diff --git a/MessageBird/Objects/Conversations/MessagesCount.cs b/MessageBird/Objects/Conversations/MessagesCount.cs
index 0b8a938..f762041 100644
--- a/MessageBird/Objects/Conversations/MessagesCount.cs
+++ b/MessageBird/Objects/Conversations/MessagesCount.cs
@@ -9,5 +9,8 @@ public class MessagesCount
         
         [JsonProperty("totalCount")]
         public int TotalCount {get;set;}
+
+        [JsonProperty("lastMessageId")]
+        public string LastMesssageId {get;set;}
     }
 }
\ No newline at end of file
diff --git a/Tests/UnitTests/MessageBirdUnitTests/Resources/ConversationTest.cs b/Tests/UnitTests/MessageBirdUnitTests/Resources/ConversationTest.cs
index 638ba57..e44a3af 100644
--- a/Tests/UnitTests/MessageBirdUnitTests/Resources/ConversationTest.cs
+++ b/Tests/UnitTests/MessageBirdUnitTests/Resources/ConversationTest.cs
@@ -58,6 +58,7 @@ public void List()
 
             Assert.AreEqual(2, groups.TotalCount);
             Assert.AreEqual(10, groups.Items[0].Messages.TotalCount);
+            Assert.AreEqual("9d5d5921f5b34f8db415a2397eb762f8", groups.Items[0].Messages.LastMesssageId);
         }
 
         [TestMethod]
diff --git a/Tests/UnitTests/MessageBirdUnitTests/Responses/ConversationList.json b/Tests/UnitTests/MessageBirdUnitTests/Responses/ConversationList.json
index 06b49ae..5ab2a0c 100644
--- a/Tests/UnitTests/MessageBirdUnitTests/Responses/ConversationList.json
+++ b/Tests/UnitTests/MessageBirdUnitTests/Responses/ConversationList.json
@@ -39,7 +39,8 @@
       "lastUsedChannelId": "619747f69cf940a98fb443140ce9aed2",
       "messages": {
         "totalCount": 10,
-        "href": "https://conversations.messagebird.com/v1/conversations/fbbdde79129f45e3a179458a91e2ead6/messages"
+        "href": "https://conversations.messagebird.com/v1/conversations/fbbdde79129f45e3a179458a91e2ead6/messages",
+        "lastMessageId": "9d5d5921f5b34f8db415a2397eb762f8"
       }
     },
     {
@@ -85,7 +86,8 @@
       "lastUsedChannelId": "853eeb5348e541a595da93b48c61a1ae",
       "messages": {
         "totalCount": 23,
-        "href": "https://conversations.messagebird.com/v1/conversations/2e15efafec384e1c82e9842075e87beb/messages"
+        "href": "https://conversations.messagebird.com/v1/conversations/2e15efafec384e1c82e9842075e87beb/messages",
+        "lastMessageId": "9d5d5921f5b34f8db415a2397eb762f9"
       }
     },
   ]