diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0ab66068d20..61aab404856 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+Changes in [23.1.1](https://github.com/matrix-org/matrix-js-sdk/releases/tag/v23.1.1) (2023-01-20)
+==================================================================================================
+
+## 🐛 Bug Fixes
+ * Fix backwards compability for environment not support Array.prototype.at ([\#3080](https://github.com/matrix-org/matrix-js-sdk/pull/3080)).
+
 Changes in [23.1.0](https://github.com/matrix-org/matrix-js-sdk/releases/tag/v23.1.0) (2023-01-18)
 ==================================================================================================
 
diff --git a/package.json b/package.json
index 0c5c9851618..ab0427a88de 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
     "name": "matrix-js-sdk",
-    "version": "23.1.0",
+    "version": "23.1.1",
     "description": "Matrix Client-Server SDK for Javascript",
     "engines": {
         "node": ">=16.0.0"
diff --git a/src/models/thread.ts b/src/models/thread.ts
index 31587bbafb7..b688d12ac11 100644
--- a/src/models/thread.ts
+++ b/src/models/thread.ts
@@ -572,7 +572,7 @@ export class Thread extends ReadReceipt<EmittedEvents, EventHandlerMap> {
      */
     public getEventReadUpTo(userId: string, ignoreSynthesized?: boolean): string | null {
         const isCurrentUser = userId === this.client.getUserId();
-        const lastReply = this.timeline.at(-1);
+        const lastReply = this.timeline[this.timeline.length - 1];
         if (isCurrentUser && lastReply) {
             // If the last activity in a thread is prior to the first threaded read receipt
             // sent in the room (suggesting that it was sent before the user started