diff --git a/federationapi/routing/join.go b/federationapi/routing/join.go
index 7dde70306..a27359711 100644
--- a/federationapi/routing/join.go
+++ b/federationapi/routing/join.go
@@ -172,14 +172,18 @@ func MakeJoin(
 				code = http.StatusBadRequest
 			case spec.ErrorBadJSON:
 				code = http.StatusBadRequest
-			case spec.ErrorIncompatibleRoomVersion:
-				code = http.StatusBadRequest
 			}
 
 			return util.JSONResponse{
 				Code: code,
 				JSON: e,
 			}
+		case spec.IncompatibleRoomVersionError:
+			util.GetLogger(httpReq.Context()).WithError(internalErr)
+			return util.JSONResponse{
+				Code: http.StatusBadRequest,
+				JSON: e,
+			}
 		default:
 			util.GetLogger(httpReq.Context()).WithError(internalErr)
 			return util.JSONResponse{