diff --git a/src/@types/worker-loader.d.ts b/src/@types/worker-loader.d.ts
new file mode 100644
index 0000000000..a8f5d8e9a4
--- /dev/null
+++ b/src/@types/worker-loader.d.ts
@@ -0,0 +1,23 @@
+/*
+Copyright 2021 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+declare module "*.worker.ts" {
+    class WebpackWorker extends Worker {
+        constructor();
+    }
+
+    export default WebpackWorker;
+}
diff --git a/src/MatrixClientPeg.ts b/src/MatrixClientPeg.ts
index 7de62ba075..e9364b1b47 100644
--- a/src/MatrixClientPeg.ts
+++ b/src/MatrixClientPeg.ts
@@ -50,15 +50,6 @@ export interface IMatrixClientCreds {
 export interface IMatrixClientPeg {
     opts: IStartClientOpts;
 
-    /**
-     * Sets the script href passed to the IndexedDB web worker
-     * If set, a separate web worker will be started to run the IndexedDB
-     * queries on.
-     *
-     * @param {string} script href to the script to be passed to the web worker
-     */
-    setIndexedDbWorkerScript(script: string): void;
-
     /**
      * Return the server name of the user's homeserver
      * Throws an error if unable to deduce the homeserver name
@@ -133,10 +124,6 @@ class _MatrixClientPeg implements IMatrixClientPeg {
     constructor() {
     }
 
-    public setIndexedDbWorkerScript(script: string): void {
-        createMatrixClient.indexedDbWorkerScript = script;
-    }
-
     public get(): MatrixClient {
         return this.matrixClient;
     }
diff --git a/src/components/views/dialogs/ShareDialog.tsx b/src/components/views/dialogs/ShareDialog.tsx
index a3443ada02..85e9c6f192 100644
--- a/src/components/views/dialogs/ShareDialog.tsx
+++ b/src/components/views/dialogs/ShareDialog.tsx
@@ -35,7 +35,7 @@ import SettingsStore from "../../../settings/SettingsStore";
 import { UIFeature } from "../../../settings/UIFeature";
 import { replaceableComponent } from "../../../utils/replaceableComponent";
 import BaseDialog from "./BaseDialog";
-import GenericTextContextMenu from "../context_menus/GenericTextContextMenu.js";
+import GenericTextContextMenu from "../context_menus/GenericTextContextMenu";
 
 const socials = [
     {
diff --git a/src/utils/createMatrixClient.ts b/src/utils/createMatrixClient.ts
index caaf75616d..0cce729e65 100644
--- a/src/utils/createMatrixClient.ts
+++ b/src/utils/createMatrixClient.ts
@@ -14,6 +14,8 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+// @ts-ignore - `.ts` is needed here to make TS happy
+import IndexedDBWorker from "../workers/indexeddb.worker.ts";
 import { createClient, ICreateClientOpts } from "matrix-js-sdk/src/matrix";
 import { IndexedDBCryptoStore } from "matrix-js-sdk/src/crypto/store/indexeddb-crypto-store";
 import { WebStorageSessionStore } from "matrix-js-sdk/src/store/session/webstorage";
@@ -35,10 +37,6 @@ try {
  * @param {Object} opts  options to pass to Matrix.createClient. This will be
  *    extended with `sessionStore` and `store` members.
  *
- * @property {string} indexedDbWorkerScript  Optional URL for a web worker script
- *    for IndexedDB store operations. By default, indexeddb ops are done on
- *    the main thread.
- *
  * @returns {MatrixClient} the newly-created MatrixClient
  */
 export default function createMatrixClient(opts: ICreateClientOpts) {
@@ -51,7 +49,7 @@ export default function createMatrixClient(opts: ICreateClientOpts) {
             indexedDB: indexedDB,
             dbName: "riot-web-sync",
             localStorage: localStorage,
-            workerScript: createMatrixClient.indexedDbWorkerScript,
+            workerFactory: () => new IndexedDBWorker(),
         });
     }
 
@@ -70,5 +68,3 @@ export default function createMatrixClient(opts: ICreateClientOpts) {
         ...opts,
     });
 }
-
-createMatrixClient.indexedDbWorkerScript = null;
diff --git a/src/workers/indexeddb.worker.ts b/src/workers/indexeddb.worker.ts
new file mode 100644
index 0000000000..a05add1c7d
--- /dev/null
+++ b/src/workers/indexeddb.worker.ts
@@ -0,0 +1,23 @@
+/*
+Copyright 2017 Vector Creations Ltd
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { IndexedDBStoreWorker } from "matrix-js-sdk/src/indexeddb-worker";
+
+const ctx: Worker = self as any;
+
+const remoteWorker = new IndexedDBStoreWorker(ctx.postMessage);
+
+ctx.onmessage = remoteWorker.onMessage;