache the offline status cache to set
 	 * @since Envoy Client v0.3-alpha
 	 */
-	public void setStatusCache(Cache<MessageStatusChangeEvent> statusCache) { this.statusCache = statusCache; }
+	public void setStatusCache(Cache<MessageStatusChange> statusCache) { this.statusCache = statusCache; }
 
 	/**
 	 * Searches for a message by ID.
@@ -169,20 +169,20 @@ public abstract class LocalDB {
 	/**
 	 * Performs a contact name change if the corresponding contact is present.
 	 *
-	 * @param event the {@link NameChangeEvent} to process
+	 * @param event the {@link NameChange} to process
 	 * @since Envoy Client v0.1-beta
 	 */
-	public void replaceContactName(NameChangeEvent event) {
+	public void replaceContactName(NameChange event) {
 		chats.stream().map(Chat::getRecipient).filter(c -> c.getID() == event.getID()).findAny().ifPresent(c -> c.setName(event.get()));
 	}
 
 	/**
 	 * Performs a group resize operation if the corresponding group is present.
 	 *
-	 * @param event the {@link GroupResizeEvent} to process
+	 * @param event the {@link GroupResize} to process
 	 * @since Envoy Client v0.1-beta
 	 */
-	public void updateGroup(GroupResizeEvent event) {
+	public void updateGroup(GroupResize event) {
 		chats.stream()
 			.map(Chat::getRecipient)
 			.filter(Group.class::isInstance)
diff --git a/src/main/java/envoy/client/net/Client.java b/src/main/java/envoy/client/net/Client.java
index 9f9dad7..a0ad746 100644
--- a/src/main/java/envoy/client/net/Client.java
+++ b/src/main/java/envoy/client/net/Client.java
@@ -15,7 +15,7 @@ import envoy.client.data.LocalDB;
 import envoy.client.event.SendEvent;
 import envoy.data.*;
 import envoy.event.*;
-import envoy.event.contact.ContactOperationEvent;
+import envoy.event.contact.ContactOperation;
 import envoy.event.contact.ContactSearchResult;
 import envoy.util.EnvoyLog;
 import envoy.util.SerializationUtils;
@@ -56,11 +56,16 @@ public class Client implements Closeable {
 	 * will block for up to 5 seconds. If the handshake does exceed this time limit,
 	 * an exception is thrown.
 	 *
-	 * @param credentials          the login credentials of the user
-	 * @param receivedMessageCache a message cache containing all unread messages
-	 *                             from the server that can be relayed after
-	 *                             initialization
-	 * @param receivedMessageStatusChangeEventCache an event cache containing all received messageStatusChangeEvents from the server that can be relayed after initialization
+	 * @param credentials                      the login credentials of the user
+	 * @param receivedMessageCache             a message cache containing all unread
+	 *                                         messages
+	 *                                         from the server that can be relayed
+	 *                                         after
+	 *                                         initialization
+	 * @param receivedMessageStatusChangeCache an event cache containing all
+	 *                                         received messageStatusChangeEvents
+	 *                                         from the server that can be relayed
+	 *                                         after initialization
 	 * @throws TimeoutException     if the server could not be reached
 	 * @throws IOException          if the login credentials could not be
 	 *                              written
@@ -68,7 +73,7 @@ public class Client implements Closeable {
 	 *                              waiting for the handshake response
 	 */
 	public void performHandshake(LoginCredentials credentials, Cache<Message> receivedMessageCache,
-			Cache<MessageStatusChangeEvent> receivedMessageStatusChangeEventCache)
+			Cache<MessageStatusChange> receivedMessageStatusChangeCache)
 			throws TimeoutException, IOException, InterruptedException {
 		if (online) throw new IllegalStateException("Handshake has already been performed successfully");
 		// Establish TCP connection
@@ -82,8 +87,8 @@ public class Client implements Closeable {
 		// Register user creation processor, contact list processor and message cache
 		receiver.registerProcessor(User.class, sender -> { this.sender = sender; contacts = sender.getContacts(); });
 		receiver.registerProcessor(Message.class, receivedMessageCache);
-		receiver.registerProcessor(MessageStatusChangeEvent.class, receivedMessageStatusChangeEventCache);
-		receiver.registerProcessor(HandshakeRejectionEvent.class, evt -> { rejected = true; eventBus.dispatch(evt); });
+		receiver.registerProcessor(MessageStatusChange.class, receivedMessageStatusChangeCache);
+		receiver.registerProcessor(HandshakeRejection.class, evt -> { rejected = true; eventBus.dispatch(evt); });
 
 		rejected = false;
 
@@ -121,23 +126,29 @@ public class Client implements Closeable {
 	 * Initializes the {@link Receiver} used to process data sent from the server to
 	 * this client.
 	 *
-	 * @param localDB              the local database used to persist the current
-	 *                             {@link IDGenerator}
-	 * @param receivedMessageCache a message cache containing all unread messages
-	 *                             from the server that can be relayed after
-	 *                             initialization
-	 * @param receivedMessageStatusChangeEventCache an event cache containing all received messageStatusChangeEvents from the server that can be relayed after initialization
+	 * @param localDB                          the local database used to persist
+	 *                                         the current
+	 *                                         {@link IDGenerator}
+	 * @param receivedMessageCache             a message cache containing all unread
+	 *                                         messages
+	 *                                         from the server that can be relayed
+	 *                                         after
+	 *                                         initialization
+	 * @param receivedMessageStatusChangeCache an event cache containing all
+	 *                                         received messageStatusChangeEvents
+	 *                                         from the server that can be relayed
+	 *                                         after initialization
 	 * @throws IOException if no {@link IDGenerator} is present and none could be
 	 *                     requested from the server
 	 * @since Envoy Client v0.2-alpha
 	 */
 	public void initReceiver(LocalDB localDB, Cache<Message> receivedMessageCache,
-			Cache<MessageStatusChangeEvent> receivedMessageStatusChangeEventCache) throws IOException {
+			Cache<MessageStatusChange> receivedMessageStatusChangeCache) throws IOException {
 		checkOnline();
 
 		// Process incoming messages
 		final ReceivedMessageProcessor receivedMessageProcessor = new ReceivedMessageProcessor();
-		final MessageStatusChangeEventProcessor	messageStatusChangeEventProcessor	= new MessageStatusChangeEventProcessor();
+		final MessageStatusChangeProcessor	messageStatusChangeEventProcessor	= new MessageStatusChangeProcessor();
 
 		receiver.registerProcessor(Message.class, receivedMessageProcessor);
 
@@ -145,26 +156,26 @@ public class Client implements Closeable {
 		receivedMessageCache.setProcessor(receivedMessageProcessor);
 
 		// Process message status changes
-		receiver.registerProcessor(MessageStatusChangeEvent.class, messageStatusChangeEventProcessor);
-		receivedMessageStatusChangeEventCache.setProcessor(messageStatusChangeEventProcessor);
+		receiver.registerProcessor(MessageStatusChange.class, messageStatusChangeEventProcessor);
+		receivedMessageStatusChangeCache.setProcessor(messageStatusChangeEventProcessor);
 
 		// Process user status changes
-		receiver.registerProcessor(UserStatusChangeEvent.class, eventBus::dispatch);
+		receiver.registerProcessor(UserStatusChange.class, eventBus::dispatch);
 
 		// Process message ID generation
 		receiver.registerProcessor(IDGenerator.class, localDB::setIDGenerator);
 
 		// Process name changes
-		receiver.registerProcessor(NameChangeEvent.class, evt -> { localDB.replaceContactName(evt); eventBus.dispatch(evt); });
+		receiver.registerProcessor(NameChange.class, evt -> { localDB.replaceContactName(evt); eventBus.dispatch(evt); });
 
 		// Process contact searches
 		receiver.registerProcessor(ContactSearchResult.class, eventBus::dispatch);
 
 		// Process contact operations
-		receiver.registerProcessor(ContactOperationEvent.class, eventBus::dispatch);
+		receiver.registerProcessor(ContactOperation.class, eventBus::dispatch);
 
 		// Process group size changes
-		receiver.registerProcessor(GroupResizeEvent.class, evt -> { localDB.updateGroup(evt); eventBus.dispatch(evt); });
+		receiver.registerProcessor(GroupResize.class, evt -> { localDB.updateGroup(evt); eventBus.dispatch(evt); });
 
 		// Send event
 		eventBus.register(SendEvent.class, evt -> {
diff --git a/src/main/java/envoy/client/net/MessageStatusChangeEventProcessor.java b/src/main/java/envoy/client/net/MessageStatusChangeProcessor.java
similarity index 67%
rename from src/main/java/envoy/client/net/MessageStatusChangeEventProcessor.java
rename to src/main/java/envoy/client/net/MessageStatusChangeProcessor.java
index ce53139..106cda4 100644
--- a/src/main/java/envoy/client/net/MessageStatusChangeEventProcessor.java
+++ b/src/main/java/envoy/client/net/MessageStatusChangeProcessor.java
@@ -5,30 +5,30 @@ import java.util.logging.Logger;
 
 import envoy.data.Message.MessageStatus;
 import envoy.event.EventBus;
-import envoy.event.MessageStatusChangeEvent;
+import envoy.event.MessageStatusChange;
 import envoy.util.EnvoyLog;
 
 /**
  * Project: <strong>envoy-client</strong><br>
- * File: <strong>MessageStatusChangeEventProcessor.java</strong><br>
+ * File: <strong>MessageStatusChangeProcessor.java</strong><br>
  * Created: <strong>4 Feb 2020</strong><br>
  *
  * @author Kai S. K. Engelbart
  * @since Envoy Client v0.3-alpha
  */
-public class MessageStatusChangeEventProcessor implements Consumer<MessageStatusChangeEvent> {
+public class MessageStatusChangeProcessor implements Consumer<MessageStatusChange> {
 
-	private static final Logger logger = EnvoyLog.getLogger(MessageStatusChangeEventProcessor.class);
+	private static final Logger logger = EnvoyLog.getLogger(MessageStatusChangeProcessor.class);
 
 	/**
-	 * Dispatches a {@link MessageStatusChangeEvent} if the status is
+	 * Dispatches a {@link MessageStatusChange} if the status is
 	 * {@code RECEIVED} or {@code READ}.
 	 *
 	 * @param evt the status change event
 	 * @since Envoy Client v0.3-alpha
 	 */
 	@Override
-	public void accept(MessageStatusChangeEvent evt) {
+	public void accept(MessageStatusChange evt) {
 		if (evt.get().ordinal() < MessageStatus.RECEIVED.ordinal()) logger.warning("Received invalid message status change " + evt);
 		else EventBus.getInstance().dispatch(evt);
 	}
diff --git a/src/main/java/envoy/client/net/WriteProxy.java b/src/main/java/envoy/client/net/WriteProxy.java
index 97848df..372180b 100644
--- a/src/main/java/envoy/client/net/WriteProxy.java
+++ b/src/main/java/envoy/client/net/WriteProxy.java
@@ -6,12 +6,12 @@ import java.util.logging.Logger;
 
 import envoy.client.data.LocalDB;
 import envoy.data.Message;
-import envoy.event.MessageStatusChangeEvent;
+import envoy.event.MessageStatusChange;
 import envoy.util.EnvoyLog;
 
 /**
  * Implements methods to send {@link Message}s and
- * {@link MessageStatusChangeEvent}s to the server or cache them inside a
+ * {@link MessageStatusChange}s to the server or cache them inside a
  * {@link LocalDB} depending on the online status.<br>
  * <br>
  * Project: <strong>envoy-client</strong><br>
@@ -65,7 +65,7 @@ public class WriteProxy {
 	}
 
 	/**
-	 * Sends cached {@link Message}s and {@link MessageStatusChangeEvent}s to the
+	 * Sends cached {@link Message}s and {@link MessageStatusChange}s to the
 	 * server.
 	 *
 	 * @since Envoy Client v0.3-alpha
@@ -99,7 +99,7 @@ public class WriteProxy {
 	 * @throws IOException if the event could not be sent
 	 * @since Envoy Client v0.3-alpha
 	 */
-	public void writeMessageStatusChangeEvent(MessageStatusChangeEvent evt) throws IOException {
+	public void writeMessageStatusChange(MessageStatusChange evt) throws IOException {
 		if (client.isOnline()) client.sendEvent(evt);
 		else localDB.getStatusCache().accept(evt);
 	}
diff --git a/src/main/java/envoy/client/ui/MessageListCell.java b/src/main/java/envoy/client/ui/MessageListCell.java
index 7b7a479..16759ea 100644
--- a/src/main/java/envoy/client/ui/MessageListCell.java
+++ b/src/main/java/envoy/client/ui/MessageListCell.java
@@ -1,7 +1,7 @@
 package envoy.client.ui;
 
 import java.io.IOException;
-import java.text.SimpleDateFormat;
+import java.time.format.DateTimeFormatter;
 import java.util.Map;
 
 import javafx.scene.control.Label;
@@ -26,7 +26,7 @@ import envoy.data.Message.MessageStatus;
  */
 public class MessageListCell extends ListCell<Message> {
 
-	private static final SimpleDateFormat		dateFormat	= new SimpleDateFormat("dd.MM.yyyy HH:mm");
+	private static final DateTimeFormatter		dateFormat	= DateTimeFormatter.ofPattern("dd.MM.yyyy HH:mm");
 	private static Map<MessageStatus, Image>	statusImages;
 
 	static {
diff --git a/src/main/java/envoy/client/ui/Startup.java b/src/main/java/envoy/client/ui/Startup.java
index dbadfc3..30ee7b2 100644
--- a/src/main/java/envoy/client/ui/Startup.java
+++ b/src/main/java/envoy/client/ui/Startup.java
@@ -16,7 +16,7 @@ import envoy.client.net.Client;
 import envoy.client.ui.SceneContext.SceneInfo;
 import envoy.client.ui.controller.LoginScene;
 import envoy.data.Message;
-import envoy.event.MessageStatusChangeEvent;
+import envoy.event.MessageStatusChange;
 import envoy.exception.EnvoyException;
 import envoy.util.EnvoyLog;
 
@@ -33,10 +33,17 @@ import envoy.util.EnvoyLog;
  */
 public final class Startup extends Application {
 
-	private LocalDB			localDB;
-	private Client			client;
-	private Cache<Message>	messageCache;
-	private Cache<MessageStatusChangeEvent>	messageStatusCache;
+	/**
+	 * The version of this client. Used to verify compatibility with the server.
+	 * 
+	 * @since Envoy Client v0.1-beta
+	 */
+	public static final String VERSION = "0.1-beta";
+
+	private LocalDB						localDB;
+	private Client						client;
+	private Cache<Message>				messageCache;
+	private Cache<MessageStatusChange>	messageStatusCache;
 
 	private static final ClientConfig	config	= ClientConfig.getInstance();
 	private static final Logger			logger	= EnvoyLog.getLogger(Startup.class);
@@ -89,8 +96,8 @@ public final class Startup extends Application {
 		}
 
 		// Initialize client and unread message cache
-		client	= new Client();
-		messageCache	= new Cache<>();
+		client				= new Client();
+		messageCache		= new Cache<>();
 		messageStatusCache	= new Cache<>();
 
 		stage.setTitle("Envoy");
diff --git a/src/main/java/envoy/client/ui/controller/ChatScene.java b/src/main/java/envoy/client/ui/controller/ChatScene.java
index c25b2f8..727bdc1 100644
--- a/src/main/java/envoy/client/ui/controller/ChatScene.java
+++ b/src/main/java/envoy/client/ui/controller/ChatScene.java
@@ -25,9 +25,9 @@ import envoy.client.ui.MessageListCell;
 import envoy.client.ui.SceneContext;
 import envoy.data.*;
 import envoy.event.EventBus;
-import envoy.event.MessageStatusChangeEvent;
-import envoy.event.UserStatusChangeEvent;
-import envoy.event.contact.ContactOperationEvent;
+import envoy.event.MessageStatusChange;
+import envoy.event.UserStatusChange;
+import envoy.event.contact.ContactOperation;
 import envoy.util.EnvoyLog;
 
 /**
@@ -103,8 +103,7 @@ public final class ChatScene {
 		});
 
 		// Listen to message status changes
-		eventBus.register(MessageStatusChangeEvent.class, e ->
-			localDB.getMessage(e.getID()).ifPresent(message -> {
+		eventBus.register(MessageStatusChange.class, e -> localDB.getMessage(e.getID()).ifPresent(message -> {
 			message.setStatus(e.get());
 
 			// Update UI if in current chat
@@ -112,19 +111,15 @@ public final class ChatScene {
 		}));
 
 		// Listen to user status changes
-		eventBus.register(UserStatusChangeEvent.class, e ->
-			userList.getItems()
-				.stream()
-				.filter(c -> c.getID() == e.getID())
-				.findAny()
-				.ifPresent(u -> {
-					((User) u).setStatus(e.get());
-					Platform.runLater(userList::refresh);
-				})
-		);
+		eventBus.register(UserStatusChange.class,
+				e -> userList.getItems()
+					.stream()
+					.filter(c -> c.getID() == e.getID())
+					.findAny()
+					.ifPresent(u -> { ((User) u).setStatus(e.get()); Platform.runLater(userList::refresh); }));
 
 		// Listen to contacts changes
-		eventBus.register(ContactOperationEvent.class, e -> {
+		eventBus.register(ContactOperation.class, e -> {
 			final var contact = e.get();
 			switch (e.getOperationType()) {
 				case ADD:
@@ -174,8 +169,7 @@ public final class ChatScene {
 			// LEON: JFC <===> JAVA FRIED CHICKEN <=/=> Java Foundation Classes
 
 			// Load the chat or create a new one and add it to the LocalDB
-			currentChat = localDB
-				.getChat(user.getID())
+			currentChat = localDB.getChat(user.getID())
 				.orElseGet(() -> { final var chat = new Chat(user); localDB.getChats().add(chat); return chat; });
 
 			messageList.setItems(FXCollections.observableList(currentChat.getMessages()));
diff --git a/src/main/java/envoy/client/ui/controller/ContactSearchScene.java b/src/main/java/envoy/client/ui/controller/ContactSearchScene.java
index f2976c9..a5d4457 100644
--- a/src/main/java/envoy/client/ui/controller/ContactSearchScene.java
+++ b/src/main/java/envoy/client/ui/controller/ContactSearchScene.java
@@ -15,7 +15,7 @@ import envoy.client.ui.SceneContext;
 import envoy.data.Contact;
 import envoy.event.ElementOperation;
 import envoy.event.EventBus;
-import envoy.event.contact.ContactOperationEvent;
+import envoy.event.contact.ContactOperation;
 import envoy.event.contact.ContactSearchRequest;
 import envoy.event.contact.ContactSearchResult;
 import envoy.util.EnvoyLog;
@@ -57,6 +57,7 @@ public class ContactSearchScene {
 
 	/**
 	 * @param sceneContext enables the user to return to the chat scene
+	 * @param localDB      the local database to which new contacts are added
 	 * @since Envoy Client v0.1-beta
 	 */
 	public void initializeData(SceneContext sceneContext, LocalDB localDB) {
@@ -108,7 +109,7 @@ public class ContactSearchScene {
 	}
 
 	/**
-	 * Sends an {@link ContactOperationEvent} for every selected contact to the
+	 * Sends an {@link ContactOperation} for every selected contact to the
 	 * server.
 	 *
 	 * @since Envoy Client v0.1-beta
@@ -121,7 +122,7 @@ public class ContactSearchScene {
 			alert.setTitle("Add Contact to Contact List");
 			alert.setHeaderText("Add the user " + contact.getName() + " to your contact list?");
 			alert.showAndWait().filter(btn -> btn == ButtonType.OK).ifPresent(btn -> {
-				final var event = new ContactOperationEvent(contact, ElementOperation.ADD);
+				final var event = new ContactOperation(contact, ElementOperation.ADD);
 				// Sends the event to the server
 				eventBus.dispatch(new SendEvent(event));
 				// Updates the UI
diff --git a/src/main/java/envoy/client/ui/controller/GroupCreationScene.java b/src/main/java/envoy/client/ui/controller/GroupCreationScene.java
index af91d91..ea4a58e 100644
--- a/src/main/java/envoy/client/ui/controller/GroupCreationScene.java
+++ b/src/main/java/envoy/client/ui/controller/GroupCreationScene.java
@@ -13,7 +13,7 @@ import envoy.client.ui.SceneContext;
 import envoy.data.Contact;
 import envoy.data.User;
 import envoy.event.EventBus;
-import envoy.event.GroupCreationEvent;
+import envoy.event.GroupCreation;
 
 /**
  * Project: <strong>envoy-client</strong><br>
@@ -39,7 +39,7 @@ public class GroupCreationScene {
 
 	private SceneContext sceneContext;
 
-	private static EventBus		eventBus	= EventBus.getInstance();
+	private static EventBus eventBus = EventBus.getInstance();
 
 	@FXML
 	private void initialize() {
@@ -49,10 +49,12 @@ public class GroupCreationScene {
 
 	/**
 	 * @param sceneContext enables the user to return to the chat scene
+	 * @param localDB      the local database from which potential group members can
+	 *                     be selected
 	 * @since Envoy Client v0.1-beta
 	 */
 	public void initializeData(SceneContext sceneContext, LocalDB localDB) {
-		this.sceneContext	= sceneContext;
+		this.sceneContext = sceneContext;
 		Platform.runLater(() -> contactList.getItems()
 			.addAll(localDB.getUsers()
 				.values()
@@ -62,13 +64,13 @@ public class GroupCreationScene {
 	}
 
 	/**
-	 * Sends a {@link GroupCreationEvent} to the server.
+	 * Sends a {@link GroupCreation} to the server.
 	 *
 	 * @since Envoy Client v0.1-beta
 	 */
 	@FXML
 	private void sendGroupObject() {
-		eventBus.dispatch(new SendEvent(new GroupCreationEvent(groupNameBar.getText(),
+		eventBus.dispatch(new SendEvent(new GroupCreation(groupNameBar.getText(),
 				contactList.getSelectionModel().getSelectedItems().stream().map(Contact::getID).collect(Collectors.toSet()))));
 	}
 
diff --git a/src/main/java/envoy/client/ui/controller/LoginScene.java b/src/main/java/envoy/client/ui/controller/LoginScene.java
index f015b6e..c772874 100644
--- a/src/main/java/envoy/client/ui/controller/LoginScene.java
+++ b/src/main/java/envoy/client/ui/controller/LoginScene.java
@@ -15,13 +15,14 @@ import envoy.client.data.ClientConfig;
 import envoy.client.data.LocalDB;
 import envoy.client.net.Client;
 import envoy.client.ui.SceneContext;
+import envoy.client.ui.Startup;
 import envoy.data.LoginCredentials;
 import envoy.data.Message;
 import envoy.data.User;
 import envoy.data.User.UserStatus;
 import envoy.event.EventBus;
-import envoy.event.HandshakeRejectionEvent;
-import envoy.event.MessageStatusChangeEvent;
+import envoy.event.HandshakeRejection;
+import envoy.event.MessageStatusChange;
 import envoy.exception.EnvoyException;
 import envoy.util.EnvoyLog;
 
@@ -54,11 +55,11 @@ public final class LoginScene {
 	@FXML
 	private Label connectionLabel;
 
-	private Client			client;
-	private LocalDB			localDB;
-	private Cache<Message>	receivedMessageCache;
-	private Cache<MessageStatusChangeEvent>	receivedMessageStatusChangeEventCache;
-	private SceneContext	sceneContext;
+	private Client						client;
+	private LocalDB						localDB;
+	private Cache<Message>				receivedMessageCache;
+	private Cache<MessageStatusChange>	receivedMessageStatusChangeCache;
+	private SceneContext				sceneContext;
 
 	private static final Logger			logger		= EnvoyLog.getLogger(LoginScene.class);
 	private static final EventBus		eventBus	= EventBus.getInstance();
@@ -69,29 +70,36 @@ public final class LoginScene {
 		connectionLabel.setText("Server: " + config.getServer() + ":" + config.getPort());
 
 		// Show an alert after an unsuccessful handshake
-		eventBus.register(HandshakeRejectionEvent.class,
+		eventBus.register(
+				HandshakeRejection.class,
 				e -> Platform.runLater(() -> { clearPasswordFields(); new Alert(AlertType.ERROR, e.get()).showAndWait(); }));
 	}
 
 	/**
 	 * Loads the login dialog using the FXML file {@code LoginDialog.fxml}.
 	 *
-	 * @param client               the client used to perform the handshake
-	 * @param localDB              the local database used for offline login
-	 * @param receivedMessageCache the cache storing messages received during
-	 *                             the handshake
-	 * @param receivedMessageStatusChangeEventCache the cache storing messageStatusChangeEvents received during handshake
-	 * @param sceneContext         the scene context used to initialize the chat
-	 *                             scene
+	 * @param client                           the client used to perform the
+	 *                                         handshake
+	 * @param localDB                          the local database used for offline
+	 *                                         login
+	 * @param receivedMessageCache             the cache storing messages received
+	 *                                         during
+	 *                                         the handshake
+	 * @param receivedMessageStatusChangeCache the cache storing
+	 *                                         messageStatusChangeEvents received
+	 *                                         during handshake
+	 * @param sceneContext                     the scene context used to initialize
+	 *                                         the chat
+	 *                                         scene
 	 * @since Envoy Client v0.1-beta
 	 */
 	public void initializeData(Client client, LocalDB localDB, Cache<Message> receivedMessageCache,
-			Cache<MessageStatusChangeEvent> receivedMessageStatusChangeEventCache, SceneContext sceneContext) {
-		this.client					= client;
-		this.localDB				= localDB;
-		this.receivedMessageCache	= receivedMessageCache;
-		this.receivedMessageStatusChangeEventCache	= receivedMessageStatusChangeEventCache;
-		this.sceneContext			= sceneContext;
+			Cache<MessageStatusChange> receivedMessageStatusChangeCache, SceneContext sceneContext) {
+		this.client								= client;
+		this.localDB							= localDB;
+		this.receivedMessageCache				= receivedMessageCache;
+		this.receivedMessageStatusChangeCache	= receivedMessageStatusChangeCache;
+		this.sceneContext						= sceneContext;
 
 		// Prepare handshake
 		localDB.loadIDGenerator();
@@ -110,12 +118,13 @@ public final class LoginScene {
 		if (registerCheckBox.isSelected() && !passwordField.getText().equals(repeatPasswordField.getText())) {
 			clearPasswordFields();
 			new Alert(AlertType.ERROR, "The entered password is unequal to the repeated one").showAndWait();
-		} else performHandshake(new LoginCredentials(userTextField.getText(), passwordField.getText().toCharArray(), registerCheckBox.isSelected()));
+		} else performHandshake(
+				new LoginCredentials(userTextField.getText(), passwordField.getText().toCharArray(), registerCheckBox.isSelected(), Startup.VERSION));
 	}
 
 	@FXML
 	private void offlineModeButtonPressed() {
-		attemptOfflineMode(new LoginCredentials(userTextField.getText(), passwordField.getText().toCharArray(), false));
+		attemptOfflineMode(new LoginCredentials(userTextField.getText(), passwordField.getText().toCharArray(), false, Startup.VERSION));
 	}
 
 	@FXML
@@ -135,9 +144,9 @@ public final class LoginScene {
 
 	private void performHandshake(LoginCredentials credentials) {
 		try {
-			client.performHandshake(credentials, receivedMessageCache, receivedMessageStatusChangeEventCache);
+			client.performHandshake(credentials, receivedMessageCache, receivedMessageStatusChangeCache);
 			if (client.isOnline()) {
-				client.initReceiver(localDB, receivedMessageCache, receivedMessageStatusChangeEventCache);
+				client.initReceiver(localDB, receivedMessageCache, receivedMessageStatusChangeCache);
 				loadChatScene();
 			}
 		} catch (IOException | InterruptedException | TimeoutException e) {
@@ -200,7 +209,7 @@ public final class LoginScene {
 
 		// Relay unread messages from cache
 		if (receivedMessageCache != null && client.isOnline()) receivedMessageCache.relay();
-		if (receivedMessageStatusChangeEventCache != null && client.isOnline()) receivedMessageStatusChangeEventCache.relay();
+		if (receivedMessageStatusChangeCache != null && client.isOnline()) receivedMessageStatusChangeCache.relay();
 	}
 
 	private void clearPasswordFields() {