diff --git a/bramble-api/src/main/java/org/briarproject/bramble/api/sync/event/MessageToAckEvent.java b/bramble-api/src/main/java/org/briarproject/bramble/api/sync/event/MessagesToAckEvent.java
similarity index 65%
rename from bramble-api/src/main/java/org/briarproject/bramble/api/sync/event/MessageToAckEvent.java
rename to bramble-api/src/main/java/org/briarproject/bramble/api/sync/event/MessagesToAckEvent.java
index cc35d59a9..a298bfbfc 100644
--- a/bramble-api/src/main/java/org/briarproject/bramble/api/sync/event/MessageToAckEvent.java
+++ b/bramble-api/src/main/java/org/briarproject/bramble/api/sync/event/MessagesToAckEvent.java
@@ -7,16 +7,16 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import javax.annotation.concurrent.Immutable;
 
 /**
- * An event that is broadcast when a message is received from, or offered by, a
- * contact and needs to be acknowledged.
+ * An event that is broadcast when one or more messages are received from, or
+ * offered by, a contact and need to be acknowledged.
  */
 @Immutable
 @NotNullByDefault
-public class MessageToAckEvent extends Event {
+public class MessagesToAckEvent extends Event {
 
 	private final ContactId contactId;
 
-	public MessageToAckEvent(ContactId contactId) {
+	public MessagesToAckEvent(ContactId contactId) {
 		this.contactId = contactId;
 	}
 
diff --git a/bramble-api/src/main/java/org/briarproject/bramble/api/sync/event/MessageToRequestEvent.java b/bramble-api/src/main/java/org/briarproject/bramble/api/sync/event/MessagesToRequestEvent.java
similarity index 79%
rename from bramble-api/src/main/java/org/briarproject/bramble/api/sync/event/MessageToRequestEvent.java
rename to bramble-api/src/main/java/org/briarproject/bramble/api/sync/event/MessagesToRequestEvent.java
index 4d59c77d7..116ebb499 100644
--- a/bramble-api/src/main/java/org/briarproject/bramble/api/sync/event/MessageToRequestEvent.java
+++ b/bramble-api/src/main/java/org/briarproject/bramble/api/sync/event/MessagesToRequestEvent.java
@@ -12,17 +12,17 @@ import javax.annotation.Nullable;
 import javax.annotation.concurrent.Immutable;
 
 /**
- * An event that is broadcast when a message is offered by a contact and needs
- * to be requested.
+ * An event that is broadcast when one or more messages are offered by a
+ * contact and need to be requested.
  */
 @Immutable
 @NotNullByDefault
-public class MessageToRequestEvent extends Event {
+public class MessagesToRequestEvent extends Event {
 
 	private final ContactId contactId;
 	private final Consumable<Collection<MessageId>> ids;
 
-	public MessageToRequestEvent(ContactId contactId,
+	public MessagesToRequestEvent(ContactId contactId,
 			Collection<MessageId> ids) {
 		this.contactId = contactId;
 		this.ids = new Consumable<>(ids);
diff --git a/bramble-core/src/main/java/org/briarproject/bramble/db/DatabaseComponentImpl.java b/bramble-core/src/main/java/org/briarproject/bramble/db/DatabaseComponentImpl.java
index da8196abf..833e2167e 100644
--- a/bramble-core/src/main/java/org/briarproject/bramble/db/DatabaseComponentImpl.java
+++ b/bramble-core/src/main/java/org/briarproject/bramble/db/DatabaseComponentImpl.java
@@ -61,10 +61,10 @@ import org.briarproject.bramble.api.sync.event.MessageAddedEvent;
 import org.briarproject.bramble.api.sync.event.MessageRequestedEvent;
 import org.briarproject.bramble.api.sync.event.MessageSharedEvent;
 import org.briarproject.bramble.api.sync.event.MessageStateChangedEvent;
-import org.briarproject.bramble.api.sync.event.MessageToAckEvent;
-import org.briarproject.bramble.api.sync.event.MessageToRequestEvent;
 import org.briarproject.bramble.api.sync.event.MessagesAckedEvent;
 import org.briarproject.bramble.api.sync.event.MessagesSentEvent;
+import org.briarproject.bramble.api.sync.event.MessagesToAckEvent;
+import org.briarproject.bramble.api.sync.event.MessagesToRequestEvent;
 import org.briarproject.bramble.api.sync.event.SyncVersionsUpdatedEvent;
 import org.briarproject.bramble.api.sync.validation.MessageState;
 import org.briarproject.bramble.api.transport.KeySetId;
@@ -808,7 +808,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 				db.addMessage(txn, m, UNKNOWN, false, false, c);
 				transaction.attach(new MessageAddedEvent(m, c));
 			}
-			transaction.attach(new MessageToAckEvent(c));
+			transaction.attach(new MessagesToAckEvent(c));
 		}
 	}
 
@@ -830,9 +830,9 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 				request.add(m);
 			}
 		}
-		if (ack) transaction.attach(new MessageToAckEvent(c));
+		if (ack) transaction.attach(new MessagesToAckEvent(c));
 		if (!request.isEmpty())
-			transaction.attach(new MessageToRequestEvent(c, request));
+			transaction.attach(new MessagesToRequestEvent(c, request));
 	}
 
 	@Override
diff --git a/bramble-core/src/main/java/org/briarproject/bramble/sync/DuplexOutgoingSession.java b/bramble-core/src/main/java/org/briarproject/bramble/sync/DuplexOutgoingSession.java
index 6d0700e99..8114fb9c1 100644
--- a/bramble-core/src/main/java/org/briarproject/bramble/sync/DuplexOutgoingSession.java
+++ b/bramble-core/src/main/java/org/briarproject/bramble/sync/DuplexOutgoingSession.java
@@ -26,8 +26,8 @@ import org.briarproject.bramble.api.sync.event.CloseSyncConnectionsEvent;
 import org.briarproject.bramble.api.sync.event.GroupVisibilityUpdatedEvent;
 import org.briarproject.bramble.api.sync.event.MessageRequestedEvent;
 import org.briarproject.bramble.api.sync.event.MessageSharedEvent;
-import org.briarproject.bramble.api.sync.event.MessageToAckEvent;
-import org.briarproject.bramble.api.sync.event.MessageToRequestEvent;
+import org.briarproject.bramble.api.sync.event.MessagesToAckEvent;
+import org.briarproject.bramble.api.sync.event.MessagesToRequestEvent;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.transport.StreamWriter;
 
@@ -220,11 +220,11 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 		} else if (e instanceof MessageRequestedEvent) {
 			if (((MessageRequestedEvent) e).getContactId().equals(contactId))
 				generateBatch();
-		} else if (e instanceof MessageToAckEvent) {
-			if (((MessageToAckEvent) e).getContactId().equals(contactId))
+		} else if (e instanceof MessagesToAckEvent) {
+			if (((MessagesToAckEvent) e).getContactId().equals(contactId))
 				generateAck();
-		} else if (e instanceof MessageToRequestEvent) {
-			MessageToRequestEvent m = (MessageToRequestEvent) e;
+		} else if (e instanceof MessagesToRequestEvent) {
+			MessagesToRequestEvent m = (MessagesToRequestEvent) e;
 			if (m.getContactId().equals(contactId)) {
 				Collection<MessageId> ids = m.consumeIds();
 				if (ids != null)
diff --git a/bramble-core/src/test/java/org/briarproject/bramble/db/DatabaseComponentImplTest.java b/bramble-core/src/test/java/org/briarproject/bramble/db/DatabaseComponentImplTest.java
index ea635a765..801827a69 100644
--- a/bramble-core/src/test/java/org/briarproject/bramble/db/DatabaseComponentImplTest.java
+++ b/bramble-core/src/test/java/org/briarproject/bramble/db/DatabaseComponentImplTest.java
@@ -44,10 +44,10 @@ import org.briarproject.bramble.api.sync.event.MessageAddedEvent;
 import org.briarproject.bramble.api.sync.event.MessageRequestedEvent;
 import org.briarproject.bramble.api.sync.event.MessageSharedEvent;
 import org.briarproject.bramble.api.sync.event.MessageStateChangedEvent;
-import org.briarproject.bramble.api.sync.event.MessageToAckEvent;
-import org.briarproject.bramble.api.sync.event.MessageToRequestEvent;
 import org.briarproject.bramble.api.sync.event.MessagesAckedEvent;
 import org.briarproject.bramble.api.sync.event.MessagesSentEvent;
+import org.briarproject.bramble.api.sync.event.MessagesToAckEvent;
+import org.briarproject.bramble.api.sync.event.MessagesToRequestEvent;
 import org.briarproject.bramble.api.transport.IncomingKeys;
 import org.briarproject.bramble.api.transport.KeySetId;
 import org.briarproject.bramble.api.transport.OutgoingKeys;
@@ -987,10 +987,10 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			oneOf(database).raiseAckFlag(txn, contactId, messageId);
 			oneOf(database).commitTransaction(txn);
 			// First time: the message was received and added
-			oneOf(eventBus).broadcast(with(any(MessageToAckEvent.class)));
+			oneOf(eventBus).broadcast(with(any(MessagesToAckEvent.class)));
 			oneOf(eventBus).broadcast(with(any(MessageAddedEvent.class)));
 			// Second time: the message needs to be acked
-			oneOf(eventBus).broadcast(with(any(MessageToAckEvent.class)));
+			oneOf(eventBus).broadcast(with(any(MessagesToAckEvent.class)));
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
 				eventExecutor, shutdownManager);
@@ -1018,7 +1018,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			oneOf(database).raiseAckFlag(txn, contactId, messageId);
 			oneOf(database).commitTransaction(txn);
 			// The message was received but not added
-			oneOf(eventBus).broadcast(with(any(MessageToAckEvent.class)));
+			oneOf(eventBus).broadcast(with(any(MessagesToAckEvent.class)));
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
 				eventExecutor, shutdownManager);
@@ -1067,8 +1067,8 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			oneOf(database).containsVisibleMessage(txn, contactId, messageId2);
 			will(returnValue(false));
 			oneOf(database).commitTransaction(txn);
-			oneOf(eventBus).broadcast(with(any(MessageToAckEvent.class)));
-			oneOf(eventBus).broadcast(with(any(MessageToRequestEvent.class)));
+			oneOf(eventBus).broadcast(with(any(MessagesToAckEvent.class)));
+			oneOf(eventBus).broadcast(with(any(MessagesToRequestEvent.class)));
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
 				eventExecutor, shutdownManager);