diff --git a/federationapi/inthttp/client.go b/federationapi/inthttp/client.go
index 0d0a02883..a65df906f 100644
--- a/federationapi/inthttp/client.go
+++ b/federationapi/inthttp/client.go
@@ -360,14 +360,16 @@ type lookupMissingEvents struct {
 	RoomID      string
 	Missing     gomatrixserverlib.MissingEvents
 	RoomVersion gomatrixserverlib.RoomVersion
-	Res         *gomatrixserverlib.RespMissingEvents
-	Err         *api.FederationClientError
+	Res         struct {
+		Events []gomatrixserverlib.RawJSON `json:"events"`
+	}
+	Err *api.FederationClientError
 }
 
 func (h *httpFederationInternalAPI) LookupMissingEvents(
 	ctx context.Context, s gomatrixserverlib.ServerName, roomID string,
 	missing gomatrixserverlib.MissingEvents, roomVersion gomatrixserverlib.RoomVersion,
-) (gomatrixserverlib.RespMissingEvents, error) {
+) (res gomatrixserverlib.RespMissingEvents, err error) {
 	span, ctx := opentracing.StartSpanFromContext(ctx, "LookupMissingEvents")
 	defer span.Finish()
 
@@ -377,16 +379,23 @@ func (h *httpFederationInternalAPI) LookupMissingEvents(
 		Missing:     missing,
 		RoomVersion: roomVersion,
 	}
-	var response lookupMissingEvents
 	apiURL := h.federationAPIURL + FederationAPILookupMissingEventsPath
-	err := httputil.PostJSON(ctx, span, h.httpClient, apiURL, &request, &response)
+	err = httputil.PostJSON(ctx, span, h.httpClient, apiURL, &request, &request)
 	if err != nil {
-		return gomatrixserverlib.RespMissingEvents{}, err
+		return res, err
 	}
-	if response.Err != nil {
-		return gomatrixserverlib.RespMissingEvents{}, response.Err
+	if request.Err != nil {
+		return res, request.Err
 	}
-	return *response.Res, nil
+	res.Events = make([]*gomatrixserverlib.Event, 0, len(request.Res.Events))
+	for _, js := range request.Res.Events {
+		ev, err := gomatrixserverlib.NewEventFromUntrustedJSON(js, roomVersion)
+		if err != nil {
+			return res, err
+		}
+		res.Events = append(res.Events, ev)
+	}
+	return res, nil
 }
 
 type getEvent struct {
diff --git a/federationapi/inthttp/server.go b/federationapi/inthttp/server.go
index d5ebb508c..8d193d9c9 100644
--- a/federationapi/inthttp/server.go
+++ b/federationapi/inthttp/server.go
@@ -259,7 +259,13 @@ func AddRoutes(intAPI api.FederationInternalAPI, internalAPIMux *mux.Router) {
 					}
 				}
 			}
-			request.Res = &res
+			for _, event := range res.Events {
+				js, err := json.Marshal(event)
+				if err != nil {
+					return util.MessageResponse(http.StatusInternalServerError, err.Error())
+				}
+				request.Res.Events = append(request.Res.Events, js)
+			}
 			return util.JSONResponse{Code: http.StatusOK, JSON: request}
 		}),
 	)
diff --git a/roomserver/internal/input/input_events.go b/roomserver/internal/input/input_events.go
index 59ce99691..b9f6cb2dc 100644
--- a/roomserver/internal/input/input_events.go
+++ b/roomserver/internal/input/input_events.go
@@ -101,6 +101,10 @@ func (r *Inputer) processRoomEvent(
 		"type":     event.Type(),
 	})
 
+	if _, err := headered.RoomVersion.EventIDFormat(); err != nil {
+		panic("UNKNOWN ROOM VERSION")
+	}
+
 	// if we have already got this event then do not process it again, if the input kind is an outlier.
 	// Outliers contain no extra information which may warrant a re-processing.
 	if input.Kind == api.KindOutlier {