diff --git a/ts/textsecure.d.ts b/ts/textsecure.d.ts
index ec9c3556bb3..e47509af98a 100644
--- a/ts/textsecure.d.ts
+++ b/ts/textsecure.d.ts
@@ -1196,8 +1196,8 @@ export declare namespace SyncMessageClass {
     groupIds?: Array<ProtoBinaryType>;
   }
   class Read {
-    sender?: string;
-    senderUuid?: string;
+    sender: string | null;
+    senderUuid: string | null;
     timestamp?: ProtoBigNumberType;
   }
   class Request {
diff --git a/ts/textsecure/SendMessage.ts b/ts/textsecure/SendMessage.ts
index 05caaf9dfc0..6dc17281dca 100644
--- a/ts/textsecure/SendMessage.ts
+++ b/ts/textsecure/SendMessage.ts
@@ -1232,8 +1232,8 @@ export default class MessageSender {
       for (let i = 0; i < reads.length; i += 1) {
         const read = new window.textsecure.protobuf.SyncMessage.Read();
         read.timestamp = reads[i].timestamp;
-        read.sender = reads[i].senderE164;
-        read.senderUuid = reads[i].senderUuid;
+        read.sender = reads[i].senderE164 || null;
+        read.senderUuid = reads[i].senderUuid || null;
 
         syncMessage.read.push(read);
       }