diff --git a/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/Subscriber.java b/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/Subscriber.java
index 37440ba40..a2d4f3b38 100644
--- a/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/Subscriber.java
+++ b/google-cloud-pubsub/src/main/java/com/google/cloud/pubsub/v1/Subscriber.java
@@ -144,7 +144,7 @@ public class Subscriber extends AbstractApiService implements SubscriberInterfac
   private final boolean maxDurationPerAckExtensionDefaultUsed;
   private final java.time.Duration minDurationPerAckExtension;
   private final boolean minDurationPerAckExtensionDefaultUsed;
-  private final long protocolVersion = 0L;
+  private final long protocolVersion = 1L;
 
   // The ExecutorProvider used to generate executors for processing messages.
   private final ExecutorProvider executorProvider;