diff --git a/clientapi/routing/joinroom.go b/clientapi/routing/joinroom.go
index 432fabe41..09e454bca 100644
--- a/clientapi/routing/joinroom.go
+++ b/clientapi/routing/joinroom.go
@@ -331,7 +331,7 @@ func (r joinRoomReq) joinRoomUsingServer(roomID string, server gomatrixserverlib
 	if respMakeJoin.RoomVersion == "" {
 		respMakeJoin.RoomVersion = gomatrixserverlib.RoomVersionV1
 	}
-	if _, err := respMakeJoin.RoomVersion.EventFormat(); err != nil {
+	if _, err = respMakeJoin.RoomVersion.EventFormat(); err != nil {
 		return &util.JSONResponse{
 			Code: http.StatusBadRequest,
 			JSON: jsonerror.UnsupportedRoomVersion(
diff --git a/common/events.go b/common/events.go
index 159569fdd..c0189b469 100644
--- a/common/events.go
+++ b/common/events.go
@@ -102,17 +102,6 @@ func AddPrevEventsToEvent(
 
 	builder.Depth = queryRes.Depth
 
-	switch eventFormat {
-	case gomatrixserverlib.EventFormatV1:
-		builder.PrevEvents = queryRes.LatestEvents
-	case gomatrixserverlib.EventFormatV2:
-		v2Refs := []string{}
-		for _, ref := range queryRes.LatestEvents {
-			v2Refs = append(v2Refs, ref.EventID)
-		}
-		builder.PrevEvents = v2Refs
-	}
-
 	authEvents := gomatrixserverlib.NewAuthEvents(nil)
 
 	for i := range queryRes.StateEvents {
@@ -126,15 +115,22 @@ func AddPrevEventsToEvent(
 	if err != nil {
 		return err
 	}
+
 	switch eventFormat {
 	case gomatrixserverlib.EventFormatV1:
 		builder.AuthEvents = refs
+		builder.PrevEvents = queryRes.LatestEvents
 	case gomatrixserverlib.EventFormatV2:
-		v2Refs := []string{}
+		v2AuthRefs := []string{}
+		v2PrevRefs := []string{}
 		for _, ref := range refs {
-			v2Refs = append(v2Refs, ref.EventID)
+			v2AuthRefs = append(v2AuthRefs, ref.EventID)
 		}
-		builder.AuthEvents = v2Refs
+		for _, ref := range queryRes.LatestEvents {
+			v2PrevRefs = append(v2PrevRefs, ref.EventID)
+		}
+		builder.AuthEvents = v2AuthRefs
+		builder.PrevEvents = v2PrevRefs
 	}
 
 	return nil
diff --git a/federationapi/routing/invite.go b/federationapi/routing/invite.go
index 9713b7229..09c3734be 100644
--- a/federationapi/routing/invite.go
+++ b/federationapi/routing/invite.go
@@ -15,12 +15,13 @@
 package routing
 
 import (
-	"encoding/json"
+	"context"
 	"net/http"
 
 	"github.com/matrix-org/dendrite/clientapi/jsonerror"
 	"github.com/matrix-org/dendrite/clientapi/producers"
 	"github.com/matrix-org/dendrite/common/config"
+	"github.com/matrix-org/dendrite/roomserver/api"
 	"github.com/matrix-org/gomatrixserverlib"
 	"github.com/matrix-org/util"
 )
@@ -35,10 +36,19 @@ func Invite(
 	producer *producers.RoomserverProducer,
 	keys gomatrixserverlib.KeyRing,
 ) util.JSONResponse {
+	// Look up the room version for the room.
+	verReq := api.QueryRoomVersionForRoomRequest{RoomID: roomID}
+	verRes := api.QueryRoomVersionForRoomResponse{}
+	if err := producer.QueryAPI.QueryRoomVersionForRoom(context.Background(), &verReq, &verRes); err != nil {
+		return util.JSONResponse{
+			Code: http.StatusBadRequest,
+			JSON: jsonerror.UnsupportedRoomVersion(err.Error()),
+		}
+	}
 
 	// Decode the event JSON from the request.
-	var event gomatrixserverlib.Event
-	if err := json.Unmarshal(request.Content(), &event); err != nil {
+	event, err := gomatrixserverlib.NewEventFromUntrustedJSON(request.Content(), verRes.RoomVersion)
+	if err != nil {
 		return util.JSONResponse{
 			Code: http.StatusBadRequest,
 			JSON: jsonerror.NotJSON("The request body could not be decoded into valid JSON. " + err.Error()),
diff --git a/federationapi/routing/leave.go b/federationapi/routing/leave.go
index 888683dd9..e0a142631 100644
--- a/federationapi/routing/leave.go
+++ b/federationapi/routing/leave.go
@@ -13,7 +13,6 @@
 package routing
 
 import (
-	"encoding/json"
 	"net/http"
 	"time"
 
@@ -110,8 +109,9 @@ func SendLeave(
 		}
 	}
 
-	var event gomatrixserverlib.Event
-	if err := json.Unmarshal(request.Content(), &event); err != nil {
+	// Decode the event JSON from the request.
+	event, err := gomatrixserverlib.NewEventFromUntrustedJSON(request.Content(), verRes.RoomVersion)
+	if err != nil {
 		return util.JSONResponse{
 			Code: http.StatusBadRequest,
 			JSON: jsonerror.NotJSON("The request body could not be decoded into valid JSON. " + err.Error()),
diff --git a/federationapi/routing/send.go b/federationapi/routing/send.go
index e829a38d7..709ac0a3b 100644
--- a/federationapi/routing/send.go
+++ b/federationapi/routing/send.go
@@ -48,7 +48,7 @@ func Send(
 	}
 
 	var txnEvents struct {
-		events []json.RawMessage `json:"events"`
+		Events []json.RawMessage `json:"events"`
 	}
 
 	if err := json.Unmarshal(request.Content(), &txnEvents); err != nil {
diff --git a/federationapi/routing/threepid.go b/federationapi/routing/threepid.go
index d17470eae..ff0473f95 100644
--- a/federationapi/routing/threepid.go
+++ b/federationapi/routing/threepid.go
@@ -149,7 +149,7 @@ func ExchangeThirdPartyInvite(
 
 	verReq := api.QueryRoomVersionForRoomRequest{RoomID: roomID}
 	verRes := api.QueryRoomVersionForRoomResponse{}
-	if err := queryAPI.QueryRoomVersionForRoom(httpReq.Context(), &verReq, &verRes); err != nil {
+	if err = queryAPI.QueryRoomVersionForRoom(httpReq.Context(), &verReq, &verRes); err != nil {
 		return util.JSONResponse{
 			Code: http.StatusBadRequest,
 			JSON: jsonerror.UnsupportedRoomVersion(err.Error()),