diff --git a/federation.go b/federation.go
index 3aab6e5..9b609c8 100644
--- a/federation.go
+++ b/federation.go
@@ -454,7 +454,8 @@ func (c *FederationClient) sendHelloLocked(auth *FederationAuthParams) error {
 		Id:   c.helloMsgId,
 		Type: "hello",
 		Hello: &HelloClientMessage{
-			Version: HelloVersionV2,
+			Version:  HelloVersionV2,
+			Features: c.session.GetFeatures(),
 		},
 	}
 	if resumeId := c.resumeId; resumeId != "" {
diff --git a/federation_test.go b/federation_test.go
index ea4a504..c185b5c 100644
--- a/federation_test.go
+++ b/federation_test.go
@@ -82,11 +82,13 @@ func Test_Federation(t *testing.T) {
 
 	client1 := NewTestClient(t, server1, hub1)
 	defer client1.CloseWithBye()
-	require.NoError(client1.SendHelloV2(testDefaultUserId + "1"))
+	features1 := []string{"one", "two", "three"}
+	require.NoError(client1.SendHelloV2WithFeatures(testDefaultUserId+"1", features1))
 
 	client2 := NewTestClient(t, server2, hub2)
 	defer client2.CloseWithBye()
-	require.NoError(client2.SendHelloV2(testDefaultUserId + "2"))
+	features2 := []string{"1", "2", "3"}
+	require.NoError(client2.SendHelloV2WithFeatures(testDefaultUserId+"2", features2))
 
 	ctx, cancel := context.WithTimeout(context.Background(), testTimeout)
 	defer cancel()
@@ -148,6 +150,7 @@ func Test_Federation(t *testing.T) {
 		assert.NotEqual(hello2.Hello.SessionId, remoteSessionId)
 		assert.Equal(testDefaultUserId+"2", evt.UserId)
 		assert.True(evt.Federated)
+		assert.Equal(features2, evt.Features)
 	}
 
 	// The client2 will see its own session id, not the one from the remote server.
@@ -252,6 +255,7 @@ func Test_Federation(t *testing.T) {
 		assert.NotEqual(hello2.Hello.SessionId, remoteSessionId)
 		assert.Equal(testDefaultUserId+"2", evt.UserId)
 		assert.True(evt.Federated)
+		assert.Equal(features2, evt.Features)
 	}
 	assert.NoError(client2.RunUntilJoined(ctx, hello1.Hello, hello2.Hello))
 
@@ -424,7 +428,7 @@ func Test_Federation(t *testing.T) {
 
 	client4 := NewTestClient(t, server2, hub1)
 	defer client4.CloseWithBye()
-	require.NoError(client4.SendHelloV2(testDefaultUserId + "4"))
+	require.NoError(client4.SendHelloV2WithFeatures(testDefaultUserId+"4", features2))
 
 	hello4, err := client4.RunUntilHello(ctx)
 	require.NoError(err)
@@ -468,6 +472,7 @@ func Test_Federation(t *testing.T) {
 		assert.NotEqual(hello4.Hello.SessionId, remoteSessionId)
 		assert.Equal(testDefaultUserId+"4", evt.UserId)
 		assert.True(evt.Federated)
+		assert.Equal(features2, evt.Features)
 	}
 
 	assert.NoError(client2.RunUntilJoined(ctx, &HelloServerMessage{
diff --git a/testclient_test.go b/testclient_test.go
index 464d986..9078bcc 100644
--- a/testclient_test.go
+++ b/testclient_test.go
@@ -389,8 +389,12 @@ func (c *TestClient) SendHelloV1(userid string) error {
 }
 
 func (c *TestClient) SendHelloV2(userid string) error {
+	return c.SendHelloV2WithFeatures(userid, nil)
+}
+
+func (c *TestClient) SendHelloV2WithFeatures(userid string, features []string) error {
 	now := time.Now()
-	return c.SendHelloV2WithTimes(userid, now, now.Add(time.Minute))
+	return c.SendHelloV2WithTimesAndFeatures(userid, now, now.Add(time.Minute), features)
 }
 
 func (c *TestClient) CreateHelloV2TokenWithUserdata(userid string, issuedAt time.Time, expiresAt time.Time, userdata map[string]interface{}) (string, error) {
@@ -434,13 +438,17 @@ func (c *TestClient) CreateHelloV2Token(userid string, issuedAt time.Time, expir
 }
 
 func (c *TestClient) SendHelloV2WithTimes(userid string, issuedAt time.Time, expiresAt time.Time) error {
+	return c.SendHelloV2WithTimesAndFeatures(userid, issuedAt, expiresAt, nil)
+}
+
+func (c *TestClient) SendHelloV2WithTimesAndFeatures(userid string, issuedAt time.Time, expiresAt time.Time, features []string) error {
 	tokenString, err := c.CreateHelloV2Token(userid, issuedAt, expiresAt)
 	require.NoError(c.t, err)
 
 	params := HelloV2AuthParams{
 		Token: tokenString,
 	}
-	return c.SendHelloParams(c.server.URL, HelloVersionV2, "", nil, params)
+	return c.SendHelloParams(c.server.URL, HelloVersionV2, "", features, params)
 }
 
 func (c *TestClient) SendHelloResume(resumeId string) error {