diff --git a/ts/test/types/Conversation_test.ts b/ts/test/types/Conversation_test.ts
index db79bc5b8..85f1c77d0 100644
--- a/ts/test/types/Conversation_test.ts
+++ b/ts/test/types/Conversation_test.ts
@@ -13,6 +13,8 @@ describe('Conversation', () => {
       const input = {};
       const expected = {
         lastMessage: '',
+        lastMessageStatus: null,
+        timestamp: null,
       };
 
       const actual = Conversation.createLastMessageUpdate(input);
@@ -58,7 +60,7 @@ describe('Conversation', () => {
         };
         const expected = {
           lastMessage: 'bingo',
-          lastMessageStatus: undefined,
+          lastMessageStatus: null,
           timestamp: 555,
         };
 
@@ -87,7 +89,7 @@ describe('Conversation', () => {
         };
         const expected = {
           lastMessage: 'Last message before expired',
-          lastMessageStatus: undefined,
+          lastMessageStatus: null,
           timestamp: 555,
         };
 
diff --git a/ts/types/Conversation.ts b/ts/types/Conversation.ts
index 58d84a697..cde17a1d4 100644
--- a/ts/types/Conversation.ts
+++ b/ts/types/Conversation.ts
@@ -2,8 +2,8 @@ import { Message } from './Message';
 
 interface ConversationLastMessageUpdate {
   lastMessage: string;
-  lastMessageStatus?: string;
-  timestamp?: number;
+  lastMessageStatus: string | null;
+  timestamp: number | null;
 }
 
 export const createLastMessageUpdate = ({
@@ -22,6 +22,8 @@ export const createLastMessageUpdate = ({
   if (!lastMessage) {
     return {
       lastMessage: '',
+      lastMessageStatus: null,
+      timestamp: null,
     };
   }
 
@@ -45,7 +47,7 @@ export const createLastMessageUpdate = ({
 
   return {
     lastMessage: newLastMessageText || '',
-    lastMessageStatus,
-    timestamp: newTimestamp,
+    lastMessageStatus: lastMessageStatus || null,
+    timestamp: newTimestamp || null,
   };
 };