diff --git a/app/src/main/java/org/thoughtcrime/securesms/messages/IncomingMessageObserver.kt b/app/src/main/java/org/thoughtcrime/securesms/messages/IncomingMessageObserver.kt
index bc542046a4..b7e28cf640 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/messages/IncomingMessageObserver.kt
+++ b/app/src/main/java/org/thoughtcrime/securesms/messages/IncomingMessageObserver.kt
@@ -398,23 +398,21 @@ class IncomingMessageObserver(private val context: Application) {
                 val startTime = System.currentTimeMillis()
                 GroupsV2ProcessingLock.acquireGroupProcessingLock().use {
                   ReentrantSessionLock.INSTANCE.acquire().use {
-                    SignalDatabase.runInTransaction {
-                      val followUpOperations: List<FollowUpOperation> = batch
-                        .mapNotNull { processEnvelope(bufferedStore, it.envelope, it.serverDeliveredTimestamp) }
-                        .flatten()
-
-                      bufferedStore.flushToDisk()
-
-                      val jobs = followUpOperations.mapNotNull { it.run() }
-                      ApplicationDependencies.getJobManager().addAll(jobs)
+                    batch.forEach {
+                      SignalDatabase.runInTransaction {
+                        val followUpOperations: List<FollowUpOperation>? = processEnvelope(bufferedStore, it.envelope, it.serverDeliveredTimestamp)
+                        bufferedStore.flushToDisk()
+                        if (followUpOperations != null) {
+                          val jobs = followUpOperations.mapNotNull { it.run() }
+                          ApplicationDependencies.getJobManager().addAll(jobs)
+                        }
+                      }
+                      signalWebSocket.sendAck(it)
                     }
                   }
                 }
-
                 val duration = System.currentTimeMillis() - startTime
                 Log.d(TAG, "Decrypted ${batch.size} envelopes in $duration ms (~${duration / batch.size} ms per message)")
-
-                true
               }
 
               attempts = 0
diff --git a/libsignal/service/src/main/java/org/whispersystems/signalservice/api/SignalWebSocket.java b/libsignal/service/src/main/java/org/whispersystems/signalservice/api/SignalWebSocket.java
index a3ba6a24d6..709c338131 100644
--- a/libsignal/service/src/main/java/org/whispersystems/signalservice/api/SignalWebSocket.java
+++ b/libsignal/service/src/main/java/org/whispersystems/signalservice/api/SignalWebSocket.java
@@ -273,22 +273,16 @@ public final class SignalWebSocket {
     }
 
     if (responses.size() > 0) {
-      boolean successfullyProcessed = false;
-
-      try {
-        successfullyProcessed = callback.onMessageBatch(responses);
-      } finally {
-        if (successfullyProcessed) {
-          for (EnvelopeResponse response : responses) {
-            getWebSocket().sendResponse(createWebSocketResponse(response.getWebsocketRequest()));
-          }
-        }
-      }
+      callback.onMessageBatch(responses);
     }
 
     return !hitEndOfQueue;
   }
 
+  public void sendAck(EnvelopeResponse response) throws IOException {
+    getWebSocket().sendResponse(createWebSocketResponse(response.getWebsocketRequest()));
+  }
+
   @SuppressWarnings("DuplicateThrows")
   private Optional<EnvelopeResponse> waitForSingleMessage(long timeout)
       throws TimeoutException, WebSocketUnavailableException, IOException
@@ -370,7 +364,7 @@ public final class SignalWebSocket {
    */
   public interface MessageReceivedCallback {
 
-    /** True if you successfully processed the message, otherwise false. **/
-    boolean onMessageBatch(List<EnvelopeResponse> envelopeResponses);
+    /** Called with the batch of envelopes. You are responsible for sending acks. **/
+    void onMessageBatch(List<EnvelopeResponse> envelopeResponses);
   }
 }