diff --git a/src/matrix/room/timeline/persistence/GapWriter.js b/src/matrix/room/timeline/persistence/GapWriter.js
index 3e520608..4458e1c5 100644
--- a/src/matrix/room/timeline/persistence/GapWriter.js
+++ b/src/matrix/room/timeline/persistence/GapWriter.js
@@ -163,7 +163,7 @@ export class GapWriter {
         if (!Array.isArray(chunk)) {
             throw new Error("Invalid chunk in response");
         }
-        if (typeof end !== "string") {
+        if (typeof end !== "string" && typeof end !== "undefined") {
             throw new Error("Invalid end token in response");
         }