diff --git a/axon/pom.xml b/axon/pom.xml
index 2b9ac1fcdd..3d30cceb83 100644
--- a/axon/pom.xml
+++ b/axon/pom.xml
@@ -18,12 +18,6 @@
             <groupId>org.axonframework</groupId>
             <artifactId>axon-spring-boot-starter</artifactId>
             <version>${axon.version}</version>
-            <exclusions>
-                <exclusion>
-                    <groupId>org.axonframework</groupId>
-                    <artifactId>axon-server-connector</artifactId>
-                </exclusion>
-            </exclusions>
         </dependency>
 
         <dependency>
@@ -58,7 +52,7 @@
     </dependencies>
 
     <properties>
-        <axon.version>4.0.3</axon.version>
+        <axon.version>4.1.2</axon.version>
     </properties>
 
 </project>
\ No newline at end of file
diff --git a/axon/src/main/java/com/baeldung/axon/commandmodel/OrderAggregate.java b/axon/src/main/java/com/baeldung/axon/commandmodel/OrderAggregate.java
index b37b2fdd66..4ef02e6b54 100644
--- a/axon/src/main/java/com/baeldung/axon/commandmodel/OrderAggregate.java
+++ b/axon/src/main/java/com/baeldung/axon/commandmodel/OrderAggregate.java
@@ -13,6 +13,7 @@ import com.baeldung.axon.coreapi.commands.ShipOrderCommand;
 import com.baeldung.axon.coreapi.events.OrderConfirmedEvent;
 import com.baeldung.axon.coreapi.events.OrderPlacedEvent;
 import com.baeldung.axon.coreapi.events.OrderShippedEvent;
+import com.baeldung.axon.coreapi.exceptions.UnconfirmedOrderException;
 
 @Aggregate
 public class OrderAggregate {
@@ -34,7 +35,7 @@ public class OrderAggregate {
     @CommandHandler
     public void handle(ShipOrderCommand command) {
         if (!orderConfirmed) {
-            throw new IllegalStateException("Cannot ship an order which has not been confirmed yet.");
+            throw new UnconfirmedOrderException();
         }
 
         apply(new OrderShippedEvent(orderId));
@@ -43,12 +44,12 @@ public class OrderAggregate {
     @EventSourcingHandler
     public void on(OrderPlacedEvent event) {
         this.orderId = event.getOrderId();
-        orderConfirmed = false;
+        this.orderConfirmed = false;
     }
 
     @EventSourcingHandler
     public void on(OrderConfirmedEvent event) {
-        orderConfirmed = true;
+        this.orderConfirmed = true;
     }
 
     protected OrderAggregate() {
diff --git a/axon/src/main/java/com/baeldung/axon/coreapi/exceptions/UnconfirmedOrderException.java b/axon/src/main/java/com/baeldung/axon/coreapi/exceptions/UnconfirmedOrderException.java
new file mode 100644
index 0000000000..1873bc6893
--- /dev/null
+++ b/axon/src/main/java/com/baeldung/axon/coreapi/exceptions/UnconfirmedOrderException.java
@@ -0,0 +1,8 @@
+package com.baeldung.axon.coreapi.exceptions;
+
+public class UnconfirmedOrderException extends IllegalStateException {
+
+    public UnconfirmedOrderException() {
+        super("Cannot ship an order which has not been confirmed yet.");
+    }
+}
diff --git a/axon/src/main/java/com/baeldung/axon/querymodel/OrderedProductsEventHandler.java b/axon/src/main/java/com/baeldung/axon/querymodel/OrderedProductsEventHandler.java
index d4cf3d999b..a37f0111ed 100644
--- a/axon/src/main/java/com/baeldung/axon/querymodel/OrderedProductsEventHandler.java
+++ b/axon/src/main/java/com/baeldung/axon/querymodel/OrderedProductsEventHandler.java
@@ -5,6 +5,7 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+import org.axonframework.config.ProcessingGroup;
 import org.axonframework.eventhandling.EventHandler;
 import org.axonframework.queryhandling.QueryHandler;
 import org.springframework.stereotype.Service;
@@ -16,6 +17,7 @@ import com.baeldung.axon.coreapi.queries.FindAllOrderedProductsQuery;
 import com.baeldung.axon.coreapi.queries.OrderedProduct;
 
 @Service
+@ProcessingGroup("ordered-products")
 public class OrderedProductsEventHandler {
 
     private final Map<String, OrderedProduct> orderedProducts = new HashMap<>();
diff --git a/axon/src/main/resources/application.properties b/axon/src/main/resources/application.properties
new file mode 100644
index 0000000000..7c51eb8e1e
--- /dev/null
+++ b/axon/src/main/resources/application.properties
@@ -0,0 +1 @@
+spring.application.name=Order Management Service
\ No newline at end of file
diff --git a/axon/src/test/java/com/baeldung/axon/commandmodel/OrderAggregateUnitTest.java b/axon/src/test/java/com/baeldung/axon/commandmodel/OrderAggregateUnitTest.java
index 9beedbaa19..aaefe49fb1 100644
--- a/axon/src/test/java/com/baeldung/axon/commandmodel/OrderAggregateUnitTest.java
+++ b/axon/src/test/java/com/baeldung/axon/commandmodel/OrderAggregateUnitTest.java
@@ -2,6 +2,7 @@ package com.baeldung.axon.commandmodel;
 
 import java.util.UUID;
 
+import com.baeldung.axon.coreapi.exceptions.UnconfirmedOrderException;
 import org.axonframework.test.aggregate.AggregateTestFixture;
 import org.axonframework.test.aggregate.FixtureConfiguration;
 import org.junit.*;
@@ -41,12 +42,12 @@ public class OrderAggregateUnitTest {
     }
 
     @Test
-    public void givenOrderPlacedEvent_whenShipOrderCommand_thenShouldThrowIllegalStateException() {
+    public void givenOrderPlacedEvent_whenShipOrderCommand_thenShouldThrowUnconfirmedOrderException() {
         String orderId = UUID.randomUUID().toString();
         String product = "Deluxe Chair";
         fixture.given(new OrderPlacedEvent(orderId, product))
                .when(new ShipOrderCommand(orderId))
-               .expectException(IllegalStateException.class);
+               .expectException(UnconfirmedOrderException.class);
     }
 
     @Test