More sane next batch handling, typing notification tweaks, give invites their own stream position, device list fix (#1641)

* Update sync responses

* Fix positions, add ApplyUpdates

* Fix MarshalText as non-pointer, PrevBatch is optional

* Increment by number of read receipts

* Merge branch 'master' into neilalexander/devicelist

* Tweak typing

* Include keyserver position tweak

* Fix typing next position in all cases

* Tweaks

* Fix typo

* Tweaks, restore StreamingToken.MarshalText which somehow went missing?

* Rely on positions from notifier rather than manually advancing them

* Revert "Rely on positions from notifier rather than manually advancing them"

This reverts commit 53112a62cc3bfd9989acab518e69eeb27938117a.

* Give invites their own position, fix other things

* Fix test

* Fix invites maybe

* Un-whitelist tests that look to be genuinely wrong

* Use real receipt positions

* Ensure send-to-device uses real positions too

22 files changed, 227 insertions, 151 deletions

diff --git a/keyserver/storage/postgres/key_changes_table.go b/keyserver/storage/postgres/key_changes_table.go
index d7f0991a..df4b47e7 100644
--- a/keyserver/storage/postgres/key_changes_table.go
+++ b/keyserver/storage/postgres/key_changes_table.go
@@ -82,6 +82,7 @@ func (s *keyChangesStatements) SelectKeyChanges(
 	if toOffset == sarama.OffsetNewest {
 		toOffset = math.MaxInt64
 	}
+	latestOffset = fromOffset
 	rows, err := s.selectKeyChangesStmt.QueryContext(ctx, partition, fromOffset, toOffset)
 	if err != nil {
 		return nil, 0, err
diff --git a/keyserver/storage/sqlite3/key_changes_table.go b/keyserver/storage/sqlite3/key_changes_table.go
index 32721eae..b4753ccc 100644
--- a/keyserver/storage/sqlite3/key_changes_table.go
+++ b/keyserver/storage/sqlite3/key_changes_table.go
@@ -83,6 +83,7 @@ func (s *keyChangesStatements) SelectKeyChanges(
 	if toOffset == sarama.OffsetNewest {
 		toOffset = math.MaxInt64
 	}
+	latestOffset = fromOffset
 	rows, err := s.selectKeyChangesStmt.QueryContext(ctx, partition, fromOffset, toOffset)
 	if err != nil {
 		return nil, 0, err
diff --git a/syncapi/consumers/eduserver_receipts.go b/syncapi/consumers/eduserver_receipts.go
index 5c286cf0..88334b65 100644
--- a/syncapi/consumers/eduserver_receipts.go
+++ b/syncapi/consumers/eduserver_receipts.go
@@ -88,7 +88,7 @@ func (s *OutputReceiptEventConsumer) onMessage(msg *sarama.ConsumerMessage) erro
 		return err
 	}
 	// update stream position
-	s.notifier.OnNewReceipt(types.StreamingToken{ReceiptPosition: streamPos})
+	s.notifier.OnNewReceipt(output.RoomID, types.StreamingToken{ReceiptPosition: streamPos})
 
 	return nil
 }
diff --git a/syncapi/consumers/eduserver_sendtodevice.go b/syncapi/consumers/eduserver_sendtodevice.go
index 0c3f52cd..a375baf8 100644
--- a/syncapi/consumers/eduserver_sendtodevice.go
+++ b/syncapi/consumers/eduserver_sendtodevice.go
@@ -94,10 +94,8 @@ func (s *OutputSendToDeviceEventConsumer) onMessage(msg *sarama.ConsumerMessage)
 		"event_type": output.Type,
 	}).Info("sync API received send-to-device event from EDU server")
 
-	streamPos := s.db.AddSendToDevice()
-
-	_, err = s.db.StoreNewSendForDeviceMessage(
-		context.TODO(), streamPos, output.UserID, output.DeviceID, output.SendToDeviceEvent,
+	streamPos, err := s.db.StoreNewSendForDeviceMessage(
+		context.TODO(), output.UserID, output.DeviceID, output.SendToDeviceEvent,
 	)
 	if err != nil {
 		log.WithError(err).Errorf("failed to store send-to-device message")
diff --git a/syncapi/consumers/eduserver_typing.go b/syncapi/consumers/eduserver_typing.go
index 885e7fd1..28574b50 100644
--- a/syncapi/consumers/eduserver_typing.go
+++ b/syncapi/consumers/eduserver_typing.go
@@ -64,12 +64,7 @@ func NewOutputTypingEventConsumer(
 // Start consuming from EDU api
 func (s *OutputTypingEventConsumer) Start() error {
 	s.db.SetTypingTimeoutCallback(func(userID, roomID string, latestSyncPosition int64) {
-		s.notifier.OnNewEvent(
-			nil, roomID, nil,
-			types.StreamingToken{
-				TypingPosition: types.StreamPosition(latestSyncPosition),
-			},
-		)
+		s.notifier.OnNewTyping(roomID, types.StreamingToken{TypingPosition: types.StreamPosition(latestSyncPosition)})
 	})
 
 	return s.typingConsumer.Start()
@@ -97,6 +92,6 @@ func (s *OutputTypingEventConsumer) onMessage(msg *sarama.ConsumerMessage) error
 		typingPos = s.db.RemoveTypingUser(typingEvent.UserID, typingEvent.RoomID)
 	}
 
-	s.notifier.OnNewEvent(nil, output.Event.RoomID, nil, types.StreamingToken{TypingPosition: typingPos})
+	s.notifier.OnNewTyping(output.Event.RoomID, types.StreamingToken{TypingPosition: typingPos})
 	return nil
 }
diff --git a/syncapi/consumers/roomserver.go b/syncapi/consumers/roomserver.go
index be84a281..3b1f1582 100644
--- a/syncapi/consumers/roomserver.go
+++ b/syncapi/consumers/roomserver.go
@@ -259,6 +259,12 @@ func (s *OutputRoomEventConsumer) notifyJoinedPeeks(ctx context.Context, ev *gom
 func (s *OutputRoomEventConsumer) onNewInviteEvent(
 	ctx context.Context, msg api.OutputNewInviteEvent,
 ) error {
+	if msg.Event.StateKey() == nil {
+		log.WithFields(log.Fields{
+			"event": string(msg.Event.JSON()),
+		}).Panicf("roomserver output log: invite has no state key")
+		return nil
+	}
 	pduPos, err := s.db.AddInviteEvent(ctx, msg.Event)
 	if err != nil {
 		// panic rather than continue with an inconsistent database
@@ -269,14 +275,14 @@ func (s *OutputRoomEventConsumer) onNewInviteEvent(
 		}).Panicf("roomserver output log: write invite failure")
 		return nil
 	}
-	s.notifier.OnNewEvent(msg.Event, "", nil, types.StreamingToken{PDUPosition: pduPos})
+	s.notifier.OnNewInvite(types.StreamingToken{InvitePosition: pduPos}, *msg.Event.StateKey())
 	return nil
 }
 
 func (s *OutputRoomEventConsumer) onRetireInviteEvent(
 	ctx context.Context, msg api.OutputRetireInviteEvent,
 ) error {
-	sp, err := s.db.RetireInviteEvent(ctx, msg.EventID)
+	pduPos, err := s.db.RetireInviteEvent(ctx, msg.EventID)
 	if err != nil {
 		// panic rather than continue with an inconsistent database
 		log.WithFields(log.Fields{
@@ -287,7 +293,7 @@ func (s *OutputRoomEventConsumer) onRetireInviteEvent(
 	}
 	// Notify any active sync requests that the invite has been retired.
 	// Invites share the same stream counter as PDUs
-	s.notifier.OnNewEvent(nil, "", []string{msg.TargetUserID}, types.StreamingToken{PDUPosition: sp})
+	s.notifier.OnNewInvite(types.StreamingToken{InvitePosition: pduPos}, msg.TargetUserID)
 	return nil
 }
 
diff --git a/syncapi/internal/keychange.go b/syncapi/internal/keychange.go
index 6af48a9c..3f901f49 100644
--- a/syncapi/internal/keychange.go
+++ b/syncapi/internal/keychange.go
@@ -132,7 +132,7 @@ func DeviceListCatchup(
 		Partition: queryRes.Partition,
 		Offset:    queryRes.Offset,
 	}
-	res.NextBatch = to.String()
+	res.NextBatch.ApplyUpdates(to)
 
 	return hasNew, nil
 }
diff --git a/syncapi/storage/interface.go b/syncapi/storage/interface.go
index 456ca1b1..9ab6f915 100644
--- a/syncapi/storage/interface.go
+++ b/syncapi/storage/interface.go
@@ -130,9 +130,9 @@ type Database interface {
 	//      can be deleted altogether by CleanSendToDeviceUpdates
 	// The token supplied should be the current requested sync token, e.g. from the "since"
 	// parameter.
-	SendToDeviceUpdatesForSync(ctx context.Context, userID, deviceID string, token types.StreamingToken) (events []types.SendToDeviceEvent, changes []types.SendToDeviceNID, deletions []types.SendToDeviceNID, err error)
+	SendToDeviceUpdatesForSync(ctx context.Context, userID, deviceID string, token types.StreamingToken) (pos types.StreamPosition, events []types.SendToDeviceEvent, changes []types.SendToDeviceNID, deletions []types.SendToDeviceNID, err error)
 	// StoreNewSendForDeviceMessage stores a new send-to-device event for a user's device.
-	StoreNewSendForDeviceMessage(ctx context.Context, streamPos types.StreamPosition, userID, deviceID string, event gomatrixserverlib.SendToDeviceEvent) (types.StreamPosition, error)
+	StoreNewSendForDeviceMessage(ctx context.Context, userID, deviceID string, event gomatrixserverlib.SendToDeviceEvent) (types.StreamPosition, error)
 	// CleanSendToDeviceUpdates will update or remove any send-to-device updates based on the
 	// result to a previous call to SendDeviceUpdatesForSync. This is separate as it allows
 	// SendToDeviceUpdatesForSync to be called multiple times if needed (e.g. before and after
diff --git a/syncapi/storage/postgres/receipt_table.go b/syncapi/storage/postgres/receipt_table.go
index 23c66910..73bf4179 100644
--- a/syncapi/storage/postgres/receipt_table.go
+++ b/syncapi/storage/postgres/receipt_table.go
@@ -55,7 +55,7 @@ const upsertReceipt = "" +
 	" RETURNING id"
 
 const selectRoomReceipts = "" +
-	"SELECT room_id, receipt_type, user_id, event_id, receipt_ts" +
+	"SELECT id, room_id, receipt_type, user_id, event_id, receipt_ts" +
 	" FROM syncapi_receipts" +
 	" WHERE room_id = ANY($1) AND id > $2"
 
@@ -95,22 +95,27 @@ func (r *receiptStatements) UpsertReceipt(ctx context.Context, txn *sql.Tx, room
 	return
 }
 
-func (r *receiptStatements) SelectRoomReceiptsAfter(ctx context.Context, roomIDs []string, streamPos types.StreamPosition) ([]api.OutputReceiptEvent, error) {
+func (r *receiptStatements) SelectRoomReceiptsAfter(ctx context.Context, roomIDs []string, streamPos types.StreamPosition) (types.StreamPosition, []api.OutputReceiptEvent, error) {
+	lastPos := types.StreamPosition(0)
 	rows, err := r.selectRoomReceipts.QueryContext(ctx, pq.Array(roomIDs), streamPos)
 	if err != nil {
-		return nil, fmt.Errorf("unable to query room receipts: %w", err)
+		return 0, nil, fmt.Errorf("unable to query room receipts: %w", err)
 	}
 	defer internal.CloseAndLogIfError(ctx, rows, "SelectRoomReceiptsAfter: rows.close() failed")
 	var res []api.OutputReceiptEvent
 	for rows.Next() {
 		r := api.OutputReceiptEvent{}
-		err = rows.Scan(&r.RoomID, &r.Type, &r.UserID, &r.EventID, &r.Timestamp)
+		var id types.StreamPosition
+		err = rows.Scan(&id, &r.RoomID, &r.Type, &r.UserID, &r.EventID, &r.Timestamp)
 		if err != nil {
-			return res, fmt.Errorf("unable to scan row to api.Receipts: %w", err)
+			return 0, res, fmt.Errorf("unable to scan row to api.Receipts: %w", err)
 		}
 		res = append(res, r)
+		if id > lastPos {
+			lastPos = id
+		}
 	}
-	return res, rows.Err()
+	return lastPos, res, rows.Err()
 }
 
 func (s *receiptStatements) SelectMaxReceiptID(
diff --git a/syncapi/storage/postgres/send_to_device_table.go b/syncapi/storage/postgres/send_to_device_table.go
index be9c347b..ac60989c 100644
--- a/syncapi/storage/postgres/send_to_device_table.go
+++ b/syncapi/storage/postgres/send_to_device_table.go
@@ -49,6 +49,7 @@ CREATE TABLE IF NOT EXISTS syncapi_send_to_device (
 const insertSendToDeviceMessageSQL = `
 	INSERT INTO syncapi_send_to_device (user_id, device_id, content)
 	  VALUES ($1, $2, $3)
+	  RETURNING id
 `
 
 const countSendToDeviceMessagesSQL = `
@@ -107,8 +108,8 @@ func NewPostgresSendToDeviceTable(db *sql.DB) (tables.SendToDevice, error) {
 
 func (s *sendToDeviceStatements) InsertSendToDeviceMessage(
 	ctx context.Context, txn *sql.Tx, userID, deviceID, content string,
-) (err error) {
-	_, err = sqlutil.TxStmt(txn, s.insertSendToDeviceMessageStmt).ExecContext(ctx, userID, deviceID, content)
+) (pos types.StreamPosition, err error) {
+	err = sqlutil.TxStmt(txn, s.insertSendToDeviceMessageStmt).QueryRowContext(ctx, userID, deviceID, content).Scan(&pos)
 	return
 }
 
@@ -124,7 +125,7 @@ func (s *sendToDeviceStatements) CountSendToDeviceMessages(
 
 func (s *sendToDeviceStatements) SelectSendToDeviceMessages(
 	ctx context.Context, txn *sql.Tx, userID, deviceID string,
-) (events []types.SendToDeviceEvent, err error) {
+) (lastPos types.StreamPosition, events []types.SendToDeviceEvent, err error) {
 	rows, err := sqlutil.TxStmt(txn, s.selectSendToDeviceMessagesStmt).QueryContext(ctx, userID, deviceID)
 	if err != nil {
 		return
@@ -152,9 +153,12 @@ func (s *sendToDeviceStatements) SelectSendToDeviceMessages(
 			}
 		}
 		events = append(events, event)
+		if types.StreamPosition(id) > lastPos {
+			lastPos = types.StreamPosition(id)
+		}
 	}
 
-	return events, rows.Err()
+	return lastPos, events, rows.Err()
 }
 
 func (s *sendToDeviceStatements) UpdateSentSendToDeviceMessages(
diff --git a/syncapi/storage/shared/syncserver.go b/syncapi/storage/shared/syncserver.go
index 71a42003..128aaa5b 100644
--- a/syncapi/storage/shared/syncserver.go
+++ b/syncapi/storage/shared/syncserver.go
@@ -492,6 +492,7 @@ func (d *Database) syncPositionTx(
 		PDUPosition:     types.StreamPosition(maxEventID),
 		TypingPosition:  types.StreamPosition(d.EDUCache.GetLatestSyncPosition()),
 		ReceiptPosition: types.StreamPosition(maxReceiptID),
+		InvitePosition:  types.StreamPosition(maxInviteID),
 	}
 	return
 }
@@ -543,11 +544,6 @@ func (d *Database) addPDUDeltaToResponse(
 		}
 	}
 
-	// TODO: This should be done in getStateDeltas
-	if err = d.addInvitesToResponse(ctx, txn, device.UserID, r, res); err != nil {
-		return nil, fmt.Errorf("d.addInvitesToResponse: %w", err)
-	}
-
 	succeeded = true
 	return joinedRoomIDs, nil
 }
@@ -583,6 +579,7 @@ func (d *Database) addTypingDeltaToResponse(
 			res.Rooms.Join[roomID] = jr
 		}
 	}
+	res.NextBatch.TypingPosition = types.StreamPosition(d.EDUCache.GetLatestSyncPosition())
 	return nil
 }
 
@@ -593,7 +590,7 @@ func (d *Database) addReceiptDeltaToResponse(
 	joinedRoomIDs []string,
 	res *types.Response,
 ) error {
-	receipts, err := d.Receipts.SelectRoomReceiptsAfter(context.TODO(), joinedRoomIDs, since.ReceiptPosition)
+	lastPos, receipts, err := d.Receipts.SelectRoomReceiptsAfter(context.TODO(), joinedRoomIDs, since.ReceiptPosition)
 	if err != nil {
 		return fmt.Errorf("unable to select receipts for rooms: %w", err)
 	}
@@ -638,6 +635,7 @@ func (d *Database) addReceiptDeltaToResponse(
 		res.Rooms.Join[roomID] = jr
 	}
 
+	res.NextBatch.ReceiptPosition = lastPos
 	return nil
 }
 
@@ -691,8 +689,7 @@ func (d *Database) IncrementalSync(
 	numRecentEventsPerRoom int,
 	wantFullState bool,
 ) (*types.Response, error) {
-	nextBatchPos := fromPos.WithUpdates(toPos)
-	res.NextBatch = nextBatchPos.String()
+	res.NextBatch = fromPos.WithUpdates(toPos)
 
 	var joinedRoomIDs []string
 	var err error
@@ -725,6 +722,14 @@ func (d *Database) IncrementalSync(
 		return nil, fmt.Errorf("d.addEDUDeltaToResponse: %w", err)
 	}
 
+	ir := types.Range{
+		From: fromPos.InvitePosition,
+		To:   toPos.InvitePosition,
+	}
+	if err = d.addInvitesToResponse(ctx, nil, device.UserID, ir, res); err != nil {
+		return nil, fmt.Errorf("d.addInvitesToResponse: %w", err)
+	}
+
 	return res, nil
 }
 
@@ -783,8 +788,12 @@ func (d *Database) getResponseWithPDUsForCompleteSync(
 		From: 0,
 		To:   toPos.PDUPosition,
 	}
+	ir := types.Range{
+		From: 0,
+		To:   toPos.InvitePosition,
+	}
 
-	res.NextBatch = toPos.String()
+	res.NextBatch.ApplyUpdates(toPos)
 
 	// Extract room state and recent events for all rooms the user is joined to.
 	joinedRoomIDs, err = d.CurrentRoomState.SelectRoomIDsWithMembership(ctx, txn, userID, gomatrixserverlib.Join)
@@ -824,7 +833,7 @@ func (d *Database) getResponseWithPDUsForCompleteSync(
 		}
 	}
 
-	if err = d.addInvitesToResponse(ctx, txn, userID, r, res); err != nil {
+	if err = d.addInvitesToResponse(ctx, txn, userID, ir, res); err != nil {
 		return
 	}
 
@@ -884,19 +893,18 @@ func (d *Database) getJoinResponseForCompleteSync(
 
 	// Retrieve the backward topology position, i.e. the position of the
 	// oldest event in the room's topology.
-	var prevBatchStr string
+	var prevBatch *types.TopologyToken
 	if len(recentStreamEvents) > 0 {
 		var backwardTopologyPos, backwardStreamPos types.StreamPosition
 		backwardTopologyPos, backwardStreamPos, err = d.Topology.SelectPositionInTopology(ctx, txn, recentStreamEvents[0].EventID())
 		if err != nil {
 			return
 		}
-		prevBatch := types.TopologyToken{
+		prevBatch = &types.TopologyToken{
 			Depth:       backwardTopologyPos,
 			PDUPosition: backwardStreamPos,
 		}
 		prevBatch.Decrement()
-		prevBatchStr = prevBatch.String()
 	}
 
 	// We don't include a device here as we don't need to send down
@@ -905,7 +913,7 @@ func (d *Database) getJoinResponseForCompleteSync(
 	recentEvents := d.StreamEventsToEvents(&device, recentStreamEvents)
 	stateEvents = removeDuplicates(stateEvents, recentEvents)
 	jr = types.NewJoinResponse()
-	jr.Timeline.PrevBatch = prevBatchStr
+	jr.Timeline.PrevBatch = prevBatch
 	jr.Timeline.Events = gomatrixserverlib.HeaderedToClientEvents(recentEvents, gomatrixserverlib.FormatSync)
 	jr.Timeline.Limited = limited
 	jr.State.Events = gomatrixserverlib.HeaderedToClientEvents(stateEvents, gomatrixserverlib.FormatSync)
@@ -1033,7 +1041,7 @@ func (d *Database) addRoomDeltaToResponse(
 	case gomatrixserverlib.Join:
 		jr := types.NewJoinResponse()
 
-		jr.Timeline.PrevBatch = prevBatch.String()
+		jr.Timeline.PrevBatch = &prevBatch
 		jr.Timeline.Events = gomatrixserverlib.HeaderedToClientEvents(recentEvents, gomatrixserverlib.FormatSync)
 		jr.Timeline.Limited = limited
 		jr.State.Events = gomatrixserverlib.HeaderedToClientEvents(delta.stateEvents, gomatrixserverlib.FormatSync)
@@ -1041,7 +1049,7 @@ func (d *Database) addRoomDeltaToResponse(
 	case gomatrixserverlib.Peek:
 		jr := types.NewJoinResponse()
 
-		jr.Timeline.PrevBatch = prevBatch.String()
+		jr.Timeline.PrevBatch = &prevBatch
 		jr.Timeline.Events = gomatrixserverlib.HeaderedToClientEvents(recentEvents, gomatrixserverlib.FormatSync)
 		jr.Timeline.Limited = limited
 		jr.State.Events = gomatrixserverlib.HeaderedToClientEvents(delta.stateEvents, gomatrixserverlib.FormatSync)
@@ -1052,7 +1060,7 @@ func (d *Database) addRoomDeltaToResponse(
 		// TODO: recentEvents may contain events that this user is not allowed to see because they are
 		//       no longer in the room.
 		lr := types.NewLeaveResponse()
-		lr.Timeline.PrevBatch = prevBatch.String()
+		lr.Timeline.PrevBatch = &prevBatch
 		lr.Timeline.Events = gomatrixserverlib.HeaderedToClientEvents(recentEvents, gomatrixserverlib.FormatSync)
 		lr.Timeline.Limited = false // TODO: if len(events) >= numRecents + 1 and then set limited:true
 		lr.State.Events = gomatrixserverlib.HeaderedToClientEvents(delta.stateEvents, gomatrixserverlib.FormatSync)
@@ -1373,39 +1381,40 @@ func (d *Database) SendToDeviceUpdatesWaiting(
 }
 
 func (d *Database) StoreNewSendForDeviceMessage(
-	ctx context.Context, streamPos types.StreamPosition, userID, deviceID string, event gomatrixserverlib.SendToDeviceEvent,
-) (types.StreamPosition, error) {
+	ctx context.Context, userID, deviceID string, event gomatrixserverlib.SendToDeviceEvent,
+) (newPos types.StreamPosition, err error) {
 	j, err := json.Marshal(event)
 	if err != nil {
-		return streamPos, err
+		return 0, err
 	}
 	// Delegate the database write task to the SendToDeviceWriter. It'll guarantee
 	// that we don't lock the table for writes in more than one place.
 	err = d.Writer.Do(d.DB, nil, func(txn *sql.Tx) error {
-		return d.SendToDevice.InsertSendToDeviceMessage(
+		newPos, err = d.SendToDevice.InsertSendToDeviceMessage(
 			ctx, txn, userID, deviceID, string(j),
 		)
+		return err
 	})
 	if err != nil {
-		return streamPos, err
+		return 0, err
 	}
-	return streamPos, nil
+	return 0, nil
 }
 
 func (d *Database) SendToDeviceUpdatesForSync(
 	ctx context.Context,
 	userID, deviceID string,
 	token types.StreamingToken,
-) ([]types.SendToDeviceEvent, []types.SendToDeviceNID, []types.SendToDeviceNID, error) {
+) (types.StreamPosition, []types.SendToDeviceEvent, []types.SendToDeviceNID, []types.SendToDeviceNID, error) {
 	// First of all, get our send-to-device updates for this user.
-	events, err := d.SendToDevice.SelectSendToDeviceMessages(ctx, nil, userID, deviceID)
+	lastPos, events, err := d.SendToDevice.SelectSendToDeviceMessages(ctx, nil, userID, deviceID)
 	if err != nil {
-		return nil, nil, nil, fmt.Errorf("d.SendToDevice.SelectSendToDeviceMessages: %w", err)
+		return 0, nil, nil, nil, fmt.Errorf("d.SendToDevice.SelectSendToDeviceMessages: %w", err)
 	}
 
 	// If there's nothing to do then stop here.
 	if len(events) == 0 {
-		return nil, nil, nil, nil
+		return 0, nil, nil, nil, nil
 	}
 
 	// Work out whether we need to update any of the database entries.
@@ -1432,7 +1441,7 @@ func (d *Database) SendToDeviceUpdatesForSync(
 		}
 	}
 
-	return toReturn, toUpdate, toDelete, nil
+	return lastPos, toReturn, toUpdate, toDelete, nil
 }
 
 func (d *Database) CleanSendToDeviceUpdates(
@@ -1519,5 +1528,6 @@ func (d *Database) StoreReceipt(ctx context.Context, roomId, receiptType, userId
 }
 
 func (d *Database) GetRoomReceipts(ctx context.Context, roomIDs []string, streamPos types.StreamPosition) ([]eduAPI.OutputReceiptEvent, error) {
-	return d.Receipts.SelectRoomReceiptsAfter(ctx, roomIDs, streamPos)
+	_, receipts, err := d.Receipts.SelectRoomReceiptsAfter(ctx, roomIDs, streamPos)
+	return receipts, err
 }
diff --git a/syncapi/storage/sqlite3/receipt_table.go b/syncapi/storage/sqlite3/receipt_table.go
index dfde1fd2..69fc4e9d 100644
--- a/syncapi/storage/sqlite3/receipt_table.go
+++ b/syncapi/storage/sqlite3/receipt_table.go
@@ -51,7 +51,7 @@ const upsertReceipt = "" +
 	" DO UPDATE SET id = $7, event_id = $8, receipt_ts = $9"
 
 const selectRoomReceipts = "" +
-	"SELECT room_id, receipt_type, user_id, event_id, receipt_ts" +
+	"SELECT id, room_id, receipt_type, user_id, event_id, receipt_ts" +
 	" FROM syncapi_receipts" +
 	" WHERE id > $1 and room_id in ($2)"
 
@@ -99,9 +99,9 @@ func (r *receiptStatements) UpsertReceipt(ctx context.Context, txn *sql.Tx, room
 }
 
 // SelectRoomReceiptsAfter select all receipts for a given room after a specific timestamp
-func (r *receiptStatements) SelectRoomReceiptsAfter(ctx context.Context, roomIDs []string, streamPos types.StreamPosition) ([]api.OutputReceiptEvent, error) {
+func (r *receiptStatements) SelectRoomReceiptsAfter(ctx context.Context, roomIDs []string, streamPos types.StreamPosition) (types.StreamPosition, []api.OutputReceiptEvent, error) {
 	selectSQL := strings.Replace(selectRoomReceipts, "($2)", sqlutil.QueryVariadicOffset(len(roomIDs), 1), 1)
-
+	lastPos := types.StreamPosition(0)
 	params := make([]interface{}, len(roomIDs)+1)
 	params[0] = streamPos
 	for k, v := range roomIDs {
@@ -109,19 +109,23 @@ func (r *receiptStatements) SelectRoomReceiptsAfter(ctx context.Context, roomIDs
 	}
 	rows, err := r.db.QueryContext(ctx, selectSQL, params...)
 	if err != nil {
-		return nil, fmt.Errorf("unable to query room receipts: %w", err)
+		return 0, nil, fmt.Errorf("unable to query room receipts: %w", err)
 	}
 	defer internal.CloseAndLogIfError(ctx, rows, "SelectRoomReceiptsAfter: rows.close() failed")
 	var res []api.OutputReceiptEvent
 	for rows.Next() {
 		r := api.OutputReceiptEvent{}
-		err = rows.Scan(&r.RoomID, &r.Type, &r.UserID, &r.EventID, &r.Timestamp)
+		var id types.StreamPosition
+		err = rows.Scan(&id, &r.RoomID, &r.Type, &r.UserID, &r.EventID, &r.Timestamp)
 		if err != nil {
-			return res, fmt.Errorf("unable to scan row to api.Receipts: %w", err)
+			return 0, res, fmt.Errorf("unable to scan row to api.Receipts: %w", err)
 		}
 		res = append(res, r)
+		if id > lastPos {
+			lastPos = id
+		}
 	}
-	return res, rows.Err()
+	return lastPos, res, rows.Err()
 }
 
 func (s *receiptStatements) SelectMaxReceiptID(
diff --git a/syncapi/storage/sqlite3/send_to_device_table.go b/syncapi/storage/sqlite3/send_to_device_table.go
index fbc759b1..e9dcb1bf 100644
--- a/syncapi/storage/sqlite3/send_to_device_table.go
+++ b/syncapi/storage/sqlite3/send_to_device_table.go
@@ -100,8 +100,14 @@ func NewSqliteSendToDeviceTable(db *sql.DB) (tables.SendToDevice, error) {
 
 func (s *sendToDeviceStatements) InsertSendToDeviceMessage(
 	ctx context.Context, txn *sql.Tx, userID, deviceID, content string,
-) (err error) {
-	_, err = sqlutil.TxStmt(txn, s.insertSendToDeviceMessageStmt).ExecContext(ctx, userID, deviceID, content)
+) (pos types.StreamPosition, err error) {
+	var result sql.Result
+	result, err = sqlutil.TxStmt(txn, s.insertSendToDeviceMessageStmt).ExecContext(ctx, userID, deviceID, content)
+	if p, err := result.LastInsertId(); err != nil {
+		return 0, err
+	} else {
+		pos = types.StreamPosition(p)
+	}
 	return
 }
 
@@ -117,7 +123,7 @@ func (s *sendToDeviceStatements) CountSendToDeviceMessages(
 
 func (s *sendToDeviceStatements) SelectSendToDeviceMessages(
 	ctx context.Context, txn *sql.Tx, userID, deviceID string,
-) (events []types.SendToDeviceEvent, err error) {
+) (lastPos types.StreamPosition, events []types.SendToDeviceEvent, err error) {
 	rows, err := sqlutil.TxStmt(txn, s.selectSendToDeviceMessagesStmt).QueryContext(ctx, userID, deviceID)
 	if err != nil {
 		return
@@ -145,9 +151,12 @@ func (s *sendToDeviceStatements) SelectSendToDeviceMessages(
 			}
 		}
 		events = append(events, event)
+		if types.StreamPosition(id) > lastPos {
+			lastPos = types.StreamPosition(id)
+		}
 	}
 
-	return events, rows.Err()
+	return lastPos, events, rows.Err()
 }
 
 func (s *sendToDeviceStatements) UpdateSentSendToDeviceMessages(
diff --git a/syncapi/storage/storage_test.go b/syncapi/storage/storage_test.go
index 8387543f..309a3a94 100644
--- a/syncapi/storage/storage_test.go
+++ b/syncapi/storage/storage_test.go
@@ -228,7 +228,7 @@ func TestSyncResponse(t *testing.T) {
 				ReceiptPosition:      latest.ReceiptPosition,
 				SendToDevicePosition: latest.SendToDevicePosition,
 			}
-			if res.NextBatch != next.String() {
+			if res.NextBatch.String() != next.String() {
 				st.Errorf("NextBatch got %s want %s", res.NextBatch, next.String())
 			}
 			roomRes, ok := res.Rooms.Join[testRoomID]
@@ -266,7 +266,7 @@ func TestGetEventsInRangeWithPrevBatch(t *testing.T) {
 	// returns the last event "Message 10"
 	assertEventsEqual(t, "IncrementalSync Timeline", false, roomRes.Timeline.Events, reversed(events[len(events)-1:]))
 
-	prev := roomRes.Timeline.PrevBatch
+	prev := roomRes.Timeline.PrevBatch.String()
 	if prev == "" {
 		t.Fatalf("IncrementalSync expected prev_batch token")
 	}
@@ -539,7 +539,7 @@ func TestSendToDeviceBehaviour(t *testing.T) {
 
 	// At this point there should be no messages. We haven't sent anything
 	// yet.
-	events, updates, deletions, err := db.SendToDeviceUpdatesForSync(ctx, "alice", "one", types.StreamingToken{})
+	_, events, updates, deletions, err := db.SendToDeviceUpdatesForSync(ctx, "alice", "one", types.StreamingToken{})
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -552,7 +552,7 @@ func TestSendToDeviceBehaviour(t *testing.T) {
 	}
 
 	// Try sending a message.
-	streamPos, err := db.StoreNewSendForDeviceMessage(ctx, types.StreamPosition(0), "alice", "one", gomatrixserverlib.SendToDeviceEvent{
+	streamPos, err := db.StoreNewSendForDeviceMessage(ctx, "alice", "one", gomatrixserverlib.SendToDeviceEvent{
 		Sender:  "bob",
 		Type:    "m.type",
 		Content: json.RawMessage("{}"),
@@ -564,7 +564,7 @@ func TestSendToDeviceBehaviour(t *testing.T) {
 	// At this point we should get exactly one message. We're sending the sync position
 	// that we were given from the update and the send-to-device update will be updated
 	// in the database to reflect that this was the sync position we sent the message at.
-	events, updates, deletions, err = db.SendToDeviceUpdatesForSync(ctx, "alice", "one", types.StreamingToken{SendToDevicePosition: streamPos})
+	_, events, updates, deletions, err = db.SendToDeviceUpdatesForSync(ctx, "alice", "one", types.StreamingToken{SendToDevicePosition: streamPos})
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -579,7 +579,7 @@ func TestSendToDeviceBehaviour(t *testing.T) {
 	// At this point we should still have one message because we haven't progressed the
 	// sync position yet. This is equivalent to the client failing to /sync and retrying
 	// with the same position.
-	events, updates, deletions, err = db.SendToDeviceUpdatesForSync(ctx, "alice", "one", types.StreamingToken{SendToDevicePosition: streamPos})
+	_, events, updates, deletions, err = db.SendToDeviceUpdatesForSync(ctx, "alice", "one", types.StreamingToken{SendToDevicePosition: streamPos})
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -593,7 +593,7 @@ func TestSendToDeviceBehaviour(t *testing.T) {
 
 	// At this point we should now have no updates, because we've progressed the sync
 	// position. Therefore the update from before will not be sent again.
-	events, updates, deletions, err = db.SendToDeviceUpdatesForSync(ctx, "alice", "one", types.StreamingToken{SendToDevicePosition: streamPos + 1})
+	_, events, updates, deletions, err = db.SendToDeviceUpdatesForSync(ctx, "alice", "one", types.StreamingToken{SendToDevicePosition: streamPos + 1})
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -607,7 +607,7 @@ func TestSendToDeviceBehaviour(t *testing.T) {
 
 	// At this point we should still have no updates, because no new updates have been
 	// sent.
-	events, updates, deletions, err = db.SendToDeviceUpdatesForSync(ctx, "alice", "one", types.StreamingToken{SendToDevicePosition: streamPos + 2})
+	_, events, updates, deletions, err = db.SendToDeviceUpdatesForSync(ctx, "alice", "one", types.StreamingToken{SendToDevicePosition: streamPos + 2})
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -666,12 +666,8 @@ func TestInviteBehaviour(t *testing.T) {
 	assertInvitedToRooms(t, res, []string{inviteRoom2})
 
 	// a sync after we have received both invites should result in a leave for the retired room
-	beforeRetireTok, err := types.NewStreamTokenFromString(beforeRetireRes.NextBatch)
-	if err != nil {
-		t.Fatalf("NewStreamTokenFromString cannot parse next batch '%s' : %s", beforeRetireRes.NextBatch, err)
-	}
 	res = types.NewResponse()
-	res, err = db.IncrementalSync(ctx, res, testUserDeviceA, beforeRetireTok, latest, 0, false)
+	res, err = db.IncrementalSync(ctx, res, testUserDeviceA, beforeRetireRes.NextBatch, latest, 0, false)
 	if err != nil {
 		t.Fatalf("IncrementalSync failed: %s", err)
 	}
diff --git a/syncapi/storage/tables/interface.go b/syncapi/storage/tables/interface.go
index 7a166d43..1e654da5 100644
--- a/syncapi/storage/tables/interface.go
+++ b/syncapi/storage/tables/interface.go
@@ -146,8 +146,8 @@ type BackwardsExtremities interface {
 // sync parameter isn't later then we will keep including the updates in the
 // sync response, as the client is seemingly trying to repeat the same /sync.
 type SendToDevice interface {
-	InsertSendToDeviceMessage(ctx context.Context, txn *sql.Tx, userID, deviceID, content string) (err error)
-	SelectSendToDeviceMessages(ctx context.Context, txn *sql.Tx, userID, deviceID string) (events []types.SendToDeviceEvent, err error)
+	InsertSendToDeviceMessage(ctx context.Context, txn *sql.Tx, userID, deviceID, content string) (pos types.StreamPosition, err error)
+	SelectSendToDeviceMessages(ctx context.Context, txn *sql.Tx, userID, deviceID string) (lastPos types.StreamPosition, events []types.SendToDeviceEvent, err error)
 	UpdateSentSendToDeviceMessages(ctx context.Context, txn *sql.Tx, token string, nids []types.SendToDeviceNID) (err error)
 	DeleteSendToDeviceMessages(ctx context.Context, txn *sql.Tx, nids []types.SendToDeviceNID) (err error)
 	CountSendToDeviceMessages(ctx context.Context, txn *sql.Tx, userID, deviceID string) (count int, err error)
@@ -160,6 +160,6 @@ type Filter interface {
 
 type Receipts interface {
 	UpsertReceipt(ctx context.Context, txn *sql.Tx, roomId, receiptType, userId, eventId string, timestamp gomatrixserverlib.Timestamp) (pos types.StreamPosition, err error)
-	SelectRoomReceiptsAfter(ctx context.Context, roomIDs []string, streamPos types.StreamPosition) ([]eduAPI.OutputReceiptEvent, error)
+	SelectRoomReceiptsAfter(ctx context.Context, roomIDs []string, streamPos types.StreamPosition) (types.StreamPosition, []eduAPI.OutputReceiptEvent, error)
 	SelectMaxReceiptID(ctx context.Context, txn *sql.Tx) (id int64, err error)
 }
diff --git a/syncapi/sync/notifier.go b/syncapi/sync/notifier.go
index 1d8cd624..66460a8d 100644
--- a/syncapi/sync/notifier.go
+++ b/syncapi/sync/notifier.go
@@ -77,9 +77,8 @@ func (n *Notifier) OnNewEvent(
 	// This needs to be done PRIOR to waking up users as they will read this value.
 	n.streamLock.Lock()
 	defer n.streamLock.Unlock()
-	latestPos := n.currPos.WithUpdates(posUpdate)
-	n.currPos = latestPos
 
+	n.currPos.ApplyUpdates(posUpdate)
 	n.removeEmptyUserStreams()
 
 	if ev != nil {
@@ -113,11 +112,11 @@ func (n *Notifier) OnNewEvent(
 			}
 		}
 
-		n.wakeupUsers(usersToNotify, peekingDevicesToNotify, latestPos)
+		n.wakeupUsers(usersToNotify, peekingDevicesToNotify, n.currPos)
 	} else if roomID != "" {
-		n.wakeupUsers(n.joinedUsers(roomID), n.PeekingDevices(roomID), latestPos)
+		n.wakeupUsers(n.joinedUsers(roomID), n.PeekingDevices(roomID), n.currPos)
 	} else if len(userIDs) > 0 {
-		n.wakeupUsers(userIDs, nil, latestPos)
+		n.wakeupUsers(userIDs, nil, n.currPos)
 	} else {
 		log.WithFields(log.Fields{
 			"posUpdate": posUpdate.String,
@@ -155,20 +154,33 @@ func (n *Notifier) OnNewSendToDevice(
 ) {
 	n.streamLock.Lock()
 	defer n.streamLock.Unlock()
-	latestPos := n.currPos.WithUpdates(posUpdate)
-	n.currPos = latestPos
 
-	n.wakeupUserDevice(userID, deviceIDs, latestPos)
+	n.currPos.ApplyUpdates(posUpdate)
+	n.wakeupUserDevice(userID, deviceIDs, n.currPos)
+}
+
+// OnNewReceipt updates the current position
+func (n *Notifier) OnNewTyping(
+	roomID string,
+	posUpdate types.StreamingToken,
+) {
+	n.streamLock.Lock()
+	defer n.streamLock.Unlock()
+
+	n.currPos.ApplyUpdates(posUpdate)
+	n.wakeupUsers(n.joinedUsers(roomID), nil, n.currPos)
 }
 
 // OnNewReceipt updates the current position
 func (n *Notifier) OnNewReceipt(
+	roomID string,
 	posUpdate types.StreamingToken,
 ) {
 	n.streamLock.Lock()
 	defer n.streamLock.Unlock()
-	latestPos := n.currPos.WithUpdates(posUpdate)
-	n.currPos = latestPos
+
+	n.currPos.ApplyUpdates(posUpdate)
+	n.wakeupUsers(n.joinedUsers(roomID), nil, n.currPos)
 }
 
 func (n *Notifier) OnNewKeyChange(
@@ -176,9 +188,19 @@ func (n *Notifier) OnNewKeyChange(
 ) {
 	n.streamLock.Lock()
 	defer n.streamLock.Unlock()
-	latestPos := n.currPos.WithUpdates(posUpdate)
-	n.currPos = latestPos
-	n.wakeupUsers([]string{wakeUserID}, nil, latestPos)
+
+	n.currPos.ApplyUpdates(posUpdate)
+	n.wakeupUsers([]string{wakeUserID}, nil, n.currPos)
+}
+
+func (n *Notifier) OnNewInvite(
+	posUpdate types.StreamingToken, wakeUserID string,
+) {
+	n.streamLock.Lock()
+	defer n.streamLock.Unlock()
+
+	n.currPos.ApplyUpdates(posUpdate)
+	n.wakeupUsers([]string{wakeUserID}, nil, n.currPos)
 }
 
 // GetListener returns a UserStreamListener that can be used to wait for
diff --git a/syncapi/sync/notifier_test.go b/syncapi/sync/notifier_test.go
index 39124214..d24da463 100644
--- a/syncapi/sync/notifier_test.go
+++ b/syncapi/sync/notifier_test.go
@@ -335,7 +335,7 @@ func waitForEvents(n *Notifier, req syncRequest) (types.StreamingToken, error) {
 		return types.StreamingToken{}, fmt.Errorf(
 			"waitForEvents timed out waiting for %s (pos=%v)", req.device.UserID, req.since,
 		)
-	case <-listener.GetNotifyChannel(*req.since):
+	case <-listener.GetNotifyChannel(req.since):
 		p := listener.GetSyncPosition()
 		return p, nil
 	}
@@ -365,7 +365,7 @@ func newTestSyncRequest(userID, deviceID string, since types.StreamingToken) syn
 			ID:     deviceID,
 		},
 		timeout:       1 * time.Minute,
-		since:         &since,
+		since:         since,
 		wantFullState: false,
 		limit:         DefaultTimelineLimit,
 		log:           util.GetLogger(context.TODO()),
diff --git a/syncapi/sync/request.go b/syncapi/sync/request.go
index d5cf143d..f2f2894b 100644
--- a/syncapi/sync/request.go
+++ b/syncapi/sync/request.go
@@ -46,7 +46,7 @@ type syncRequest struct {
 	device        userapi.Device
 	limit         int
 	timeout       time.Duration
-	since         *types.StreamingToken // nil means that no since token was supplied
+	since         types.StreamingToken // nil means that no since token was supplied
 	wantFullState bool
 	log           *log.Entry
 }
@@ -55,17 +55,13 @@ func newSyncRequest(req *http.Request, device userapi.Device, syncDB storage.Dat
 	timeout := getTimeout(req.URL.Query().Get("timeout"))
 	fullState := req.URL.Query().Get("full_state")
 	wantFullState := fullState != "" && fullState != "false"
-	var since *types.StreamingToken
-	sinceStr := req.URL.Query().Get("since")
+	since, sinceStr := types.StreamingToken{}, req.URL.Query().Get("since")
 	if sinceStr != "" {
-		tok, err := types.NewStreamTokenFromString(sinceStr)
+		var err error
+		since, err = types.NewStreamTokenFromString(sinceStr)
 		if err != nil {
 			return nil, err
 		}
-		since = &tok
-	}
-	if since == nil {
-		since = &types.StreamingToken{}
 	}
 	timelineLimit := DefaultTimelineLimit
 	// TODO: read from stored filters too
diff --git a/syncapi/sync/requestpool.go b/syncapi/sync/requestpool.go
index 3a31edd0..0751487a 100644
--- a/syncapi/sync/requestpool.go
+++ b/syncapi/sync/requestpool.go
@@ -185,13 +185,12 @@ func (rp *RequestPool) OnIncomingSyncRequest(req *http.Request, device *userapi.
 	// respond with, so we skip the return an go back to waiting for content to
 	// be sent down or the request timing out.
 	var hasTimedOut bool
-	sincePos := *syncReq.since
+	sincePos := syncReq.since
 	for {
 		select {
 		// Wait for notifier to wake us up
 		case <-userStreamListener.GetNotifyChannel(sincePos):
 			currPos = userStreamListener.GetSyncPosition()
-			sincePos = currPos
 		// Or for timeout to expire
 		case <-timer.C:
 			// We just need to ensure we get out of the select after reaching the
@@ -279,7 +278,7 @@ func (rp *RequestPool) currentSyncForUser(req syncRequest, latestPos types.Strea
 	res := types.NewResponse()
 
 	// See if we have any new tasks to do for the send-to-device messaging.
-	events, updates, deletions, err := rp.db.SendToDeviceUpdatesForSync(req.ctx, req.device.UserID, req.device.ID, *req.since)
+	lastPos, events, updates, deletions, err := rp.db.SendToDeviceUpdatesForSync(req.ctx, req.device.UserID, req.device.ID, req.since)
 	if err != nil {
 		return nil, fmt.Errorf("rp.db.SendToDeviceUpdatesForSync: %w", err)
 	}
@@ -291,7 +290,7 @@ func (rp *RequestPool) currentSyncForUser(req syncRequest, latestPos types.Strea
 			return res, fmt.Errorf("rp.db.CompleteSync: %w", err)
 		}
 	} else {
-		res, err = rp.db.IncrementalSync(req.ctx, res, req.device, *req.since, latestPos, req.limit, req.wantFullState)
+		res, err = rp.db.IncrementalSync(req.ctx, res, req.device, req.since, latestPos, req.limit, req.wantFullState)
 		if err != nil {
 			return res, fmt.Errorf("rp.db.IncrementalSync: %w", err)
 		}
@@ -302,7 +301,7 @@ func (rp *RequestPool) currentSyncForUser(req syncRequest, latestPos types.Strea
 	if err != nil {
 		return res, fmt.Errorf("rp.appendAccountData: %w", err)
 	}
-	res, err = rp.appendDeviceLists(res, req.device.UserID, *req.since, latestPos)
+	res, err = rp.appendDeviceLists(res, req.device.UserID, req.since, latestPos)
 	if err != nil {
 		return res, fmt.Errorf("rp.appendDeviceLists: %w", err)
 	}
@@ -316,7 +315,7 @@ func (rp *RequestPool) currentSyncForUser(req syncRequest, latestPos types.Strea
 	// Then add the updates into the sync response.
 	if len(updates) > 0 || len(deletions) > 0 {
 		// Handle the updates and deletions in the database.
-		err = rp.db.CleanSendToDeviceUpdates(context.Background(), updates, deletions, *req.since)
+		err = rp.db.CleanSendToDeviceUpdates(context.Background(), updates, deletions, req.since)
 		if err != nil {
 			return res, fmt.Errorf("rp.db.CleanSendToDeviceUpdates: %w", err)
 		}
@@ -326,15 +325,9 @@ func (rp *RequestPool) currentSyncForUser(req syncRequest, latestPos types.Strea
 		for _, event := range events {
 			res.ToDevice.Events = append(res.ToDevice.Events, event.SendToDeviceEvent)
 		}
-
-		// Get the next_batch from the sync response and increase the
-		// EDU counter.
-		if pos, perr := types.NewStreamTokenFromString(res.NextBatch); perr == nil {
-			pos.SendToDevicePosition++
-			res.NextBatch = pos.String()
-		}
 	}
 
+	res.NextBatch.SendToDevicePosition = lastPos
 	return res, err
 }
 
@@ -464,7 +457,7 @@ func (rp *RequestPool) appendAccountData(
 // or timeout=0, or full_state=true, in any of the cases the request should
 // return immediately.
 func (rp *RequestPool) shouldReturnImmediately(syncReq *syncRequest) bool {
-	if syncReq.since == nil || syncReq.timeout == 0 || syncReq.wantFullState {
+	if syncReq.since.IsEmpty() || syncReq.timeout == 0 || syncReq.wantFullState {
 		return true
 	}
 	waiting, werr := rp.db.SendToDeviceUpdatesWaiting(context.TODO(), syncReq.device.UserID, syncReq.device.ID)
diff --git a/syncapi/types/types.go b/syncapi/types/types.go
index 78c3a41a..8e526032 100644
--- a/syncapi/types/types.go
+++ b/syncapi/types/types.go
@@ -113,14 +113,27 @@ type StreamingToken struct {
 	TypingPosition       StreamPosition
 	ReceiptPosition      StreamPosition
 	SendToDevicePosition StreamPosition
+	InvitePosition       StreamPosition
 	DeviceListPosition   LogPosition
 }
 
+// This will be used as a fallback by json.Marshal.
+func (s StreamingToken) MarshalText() ([]byte, error) {
+	return []byte(s.String()), nil
+}
+
+// This will be used as a fallback by json.Unmarshal.
+func (s *StreamingToken) UnmarshalText(text []byte) (err error) {
+	*s, err = NewStreamTokenFromString(string(text))
+	return err
+}
+
 func (t StreamingToken) String() string {
 	posStr := fmt.Sprintf(
-		"s%d_%d_%d_%d",
+		"s%d_%d_%d_%d_%d",
 		t.PDUPosition, t.TypingPosition,
 		t.ReceiptPosition, t.SendToDevicePosition,
+		t.InvitePosition,
 	)
 	if dl := t.DeviceListPosition; !dl.IsEmpty() {
 		posStr += fmt.Sprintf(".dl-%d-%d", dl.Partition, dl.Offset)
@@ -139,6 +152,8 @@ func (t *StreamingToken) IsAfter(other StreamingToken) bool {
 		return true
 	case t.SendToDevicePosition > other.SendToDevicePosition:
 		return true
+	case t.InvitePosition > other.InvitePosition:
+		return true
 	case t.DeviceListPosition.IsAfter(&other.DeviceListPosition):
 		return true
 	}
@@ -146,35 +161,59 @@ func (t *StreamingToken) IsAfter(other StreamingToken) bool {
 }
 
 func (t *StreamingToken) IsEmpty() bool {
-	return t == nil || t.PDUPosition+t.TypingPosition+t.ReceiptPosition+t.SendToDevicePosition == 0 && t.DeviceListPosition.IsEmpty()
+	return t == nil || t.PDUPosition+t.TypingPosition+t.ReceiptPosition+t.SendToDevicePosition+t.InvitePosition == 0 && t.DeviceListPosition.IsEmpty()
 }
 
 // WithUpdates returns a copy of the StreamingToken with updates applied from another StreamingToken.
 // If the latter StreamingToken contains a field that is not 0, it is considered an update,
 // and its value will replace the corresponding value in the StreamingToken on which WithUpdates is called.
 // If the other token has a log, they will replace any existing log on this token.
-func (t *StreamingToken) WithUpdates(other StreamingToken) (ret StreamingToken) {
-	ret = *t
-	switch {
-	case other.PDUPosition > 0:
-		ret.PDUPosition = other.PDUPosition
-	case other.TypingPosition > 0:
-		ret.TypingPosition = other.TypingPosition
-	case other.ReceiptPosition > 0:
-		ret.ReceiptPosition = other.ReceiptPosition
-	case other.SendToDevicePosition > 0:
-		ret.SendToDevicePosition = other.SendToDevicePosition
-	case other.DeviceListPosition.Offset > 0:
-		ret.DeviceListPosition = other.DeviceListPosition
-	}
+func (t *StreamingToken) WithUpdates(other StreamingToken) StreamingToken {
+	ret := *t
+	ret.ApplyUpdates(other)
 	return ret
 }
 
+// ApplyUpdates applies any changes from the supplied StreamingToken. If the supplied
+// streaming token contains any positions that are not 0, they are considered updates
+// and will overwrite the value in the token.
+func (t *StreamingToken) ApplyUpdates(other StreamingToken) {
+	if other.PDUPosition > 0 {
+		t.PDUPosition = other.PDUPosition
+	}
+	if other.TypingPosition > 0 {
+		t.TypingPosition = other.TypingPosition
+	}
+	if other.ReceiptPosition > 0 {
+		t.ReceiptPosition = other.ReceiptPosition
+	}
+	if other.SendToDevicePosition > 0 {
+		t.SendToDevicePosition = other.SendToDevicePosition
+	}
+	if other.InvitePosition > 0 {
+		t.InvitePosition = other.InvitePosition
+	}
+	if other.DeviceListPosition.Offset > 0 {
+		t.DeviceListPosition = other.DeviceListPosition
+	}
+}
+
 type TopologyToken struct {
 	Depth       StreamPosition
 	PDUPosition StreamPosition
 }
 
+// This will be used as a fallback by json.Marshal.
+func (t TopologyToken) MarshalText() ([]byte, error) {
+	return []byte(t.String()), nil
+}
+
+// This will be used as a fallback by json.Unmarshal.
+func (t *TopologyToken) UnmarshalText(text []byte) (err error) {
+	*t, err = NewTopologyTokenFromString(string(text))
+	return err
+}
+
 func (t *TopologyToken) StreamToken() StreamingToken {
 	return StreamingToken{
 		PDUPosition: t.PDUPosition,
@@ -247,7 +286,7 @@ func NewStreamTokenFromString(tok string) (token StreamingToken, err error) {
 	}
 	categories := strings.Split(tok[1:], ".")
 	parts := strings.Split(categories[0], "_")
-	var positions [4]StreamPosition
+	var positions [5]StreamPosition
 	for i, p := range parts {
 		if i > len(positions) {
 			break
@@ -264,6 +303,7 @@ func NewStreamTokenFromString(tok string) (token StreamingToken, err error) {
 		TypingPosition:       positions[1],
 		ReceiptPosition:      positions[2],
 		SendToDevicePosition: positions[3],
+		InvitePosition:       positions[4],
 	}
 	// dl-0-1234
 	// $log_name-$partition-$offset
@@ -302,7 +342,7 @@ type PrevEventRef struct {
 
 // Response represents a /sync API response. See https://matrix.org/docs/spec/client_server/r0.2.0.html#get-matrix-client-r0-sync
 type Response struct {
-	NextBatch   string `json:"next_batch"`
+	NextBatch   StreamingToken `json:"next_batch"`
 	AccountData struct {
 		Events []gomatrixserverlib.ClientEvent `json:"events"`
 	} `json:"account_data,omitempty"`
@@ -366,7 +406,7 @@ type JoinResponse struct {
 	Timeline struct {
 		Events    []gomatrixserverlib.ClientEvent `json:"events"`
 		Limited   bool                            `json:"limited"`
-		PrevBatch string                          `json:"prev_batch"`
+		PrevBatch *TopologyToken                  `json:"prev_batch,omitempty"`
 	} `json:"timeline"`
 	Ephemeral struct {
 		Events []gomatrixserverlib.ClientEvent `json:"events"`
@@ -424,7 +464,7 @@ type LeaveResponse struct {
 	Timeline struct {
 		Events    []gomatrixserverlib.ClientEvent `json:"events"`
 		Limited   bool                            `json:"limited"`
-		PrevBatch string                          `json:"prev_batch"`
+		PrevBatch *TopologyToken                  `json:"prev_batch,omitempty"`
 	} `json:"timeline"`
 }
 
diff --git a/syncapi/types/types_test.go b/syncapi/types/types_test.go
index ecb0ab6f..3698fbee 100644
--- a/syncapi/types/types_test.go
+++ b/syncapi/types/types_test.go
@@ -10,10 +10,10 @@ import (
 
 func TestNewSyncTokenWithLogs(t *testing.T) {
 	tests := map[string]*StreamingToken{
-		"s4_0_0_0": {
+		"s4_0_0_0_0": {
 			PDUPosition: 4,
 		},
-		"s4_0_0_0.dl-0-123": {
+		"s4_0_0_0_0.dl-0-123": {
 			PDUPosition: 4,
 			DeviceListPosition: LogPosition{
 				Partition: 0,
@@ -42,10 +42,10 @@ func TestNewSyncTokenWithLogs(t *testing.T) {
 
 func TestSyncTokens(t *testing.T) {
 	shouldPass := map[string]string{
-		"s4_0_0_0":        StreamingToken{4, 0, 0, 0, LogPosition{}}.String(),
-		"s3_1_0_0.dl-1-2": StreamingToken{3, 1, 0, 0, LogPosition{1, 2}}.String(),
-		"s3_1_2_3":        StreamingToken{3, 1, 2, 3, LogPosition{}}.String(),
-		"t3_1":            TopologyToken{3, 1}.String(),
+		"s4_0_0_0_0":        StreamingToken{4, 0, 0, 0, 0, LogPosition{}}.String(),
+		"s3_1_0_0_0.dl-1-2": StreamingToken{3, 1, 0, 0, 0, LogPosition{1, 2}}.String(),
+		"s3_1_2_3_5":        StreamingToken{3, 1, 2, 3, 5, LogPosition{}}.String(),
+		"t3_1":              TopologyToken{3, 1}.String(),
 	}
 
 	for a, b := range shouldPass {
diff --git a/sytest-whitelist b/sytest-whitelist
index eb163436..4ef2304a 100644
--- a/sytest-whitelist
+++ b/sytest-whitelist
@@ -141,18 +141,14 @@ New users appear in /keys/changes
 Local delete device changes appear in v2 /sync
 Local new device changes appear in v2 /sync
 Local update device changes appear in v2 /sync
-Users receive device_list updates for their own devices
 Get left notifs for other users in sync and /keys/changes when user leaves
 Local device key changes get to remote servers
 Local device key changes get to remote servers with correct prev_id
 Server correctly handles incoming m.device_list_update
-Device deletion propagates over federation
 If remote user leaves room, changes device and rejoins we see update in sync
 If remote user leaves room, changes device and rejoins we see update in /keys/changes
 If remote user leaves room we no longer receive device updates
 If a device list update goes missing, the server resyncs on the next one
-Get left notifs in sync and /keys/changes when other user leaves
-Can query remote device keys using POST after notification
 Server correctly resyncs when client query keys and there is no remote cache
 Server correctly resyncs when server leaves and rejoins a room
 Device list doesn't change if remote server is down