diff --git a/core/store/primitives/pom.xml b/core/store/primitives/pom.xml
index 51aca18..94fb18e 100644
--- a/core/store/primitives/pom.xml
+++ b/core/store/primitives/pom.xml
@@ -70,18 +70,18 @@
         <dependency>
             <groupId>io.atomix</groupId>
             <artifactId>atomix</artifactId>
-            <version>1.0.4</version>
+            <version>1.0.5</version>
         </dependency>
 
         <dependency>
             <groupId>io.atomix.catalyst</groupId>
             <artifactId>catalyst-netty</artifactId>
-            <version>1.1.2</version>
+            <version>1.2.0</version>
         </dependency>
         <dependency>
             <groupId>io.atomix.catalyst</groupId>
             <artifactId>catalyst-transport</artifactId>
-            <version>1.1.2</version>
+            <version>1.2.0</version>
         </dependency>
         <dependency>
             <groupId>org.onosproject</groupId>
diff --git a/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/CopycatTransportClient.java b/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/CopycatTransportClient.java
index 3567338..80d5ffe 100644
--- a/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/CopycatTransportClient.java
+++ b/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/CopycatTransportClient.java
@@ -91,7 +91,7 @@
                                     endpoint,
                                     messagingService,
                                     context);
-                            connection.closeListener(connections::remove);
+                            connection.onClose(connections::remove);
                             connections.add(connection);
                             future.complete(connection);
                             log.debug("Created connection {}-{} to {}", partitionId, connectionId, address);
diff --git a/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/CopycatTransportConnection.java b/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/CopycatTransportConnection.java
index df37c56..a8105ed 100644
--- a/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/CopycatTransportConnection.java
+++ b/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/CopycatTransportConnection.java
@@ -15,13 +15,11 @@
  */
 package org.onosproject.store.primitives.impl;
 
-
 import io.atomix.catalyst.concurrent.Listener;
 import io.atomix.catalyst.concurrent.Listeners;
 import io.atomix.catalyst.concurrent.ThreadContext;
 import io.atomix.catalyst.serializer.SerializationException;
 import io.atomix.catalyst.transport.Connection;
-import io.atomix.catalyst.transport.MessageHandler;
 import io.atomix.catalyst.transport.TransportException;
 import io.atomix.catalyst.util.reference.ReferenceCounted;
 
@@ -36,6 +34,7 @@
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.function.Consumer;
+import java.util.function.Function;
 
 import org.apache.commons.io.IOUtils;
 import org.onlab.util.Tools;
@@ -88,7 +87,33 @@
     }
 
     @Override
-    public <T, U> CompletableFuture<U> send(T message) {
+    public CompletableFuture<Void> send(Object message) {
+        ThreadContext context = ThreadContext.currentContextOrThrow();
+        CompletableFuture<Void> future = new CompletableFuture<>();
+        try (ByteArrayOutputStream baos = new ByteArrayOutputStream()) {
+            DataOutputStream dos = new DataOutputStream(baos);
+            dos.writeByte(MESSAGE);
+            context.serializer().writeObject(message, baos);
+            if (message instanceof ReferenceCounted) {
+                ((ReferenceCounted<?>) message).release();
+            }
+
+            messagingService.sendAsync(endpoint, remoteSubject, baos.toByteArray())
+                    .whenComplete((r, e) -> {
+                        if (e != null) {
+                            context.executor().execute(() -> future.completeExceptionally(e));
+                        } else {
+                            context.executor().execute(() -> future.complete(null));
+                        }
+                    });
+        } catch (SerializationException | IOException e) {
+            future.completeExceptionally(e);
+        }
+        return future;
+    }
+
+    @Override
+    public <T, U> CompletableFuture<U> sendAndReceive(T message) {
         ThreadContext context = ThreadContext.currentContextOrThrow();
         CompletableFuture<U> future = new CompletableFuture<>();
         try (ByteArrayOutputStream baos = new ByteArrayOutputStream()) {
@@ -214,7 +239,15 @@
     }
 
     @Override
-    public <T, U> Connection handler(Class<T> type, MessageHandler<T, U> handler) {
+    public <T, U> Connection handler(Class<T> type, Consumer<T> handler) {
+        return handler(type, r -> {
+            handler.accept(r);
+            return null;
+        });
+    }
+
+    @Override
+    public <T, U> Connection handler(Class<T> type, Function<T, CompletableFuture<U>> handler) {
         if (log.isTraceEnabled()) {
             log.trace("Registered handler on connection {}-{}: {}", partitionId, connectionId, type);
         }
@@ -223,12 +256,12 @@
     }
 
     @Override
-    public Listener<Throwable> exceptionListener(Consumer<Throwable> consumer) {
+    public Listener<Throwable> onException(Consumer<Throwable> consumer) {
         return exceptionListeners.add(consumer);
     }
 
     @Override
-    public Listener<Connection> closeListener(Consumer<Connection> consumer) {
+    public Listener<Connection> onClose(Consumer<Connection> consumer) {
         return closeListeners.add(consumer);
     }
 
@@ -333,10 +366,10 @@
      * Internal container for a handler/context pair.
      */
     private static class InternalHandler {
-        private final MessageHandler handler;
+        private final Function handler;
         private final ThreadContext context;
 
-        InternalHandler(MessageHandler handler, ThreadContext context) {
+        InternalHandler(Function handler, ThreadContext context) {
             this.handler = handler;
             this.context = context;
         }
@@ -344,13 +377,18 @@
         @SuppressWarnings("unchecked")
         CompletableFuture<Object> handle(Object message) {
             CompletableFuture<Object> future = new CompletableFuture<>();
-            context.execute(() -> handler.handle(message).whenComplete((r, e) -> {
-                if (e != null) {
-                    future.completeExceptionally((Throwable) e);
-                } else {
-                    future.complete(r);
+            context.executor().execute(() -> {
+                CompletableFuture<Object> responseFuture = (CompletableFuture<Object>) handler.apply(message);
+                if (responseFuture != null) {
+                    responseFuture.whenComplete((r, e) -> {
+                        if (e != null) {
+                            future.completeExceptionally((Throwable) e);
+                        } else {
+                            future.complete(r);
+                        }
+                    });
                 }
-            }));
+            });
             return future;
         }
     }
diff --git a/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/CopycatTransportServer.java b/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/CopycatTransportServer.java
index aee7647..5743c13 100644
--- a/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/CopycatTransportServer.java
+++ b/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/CopycatTransportServer.java
@@ -76,7 +76,7 @@
                     sender,
                     messagingService,
                     context);
-            connection.closeListener(connections::remove);
+            connection.onClose(connections::remove);
             connections.add(connection);
 
             CompletableFuture<byte[]> future = new CompletableFuture<>();
diff --git a/core/store/primitives/src/test/java/org/onosproject/store/primitives/impl/CopycatTransportTest.java b/core/store/primitives/src/test/java/org/onosproject/store/primitives/impl/CopycatTransportTest.java
index 21b4d70..de76d0d 100644
--- a/core/store/primitives/src/test/java/org/onosproject/store/primitives/impl/CopycatTransportTest.java
+++ b/core/store/primitives/src/test/java/org/onosproject/store/primitives/impl/CopycatTransportTest.java
@@ -15,27 +15,6 @@
  */
 package org.onosproject.store.primitives.impl;
 
-import com.google.common.collect.Lists;
-import io.atomix.catalyst.concurrent.SingleThreadContext;
-import io.atomix.catalyst.concurrent.ThreadContext;
-import io.atomix.catalyst.transport.Address;
-import io.atomix.catalyst.transport.Client;
-import io.atomix.catalyst.transport.Server;
-import io.atomix.catalyst.transport.Transport;
-import io.atomix.copycat.protocol.ConnectRequest;
-import io.atomix.copycat.protocol.ConnectResponse;
-import io.atomix.copycat.protocol.PublishRequest;
-import io.atomix.copycat.protocol.PublishResponse;
-import io.atomix.copycat.protocol.Response;
-import org.junit.After;
-import org.junit.Before;
-import org.junit.Test;
-import org.onlab.packet.IpAddress;
-import org.onlab.util.Tools;
-import org.onosproject.cluster.PartitionId;
-import org.onosproject.store.cluster.messaging.Endpoint;
-import org.onosproject.store.cluster.messaging.MessagingService;
-
 import java.time.Duration;
 import java.util.Map;
 import java.util.UUID;
@@ -47,6 +26,25 @@
 import java.util.function.BiConsumer;
 import java.util.function.BiFunction;
 
+import com.google.common.collect.Lists;
+import io.atomix.catalyst.concurrent.SingleThreadContext;
+import io.atomix.catalyst.concurrent.ThreadContext;
+import io.atomix.catalyst.transport.Address;
+import io.atomix.catalyst.transport.Client;
+import io.atomix.catalyst.transport.Server;
+import io.atomix.catalyst.transport.Transport;
+import io.atomix.copycat.protocol.ConnectRequest;
+import io.atomix.copycat.protocol.ConnectResponse;
+import io.atomix.copycat.protocol.Response;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.onlab.packet.IpAddress;
+import org.onlab.util.Tools;
+import org.onosproject.cluster.PartitionId;
+import org.onosproject.store.cluster.messaging.Endpoint;
+import org.onosproject.store.cluster.messaging.MessagingService;
+
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.fail;
@@ -135,7 +133,7 @@
                 } catch (InterruptedException e) {
                     fail();
                 }
-                connection.<ConnectRequest, ConnectResponse>send(ConnectRequest.builder()
+                connection.<ConnectRequest, ConnectResponse>sendAndReceive(ConnectRequest.builder()
                         .withClientId(UUID.randomUUID().toString())
                         .build())
                         .thenAccept(response -> {
@@ -166,15 +164,12 @@
                 serverContext.checkThread();
                 latch.countDown();
                 serverContext.schedule(Duration.ofMillis(100), () -> {
-                    connection.<PublishRequest, PublishResponse>send(PublishRequest.builder()
-                            .withSession(1)
-                            .withEventIndex(3)
-                            .withPreviousIndex(2)
+                    connection.<ConnectRequest, ConnectResponse>sendAndReceive(ConnectRequest.builder()
+                            .withClientId("foo")
                             .build())
                             .thenAccept(response -> {
                                 serverContext.checkThread();
                                 assertEquals(Response.Status.OK, response.status());
-                                assertEquals(1, response.index());
                                 latch.countDown();
                             });
                 });
@@ -187,15 +182,14 @@
             client.connect(new Address(IP_STRING, endpoint2.port())).thenAccept(connection -> {
                 clientContext.checkThread();
                 latch.countDown();
-                connection.handler(PublishRequest.class, request -> {
+                connection.handler(ConnectRequest.class, request -> {
                     clientContext.checkThread();
                     latch.countDown();
-                    assertEquals(1, request.session());
-                    assertEquals(3, request.eventIndex());
-                    assertEquals(2, request.previousIndex());
-                    return CompletableFuture.completedFuture(PublishResponse.builder()
+                    assertEquals("foo", request.client());
+                    return CompletableFuture.completedFuture(ConnectResponse.builder()
                             .withStatus(Response.Status.OK)
-                            .withIndex(1)
+                            .withLeader(new Address(IP_STRING, endpoint2.port()))
+                            .withMembers(Lists.newArrayList(new Address(IP_STRING, endpoint2.port())))
                             .build());
                 });
             });
@@ -219,7 +213,7 @@
             server.listen(new Address(IP_STRING, endpoint2.port()), connection -> {
                 serverContext.checkThread();
                 latch.countDown();
-                connection.closeListener(c -> {
+                connection.onClose(c -> {
                     serverContext.checkThread();
                     latch.countDown();
                 });
@@ -232,7 +226,7 @@
             client.connect(new Address(IP_STRING, endpoint2.port())).thenAccept(connection -> {
                 clientContext.checkThread();
                 latch.countDown();
-                connection.closeListener(c -> {
+                connection.onClose(c -> {
                     clientContext.checkThread();
                     latch.countDown();
                 });
@@ -263,7 +257,7 @@
             server.listen(new Address(IP_STRING, endpoint2.port()), connection -> {
                 serverContext.checkThread();
                 latch.countDown();
-                connection.closeListener(c -> {
+                connection.onClose(c -> {
                     latch.countDown();
                 });
                 serverContext.schedule(Duration.ofMillis(100), () -> {
@@ -281,7 +275,7 @@
             client.connect(new Address(IP_STRING, endpoint2.port())).thenAccept(connection -> {
                 clientContext.checkThread();
                 latch.countDown();
-                connection.closeListener(c -> {
+                connection.onClose(c -> {
                     latch.countDown();
                 });
             });