diff --git a/pom.xml b/pom.xml
index db5b8da..0b85902 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~user_status_change_event-SNAPSHOT</version>
 		</dependency>
 		<dependency>
 			<groupId>com.github.informatik-ag-ngl</groupId>
diff --git a/src/main/java/envoy/server/ConnectionManager.java b/src/main/java/envoy/server/ConnectionManager.java
index 202334f..ffc64e1 100644
--- a/src/main/java/envoy/server/ConnectionManager.java
+++ b/src/main/java/envoy/server/ConnectionManager.java
@@ -64,7 +64,7 @@ public class ConnectionManager implements ISocketIdListener {
 	}
 
 	/**
-	 * @param userId the ID of the user registered at the a socket
+	 * @param userId the ID of the user registered at a socket
 	 * @return the ID of the socket
 	 * @since Envoy Server Standalone v0.1-alpha
 	 */
diff --git a/src/main/java/envoy/server/Startup.java b/src/main/java/envoy/server/Startup.java
index 097399e..82d9915 100644
--- a/src/main/java/envoy/server/Startup.java
+++ b/src/main/java/envoy/server/Startup.java
@@ -36,6 +36,7 @@ public class Startup {
 		processors.add(new LoginCredentialProcessor());
 		processors.add(new MessageProcessor());
 		processors.add(new MessageStatusChangeProcessor());
+		processors.add(new UserStatusChangeProcessor());
 		processors.add(new IdGeneratorRequestProcessor());
 		Server server = new Server(8080, () -> new ObjectMessageReader(), new ObjectMessageProcessor(processors));
 
diff --git a/src/main/java/envoy/server/database/PersistenceManager.java b/src/main/java/envoy/server/database/PersistenceManager.java
index 3ec686a..614a641 100644
--- a/src/main/java/envoy/server/database/PersistenceManager.java
+++ b/src/main/java/envoy/server/database/PersistenceManager.java
@@ -5,6 +5,7 @@ import java.util.List;
 import javax.persistence.EntityManager;
 import javax.persistence.Persistence;
 
+import envoy.data.User.UserStatus;
 import envoy.server.data.ConfigItem;
 import envoy.server.data.Message;
 import envoy.server.data.User;
@@ -164,4 +165,16 @@ public class PersistenceManager {
 	// TODO current solution gets all users, not just contacts. Should be changed to
 	// entityManager.createNamedQuery("getContactsOfUser").setParameter("user",
 	// user).getResultList();
+
+	/**
+	 * Updates the {@link UserStatus} in the database.
+	 *
+	 * @param user   the {@link User} who changes his status
+	 * @param status the new status of that user
+	 * @since Envoy Server Standalone v0.1-alpha
+	 */
+	public void updateUserStatusInDatabase(User user, UserStatus status) {
+		user.setStatus(status);
+		persistenceManager.updateUser(user);
+	}
 }
\ No newline at end of file
diff --git a/src/main/java/envoy/server/net/ObjectMessageProcessor.java b/src/main/java/envoy/server/net/ObjectMessageProcessor.java
index 226fb69..3bbe43e 100644
--- a/src/main/java/envoy/server/net/ObjectMessageProcessor.java
+++ b/src/main/java/envoy/server/net/ObjectMessageProcessor.java
@@ -33,7 +33,6 @@ public class ObjectMessageProcessor implements IMessageProcessor {
 	 */
 	public ObjectMessageProcessor(Set<ObjectProcessor<?>> processors) { this.processors = processors; }
 
-	@SuppressWarnings("unchecked")
 	@Override
 	public void process(Message message, WriteProxy writeProxy) {
 		try (ObjectInputStream in = new ObjectInputStream(new ByteArrayInputStream(message.sharedArray, message.offset + 4, message.length - 4))) {
diff --git a/src/main/java/envoy/server/net/ObjectWriteProxy.java b/src/main/java/envoy/server/net/ObjectWriteProxy.java
index 2ec9223..825daeb 100644
--- a/src/main/java/envoy/server/net/ObjectWriteProxy.java
+++ b/src/main/java/envoy/server/net/ObjectWriteProxy.java
@@ -22,7 +22,7 @@ public class ObjectWriteProxy {
 	private final WriteProxy writeProxy;
 
 	/**
-	 * Creates an instance of @link{ObjectWriteProxy}.
+	 * Creates an instance of {@link ObjectWriteProxy}.
 	 *
 	 * @param writeProxy the {@link WriteProxy} to write objects to another client
 	 * @since Envoy Server Standalone v0.1-alpha
diff --git a/src/main/java/envoy/server/processors/LoginCredentialProcessor.java b/src/main/java/envoy/server/processors/LoginCredentialProcessor.java
index 376989a..274d6fd 100644
--- a/src/main/java/envoy/server/processors/LoginCredentialProcessor.java
+++ b/src/main/java/envoy/server/processors/LoginCredentialProcessor.java
@@ -10,6 +10,7 @@ import envoy.data.Contacts;
 import envoy.data.LoginCredentials;
 import envoy.data.Message.MessageStatus;
 import envoy.data.User;
+import envoy.event.UserStatusChangeEvent;
 import envoy.server.ConnectionManager;
 import envoy.server.ObjectProcessor;
 import envoy.server.data.Message;
@@ -29,7 +30,7 @@ import envoy.server.net.ObjectWriteProxy;
  */
 public class LoginCredentialProcessor implements ObjectProcessor<LoginCredentials> {
 
-	private PersistenceManager	persistenceManager	= PersistenceManager.getPersistenceManager();
+	private PersistenceManager persistenceManager = PersistenceManager.getPersistenceManager();
 
 	@Override
 	public Class<LoginCredentials> getInputClass() { return LoginCredentials.class; }
@@ -41,9 +42,10 @@ public class LoginCredentialProcessor implements ObjectProcessor<LoginCredential
 		envoy.server.data.User user = getUser(input);
 
 		// Not logged in successfully
-		if (user == null) {
-			return;
-		}
+		if (user == null) return;
+		// notifies contacts of this users online-going and updates his status in the
+		// database
+		UserStatusChangeProcessor.updateUserStatus(new UserStatusChangeEvent(user.toCommonUser()), writeProxy);
 
 		ConnectionManager.getInstance().registerUser(user.getId(), socketId);
 
@@ -73,7 +75,7 @@ public class LoginCredentialProcessor implements ObjectProcessor<LoginCredential
 
 	private envoy.server.data.User getUser(LoginCredentials credentials) {
 		envoy.server.data.User user;
-		
+
 		if (credentials.isRegistration()) {
 			user = new envoy.server.data.User();
 			user.setName(credentials.getName());
@@ -84,10 +86,8 @@ public class LoginCredentialProcessor implements ObjectProcessor<LoginCredential
 		} else {
 			user = persistenceManager.getUserByName(credentials.getName());
 			// TODO: Implement error when user does not exist
-			if (!Arrays.equals(credentials.getPasswordHash(), user.getPasswordHash())) {
-				// TODO: Wrong Password Response
+			if (!Arrays.equals(credentials.getPasswordHash(), user.getPasswordHash())) // TODO: Wrong Password Response
 				return null;
-			}
 		}
 		return user;
 	}
diff --git a/src/main/java/envoy/server/processors/UserStatusChangeProcessor.java b/src/main/java/envoy/server/processors/UserStatusChangeProcessor.java
new file mode 100644
index 0000000..35de77e
--- /dev/null
+++ b/src/main/java/envoy/server/processors/UserStatusChangeProcessor.java
@@ -0,0 +1,78 @@
+package envoy.server.processors;
+
+import java.io.IOException;
+
+import envoy.data.User.UserStatus;
+import envoy.event.UserStatusChangeEvent;
+import envoy.server.ConnectionManager;
+import envoy.server.ObjectProcessor;
+import envoy.server.data.User;
+import envoy.server.database.PersistenceManager;
+import envoy.server.net.ObjectWriteProxy;
+
+/**
+ * This processor handles incoming {@link UserStatusChangeEvent}.<br>
+ * <br>
+ * Project: <strong>envoy-server-standalone</strong><br>
+ * File: <strong>UserStatusChangeProcessor.java</strong><br>
+ * Created: <strong>1 Feb 2020</strong><br>
+ *
+ * @author Leon Hofmeister
+ * @since Envoy Server Standalone v0.1-alpha
+ */
+public class UserStatusChangeProcessor implements ObjectProcessor<UserStatusChangeEvent> {
+
+	@Override
+	public Class<UserStatusChangeEvent> getInputClass() { return UserStatusChangeEvent.class; }
+
+	@Override
+	public void process(UserStatusChangeEvent input, long socketId, ObjectWriteProxy writeProxy) throws IOException {
+
+		PersistenceManager perMan = PersistenceManager.getPersistenceManager();
+		// new status should not equal old status
+		if (input.get().equals(perMan.getUserById(input.getId()).getStatus())) {
+			System.out.println("Received an unnecessary UserStatusChangeEvent");
+			return;
+		}
+		updateUserStatus(input, writeProxy);
+
+	}
+
+	/**
+	 * Sets the {@link UserStatus} for a given user. Both offline contacts and
+	 * currently online contacts are notified.
+	 *
+	 * @param evt        the {@link UserStatusChangeEvent} that signals the change
+	 * @param writeProxy the {@link ObjectWriteProxy} that is used to send objects
+	 *                   back to clients
+	 * @throws IOException if sending this update failed for any contact
+	 * @since Envoy Server Standalone v0.1-alpha
+	 */
+	public static void updateUserStatus(UserStatusChangeEvent evt, ObjectWriteProxy writeProxy) throws IOException {
+		PersistenceManager		perMan	= PersistenceManager.getPersistenceManager();
+		envoy.server.data.User	user	= perMan.getUserById(evt.getId());
+		// handling for newly logged in clients
+		perMan.updateUserStatusInDatabase(user, evt.get());
+
+		// handling for contacts that are already online
+		notifyContacts(evt, user, writeProxy);
+	}
+
+	/**
+	 * notifies active contacts of this {@link User} that his {@link UserStatus} has
+	 * changed
+	 *
+	 * @param evt        the {@link UserStatusChangeEvent} to send to other clients
+	 * @param user       the {@link User}
+	 * @param writeProxy the {@link ObjectWriteProxy} that is used to send objects
+	 *                   back to clients
+	 * @throws IOException if sending this update failed for any contact
+	 * @since Envoy Server Standalone v0.1-alpha
+	 */
+	public static void notifyContacts(UserStatusChangeEvent evt, envoy.server.data.User user, ObjectWriteProxy writeProxy) throws IOException {
+		ConnectionManager conMan = ConnectionManager.getInstance();
+		for (User contact : user.getContacts())
+			if (conMan.isOnline(contact.getId())) writeProxy.write(conMan.getSocketId(contact.getId()), evt);
+	}
+
+}
\ No newline at end of file