diff --git a/go/src/mojom/vanadium/discovery/discovery.mojom.go b/go/src/mojom/vanadium/discovery/discovery.mojom.go
index bf1b8dd..ebc0dbf 100644
--- a/go/src/mojom/vanadium/discovery/discovery.mojom.go
+++ b/go/src/mojom/vanadium/discovery/discovery.mojom.go
@@ -22,7 +22,9 @@
 // These IDs are the Mojom Identifiers / Type Keys.
 // Mojom libraries importing this one will use these identifiers when building
 // TypeReference objects.
+var ID_discovery_UpdateType__ string = "discovery_UpdateType__"
 var ID_discovery_Service__ string = "discovery_Service__"
+var ID_discovery_Update__ string = "discovery_Update__"
 var ID_discovery_Error__ string = "discovery_Error__"
 var ID_discovery_Advertiser__ string = "discovery_Advertiser__"
 var ID_discovery_Scanner__ string = "discovery_Scanner__"
@@ -31,12 +33,21 @@
 var discoveryDesc__ = make(map[string]mojom_types.UserDefinedType)
 
 func init() {
+	discoveryDesc__["discovery_UpdateType__"] = &mojom_types.UserDefinedTypeEnumType{
+		Value: discovery_UpdateType__(),
+	}
 	discoveryDesc__["discovery_Service__"] = &mojom_types.UserDefinedTypeStructType{
 		Value: discovery_Service__(),
 	}
+
+	discoveryDesc__["discovery_Update__"] = &mojom_types.UserDefinedTypeStructType{
+		Value: discovery_Update__(),
+	}
+
 	discoveryDesc__["discovery_Error__"] = &mojom_types.UserDefinedTypeStructType{
 		Value: discovery_Error__(),
 	}
+
 	discoveryDesc__["discovery_Advertiser__"] = &mojom_types.UserDefinedTypeInterfaceType{
 		Value: discovery_Advertiser__(),
 	}
@@ -47,6 +58,7 @@
 	discoveryDesc__["discovery_Advertiser_Advertise_ResponseParams__"] = &mojom_types.UserDefinedTypeStructType{
 		Value: discovery_Advertiser_Advertise_ResponseParams__(),
 	}
+
 	discoveryDesc__["discovery_Advertiser_Stop_Params__"] = &mojom_types.UserDefinedTypeStructType{
 		Value: discovery_Advertiser_Stop_Params__(),
 	}
@@ -54,6 +66,7 @@
 	discoveryDesc__["discovery_Advertiser_Stop_ResponseParams__"] = &mojom_types.UserDefinedTypeStructType{
 		Value: discovery_Advertiser_Stop_ResponseParams__(),
 	}
+
 	discoveryDesc__["discovery_Scanner__"] = &mojom_types.UserDefinedTypeInterfaceType{
 		Value: discovery_Scanner__(),
 	}
@@ -61,9 +74,17 @@
 		Value: discovery_Scanner_Scan_Params__(),
 	}
 
+	discoveryDesc__["discovery_ScanHandler__"] = &mojom_types.UserDefinedTypeInterfaceType{
+		Value: discovery_ScanHandler__(),
+	}
+	discoveryDesc__["discovery_ScanHandler_Update_Params__"] = &mojom_types.UserDefinedTypeStructType{
+		Value: discovery_ScanHandler_Update_Params__(),
+	}
+
 	discoveryDesc__["discovery_Scanner_Scan_ResponseParams__"] = &mojom_types.UserDefinedTypeStructType{
 		Value: discovery_Scanner_Scan_ResponseParams__(),
 	}
+
 	discoveryDesc__["discovery_Scanner_Stop_Params__"] = &mojom_types.UserDefinedTypeStructType{
 		Value: discovery_Scanner_Stop_Params__(),
 	}
@@ -71,22 +92,49 @@
 	discoveryDesc__["discovery_Scanner_Stop_ResponseParams__"] = &mojom_types.UserDefinedTypeStructType{
 		Value: discovery_Scanner_Stop_ResponseParams__(),
 	}
-	discoveryDesc__["discovery_ScanHandler__"] = &mojom_types.UserDefinedTypeInterfaceType{
-		Value: discovery_ScanHandler__(),
-	}
-	discoveryDesc__["discovery_ScanHandler_Found_Params__"] = &mojom_types.UserDefinedTypeStructType{
-		Value: discovery_ScanHandler_Found_Params__(),
-	}
-
-	discoveryDesc__["discovery_ScanHandler_Lost_Params__"] = &mojom_types.UserDefinedTypeStructType{
-		Value: discovery_ScanHandler_Lost_Params__(),
-	}
 
 }
 func GetAllMojomTypeDefinitions() map[string]mojom_types.UserDefinedType {
 	return discoveryDesc__
 }
 
+type UpdateType int32
+
+const (
+	UpdateType_Found = 1
+	UpdateType_Lost  = UpdateType_Found + 1
+)
+
+// String names and labels used by the MojomEnum types.
+var (
+	enumName_UpdateType            = "UpdateType"
+	enumFullIdentifier_UpdateType  = "discovery.UpdateType"
+	enumFieldName_UpdateType_Found = "Found"
+	enumFieldName_UpdateType_Lost  = "Lost"
+)
+
+func discovery_UpdateType__() mojom_types.MojomEnum {
+	return mojom_types.MojomEnum{
+		DeclData: &mojom_types.DeclarationData{
+			ShortName:      &enumName_UpdateType,
+			FullIdentifier: &enumFullIdentifier_UpdateType,
+		},
+		Values: []mojom_types.EnumValue{mojom_types.EnumValue{
+			DeclData: &mojom_types.DeclarationData{
+				ShortName: &enumFieldName_UpdateType_Found,
+			},
+			EnumTypeKey: ID_discovery_UpdateType__,
+			IntValue:    int32(1),
+		}, mojom_types.EnumValue{
+			DeclData: &mojom_types.DeclarationData{
+				ShortName: &enumFieldName_UpdateType_Lost,
+			},
+			EnumTypeKey: ID_discovery_UpdateType__,
+			IntValue:    int32(2),
+		}},
+	}
+}
+
 type Advertiser interface {
 	Advertise(inService Service, inVisibility *[]string) (outHandle uint32, outInstanceId string, outErr *Error, err error)
 	Stop(inH uint32) (outErr *Error, err error)
@@ -1465,8 +1513,7 @@
 }
 
 type ScanHandler interface {
-	Found(inService Service) (err error)
-	Lost(inInstanceId string) (err error)
+	Update(inUpdate Update) (err error)
 }
 
 var scanHandler_Name = "v23::discovery::ScanHandler"
@@ -1511,8 +1558,7 @@
 	return ScanHandler_Request(r), ScanHandler_Pointer(p)
 }
 
-const scanHandler_Found_Name uint32 = 0
-const scanHandler_Lost_Name uint32 = 1
+const scanHandler_Update_Name uint32 = 0
 
 type ScanHandler_Proxy struct {
 	router *bindings.Router
@@ -1530,16 +1576,16 @@
 	p.router.Close()
 }
 
-type scanHandler_Found_Params struct {
-	inService Service
+type scanHandler_Update_Params struct {
+	inUpdate Update
 }
 
-func (s *scanHandler_Found_Params) Encode(encoder *bindings.Encoder) error {
+func (s *scanHandler_Update_Params) Encode(encoder *bindings.Encoder) error {
 	encoder.StartStruct(8, 0)
 	if err := encoder.WritePointer(); err != nil {
 		return err
 	}
-	if err := s.inService.Encode(encoder); err != nil {
+	if err := s.inUpdate.Encode(encoder); err != nil {
 		return err
 	}
 	if err := encoder.Finish(); err != nil {
@@ -1548,23 +1594,23 @@
 	return nil
 }
 
-var scanHandler_Found_Params_Versions []bindings.DataHeader = []bindings.DataHeader{
+var scanHandler_Update_Params_Versions []bindings.DataHeader = []bindings.DataHeader{
 	bindings.DataHeader{16, 0},
 }
 
-func (s *scanHandler_Found_Params) Decode(decoder *bindings.Decoder) error {
+func (s *scanHandler_Update_Params) Decode(decoder *bindings.Decoder) error {
 	header, err := decoder.StartStruct()
 	if err != nil {
 		return err
 	}
-	index := sort.Search(len(scanHandler_Found_Params_Versions), func(i int) bool {
-		return scanHandler_Found_Params_Versions[i].ElementsOrVersion >= header.ElementsOrVersion
+	index := sort.Search(len(scanHandler_Update_Params_Versions), func(i int) bool {
+		return scanHandler_Update_Params_Versions[i].ElementsOrVersion >= header.ElementsOrVersion
 	})
-	if index < len(scanHandler_Found_Params_Versions) {
-		if scanHandler_Found_Params_Versions[index].ElementsOrVersion > header.ElementsOrVersion {
+	if index < len(scanHandler_Update_Params_Versions) {
+		if scanHandler_Update_Params_Versions[index].ElementsOrVersion > header.ElementsOrVersion {
 			index--
 		}
-		expectedSize := scanHandler_Found_Params_Versions[index].Size
+		expectedSize := scanHandler_Update_Params_Versions[index].Size
 		if expectedSize != header.Size {
 			return &bindings.ValidationError{bindings.UnexpectedStructHeader,
 				fmt.Sprintf("invalid struct header size: should be %d, but was %d", expectedSize, header.Size),
@@ -1579,7 +1625,7 @@
 		if pointer0 == 0 {
 			return &bindings.ValidationError{bindings.UnexpectedNullPointer, "unexpected null pointer"}
 		} else {
-			if err := s.inService.Decode(decoder); err != nil {
+			if err := s.inUpdate.Decode(decoder); err != nil {
 				return err
 			}
 		}
@@ -1592,138 +1638,34 @@
 
 // String names and labels used by the MojomStruct types.
 var (
-	structName_ScanHandlerFoundParams                = "ScanHandlerFoundParams"
-	structFullIdentifier_ScanHandlerFoundParams      = "discovery.ScanHandlerFoundParams"
-	structFieldName_ScanHandlerFoundParams_InService = "InService"
+	structName_ScanHandlerUpdateParams               = "ScanHandlerUpdateParams"
+	structFullIdentifier_ScanHandlerUpdateParams     = "discovery.ScanHandlerUpdateParams"
+	structFieldName_ScanHandlerUpdateParams_InUpdate = "InUpdate"
 )
 
-func discovery_ScanHandler_Found_Params__() mojom_types.MojomStruct {
+func discovery_ScanHandler_Update_Params__() mojom_types.MojomStruct {
 	return mojom_types.MojomStruct{
 		DeclData: &mojom_types.DeclarationData{
-			ShortName:      &structName_ScanHandlerFoundParams,
-			FullIdentifier: &structFullIdentifier_ScanHandlerFoundParams,
+			ShortName:      &structName_ScanHandlerUpdateParams,
+			FullIdentifier: &structFullIdentifier_ScanHandlerUpdateParams,
 		}, Fields: []mojom_types.StructField{mojom_types.StructField{
 			DeclData: &mojom_types.DeclarationData{
-				ShortName: &structFieldName_ScanHandlerFoundParams_InService,
+				ShortName: &structFieldName_ScanHandlerUpdateParams_InUpdate,
 			},
 			Type: &mojom_types.TypeTypeReference{
-				Value: mojom_types.TypeReference{Identifier: &ID_discovery_Service__,
-					TypeKey: &ID_discovery_Service__},
+				Value: mojom_types.TypeReference{Identifier: &ID_discovery_Update__,
+					TypeKey: &ID_discovery_Update__},
 			},
 		}},
 	}
 }
 
-func (p *ScanHandler_Proxy) Found(inService Service) (err error) {
-	payload := &scanHandler_Found_Params{
-		inService,
+func (p *ScanHandler_Proxy) Update(inUpdate Update) (err error) {
+	payload := &scanHandler_Update_Params{
+		inUpdate,
 	}
 	header := bindings.MessageHeader{
-		Type:  scanHandler_Found_Name,
-		Flags: bindings.MessageNoFlag,
-	}
-	var message *bindings.Message
-	if message, err = bindings.EncodeMessage(header, payload); err != nil {
-		err = fmt.Errorf("can't encode request: %v", err.Error())
-		p.Close_Proxy()
-		return
-	}
-	if err = p.router.Accept(message); err != nil {
-		p.Close_Proxy()
-		return
-	}
-	return
-}
-
-type scanHandler_Lost_Params struct {
-	inInstanceId string
-}
-
-func (s *scanHandler_Lost_Params) Encode(encoder *bindings.Encoder) error {
-	encoder.StartStruct(8, 0)
-	if err := encoder.WritePointer(); err != nil {
-		return err
-	}
-	if err := encoder.WriteString(s.inInstanceId); err != nil {
-		return err
-	}
-	if err := encoder.Finish(); err != nil {
-		return err
-	}
-	return nil
-}
-
-var scanHandler_Lost_Params_Versions []bindings.DataHeader = []bindings.DataHeader{
-	bindings.DataHeader{16, 0},
-}
-
-func (s *scanHandler_Lost_Params) Decode(decoder *bindings.Decoder) error {
-	header, err := decoder.StartStruct()
-	if err != nil {
-		return err
-	}
-	index := sort.Search(len(scanHandler_Lost_Params_Versions), func(i int) bool {
-		return scanHandler_Lost_Params_Versions[i].ElementsOrVersion >= header.ElementsOrVersion
-	})
-	if index < len(scanHandler_Lost_Params_Versions) {
-		if scanHandler_Lost_Params_Versions[index].ElementsOrVersion > header.ElementsOrVersion {
-			index--
-		}
-		expectedSize := scanHandler_Lost_Params_Versions[index].Size
-		if expectedSize != header.Size {
-			return &bindings.ValidationError{bindings.UnexpectedStructHeader,
-				fmt.Sprintf("invalid struct header size: should be %d, but was %d", expectedSize, header.Size),
-			}
-		}
-	}
-	if header.ElementsOrVersion >= 0 {
-		pointer0, err := decoder.ReadPointer()
-		if err != nil {
-			return err
-		}
-		if pointer0 == 0 {
-			return &bindings.ValidationError{bindings.UnexpectedNullPointer, "unexpected null pointer"}
-		} else {
-			value0, err := decoder.ReadString()
-			if err != nil {
-				return err
-			}
-			s.inInstanceId = value0
-		}
-	}
-	if err := decoder.Finish(); err != nil {
-		return err
-	}
-	return nil
-}
-
-// String names and labels used by the MojomStruct types.
-var (
-	structName_ScanHandlerLostParams                   = "ScanHandlerLostParams"
-	structFullIdentifier_ScanHandlerLostParams         = "discovery.ScanHandlerLostParams"
-	structFieldName_ScanHandlerLostParams_InInstanceId = "InInstanceId"
-)
-
-func discovery_ScanHandler_Lost_Params__() mojom_types.MojomStruct {
-	return mojom_types.MojomStruct{
-		DeclData: &mojom_types.DeclarationData{
-			ShortName:      &structName_ScanHandlerLostParams,
-			FullIdentifier: &structFullIdentifier_ScanHandlerLostParams,
-		}, Fields: []mojom_types.StructField{mojom_types.StructField{
-			DeclData: &mojom_types.DeclarationData{
-				ShortName: &structFieldName_ScanHandlerLostParams_InInstanceId,
-			},
-			Type: &mojom_types.TypeStringType{mojom_types.StringType{false}},
-		}},
-	}
-}
-
-func (p *ScanHandler_Proxy) Lost(inInstanceId string) (err error) {
-	payload := &scanHandler_Lost_Params{
-		inInstanceId,
-	}
-	header := bindings.MessageHeader{
-		Type:  scanHandler_Lost_Name,
+		Type:  scanHandler_Update_Name,
 		Flags: bindings.MessageNoFlag,
 	}
 	var message *bindings.Message
@@ -1750,10 +1692,9 @@
 }
 
 var (
-	interfaceName_ScanHandler             = "ScanHandler"
-	interfaceFullIdentifier_ScanHandler   = "discovery.ScanHandler"
-	interfaceMethodName_ScanHandler_Found = "Found"
-	interfaceMethodName_ScanHandler_Lost  = "Lost"
+	interfaceName_ScanHandler              = "ScanHandler"
+	interfaceFullIdentifier_ScanHandler    = "discovery.ScanHandler"
+	interfaceMethodName_ScanHandler_Update = "Update"
 )
 
 func discovery_ScanHandler__() mojom_types.MojomInterface {
@@ -1764,18 +1705,12 @@
 			ShortName:      &interfaceName_ScanHandler,
 			FullIdentifier: &interfaceFullIdentifier_ScanHandler,
 		},
-		Methods: map[uint32]mojom_types.MojomMethod{scanHandler_Found_Name: mojom_types.MojomMethod{
+		Methods: map[uint32]mojom_types.MojomMethod{scanHandler_Update_Name: mojom_types.MojomMethod{
 			DeclData: &mojom_types.DeclarationData{
-				ShortName: &interfaceMethodName_ScanHandler_Found,
+				ShortName: &interfaceMethodName_ScanHandler_Update,
 			},
-			Parameters:     discovery_ScanHandler_Found_Params__(),
-			ResponseParams: responseParamsMap[interfaceMethodName_ScanHandler_Found],
-		}, scanHandler_Lost_Name: mojom_types.MojomMethod{
-			DeclData: &mojom_types.DeclarationData{
-				ShortName: &interfaceMethodName_ScanHandler_Lost,
-			},
-			Parameters:     discovery_ScanHandler_Lost_Params__(),
-			ResponseParams: responseParamsMap[interfaceMethodName_ScanHandler_Lost],
+			Parameters:     discovery_ScanHandler_Update_Params__(),
+			ResponseParams: responseParamsMap[interfaceMethodName_ScanHandler_Update],
 		}},
 	}
 }
@@ -1806,31 +1741,17 @@
 
 func (s *scanHandler_Stub) Accept(message *bindings.Message) (err error) {
 	switch message.Header.Type {
-	case scanHandler_Found_Name:
+	case scanHandler_Update_Name:
 		if message.Header.Flags != bindings.MessageNoFlag {
 			return &bindings.ValidationError{bindings.MessageHeaderInvalidFlags,
 				fmt.Sprintf("invalid message header flag: %v", message.Header.Flags),
 			}
 		}
-		var request scanHandler_Found_Params
+		var request scanHandler_Update_Params
 		if err := message.DecodePayload(&request); err != nil {
 			return err
 		}
-		err = s.impl.Found(request.inService)
-		if err != nil {
-			return
-		}
-	case scanHandler_Lost_Name:
-		if message.Header.Flags != bindings.MessageNoFlag {
-			return &bindings.ValidationError{bindings.MessageHeaderInvalidFlags,
-				fmt.Sprintf("invalid message header flag: %v", message.Header.Flags),
-			}
-		}
-		var request scanHandler_Lost_Params
-		if err := message.DecodePayload(&request); err != nil {
-			return err
-		}
-		err = s.impl.Lost(request.inInstanceId)
+		err = s.impl.Update(request.inUpdate)
 		if err != nil {
 			return
 		}
@@ -2205,6 +2126,110 @@
 	}
 }
 
+type Update struct {
+	Service    Service
+	UpdateType UpdateType
+}
+
+func (s *Update) Encode(encoder *bindings.Encoder) error {
+	encoder.StartStruct(16, 0)
+	if err := encoder.WritePointer(); err != nil {
+		return err
+	}
+	if err := s.Service.Encode(encoder); err != nil {
+		return err
+	}
+	if err := encoder.WriteInt32(int32(s.UpdateType)); err != nil {
+		return err
+	}
+	if err := encoder.Finish(); err != nil {
+		return err
+	}
+	return nil
+}
+
+var update_Versions []bindings.DataHeader = []bindings.DataHeader{
+	bindings.DataHeader{24, 0},
+}
+
+func (s *Update) Decode(decoder *bindings.Decoder) error {
+	header, err := decoder.StartStruct()
+	if err != nil {
+		return err
+	}
+	index := sort.Search(len(update_Versions), func(i int) bool {
+		return update_Versions[i].ElementsOrVersion >= header.ElementsOrVersion
+	})
+	if index < len(update_Versions) {
+		if update_Versions[index].ElementsOrVersion > header.ElementsOrVersion {
+			index--
+		}
+		expectedSize := update_Versions[index].Size
+		if expectedSize != header.Size {
+			return &bindings.ValidationError{bindings.UnexpectedStructHeader,
+				fmt.Sprintf("invalid struct header size: should be %d, but was %d", expectedSize, header.Size),
+			}
+		}
+	}
+	if header.ElementsOrVersion >= 0 {
+		pointer0, err := decoder.ReadPointer()
+		if err != nil {
+			return err
+		}
+		if pointer0 == 0 {
+			return &bindings.ValidationError{bindings.UnexpectedNullPointer, "unexpected null pointer"}
+		} else {
+			if err := s.Service.Decode(decoder); err != nil {
+				return err
+			}
+		}
+	}
+	if header.ElementsOrVersion >= 0 {
+		value0, err := decoder.ReadInt32()
+		if err != nil {
+			return err
+		}
+		s.UpdateType = UpdateType(value0)
+	}
+	if err := decoder.Finish(); err != nil {
+		return err
+	}
+	return nil
+}
+
+// String names and labels used by the MojomStruct types.
+var (
+	structName_Update                 = "Update"
+	structFullIdentifier_Update       = "discovery.Update"
+	structFieldName_Update_Service    = "Service"
+	structFieldName_Update_UpdateType = "UpdateType"
+)
+
+func discovery_Update__() mojom_types.MojomStruct {
+	return mojom_types.MojomStruct{
+		DeclData: &mojom_types.DeclarationData{
+			ShortName:      &structName_Update,
+			FullIdentifier: &structFullIdentifier_Update,
+		}, Fields: []mojom_types.StructField{mojom_types.StructField{
+			DeclData: &mojom_types.DeclarationData{
+				ShortName: &structFieldName_Update_Service,
+			},
+			Type: &mojom_types.TypeTypeReference{
+				Value: mojom_types.TypeReference{Identifier: &ID_discovery_Service__,
+					TypeKey: &ID_discovery_Service__},
+			},
+		}, mojom_types.StructField{
+			DeclData: &mojom_types.DeclarationData{
+				ShortName: &structFieldName_Update_UpdateType,
+			},
+			Type: &mojom_types.TypeTypeReference{
+				Value: mojom_types.TypeReference{Identifier: &ID_discovery_UpdateType__,
+					TypeKey: &ID_discovery_UpdateType__},
+			},
+		}},
+	}
+}
+
 type Error struct {
 	Id     string
 	Action int32
diff --git a/go/src/vanadium/discovery/internal/discovery.go b/go/src/vanadium/discovery/internal/discovery.go
index 41bd5f5..5d28a81 100644
--- a/go/src/vanadium/discovery/internal/discovery.go
+++ b/go/src/vanadium/discovery/internal/discovery.go
@@ -152,9 +152,17 @@
 		for v := range scanCh {
 			switch value := v.(type) {
 			case discovery.UpdateFound:
-				proxy.Found(v2mService(value.Value.Service))
+				update := mojom.Update{
+					Service:    v2mService(value.Value.Service),
+					UpdateType: mojom.UpdateType_Found,
+				}
+				proxy.Update(update)
 			case discovery.UpdateLost:
-				proxy.Lost(value.Value.InstanceId)
+				update := mojom.Update{
+					Service:    v2mService(value.Value.Service),
+					UpdateType: mojom.UpdateType_Lost,
+				}
+				proxy.Update(update)
 			}
 		}
 	}()
diff --git a/java/build.gradle b/java/build.gradle
index d410fd4..30d92e7 100644
--- a/java/build.gradle
+++ b/java/build.gradle
@@ -48,12 +48,10 @@
 android.sourceSets.main.java.srcDirs += 'generated-src'
 
 dependencies {
-    compile 'io.v:vanadium-android:0.9'
+    compile 'io.v:vanadium-android:1.3'
     compile files(System.getenv("MOJO_DIR") + "/src/out/android_Debug/gen/mojo/public/java/application.jar")
     compile files(System.getenv("MOJO_DIR") + "/src/out/android_Debug/gen/mojo/public/interfaces/application/application_java.jar")
     compile files(System.getenv("MOJO_DIR") + "/src/out/android_Debug/gen/mojo/public/java/bindings.jar")
 
     provided files(System.getenv("MOJO_DIR") + "/src/out/android_Debug/gen/mojo/public/java/system.jar")
 }
-
-
diff --git a/java/generated-src/io/v/mojo/discovery/ScanHandler.java b/java/generated-src/io/v/mojo/discovery/ScanHandler.java
index 25cddab..08885bf 100644
--- a/java/generated-src/io/v/mojo/discovery/ScanHandler.java
+++ b/java/generated-src/io/v/mojo/discovery/ScanHandler.java
@@ -21,8 +21,6 @@
 
     NamedManager<ScanHandler, ScanHandler.Proxy> MANAGER = ScanHandler_Internal.MANAGER;
 
-    void found(Service service);
-
-    void lost(String instanceId);
+    void update(Update update);
 }
 
diff --git a/java/generated-src/io/v/mojo/discovery/ScanHandler_Internal.java b/java/generated-src/io/v/mojo/discovery/ScanHandler_Internal.java
index d649ea2..477d0e7 100644
--- a/java/generated-src/io/v/mojo/discovery/ScanHandler_Internal.java
+++ b/java/generated-src/io/v/mojo/discovery/ScanHandler_Internal.java
@@ -41,8 +41,7 @@
         }
     };
 
-    private static final int FOUND_ORDINAL = 0;
-    private static final int LOST_ORDINAL = 1;
+    private static final int UPDATE_ORDINAL = 0;
 
     static final class Proxy extends org.chromium.mojo.bindings.Interface.AbstractProxy implements ScanHandler.Proxy {
 
@@ -52,23 +51,13 @@
         }
 
         @Override
-        public void found(Service service) {
-            ScanHandlerFoundParams _message = new ScanHandlerFoundParams();
-            _message.service = service;
+        public void update(Update update) {
+            ScanHandlerUpdateParams _message = new ScanHandlerUpdateParams();
+            _message.update = update;
             getProxyHandler().getMessageReceiver().accept(
                     _message.serializeWithHeader(
                             getProxyHandler().getCore(),
-                            new org.chromium.mojo.bindings.MessageHeader(FOUND_ORDINAL)));
-        }
-
-        @Override
-        public void lost(String instanceId) {
-            ScanHandlerLostParams _message = new ScanHandlerLostParams();
-            _message.instanceId = instanceId;
-            getProxyHandler().getMessageReceiver().accept(
-                    _message.serializeWithHeader(
-                            getProxyHandler().getCore(),
-                            new org.chromium.mojo.bindings.MessageHeader(LOST_ORDINAL)));
+                            new org.chromium.mojo.bindings.MessageHeader(UPDATE_ORDINAL)));
         }
 
     }
@@ -92,16 +81,10 @@
                     case org.chromium.mojo.bindings.InterfaceControlMessagesConstants.RUN_OR_CLOSE_PIPE_MESSAGE_ID:
                         return org.chromium.mojo.bindings.InterfaceControlMessagesHelper.handleRunOrClosePipe(
                                 ScanHandler_Internal.MANAGER, messageWithHeader);
-                    case FOUND_ORDINAL: {
-                        ScanHandlerFoundParams data =
-                                ScanHandlerFoundParams.deserialize(messageWithHeader.getPayload());
-                        getImpl().found(data.service);
-                        return true;
-                    }
-                    case LOST_ORDINAL: {
-                        ScanHandlerLostParams data =
-                                ScanHandlerLostParams.deserialize(messageWithHeader.getPayload());
-                        getImpl().lost(data.instanceId);
+                    case UPDATE_ORDINAL: {
+                        ScanHandlerUpdateParams data =
+                                ScanHandlerUpdateParams.deserialize(messageWithHeader.getPayload());
+                        getImpl().update(data.update);
                         return true;
                     }
                     default:
@@ -136,36 +119,36 @@
         }
     }
 
-    static final class ScanHandlerFoundParams extends org.chromium.mojo.bindings.Struct {
+    static final class ScanHandlerUpdateParams extends org.chromium.mojo.bindings.Struct {
     
         private static final int STRUCT_SIZE = 16;
         private static final org.chromium.mojo.bindings.DataHeader[] VERSION_ARRAY = new org.chromium.mojo.bindings.DataHeader[] {new org.chromium.mojo.bindings.DataHeader(16, 0)};
         private static final org.chromium.mojo.bindings.DataHeader DEFAULT_STRUCT_INFO = VERSION_ARRAY[0];
     
-        public Service service;
+        public Update update;
     
-        private ScanHandlerFoundParams(int version) {
+        private ScanHandlerUpdateParams(int version) {
             super(STRUCT_SIZE, version);
         }
     
-        public ScanHandlerFoundParams() {
+        public ScanHandlerUpdateParams() {
             this(0);
         }
     
-        public static ScanHandlerFoundParams deserialize(org.chromium.mojo.bindings.Message message) {
+        public static ScanHandlerUpdateParams deserialize(org.chromium.mojo.bindings.Message message) {
             return decode(new org.chromium.mojo.bindings.Decoder(message));
         }
     
         @SuppressWarnings("unchecked")
-        public static ScanHandlerFoundParams decode(org.chromium.mojo.bindings.Decoder decoder0) {
+        public static ScanHandlerUpdateParams decode(org.chromium.mojo.bindings.Decoder decoder0) {
             if (decoder0 == null) {
                 return null;
             }
             org.chromium.mojo.bindings.DataHeader mainDataHeader = decoder0.readAndValidateDataHeader(VERSION_ARRAY);
-            ScanHandlerFoundParams result = new ScanHandlerFoundParams(mainDataHeader.elementsOrVersion);
+            ScanHandlerUpdateParams result = new ScanHandlerUpdateParams(mainDataHeader.elementsOrVersion);
             if (mainDataHeader.elementsOrVersion >= 0) {
                 org.chromium.mojo.bindings.Decoder decoder1 = decoder0.readPointer(8, false);
-                result.service = Service.decode(decoder1);
+                result.update = Update.decode(decoder1);
             }
             return result;
         }
@@ -174,7 +157,7 @@
         @Override
         protected final void encode(org.chromium.mojo.bindings.Encoder encoder) {
             org.chromium.mojo.bindings.Encoder encoder0 = encoder.getEncoderAtDataOffset(DEFAULT_STRUCT_INFO);
-            encoder0.encode(service, 8, false);
+            encoder0.encode(update, 8, false);
         }
     
         /**
@@ -188,8 +171,8 @@
                 return false;
             if (getClass() != object.getClass())
                 return false;
-            ScanHandlerFoundParams other = (ScanHandlerFoundParams) object;
-            if (!org.chromium.mojo.bindings.BindingsHelper.equals(this.service, other.service))
+            ScanHandlerUpdateParams other = (ScanHandlerUpdateParams) object;
+            if (!org.chromium.mojo.bindings.BindingsHelper.equals(this.update, other.update))
                 return false;
             return true;
         }
@@ -201,76 +184,7 @@
         public int hashCode() {
             final int prime = 31;
             int result = prime + getClass().hashCode();
-            result = prime * result + org.chromium.mojo.bindings.BindingsHelper.hashCode(service);
-            return result;
-        }
-    }
-
-    static final class ScanHandlerLostParams extends org.chromium.mojo.bindings.Struct {
-    
-        private static final int STRUCT_SIZE = 16;
-        private static final org.chromium.mojo.bindings.DataHeader[] VERSION_ARRAY = new org.chromium.mojo.bindings.DataHeader[] {new org.chromium.mojo.bindings.DataHeader(16, 0)};
-        private static final org.chromium.mojo.bindings.DataHeader DEFAULT_STRUCT_INFO = VERSION_ARRAY[0];
-    
-        public String instanceId;
-    
-        private ScanHandlerLostParams(int version) {
-            super(STRUCT_SIZE, version);
-        }
-    
-        public ScanHandlerLostParams() {
-            this(0);
-        }
-    
-        public static ScanHandlerLostParams deserialize(org.chromium.mojo.bindings.Message message) {
-            return decode(new org.chromium.mojo.bindings.Decoder(message));
-        }
-    
-        @SuppressWarnings("unchecked")
-        public static ScanHandlerLostParams decode(org.chromium.mojo.bindings.Decoder decoder0) {
-            if (decoder0 == null) {
-                return null;
-            }
-            org.chromium.mojo.bindings.DataHeader mainDataHeader = decoder0.readAndValidateDataHeader(VERSION_ARRAY);
-            ScanHandlerLostParams result = new ScanHandlerLostParams(mainDataHeader.elementsOrVersion);
-            if (mainDataHeader.elementsOrVersion >= 0) {
-                result.instanceId = decoder0.readString(8, false);
-            }
-            return result;
-        }
-    
-        @SuppressWarnings("unchecked")
-        @Override
-        protected final void encode(org.chromium.mojo.bindings.Encoder encoder) {
-            org.chromium.mojo.bindings.Encoder encoder0 = encoder.getEncoderAtDataOffset(DEFAULT_STRUCT_INFO);
-            encoder0.encode(instanceId, 8, false);
-        }
-    
-        /**
-         * @see Object#equals(Object)
-         */
-        @Override
-        public boolean equals(Object object) {
-            if (object == this)
-                return true;
-            if (object == null)
-                return false;
-            if (getClass() != object.getClass())
-                return false;
-            ScanHandlerLostParams other = (ScanHandlerLostParams) object;
-            if (!org.chromium.mojo.bindings.BindingsHelper.equals(this.instanceId, other.instanceId))
-                return false;
-            return true;
-        }
-    
-        /**
-         * @see Object#hashCode()
-         */
-        @Override
-        public int hashCode() {
-            final int prime = 31;
-            int result = prime + getClass().hashCode();
-            result = prime * result + org.chromium.mojo.bindings.BindingsHelper.hashCode(instanceId);
+            result = prime * result + org.chromium.mojo.bindings.BindingsHelper.hashCode(update);
             return result;
         }
     }
diff --git a/java/generated-src/io/v/mojo/discovery/Update.java b/java/generated-src/io/v/mojo/discovery/Update.java
new file mode 100644
index 0000000..97a9bdc
--- /dev/null
+++ b/java/generated-src/io/v/mojo/discovery/Update.java
@@ -0,0 +1,94 @@
+// Copyright 2015 The Vanadium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// This file is autogenerated by:
+//     mojo/public/tools/bindings/mojom_bindings_generator.py
+// For:
+//     mojom/vanadium/discovery.mojom
+//
+
+package io.v.mojo.discovery;
+
+public final class Update extends org.chromium.mojo.bindings.Struct {
+
+    private static final int STRUCT_SIZE = 24;
+    private static final org.chromium.mojo.bindings.DataHeader[] VERSION_ARRAY = new org.chromium.mojo.bindings.DataHeader[] {new org.chromium.mojo.bindings.DataHeader(24, 0)};
+    private static final org.chromium.mojo.bindings.DataHeader DEFAULT_STRUCT_INFO = VERSION_ARRAY[0];
+
+    public Service service;
+    public int updateType;
+
+    private Update(int version) {
+        super(STRUCT_SIZE, version);
+    }
+
+    public Update() {
+        this(0);
+    }
+
+    public static Update deserialize(org.chromium.mojo.bindings.Message message) {
+        return decode(new org.chromium.mojo.bindings.Decoder(message));
+    }
+
+    @SuppressWarnings("unchecked")
+    public static Update decode(org.chromium.mojo.bindings.Decoder decoder0) {
+        if (decoder0 == null) {
+            return null;
+        }
+        org.chromium.mojo.bindings.DataHeader mainDataHeader = decoder0.readAndValidateDataHeader(VERSION_ARRAY);
+        Update result = new Update(mainDataHeader.elementsOrVersion);
+        if (mainDataHeader.elementsOrVersion >= 0) {
+            org.chromium.mojo.bindings.Decoder decoder1 = decoder0.readPointer(8, false);
+            result.service = Service.decode(decoder1);
+        }
+        if (mainDataHeader.elementsOrVersion >= 0) {
+            result.updateType = decoder0.readInt(16);
+        }
+        return result;
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    protected final void encode(org.chromium.mojo.bindings.Encoder encoder) {
+        org.chromium.mojo.bindings.Encoder encoder0 = encoder.getEncoderAtDataOffset(DEFAULT_STRUCT_INFO);
+        encoder0.encode(service, 8, false);
+        encoder0.encode(updateType, 16);
+    }
+
+    /**
+     * @see Object#equals(Object)
+     */
+    @Override
+    public boolean equals(Object object) {
+        if (object == this)
+            return true;
+        if (object == null)
+            return false;
+        if (getClass() != object.getClass())
+            return false;
+        Update other = (Update) object;
+        if (!org.chromium.mojo.bindings.BindingsHelper.equals(this.service, other.service))
+            return false;
+        if (this.updateType != other.updateType)
+            return false;
+        return true;
+    }
+
+    /**
+     * @see Object#hashCode()
+     */
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = prime + getClass().hashCode();
+        result = prime * result + org.chromium.mojo.bindings.BindingsHelper.hashCode(service);
+        result = prime * result + org.chromium.mojo.bindings.BindingsHelper.hashCode(updateType);
+        return result;
+    }
+}
+
diff --git a/java/generated-src/io/v/mojo/discovery/UpdateType.java b/java/generated-src/io/v/mojo/discovery/UpdateType.java
new file mode 100644
index 0000000..279da0b
--- /dev/null
+++ b/java/generated-src/io/v/mojo/discovery/UpdateType.java
@@ -0,0 +1,24 @@
+// Copyright 2015 The Vanadium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// This file is autogenerated by:
+//     mojo/public/tools/bindings/mojom_bindings_generator.py
+// For:
+//     mojom/vanadium/discovery.mojom
+//
+
+package io.v.mojo.discovery;
+
+public final class UpdateType {
+
+    public static final int FOUND = (int) (1L);
+    public static final int LOST = FOUND + 1;
+
+    private UpdateType() {}
+
+}
diff --git a/java/generated-src/mojom/vanadium/discovery.mojom.srcjar b/java/generated-src/mojom/vanadium/discovery.mojom.srcjar
index e2f880f..f97e92e 100644
--- a/java/generated-src/mojom/vanadium/discovery.mojom.srcjar
+++ b/java/generated-src/mojom/vanadium/discovery.mojom.srcjar
Binary files differ
diff --git a/java/src/main/java/io/v/mojo/discovery/AdvertiserImpl.java b/java/src/main/java/io/v/mojo/discovery/AdvertiserImpl.java
index 00f327a..7f5ff24 100644
--- a/java/src/main/java/io/v/mojo/discovery/AdvertiserImpl.java
+++ b/java/src/main/java/io/v/mojo/discovery/AdvertiserImpl.java
@@ -11,6 +11,7 @@
 import com.google.common.util.concurrent.Futures;
 import com.google.common.util.concurrent.ListenableFuture;
 
+import io.v.v23.discovery.Attachments;
 import org.chromium.mojo.system.MojoException;
 
 import java.lang.Override;
@@ -22,7 +23,6 @@
 import java.util.Map;
 import java.util.concurrent.atomic.AtomicInteger;
 
-import io.v.v23.context.CancelableVContext;
 import io.v.v23.context.VContext;
 import io.v.v23.discovery.Attributes;
 import io.v.v23.discovery.VDiscovery;
@@ -35,7 +35,7 @@
 
     private final AtomicInteger nextAdvertiser = new AtomicInteger(0);
 
-    private final Map<Integer, CancelableVContext> contextMap = new HashMap<>();
+    private final Map<Integer, VContext> contextMap = new HashMap<>();
 
     public AdvertiserImpl(VDiscovery discovery, VContext rootCtx) {
         this.discovery = discovery;
@@ -45,12 +45,12 @@
     public void advertise(Service service, String[] visibility, final AdvertiseResponse callback) {
         synchronized (this) {
             final Integer nextValue = nextAdvertiser.getAndAdd(1);
-            CancelableVContext ctx = rootCtx.withCancel();
+            VContext ctx = rootCtx.withCancel();
             contextMap.put(nextValue, ctx);
             Attributes attrs = null;
             final io.v.v23.discovery.Service vService = new io.v.v23.discovery.Service(
                     service.instanceId, service.instanceName, service.interfaceName,
-                    new Attributes(service.attrs), Arrays.asList(service.addrs));
+                    new Attributes(service.attrs), Arrays.asList(service.addrs), new Attachments());
             if (service.attrs == null) {
                 vService.setAttrs(new Attributes(new HashMap<String, String>()));
             }
@@ -85,7 +85,7 @@
     @Override
     public void stop(int h, StopResponse response) {
         synchronized (this) {
-            CancelableVContext ctx = contextMap.get(h);
+            VContext ctx = contextMap.get(h);
             if (ctx != null) {
                 contextMap.remove(h);
                 ctx.cancel();
diff --git a/java/src/main/java/io/v/mojo/discovery/ScannerImpl.java b/java/src/main/java/io/v/mojo/discovery/ScannerImpl.java
index 5e854d6..fb2431e 100644
--- a/java/src/main/java/io/v/mojo/discovery/ScannerImpl.java
+++ b/java/src/main/java/io/v/mojo/discovery/ScannerImpl.java
@@ -5,8 +5,10 @@
 package io.v.mojo.discovery;
 
 import com.google.common.util.concurrent.FutureCallback;
+import com.google.common.util.concurrent.Futures;
 import com.google.common.util.concurrent.ListenableFuture;
 
+import io.v.v23.InputChannelCallback;
 import org.chromium.mojo.system.MojoException;
 
 import java.util.HashMap;
@@ -14,9 +16,7 @@
 import java.util.concurrent.atomic.AtomicInteger;
 
 import io.v.v23.InputChannels;
-import io.v.v23.context.CancelableVContext;
 import io.v.v23.context.VContext;
-import io.v.v23.discovery.Update;
 import io.v.v23.discovery.VDiscovery;
 import io.v.v23.rpc.Callback;
 import io.v.v23.verror.VException;
@@ -26,7 +26,7 @@
     private final VContext rootCtx;
 
 
-    private final Map<Integer, CancelableVContext> contextMap  = new HashMap<>();
+    private final Map<Integer, VContext> contextMap  = new HashMap<>();
 
     private final AtomicInteger nextScanner = new AtomicInteger(0);
 
@@ -39,33 +39,31 @@
         synchronized (this) {
             System.out.println("Got a scan call");
             int handle = nextScanner.getAndAdd(1);
-            CancelableVContext ctx = rootCtx.withCancel();
+            VContext ctx = rootCtx.withCancel();
             contextMap.put(handle, ctx);
             ListenableFuture<Void> done = InputChannels.withCallback(discovery.scan(ctx, query),
-                    new Callback<Update>() {
+                    new InputChannelCallback<io.v.v23.discovery.Update>() {
                         @Override
-                        public void onSuccess(Update update) {
-                            if (update instanceof Update.Found) {
-                                Update.Found found = (Update.Found) update;
-                                io.v.v23.discovery.Service vService = found.getElem().getService();
-                                Service mService = new Service();
-                                mService.instanceId = vService.getInstanceId();
-                                mService.instanceName = vService.getInstanceName();
-                                mService.interfaceName = vService.getInterfaceName();
-                                mService.addrs = new String[vService.getAddrs().size()];
-                                mService.addrs = vService.getAddrs().toArray(mService.addrs);
-                                mService.attrs = vService.getAttrs();
-                                scanHandler.found(mService);
+                        public ListenableFuture<Void> onNext(io.v.v23.discovery.Update update) {
+                            if (update instanceof io.v.v23.discovery.Update.Found) {
+                                io.v.v23.discovery.Update.Found found = (io.v.v23.discovery.Update.Found) update;
+                                Service mService = toMojoService(found.getElem().getService());
+                                Update mUpdate = new Update();
+                                mUpdate.service = mService;
+                                mUpdate.updateType = UpdateType.FOUND;
+                                scanHandler.update(mUpdate);
                             } else {
-                                Update.Lost lost = (Update.Lost) update;
-                                scanHandler.lost(lost.getElem().getInstanceId());
+                                io.v.v23.discovery.Update.Lost lost = (io.v.v23.discovery.Update.Lost) update;
+                                Service mService = toMojoService(lost.getElem().getService());
+                                Update mUpdate = new Update();
+                                mUpdate.service = mService;
+                                mUpdate.updateType = UpdateType.LOST;
+                                scanHandler.update(mUpdate);
                             }
+
+                            return Futures.immediateFuture(null);
                         }
 
-                        @Override
-                        public void onFailure(VException t) {
-
-                        }
                     });
             System.out.println("Returning a scan call");
             callback.call(handle, null);
@@ -75,7 +73,7 @@
     @Override
     public void stop(int h, StopResponse response) {
         synchronized (this) {
-            CancelableVContext ctx = contextMap.get(h);
+            VContext ctx = contextMap.get(h);
             if (ctx != null) {
                 contextMap.remove(h);
                 ctx.cancel();
@@ -89,4 +87,15 @@
 
     @Override
     public void onConnectionError(MojoException e) {}
+
+    private static Service toMojoService(io.v.v23.discovery.Service vService) {
+      Service mService = new Service();
+      mService.instanceId = vService.getInstanceId();
+      mService.instanceName = vService.getInstanceName();
+      mService.interfaceName = vService.getInterfaceName();
+      mService.addrs = new String[vService.getAddrs().size()];
+      mService.addrs = vService.getAddrs().toArray(mService.addrs);
+      mService.attrs = vService.getAttrs();
+      return mService;
+    }
 }
diff --git a/java/src/main/java/io/v/mojo/discovery/VDiscoveryApp.java b/java/src/main/java/io/v/mojo/discovery/VDiscoveryApp.java
index 6bd3a71..10a5219 100644
--- a/java/src/main/java/io/v/mojo/discovery/VDiscoveryApp.java
+++ b/java/src/main/java/io/v/mojo/discovery/VDiscoveryApp.java
@@ -65,7 +65,7 @@
 
     @Override
     public void quit() {
-        V.shutdown();
+        rootCtx.cancel();
     }
 
     public static void mojoMain(Context context, Core core,
diff --git a/lib/client_impl.dart b/lib/client_impl.dart
index 458ddab..476cd19 100644
--- a/lib/client_impl.dart
+++ b/lib/client_impl.dart
@@ -15,10 +15,9 @@
   }
 
   Future<Scanner> scan(String query) async {
-    StreamController<Service> onFound = new StreamController<Service>();
-    StreamController<String> onLost = new StreamController<String>();
+    StreamController<Update> onUpdate = new StreamController<Update>();
     ScanHandlerStub handlerStub = new ScanHandlerStub.unbound();
-    handlerStub.impl = new _ScanHandler(onFound, onLost);
+    handlerStub.impl = new _ScanHandler(onUpdate);
 
     ScannerScanResponseParams scanResponse =
         await _scannerProxy.ptr.scan(query, handlerStub);
@@ -29,7 +28,7 @@
     Future stop() {
       return _scannerProxy.ptr.stop(scanResponse.handle);
     }
-    return new _Scanner(stop, onFound.stream, onLost.stream);
+    return new _Scanner(stop, onUpdate.stream);
   }
 
   Future<Advertiser> advertise(Service service,
@@ -49,11 +48,10 @@
 }
 
 class _Scanner implements Scanner {
-  final Stream<Service> onFound;
-  final Stream<String> onLost;
+  final Stream<Update> onUpdate;
 
   final _StopFunction _stop;
-  _Scanner(this._stop, this.onFound, this.onLost) {}
+  _Scanner(this._stop, this.onUpdate) {}
 
   Future stop() {
     return _stop();
@@ -70,16 +68,11 @@
 }
 
 class _ScanHandler extends ScanHandler {
-  StreamController<Service> _onFound;
-  StreamController<String> _onLost;
+  StreamController<Update> _onUpdate;
 
-  _ScanHandler(this._onFound, this._onLost);
+  _ScanHandler(this._onUpdate);
 
-  found(Service s) {
-    _onFound.add(s);
-  }
-
-  lost(String instanceId) {
-    _onLost.add(instanceId);
+  update(Update update) {
+    _onUpdate.add(update);
   }
 }
diff --git a/lib/discovery.dart b/lib/discovery.dart
index eb40093..0e5a38c 100644
--- a/lib/discovery.dart
+++ b/lib/discovery.dart
@@ -8,7 +8,8 @@
 import 'package:mojo/bindings.dart' as bindings;
 import 'gen/dart-gen/mojom/lib/discovery/discovery.mojom.dart';
 
-export 'gen/dart-gen/mojom/lib/discovery/discovery.mojom.dart' show Service;
+export 'gen/dart-gen/mojom/lib/discovery/discovery.mojom.dart'
+    show Service, Update, UpdateType;
 
 part 'client_impl.dart';
 
@@ -27,7 +28,7 @@
   /// query and then stops scanning.
   ///
   ///    Scanner scanner = client.scan('v.InterfaceName = "v.io/i" AND v.Attrs["a"] = "v"');
-  ///    Service firstFoundService = await scanner.onFound.first;
+  ///    Service firstFoundService = await scanner.onUpdate.firstWhere((update) => update.updateType == UpdateTypes.found).service;
   ///    scanner.stop();
   ///
   /// The query is a WHERE expression of a syncQL query against advertised services, where
@@ -42,7 +43,7 @@
   /// An empty or null [visibility] means that there are no restrictions on visibility.
   /// Advertising will continue until [stop] is called on the [Advertiser] handle.
   ///
-  /// If service.InstanceId is not specified, a random unique identifier be
+  /// If service.InstanceId is not specified, a random unique identifier will be
   /// assigned to it. Any change to service will not be applied after advertising starts.
   ///
   /// It is an error to have simultaneously active advertisements for two identical
@@ -61,11 +62,8 @@
 
 /// Handle to a scan call.
 abstract class Scanner {
-  /// A stream of [Service] objects as they are discovered by the scanner.
-  Stream<Service> get onFound;
-
-  /// A stream of instanceIds for services that are no longer advertised.
-  Stream<String> get onLost;
+  /// A stream of [Update] objects as services are found or lost by the scanner.
+  Stream<Update> get onUpdate;
 
   /// Stops scanning.
   Future stop();
diff --git a/lib/gen/dart-gen/mojom/lib/discovery/discovery.mojom.dart b/lib/gen/dart-gen/mojom/lib/discovery/discovery.mojom.dart
index 3d27cd9..81d0426 100644
--- a/lib/gen/dart-gen/mojom/lib/discovery/discovery.mojom.dart
+++ b/lib/gen/dart-gen/mojom/lib/discovery/discovery.mojom.dart
@@ -8,6 +8,55 @@
 
 import 'package:mojo/bindings.dart' as bindings;
 import 'package:mojo/core.dart' as core;
+class UpdateType extends bindings.MojoEnum {
+  static const found = const UpdateType._(1);
+  static const lost = const UpdateType._(2);
+
+  const UpdateType._(int v) : super(v);
+
+  static const Map<String, UpdateType> valuesMap = const {
+    "found": found,
+    "lost": lost,
+  };
+  static const List<UpdateType> values = const [
+    found,
+    lost,
+  ];
+
+  static UpdateType valueOf(String name) => valuesMap[name];
+
+  factory UpdateType(int v) {
+    switch (v) {
+      case 1:
+        return found;
+      case 2:
+        return lost;
+      default:
+        return null;
+    }
+  }
+
+  static UpdateType decode(bindings.Decoder decoder0, int offset) {
+    int v = decoder0.decodeUint32(offset);
+    UpdateType result = new UpdateType(v);
+    if (result == null) {
+      throw new bindings.MojoCodecError(
+          'Bad value $v for enum UpdateType.');
+    }
+    return result;
+  }
+
+  String toString() {
+    switch(this) {
+      case found:
+        return 'UpdateType.found';
+      case lost:
+        return 'UpdateType.lost';
+    }
+  }
+
+  int toJson() => value;
+}
 
 
 
@@ -186,6 +235,87 @@
 }
 
 
+class Update extends bindings.Struct {
+  static const List<bindings.StructDataHeader> kVersions = const [
+    const bindings.StructDataHeader(24, 0)
+  ];
+  Service service = null;
+  UpdateType updateType = null;
+
+  Update() : super(kVersions.last.size);
+
+  static Update deserialize(bindings.Message message) {
+    var decoder = new bindings.Decoder(message);
+    var result = decode(decoder);
+    if (decoder.excessHandles != null) {
+      decoder.excessHandles.forEach((h) => h.close());
+    }
+    return result;
+  }
+
+  static Update decode(bindings.Decoder decoder0) {
+    if (decoder0 == null) {
+      return null;
+    }
+    Update result = new Update();
+
+    var mainDataHeader = decoder0.decodeStructDataHeader();
+    if (mainDataHeader.version <= kVersions.last.version) {
+      // Scan in reverse order to optimize for more recent versions.
+      for (int i = kVersions.length - 1; i >= 0; --i) {
+        if (mainDataHeader.version >= kVersions[i].version) {
+          if (mainDataHeader.size == kVersions[i].size) {
+            // Found a match.
+            break;
+          }
+          throw new bindings.MojoCodecError(
+              'Header size doesn\'t correspond to known version size.');
+        }
+      }
+    } else if (mainDataHeader.size < kVersions.last.size) {
+      throw new bindings.MojoCodecError(
+        'Message newer than the last known version cannot be shorter than '
+        'required by the last known version.');
+    }
+    if (mainDataHeader.version >= 0) {
+      
+      var decoder1 = decoder0.decodePointer(8, false);
+      result.service = Service.decode(decoder1);
+    }
+    if (mainDataHeader.version >= 0) {
+      
+        result.updateType = UpdateType.decode(decoder0, 16);
+        if (result.updateType == null) {
+          throw new bindings.MojoCodecError(
+            'Trying to decode null union for non-nullable UpdateType.');
+        }
+    }
+    return result;
+  }
+
+  void encode(bindings.Encoder encoder) {
+    var encoder0 = encoder.getStructEncoderAtOffset(kVersions.last);
+    
+    encoder0.encodeStruct(service, 8, false);
+    
+    encoder0.encodeEnum(updateType, 16);
+  }
+
+  String toString() {
+    return "Update("
+           "service: $service" ", "
+           "updateType: $updateType" ")";
+  }
+
+  Map toJson() {
+    Map map = new Map();
+    map["service"] = service;
+    map["updateType"] = updateType;
+    return map;
+  }
+}
+
+
 class Error extends bindings.Struct {
   static const List<bindings.StructDataHeader> kVersions = const [
     const bindings.StructDataHeader(32, 0)
@@ -873,15 +1003,15 @@
 }
 
 
-class ScanHandlerFoundParams extends bindings.Struct {
+class ScanHandlerUpdateParams extends bindings.Struct {
   static const List<bindings.StructDataHeader> kVersions = const [
     const bindings.StructDataHeader(16, 0)
   ];
-  Service service = null;
+  Update update = null;
 
-  ScanHandlerFoundParams() : super(kVersions.last.size);
+  ScanHandlerUpdateParams() : super(kVersions.last.size);
 
-  static ScanHandlerFoundParams deserialize(bindings.Message message) {
+  static ScanHandlerUpdateParams deserialize(bindings.Message message) {
     var decoder = new bindings.Decoder(message);
     var result = decode(decoder);
     if (decoder.excessHandles != null) {
@@ -890,11 +1020,11 @@
     return result;
   }
 
-  static ScanHandlerFoundParams decode(bindings.Decoder decoder0) {
+  static ScanHandlerUpdateParams decode(bindings.Decoder decoder0) {
     if (decoder0 == null) {
       return null;
     }
-    ScanHandlerFoundParams result = new ScanHandlerFoundParams();
+    ScanHandlerUpdateParams result = new ScanHandlerUpdateParams();
 
     var mainDataHeader = decoder0.decodeStructDataHeader();
     if (mainDataHeader.version <= kVersions.last.version) {
@@ -917,7 +1047,7 @@
     if (mainDataHeader.version >= 0) {
       
       var decoder1 = decoder0.decodePointer(8, false);
-      result.service = Service.decode(decoder1);
+      result.update = Update.decode(decoder1);
     }
     return result;
   }
@@ -925,84 +1055,17 @@
   void encode(bindings.Encoder encoder) {
     var encoder0 = encoder.getStructEncoderAtOffset(kVersions.last);
     
-    encoder0.encodeStruct(service, 8, false);
+    encoder0.encodeStruct(update, 8, false);
   }
 
   String toString() {
-    return "ScanHandlerFoundParams("
-           "service: $service" ")";
+    return "ScanHandlerUpdateParams("
+           "update: $update" ")";
   }
 
   Map toJson() {
     Map map = new Map();
-    map["service"] = service;
-    return map;
-  }
-}
-
-
-class ScanHandlerLostParams extends bindings.Struct {
-  static const List<bindings.StructDataHeader> kVersions = const [
-    const bindings.StructDataHeader(16, 0)
-  ];
-  String instanceId = null;
-
-  ScanHandlerLostParams() : super(kVersions.last.size);
-
-  static ScanHandlerLostParams deserialize(bindings.Message message) {
-    var decoder = new bindings.Decoder(message);
-    var result = decode(decoder);
-    if (decoder.excessHandles != null) {
-      decoder.excessHandles.forEach((h) => h.close());
-    }
-    return result;
-  }
-
-  static ScanHandlerLostParams decode(bindings.Decoder decoder0) {
-    if (decoder0 == null) {
-      return null;
-    }
-    ScanHandlerLostParams result = new ScanHandlerLostParams();
-
-    var mainDataHeader = decoder0.decodeStructDataHeader();
-    if (mainDataHeader.version <= kVersions.last.version) {
-      // Scan in reverse order to optimize for more recent versions.
-      for (int i = kVersions.length - 1; i >= 0; --i) {
-        if (mainDataHeader.version >= kVersions[i].version) {
-          if (mainDataHeader.size == kVersions[i].size) {
-            // Found a match.
-            break;
-          }
-          throw new bindings.MojoCodecError(
-              'Header size doesn\'t correspond to known version size.');
-        }
-      }
-    } else if (mainDataHeader.size < kVersions.last.size) {
-      throw new bindings.MojoCodecError(
-        'Message newer than the last known version cannot be shorter than '
-        'required by the last known version.');
-    }
-    if (mainDataHeader.version >= 0) {
-      
-      result.instanceId = decoder0.decodeString(8, false);
-    }
-    return result;
-  }
-
-  void encode(bindings.Encoder encoder) {
-    var encoder0 = encoder.getStructEncoderAtOffset(kVersions.last);
-    
-    encoder0.encodeString(instanceId, 8, false);
-  }
-
-  String toString() {
-    return "ScanHandlerLostParams("
-           "instanceId: $instanceId" ")";
-  }
-
-  Map toJson() {
-    Map map = new Map();
-    map["instanceId"] = instanceId;
+    map["update"] = update;
     return map;
   }
 }
@@ -1556,13 +1619,11 @@
   int get version => 0;
 }
 
-const int kScanHandler_found_name = 0;
-const int kScanHandler_lost_name = 1;
+const int kScanHandler_update_name = 0;
 const String ScanHandlerName = "v23::discovery::ScanHandler";
 
 abstract class ScanHandler {
-  void found(Service service);
-  void lost(String instanceId);
+  void update(Update update);
 
 }
 
@@ -1604,24 +1665,14 @@
   ScanHandlerProxyImpl _proxyImpl;
 
   _ScanHandlerProxyCalls(this._proxyImpl);
-    void found(Service service) {
+    void update(Update update) {
       if (!_proxyImpl.isBound) {
         _proxyImpl.proxyError("The Proxy is closed.");
         return;
       }
-      var params = new ScanHandlerFoundParams();
-      params.service = service;
-      _proxyImpl.sendMessage(params, kScanHandler_found_name);
-    }
-  
-    void lost(String instanceId) {
-      if (!_proxyImpl.isBound) {
-        _proxyImpl.proxyError("The Proxy is closed.");
-        return;
-      }
-      var params = new ScanHandlerLostParams();
-      params.instanceId = instanceId;
-      _proxyImpl.sendMessage(params, kScanHandler_lost_name);
+      var params = new ScanHandlerUpdateParams();
+      params.update = update;
+      _proxyImpl.sendMessage(params, kScanHandler_update_name);
     }
   
 }
@@ -1715,15 +1766,10 @@
     }
     assert(_impl != null);
     switch (message.header.type) {
-      case kScanHandler_found_name:
-        var params = ScanHandlerFoundParams.deserialize(
+      case kScanHandler_update_name:
+        var params = ScanHandlerUpdateParams.deserialize(
             message.payload);
-        _impl.found(params.service);
-        break;
-      case kScanHandler_lost_name:
-        var params = ScanHandlerLostParams.deserialize(
-            message.payload);
-        _impl.lost(params.instanceId);
+        _impl.update(params.update);
         break;
       default:
         throw new bindings.MojoCodecError("Unexpected message name");
diff --git a/mojom/vanadium/discovery.mojom b/mojom/vanadium/discovery.mojom
index 7a716fb..d638974 100644
--- a/mojom/vanadium/discovery.mojom
+++ b/mojom/vanadium/discovery.mojom
@@ -23,6 +23,16 @@
   array<string> Addrs;
 };
 
+enum UpdateType {
+	  found = 1,
+	  lost,
+};
+
+struct Update {
+  Service service;
+  UpdateType update_type;
+};
+
 struct Error {
   string id;
   int32 action;
@@ -71,9 +81,6 @@
 // the scan.
 [ServiceName="v23::discovery::ScanHandler"]
 interface ScanHandler {
-  // Found will be called when a Service is found.
-  Found(Service service);
-
-  // Lost will be called when a service is lost.
-  Lost(string instanceId);
+  // Update will be called when a Service is found or lost.
+  Update(Update update);
 };
diff --git a/pubspec.yaml b/pubspec.yaml
index 079085f..726e4a4 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -2,7 +2,7 @@
 description: Discovery is a discovery system for developers that makes it easy to advertise apps and scan for them. It works over MDNS and BLE.
 homepage: https://github.com/vanadium/mojo.discovery
 name: v23discovery
-version: 0.0.10
+version: 0.0.11
 dependencies:
   mojo_sdk: 0.2.7
 dev_dependencies: