diff --git a/federationapi/routing/invite.go b/federationapi/routing/invite.go
index e8ab6b0be..7241173ec 100644
--- a/federationapi/routing/invite.go
+++ b/federationapi/routing/invite.go
@@ -37,26 +37,39 @@ func Invite(
 	producer *producers.RoomserverProducer,
 	keys gomatrixserverlib.KeyRing,
 ) util.JSONResponse {
-	inviteReq := gomatrixserverlib.InviteV2Request{}
-	if err := json.Unmarshal(request.Content(), &inviteReq); err != nil {
+	var intermediate struct {
+		Event           json.RawMessage                           `json:"event"`
+		InviteRoomState []gomatrixserverlib.InviteV2StrippedState `json:"invite_room_state"`
+		RoomVersion     gomatrixserverlib.RoomVersion             `json:"room_version"`
+	}
+
+	// Unmarshal the request into the intermediate form.
+	if err := json.Unmarshal(request.Content(), &intermediate); err != nil {
 		return util.JSONResponse{
 			Code: http.StatusBadRequest,
-			JSON: jsonerror.NotJSON("The request body could not be decoded into an invite request. " + err.Error()),
+			JSON: jsonerror.NotJSON("The request body could not be decoded into an invite request: " + err.Error()),
 		}
 	}
-	event := inviteReq.Event()
 
-	// Check if we support the room version for the invite.
-	roomVersion := inviteReq.RoomVersion()
-	if _, err := roomserverVersion.SupportedRoomVersion(roomVersion); err != nil {
+	// Check if we support the supplied room version before doing anything else.
+	if _, err := roomserverVersion.SupportedRoomVersion(intermediate.RoomVersion); err != nil {
 		return util.JSONResponse{
 			Code: http.StatusBadRequest,
 			JSON: jsonerror.UnsupportedRoomVersion(
-				fmt.Sprintf("Users of this server cannot join version %q rooms.", roomVersion),
+				fmt.Sprintf("Users of this server cannot join version %q rooms.", intermediate.RoomVersion),
 			),
 		}
 	}
 
+	// Unmarshal the event.
+	event, err := gomatrixserverlib.NewEventFromUntrustedJSON(intermediate.Event, intermediate.RoomVersion)
+	if err != nil {
+		return util.JSONResponse{
+			Code: http.StatusBadRequest,
+			JSON: jsonerror.NotJSON("The event in the request body could not be parsed: " + err.Error()),
+		}
+	}
+
 	// Check that the room ID is correct.
 	if event.RoomID() != roomID {
 		return util.JSONResponse{
@@ -101,8 +114,8 @@ func Invite(
 	// Add the invite event to the roomserver.
 	if err = producer.SendInvite(
 		httpReq.Context(),
-		signedEvent.Headered(inviteReq.RoomVersion()),
-		inviteReq.InviteRoomState(),
+		signedEvent.Headered(intermediate.RoomVersion),
+		intermediate.InviteRoomState,
 	); err != nil {
 		util.GetLogger(httpReq.Context()).WithError(err).Error("producer.SendInvite failed")
 		return jsonerror.InternalServerError()
diff --git a/federationsender/consumers/roomserver.go b/federationsender/consumers/roomserver.go
index c72464932..a36fb3792 100644
--- a/federationsender/consumers/roomserver.go
+++ b/federationsender/consumers/roomserver.go
@@ -190,12 +190,8 @@ func (s *OutputRoomEventConsumer) processInvite(oie api.OutputNewInviteEvent) er
 	// When sending a v2 invite, the inviting server should try and include
 	// a "stripped down" version of the room state. This is pretty much just
 	// enough information for the remote side to show something useful to the
-	// user, like the room name, aliases etc. Initially we'll strip down
-	// the invite event itself, as this satisfies the membership event in the
-	// stripped state.
-	strippedState := []gomatrixserverlib.InviteV2StrippedState{
-		gomatrixserverlib.NewInviteV2StrippedState(&oie.Event.Event),
-	}
+	// user, like the room name, aliases etc.
+	strippedState := []gomatrixserverlib.InviteV2StrippedState{}
 	stateWanted := []string{
 		gomatrixserverlib.MRoomName, gomatrixserverlib.MRoomCanonicalAlias,
 		gomatrixserverlib.MRoomAliases, gomatrixserverlib.MRoomJoinRules,
diff --git a/roomserver/input/events.go b/roomserver/input/events.go
index 2bb0d0a05..5f67c7f49 100644
--- a/roomserver/input/events.go
+++ b/roomserver/input/events.go
@@ -247,8 +247,10 @@ func processInviteEvent(
 
 	event := input.Event.Unwrap()
 
-	if err = event.SetUnsignedField("invite_room_state", input.InviteRoomState); err != nil {
-		return err
+	if len(input.InviteRoomState) > 0 {
+		if err = event.SetUnsignedField("invite_room_state", input.InviteRoomState); err != nil {
+			return err
+		}
 	}
 
 	outputUpdates, err := updateToInviteMembership(updater, &event, nil, input.Event.RoomVersion)