diff --git a/libsignal/service/src/main/java/org/whispersystems/signalservice/api/SignalServiceMessageSender.java b/libsignal/service/src/main/java/org/whispersystems/signalservice/api/SignalServiceMessageSender.java
index e0a0706f4..cb2867eb8 100644
--- a/libsignal/service/src/main/java/org/whispersystems/signalservice/api/SignalServiceMessageSender.java
+++ b/libsignal/service/src/main/java/org/whispersystems/signalservice/api/SignalServiceMessageSender.java
@@ -549,6 +549,8 @@ public class SignalServiceMessageSender {
       return sendVerifiedSyncMessage(message.getVerified().get());
     } else if (message.getRequest().isPresent()) {
       content = createRequestContent(message.getRequest().get().getRequest());
+    } else if (message.getPniIdentity().isPresent()) {
+      content = createPniIdentityContent(message.getPniIdentity().get());
     } else {
       throw new IOException("Unsupported sync message!");
     }
@@ -1401,6 +1403,13 @@ public class SignalServiceMessageSender {
     return container.setSyncMessage(builder).build();
   }
 
+  private Content createPniIdentityContent(SyncMessage.PniIdentity proto) {
+    Content.Builder     container = Content.newBuilder();
+    SyncMessage.Builder builder   = SyncMessage.newBuilder().setPniIdentity(proto);
+
+    return container.setSyncMessage(builder).build();
+  }
+
   private SyncMessage.Builder createSyncMessageBuilder() {
     SecureRandom random  = new SecureRandom();
     byte[]       padding = Util.getRandomLengthBytes(512);
diff --git a/libsignal/service/src/main/proto/SignalService.proto b/libsignal/service/src/main/proto/SignalService.proto
index b9500c824..11ac8fa8d 100644
--- a/libsignal/service/src/main/proto/SignalService.proto
+++ b/libsignal/service/src/main/proto/SignalService.proto
@@ -565,6 +565,7 @@ message SyncMessage {
   optional MessageRequestResponse messageRequestResponse = 14;
   optional OutgoingPayment        outgoingPayment        = 15;
   repeated Viewed                 viewed                 = 16;
+  optional PniIdentity            pniIdentity            = 17;
 }
 
 message AttachmentPointer {